<SEC-DOCUMENT>0001047469-13-010961.txt : 20131203
<SEC-HEADER>0001047469-13-010961.hdr.sgml : 20131203
<ACCEPTANCE-DATETIME>20131203160259
ACCESSION NUMBER:		0001047469-13-010961
CONFORMED SUBMISSION TYPE:	S-3ASR
PUBLIC DOCUMENT COUNT:		4
FILED AS OF DATE:		20131203
DATE AS OF CHANGE:		20131203
EFFECTIVENESS DATE:		20131203

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Celldex Therapeutics, Inc.
		CENTRAL INDEX KEY:			0000744218
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				133191702
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		S-3ASR
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-192640
		FILM NUMBER:		131254468

	BUSINESS ADDRESS:	
		STREET 1:		119 FOURTH AVE
		CITY:			NEEDHAM
		STATE:			MA
		ZIP:			02494
		BUSINESS PHONE:		7814330771

	MAIL ADDRESS:	
		STREET 1:		119 FOURTH AVE
		CITY:			NEEDHAM
		STATE:			MA
		ZIP:			02494-2725

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AVANT IMMUNOTHERAPEUTICS INC
		DATE OF NAME CHANGE:	19980828

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	T CELL SCIENCES INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>S-3ASR
<SEQUENCE>1
<FILENAME>a2217428zs-3asr.htm
<DESCRIPTION>S-3ASR
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<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>As filed with the Securities and Exchange Commission on December&nbsp;3, 2013  </B></FONT></P>

<P ALIGN="RIGHT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B> Registration Statement No.&nbsp;333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </B></FONT></P>


<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B> <div style="width:100%;border-top:solid #000000 3.0pt;padding:0in 0in 0in 0in;font-size:3.0pt;"></div>
<div style="width:100%;border-top:solid #000000 1.0pt;padding:0in 0in 0in 0in;font-size:4.0pt;"></div>  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B>UNITED STATES<BR>
SECURITIES AND EXCHANGE COMMISSION<BR>  </B></FONT><FONT  style="font-size:8pt;line-height:9pt;"><B>Washington, D.C. 20549  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B>FORM S-3  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=3><B>REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF&nbsp;1933  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B>CELLDEX THERAPEUTICS,&nbsp;INC.<BR>  </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">(Exact name of Registrant as Specified in Its Charter) </FONT></P>
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<TD ALIGN="CENTER" style="font-family:arial;"><p style="font-family:arial;margin-left:7pt;text-indent:-7pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;"><B>Delaware<BR> </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">(State of Incorporation)</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><p align=center style="font-family:arial;margin-left:8pt;text-indent:-8pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;"><B> 13-3191702<BR> </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">(I.R.S. Employer Identification Number)<BR></FONT>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>119 Fourth Avenue<BR>
Needham, Massachusetts 02494<BR>
(781)&nbsp;433-0771<BR>  </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">(Address, including zip code and telephone number, including area code, of Registrant's principal executive offices) </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Avery W. Catlin<BR>
Chief Financial Officer<BR>
CELLDEX THERAPEUTICS,&nbsp;INC.<BR>
119 Fourth Avenue<BR>
Needham, Massachusetts 02494<BR>
(781)&nbsp;433-0771<BR>  </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">(Name, address, including zip code and telephone number, including area code, of agent for service) </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Copies to:  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B> Anthony O. Pergola, Esq.<BR>  </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">Lowenstein Sandler LLP<BR>
1251 Avenue of the Americas<BR>
New York, New York 10020<BR>
(212)&nbsp;262-6700 </FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Approximate Date of Commencement of Proposed Sale to the Public: From time to time after the effective date of this Registration Statement, as determined by the
Registrant.</B></FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If
the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.
<FONT FACE="WINGDINGS">&#111;</FONT> </FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule&nbsp;415 under the Securities Act of 1933, other
than securities offered only in connection with dividend or interest reinvestment plans, check the following box.&nbsp;<FONT FACE="WINGDINGS">&#253;</FONT> </FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If this Form is used to register additional securities for an offering pursuant to Rule&nbsp;462(b) under the Securities Act, please check the following box and list the
Securities Act Registration Statement number of the earlier effective registration statement for the same offering. <FONT FACE="WINGDINGS">&#111;</FONT> </FONT></P>


<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If this Form is a post-effective amendment filed pursuant to Rule&nbsp;462(c) under the Securities Act, check the following box and list the Securities Act Registration
Statement number of the earlier effective registration statement for the same offering. <FONT FACE="WINGDINGS">&#111;</FONT> </FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If this Form is a registration statement pursuant to General Instruction&nbsp;I.D. or a post-effective amendment thereto that shall become effective upon filing with the
Commission pursuant to Rule&nbsp;462(e) under the Securities Act, check the following box. <FONT FACE="WINGDINGS">&#253;</FONT> </FONT></P>

<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction&nbsp;I.D. filed to register additional securities or additional
classes of securities pursuant to Rule&nbsp;413(b) under the Securities Act, check the following box. <FONT FACE="WINGDINGS">&#111;</FONT> </FONT></P>


<P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Indicate by check mark whether each registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of
"large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule&nbsp;12b-2 of the Exchange Act. </FONT></P>
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<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Large&nbsp;accelerated&nbsp;filer&nbsp;<FONT FACE="WINGDINGS">&#111;</FONT></FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Accelerated&nbsp;filer&nbsp;<FONT FACE="WINGDINGS">&#253;</FONT></FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Non-accelerated&nbsp;filer&nbsp;<FONT FACE="WINGDINGS">&#111;</FONT><BR></FONT> <FONT  style="font-size:8pt;line-height:9pt;">(Do not check if a<BR>
smaller reporting company)</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Smaller&nbsp;reporting&nbsp;company&nbsp;<FONT FACE="WINGDINGS">&#111;</FONT></FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>CALCULATION OF REGISTRATION FEE  </B></FONT></P>

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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"> &nbsp;</TD>
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<TH ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Title of Each Class of Securities<BR>
to be Registered(1)</B></FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Amount to be<BR>
Registered(1)</B></FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Proposed Maximum<BR>
Offering Price Per<BR>
Unit(1)</B></FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Proposed Maximum<BR>
Aggregate Offering<BR>
Price(1)</B></FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Amount of<BR>
Registration Fee(1)</B></FONT><BR></TH>
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<TD style="font-family:arial;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B> </B></FONT><FONT  style="font-size:8pt;line-height:9pt;">Common Stock, par value $0.001 per share</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
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<TD style="font-family:arial;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;">Preferred Stock, $0.01 par value per share</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
</TR>
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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
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<TD style="font-family:arial;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;">Warrants</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
</TR>
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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
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<TD style="font-family:arial;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;">Depositary Shares(2)</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
</TR>
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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
</TR>
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<TD style="font-family:arial;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;">Units</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:10pt;text-indent:-3pt;"><FONT  style="font-size:8pt;line-height:9pt;"> </FONT><FONT  style="font-size:8pt;line-height:9pt;">Total</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
<TD ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TD>
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<TD COLSPAN=9 VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;"><p style="font-family:arial;margin-left:3pt;text-indent:-3pt;"> &nbsp;</TD>
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<DL compact>
<DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;">(1)</FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">An
indeterminate amount of the securities of each identified class is being registered as may from time to time be offered hereunder at indeterminate
prices, along with an indeterminate number of securities that may be issued upon exercise, settlement, exchange or conversion of securities offered or sold hereunder or that are represented by
depositary shares. Separate consideration may or may not be received for securities that are issuable upon conversion, exercise or exchange of other securities. In accordance with Rules&nbsp;456(b)
and 457(r) under the Securities Act of 1933, as amended, the registrant is deferring payment of all registration fees and will pay the registration fees subsequently in advance or on a "pay-as-you-go"
basis.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;">(2)</FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Each
depositary share will be issued under a deposit agreement, will represent an interest in a fractional share or multiple shares of preferred stock and
will be evidenced by a depositary receipt. </FONT></DD></DL>
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<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B>PROSPECTUS  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><I>


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<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B>CELLDEX THERAPEUTICS,&nbsp;INC.  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><I>

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<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B>Common Stock  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B> Preferred Stock  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B> Warrants  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B> Depositary Shares  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><B> Units  </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=4><I>

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<P style="font-family:arial;"><FONT SIZE=2>Celldex Therapeutics,&nbsp;Inc. or any selling securityholders may offer, issue and sell from time to time, together or separately, in one or more offerings,
any combination of:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>our common stock, </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>our preferred stock, which we may issue in one or more series, </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>warrants, </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>depositary shares, and </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>units. </FONT></DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>This
prospectus provides a general description of the securities we may offer. Each time we or any selling securityholders sell securities, we will provide specific terms of the securities offered in
a supplement to this prospectus. The prospectus supplement may also add, update or change information contained in this prospectus. You should read this prospectus and the accompanying prospectus
supplement, as well as the documents incorporated or deemed incorporated by reference in this prospectus, carefully before you make your investment decision. Our common stock is traded on the NASDAQ
Global Market under the symbol "CLDX." On November&nbsp;29, 2013, the last reported sale price of our common stock on the NASDAQ Global Market was $27.76 per share. You are urged to obtain current
market quotations of the common stock. Each prospectus supplement will indicate if the securities offered thereby will be listed on any securities exchange. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This
prospectus may not be used to sell securities unless accompanied by a prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
or any selling securityholders may offer to sell these securities on a continuous or delayed basis, through agents, dealers or underwriters, or directly to purchasers. The prospectus supplement for
each offering of securities will describe in detail the plan of distribution for that offering. If our agents or any dealers or underwriters are involved in the sale of the securities, the applicable
prospectus supplement will set forth the names of the agents, dealers or underwriters and any applicable commissions or discounts. Our net proceeds from
the sale of securities will also be set forth in the applicable prospectus supplement. For general information about the distribution of securities offered, please see "Plan of Distribution" in this
prospectus. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B>Investing in our securities involves risks. Before making an investment decisions, you should carefully review the information contained in this prospectus under the heading
"Risk Factors" beginning on page&nbsp;5 of this prospectus.</B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B>NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION OR REGULATORY BODY HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.</B></FONT></P>
 <p style="font-family:arial;line-height:1pt;margin-left:18pt;"><font> </FONT> <FONT SIZE=2>

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&nbsp;&nbsp;&nbsp;
</font></p><p align=center style="font-family:arial;"> <FONT SIZE=2>
The date of this prospectus is December&nbsp;3, 2013. </FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><B> Table of Contents  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> <A NAME="BG16901_TOC"></A>  </B></FONT></P>
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<TD style="font-family:arial;"><A HREF="#da16901_about_this_prospectus"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>ABOUT THIS PROSPECTUS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#da16901_about_this_prospectus"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>1</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#da16901_prospectus_summary"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>PROSPECTUS SUMMARY</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#da16901_prospectus_summary"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>2</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_special_note_regarding_forward-looking_statements"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_special_note_regarding_forward-looking_statements"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>4</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_risk_factors"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>RISK FACTORS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_risk_factors"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>5</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_ratios_of_combined_fixed_charg__rat02955"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>RATIOS OF COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS TO EARNINGS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_ratios_of_combined_fixed_charg__rat02955"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>6</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_use_of_proceeds"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>USE OF PROCEEDS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_use_of_proceeds"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>7</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_selling_securityholders"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>SELLING SECURITYHOLDERS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_selling_securityholders"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>7</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_descriptions_of_securities_we_may_offer"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTIONS OF SECURITIES WE MAY OFFER</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_descriptions_of_securities_we_may_offer"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>8</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#dc16901_description_of_common_stock"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTION OF COMMON STOCK</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#dc16901_description_of_common_stock"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>9</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#de16901_description_of_preferred_stock"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTION OF PREFERRED STOCK</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#de16901_description_of_preferred_stock"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>10</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#de16901_description_of_warrants"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTION OF WARRANTS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#de16901_description_of_warrants"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>13</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#de16901_description_of_depositary_shares"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTION OF DEPOSITARY SHARES</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#de16901_description_of_depositary_shares"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>15</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#de16901_description_of_units"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>DESCRIPTION OF UNITS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#de16901_description_of_units"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>16</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#Plan_of"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>PLAN OF DISTRIBUTION</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#Plan_of"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>17</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#Legal"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>LEGAL MATTERS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#Legal"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>19</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#Experts"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>EXPERTS</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#Experts"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>19</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#More_Info"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>WHERE YOU CAN FIND MORE INFORMATION</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#More_Info"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>19</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD style="font-family:arial;"><A HREF="#Incorporation"><p style="font-family:arial;margin-left:0pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><A HREF="#Incorporation"><p align=right style="font-family:arial;margin-left:14pt;text-indent:-14pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>20</FONT></A></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
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<P style="font-family:arial;"><FONT SIZE=2>
<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="da16901_about_this_prospectus"> </A>
<A NAME="toc_da16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  ABOUT THIS PROSPECTUS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This
prospectus is a part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, utilizing a "shelf" registration process. Under this shelf registration
process, we or any selling securityholders may, from time to time, sell any combination of the securities described in this prospectus in one or more offerings. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
registration statement containing this prospectus, including the exhibits to the registration statement, provides additional information about us and the securities offered under this prospectus.
You should read the registration statement and the accompanying exhibits for further information. The registration statement, including the exhibits and the documents incorporated or deemed
incorporated herein by reference, can be read and are available to the public over the Internet at the SEC's website at </FONT><FONT SIZE=2><I>http://www.sec.gov</I></FONT><FONT SIZE=2> as described
under the heading "Where You Can Find More Information." </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This
prospectus provides you with a general description of the securities we or any selling securityholders may offer. Each time we or any selling securityholders sell securities pursuant to this
prospectus, we will provide a prospectus supplement containing specific information about the terms of a particular offering by us or any selling securityholders. That prospectus supplement may
include a discussion of any risk factors or other special considerations that apply to those securities. The prospectus supplement may add, update or change information in this prospectus. If the
information in the prospectus is inconsistent with a prospectus supplement, you should rely on the information in that prospectus supplement. You should read both this prospectus and, if applicable,
any prospectus supplement. See "Where You Can Find More Information" for more information. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>You
should rely only on the information incorporated by reference or provided in this prospectus. We have not authorized any dealer, salesman or other person to give any information or to make any
representation other than those contained or incorporated by reference in this prospectus or any prospectus supplement. You must not rely upon any information or representation not contained or
incorporated by reference in this prospectus or any prospectus supplement. This prospectus and any prospectus supplement do not constitute an offer to sell or the solicitation of an offer to buy any
securities other than the registered securities to which they relate, nor do this prospectus and any prospectus supplement constitute an offer to sell or the solicitation of an offer to buy securities
in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus or any
prospectus supplement is accurate on any date subsequent to the date set forth on the front of such document or that any information we have incorporated by reference is correct on any date subsequent
to the date of the document incorporated by reference, even though this prospectus and any prospectus supplement is delivered or securities are sold on a later date. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I>Unless this prospectus indicates otherwise or the context otherwise requires, the terms "we," "our," "us," "Celldex" or the "Company" as used in this prospectus refer to Celldex
Therapeutics,&nbsp;Inc. and its subsidiaries, except that such terms refer to only Celldex Therapeutics,&nbsp;Inc. and not its subsidiaries in the sections entitled "Description of Common Stock,"
"Description of Preferred Stock," "Description of Warrants," "Description of Depositary Shares," and "Description of Units."</I></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>1</FONT></P>

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<BR></FONT><FONT SIZE=2><B>  PROSPECTUS SUMMARY    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B><I> Company Overview  </I></B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We are a biopharmaceutical company focused on the development and commercialization of several immunotherapy technologies for the treatment of cancer
and other difficult-to-treat diseases. Our lead drug candidates include rindopepimut (CDX-110), an immunotherapeutic vaccine in a pivotal Phase&nbsp;3 study for the treatment of front-line
glioblastoma and a Phase&nbsp;2 study for the treatment of recurrent glioblastoma, and CDX-011, an antibody-drug conjugate for which we initiated an accelerated approval study in December 2013 for
the treatment of advanced breast cancer. We also have a number of earlier stage candidates in clinical development, including CDX-1127, a therapeutic fully human monoclonal antibody in a
Phase&nbsp;1 study for cancer indications, CDX-1135, a molecule that inhibits a part of the immune system called the complement system, CDX-301, an immune cell mobilizing agent and dendritic cell
growth factor and CDX-1401, an APC Targeting Technology&#153; program in a Phase&nbsp;1 study for cancer indications. Our drug candidates address market opportunities for which we believe
current therapies are inadequate or non-existent. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
are building a fully integrated, commercial-stage biopharmaceutical company that develops important therapies for patients with unmet medical needs. Our program assets provide us with the strategic
options to either retain full economic rights to our innovative therapies or seek favorable economic terms through advantageous commercial partnerships. This approach allows us to maximize the overall
value of our technology and product portfolio while best ensuring the expeditious development of each individual product. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> Rindopepimut (CDX-110)  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Rindopepimut is an experimental immunotherapeutic drug that targets the tumor-specific molecule, epidermal growth factor receptor variant III, or
EGFRvIII. EGFRvIII is a mutated form of the epidermal growth factor receptor, or EGFR, that is only expressed in cancer cells and not in normal tissue and can directly contribute to cancer cell
growth. EGFRvIII is expressed in approximately 30% of glioblastoma, or GB, tumors, the most common and aggressive form of brain cancer. The rindopepimut vaccine is composed of the EGFRvIII peptide
linked to a carrier protein called Keyhole Limpet Hemocyanin, or KLH, and administered together with the adjuvant GM-CSF. The Food and Drug Administration, or FDA, and the European Medicines Agency,
or EMA, have both granted orphan drug designation for rindopepimut for the treatment of EGFRvIII expressing GB and the FDA has also granted Fast Track designation. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> Glembatumumab Vedotin (CDX-011)  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>CDX-011 is an antibody-drug conjugate, or ADC, for the treatment of patients with glycoprotein NMB, or&nbsp;gpNMB, expressing advanced, refractory
breast cancer. CDX-011 consists of a fully-human monoclonal antibody, CR011, linked to a potent cell-killing drug, monomethyl-auristatin E, or MMAE. CDX-011 targets the protein&nbsp;gpNMB, which is
over-expressed in a variety of cancers, including breast cancer and melanoma. The ADC technology, comprised of MMAE and a stable linker system for attaching it to CR011, was licensed from Seattle
Genetics,&nbsp;Inc. The FDA has granted Fast Track designation to CDX-011 for the treatment of advanced, refractory/resistant&nbsp;gpNMB-expressing breast cancer. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>In
connection with our acquisition of CuraGen Corporation, we assumed the license agreement between CuraGen and Seattle Genetics, whereby CuraGen acquired the rights to proprietary ADC technology,
with the right to sublicense, for use with its proprietary antibodies for the potential treatment of cancer. Under the terms of the agreement, we have the responsibility of using commercially
reasonable efforts to develop, commercialize and market such treatment. In furtherance of these responsibilities, technical assistance from Seattle Genetics is available to us as necessary. We may be
required to pay milestones of up to $7.5&nbsp;million upon obtaining first approval for commercial sale in a first indication and royalty payments in </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>2</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2>the
mid-single digits on any net product sales to Seattle Genetics with respect to development and commercialization of the ADC technology, including our CDX-011 program. The term of the agreement
varies country to country and may be until the later of the expiration of the last relevant patent or the 10<SUP>th</SUP>&nbsp;anniversary of the first commercial sale. The agreement allows us to
terminate with prior written notice, with both parties being able to terminate the agreement for an uncured material breach or insolvency of the other party. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
patent rights licensed from Seattle Genetics include issued patents and pending applications in Australia, Canada, Europe, the U.S. and Japan which include composition of matter claims relating to
the toxin and conjugation technology. If maintained to full term in due course, the main Seattle Genetics patent rights would have estimated patent expiry dates ranging from 2023 in Europe to 2026 in
the U.S. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> CDX-1127  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>CDX-1127 is a human monoclonal antibody that targets CD27, a potentially important target for immunotherapy of various cancers. CD27 acts downstream
from CD40 and may provide a novel way to regulate the immune responses. CD27 is a co-stimulatory molecule on T cells and is over-expressed in certain lymphomas and leukemias. CDX-1127 is an agonist
antibody designed to have two potential therapeutic mechanisms. CDX-1127 has been shown to activate immune cells that can target and eliminate cancerous cells in tumor-bearing mice and to directly
kill or inhibit the growth of CD27-expressing lymphomas and leukemias in vitro and in vivo. Both mechanisms have been seen even at low doses in preclinical models. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> CDX-1135  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>CDX-1135 is a molecule that inhibits a part of the human immune system called the complement system. The complement system is a series of proteins
that are important initiators of the body's acute inflammatory response against disease, infection and injury. Excessive complement activation also plays a role in some persistent inflammatory
conditions. CDX-1135 is a soluble form of naturally occurring Complement Receptor 1 that has been shown to inhibit the activation of the complement cascade in animal models and in human clinical
trials. In preclinical studies, CDX-1135 has been shown to inhibit both the classical and alternative pathways of complement activation. Our initial experience under an investigator sponsored IND
indicated that CDX-1135 limits complement abnormalities in Dense Deposit Disease, or DDD, which is a rare and devastating disease that is caused by uncontrolled activation of the alternative pathway
of complement activation and leads to progressive kidney damage in children. There is currently no treatment for patients with DDD and about half progress to end-stage renal disease within
10&nbsp;years. Because DDD recurs in virtually all patients who receive a kidney transplant, transplantation is not a viable option for these patients. In animal models of DDD, CDX-1135 treatment
showed evidence of reversal of kidney damage. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><B> Other Clinical and Pre-Clinical Programs  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We have several other programs in clinical and pre-clinical development. The status of each of the other programs that we currently believe is
significant to our business is summarized in the table below: </FONT></P>
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 </B></FONT></DIV></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Indication/Field </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Stage of Clinical Development </B></FONT></TH>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>CDX-1401</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Multiple solid tumors</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Phase&nbsp;1</FONT></TD>
</TR>
<TR BGCOLOR="White" VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>CDX-301</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Cancer,&nbsp;autoimmune&nbsp;disease&nbsp;and&nbsp;transplant</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Phase&nbsp;1</FONT></TD>
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 <P style="font-family:arial;"><FONT SIZE=2><B> Corporate Information  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We are a Delaware corporation organized in 1983. On October&nbsp;1, 2009, a wholly-owned subsidiary of Celldex merged with and into CuraGen
Corporation. On December&nbsp;31, 2009, CuraGen Corporation was merged with and into Celldex and the separate existence of CuraGen ceased. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>Our
principal executive offices are located at 119 Fourth Avenue, Needham, Massachusetts 02494 and our telephone number is (781)&nbsp;433-0771. Our corporate website is www.celldextherapeutics.com.
The information on our website is not incorporated by reference into this prospectus. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>3</FONT></P>

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<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

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<BR></FONT><FONT SIZE=2><B>  SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This prospectus, including the documents that we incorporate by reference, contains forward-looking statements within the meaning of
Section&nbsp;27A of the Securities Act of 1933, as amended, or the Securities Act, and Section&nbsp;21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Any statements
about our expectations, beliefs, plans, objectives, assumptions or future events or performance are not historical facts and may be forward-looking. These statements are often, but not always, made
through the use of words or phrases such as "anticipate," "estimate," "plans," "projects," "continuing," "ongoing," "expects," "management believes," "we believe," "we intend" and similar words or
phrases. Accordingly, these statements involve estimates, assumptions and uncertainties, which could cause actual results to differ materially from those expressed in them. Any forward-looking
statements are qualified in their entirety by reference to the risk factors discussed in this prospectus or discussed in documents incorporated by reference in this prospectus. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Forward-looking
statements are subject to known and unknown risks and uncertainties, which change over time, and are based on management's expectations and assumptions at the time the statements are
made, and are not guarantees of future results. Our actual results may differ materially from those expressed or anticipated in the
forward-looking statements for many reasons including the factors described in the section entitled "Risk Factors" in this prospectus and in any risk factors described in a supplement to this
prospectus or in other filings. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>You
are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date on which they were made. We undertake no obligation to publicly revise any
forward-looking statement to reflect circumstances or events after the date of this prospectus or to reflect the occurrence of unanticipated events. You should, however, review the factors and risks
we describe in the reports we file from time to time with the SEC after the date of this prospectus. We undertake no obligation to revise or update the forward-looking statements contained in this
prospectus at any time. All forward-looking statements are qualified in their entirety by this cautionary statement. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>4</FONT></P>

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<A NAME="toc_dc16901_2"> </A>
<BR></FONT><FONT SIZE=2><B>  RISK FACTORS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I>Investing in our securities involves significant risks. Before making an investment decision, you should carefully consider the
risks and other information we include or incorporate by reference in this prospectus and any prospectus supplement. In particular, you should consider the risk factors under the heading "Risk
Factors" included in our most recent Annual Report on Form&nbsp;10-K, as may be revised or supplemented by our subsequent Quarterly Reports on Form&nbsp;10-Q or Current Reports on Form&nbsp;8-K,
each of which are on file with the SEC and are incorporated herein by reference, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the
future. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not currently known to us or that we currently deem immaterial may
also affect our business operations. Additional risk factors may be included in a prospectus supplement relating to a particular offering of securities. Our business, financial condition or results of
operations could be materially adversely affected by any of these risks. The trading price of our securities could decline due to any of these risks, and you may lose all or part of your investment.
This prospectus is qualified in its entirety by these risk factors.</I></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>5</FONT></P>

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<BR></FONT><FONT SIZE=2><B>  RATIOS OF COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS TO EARNINGS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The following table sets forth our consolidated ratios of earnings to combined fixed charges and preferred stock dividends for the nine months ended
September&nbsp;30, 2013 and the years ended December&nbsp;31, 2012, 2011, 2010, 2009 and 2008. We do not have any outstanding shares of preferred stock and therefore have not paid any preferred
stock dividends. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> Ratios of Combined Fixed Charges  </B></FONT></P>
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<TH style="font-family:arial;">&nbsp;</TH>
</TR>
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<TH ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH ROWSPAN=2 style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=14 ROWSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Years ended December&nbsp;31, </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
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<TH COLSPAN=2 ROWSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Nine Months Ended<BR>
September&nbsp;30, 2013 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
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<TH ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2012 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2011 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2010 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2009 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2008 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="TOP">
<TD VALIGN="BOTTOM" style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD COLSPAN=19 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
</TABLE></DIV>
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 </DIV>
<DIV style="padding:0pt;position:relative;text-align:left;margin-left:10%;">
 <DL compact>
<DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;"><font
style="font-size:6pt;position:relative;top:-2pt;add_sup:2pt;">(1)</font></FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Due
to our losses from continuing operations for the nine months ended September&nbsp;30, 2013 and the years ended December&nbsp;31, 2012,
2011, 2010, 2009 and 2008, earnings were insufficient to cover fixed charges by $59.3 million, $58.1&nbsp;million, $43.4&nbsp;million, $6.5&nbsp;million, $36.9&nbsp;million and
$48.8&nbsp;million, respectively. For this reason, no ratios are provided. </FONT></DD></DL>
 </DIV>
 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>6</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><A
NAME="dc16901_use_of_proceeds"> </A>
<A NAME="toc_dc16901_4"> </A>
<BR></FONT><FONT SIZE=2><B>  USE OF PROCEEDS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Unless otherwise provided in the applicable prospectus supplement to this prospectus used to offer specific securities, we expect to use the net
proceeds from any offering of securities by us for general corporate purposes, which may include acquisitions, capital expenditures, investments, and the repayment, redemption or refinancing of all or
a portion of any indebtedness or other securities outstanding at a particular time, to fund our operations until we receive FDA approval of our products and are able to commercialize our products and
to make substantial investments to establish sales, marketing, quality control, and regulatory compliance capabilities in anticipation of FDA approval of our products. Pending the application of the
net proceeds, we expect to invest the net proceeds in short-term, interest-bearing instruments with a maturity of three months or less at the date of purchase that consist primarily of investments in
money market mutual funds with commercial banks and financial institutions or other investment-grade securities. Such investments may include depositing such net proceeds into, and maintaining cash
balances with, financial institutions in excess of insured limits. We will not receive any of the proceeds from the sale of our securities by any selling securityholders. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="dc16901_selling_securityholders"> </A>
<A NAME="toc_dc16901_5"> </A>
<BR></FONT><FONT SIZE=2><B>  SELLING SECURITYHOLDERS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Information about selling securityholders, if any, will be set forth in a prospectus supplement, in an amendment to the registration statement of
which this prospectus is a part, or in other filings we make with the SEC under the Exchange Act, which are incorporated by reference. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>7</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="dc16901_descriptions_of_securities_we_may_offer"> </A>
<A NAME="toc_dc16901_6"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTIONS OF SECURITIES WE MAY OFFER    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This prospectus contains summary descriptions of the common stock, preferred stock, warrants, depositary shares and units that we or any selling
securityholders may offer and sell from time to time. The preferred stock may also be exchangeable for and/or convertible into shares of common stock or another series of preferred stock. When one or
more of these securities are offered in the future, a prospectus supplement will explain the particular terms of the securities and the extent to which these general provisions may apply. These
summary descriptions and any summary descriptions in the applicable prospectus supplement do not purport to be complete descriptions of the terms and conditions of each security and are qualified in
their entirety by reference to our third restated certificate of incorporation, as amended, our by-laws and by applicable Delaware law and any other documents referenced in such summary descriptions
and from which such summary descriptions are derived. If any particular terms of a security described in the applicable prospectus supplement differ from any of the terms described herein, then the
terms described herein will be deemed superseded by the terms set forth in that prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
may issue securities in book-entry form through one or more depositaries, such as The Depository Trust Company, Euroclear or Clearstream, named in the applicable prospectus supplement. Each sale of
a security in book-entry form will settle in immediately available funds through the applicable depositary, unless otherwise stated. We will issue the securities only in registered form, without
coupons, although we may issue the securities in bearer form if so specified in the applicable prospectus supplement. If any securities are to be listed or quoted on a securities exchange or quotation
system, the applicable prospectus supplement will say so. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>8</FONT></P>

<HR NOSHADE>
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<A NAME="page_dc16901_1_9"> </A>

<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="dc16901_description_of_common_stock"> </A>
<A NAME="toc_dc16901_7"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTION OF COMMON STOCK    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>As of September&nbsp;30, 2013, we are authorized to issue up to 297,000,000 shares of common stock, par value $.001 per share. As of
September&nbsp;30, 2013, approximately 81,108,109 shares of common stock were outstanding. All outstanding shares of our common stock are fully paid and non-assessable. Our common stock is listed on
the NASDAQ Global Market under the symbol "CLDX". </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I> Dividends  </I></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The board of directors may, out of funds legally available, at any regular or special meeting, declare dividends to the holders of shares of our
common stock as and when it deems expedient, subject to the rights of holders of the preferred stock, if any. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I> Voting  </I></FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>Each share of common stock entitles the holders to one vote per share on all matters requiring a vote of the stockholders, including the election of
directors. No holders of shares of common stock shall have the right to vote such shares cumulatively in any election for the board of directors. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I> Rights Upon Liquidation  </I></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>In the event of our voluntary or involuntary liquidation, dissolution, or winding up, the holders of our common stock will be entitled to share
equally in our assets available for distribution after payment in full of all debts and after the holders of preferred stock, if any, have received their liquidation preferences in full. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><I> Miscellaneous  </I></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>No holders of shares of our common stock shall have any preemptive rights to subscribe for, purchase or receive any shares of any class, whether now
or hereafter authorized, or any options or warrants to purchase any such shares, or any securities convertible into or exchanged for any such shares, which may at any time be issued, sold or offered
for sale by Celldex. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><I> Anti-Takeover Provisions  </I></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Certain provisions in our third restated certificate of incorporation, as amended, and applicable Delaware corporate law, as well as our shareholder
rights agreement, may have the effect of discouraging a change of control of Celldex, even if such a transaction is favored by some of our stockholders and could result in stockholders receiving a
substantial premium over the current market price of our shares. The primary purpose of these provisions is to encourage negotiations with our management by persons interested in acquiring control of
our corporation. These provisions may also tend to perpetuate present management and make it difficult for stockholders owning less than a majority of the shares to be able to elect even a single
director. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Pursuant
to our shareholder rights agreement (referred to in this prospectus as the rights agreement) a dividend of one Preferred Stock Purchase Right (referred to in this prospectus as a right) for
each share of common stock of Celldex was declared for each outstanding share of common stock of Celldex on November&nbsp;11, 2004. Each share of common stock of Celldex issued after such date is
also issued with a right. Each right entitles the registered holder to purchase from Celldex a unit consisting of one one-ten thousandth of a share of Celldex Series&nbsp;C-1&nbsp;Junior
Participating Cumulative Preferred Stock, at a cash exercise price of $35 per unit, subject to adjustment as specified in the rights agreement. We describe the rights more completely in the rights
agreement itself, which is contained in Exhibit&nbsp;4.1 to our Registration Statement on Form&nbsp;8-A filed on November&nbsp;8, 2004. The summary of the provisions of the rights agreement is
qualified in its entirety by reference to that agreement. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>Computershare
Trust Company, N.A. is presently the transfer agent and registrar for our common stock. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>9</FONT></P>

<HR NOSHADE>
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 </FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2>
<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="de16901_description_of_preferred_stock"> </A>
<A NAME="toc_de16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTION OF PREFERRED STOCK    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>At September&nbsp;30, 2013, the Company had authorized preferred stock comprised of 3,000,000 shares of Class&nbsp;C Preferred Stock of which
350,000 shares has been designated as Class&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock, the terms of which are to be determined by our board of directors. As of
September&nbsp;30, 2013, there was no preferred stock outstanding. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> Class&nbsp;C Preferred Stock  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>This section describes the general terms and provisions of our Class&nbsp;C Preferred Stock. The applicable prospectus supplement will describe the
specific terms of the shares of preferred stock offered through that prospectus supplement, as well as any general terms described in this section that will not apply to those shares of preferred
stock. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Our
board of directors has been authorized to provide for the issuance of the 2,650,000 unissued and undesignated shares of our Class&nbsp;C Preferred Stock. In general, our third restated
certificate of incorporation, as amended, authorizes our board of directors to issue new shares of our common stock or preferred stock without further stockholder action, provided that there are
sufficient authorized shares. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>With
respect to each series of our Class&nbsp;C Preferred Stock, our board of directors has the authority to fix the following terms:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the designation of the series; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the number of shares within the series; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether dividends are cumulative and, if cumulative, the dates from which
dividends are cumulative; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the rate of any dividends, any conditions upon which dividends are payable,
and the dates of payment of dividends; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether interests in the shares of preferred stock will be represented by
depositary shares as more fully described below under "Description of Depositary Shares"; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether the shares are redeemable, the redemption price and the terms of
redemption; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the amount payable to you for each share you own if we dissolve or
liquidate; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether the shares are convertible or exchangeable, the price or rate of
conversion or exchange, and the applicable terms and conditions; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any restrictions on issuance of shares in the same series or any other
series; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>voting rights applicable to the series of preferred stock;
and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any other rights, priorities, preferences, restrictions or limitations of
such series. </FONT></DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>The
rights with respect to any shares of our Class&nbsp;C Preferred Stock will be subordinate to the rights of our general creditors. Shares of our Class&nbsp;C Preferred Stock that we issue in
accordance with their terms will be fully paid and nonassessable, and will not be entitled to preemptive rights unless specified in the applicable prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Our
ability to issue preferred stock, or rights to purchase such shares, could discourage an unsolicited acquisition proposal. For example, we could impede a business combination by issuing a series
of preferred stock containing class voting rights that would enable the holders of such preferred stock to block a business combination transaction. Alternatively, we could facilitate a business
combination transaction by issuing a series of preferred stock having sufficient voting rights to provide a required percentage vote of the stockholders. Additionally, under certain circumstances, our
issuance of preferred stock could adversely affect the voting power of the holders of our common stock. Although our board of directors is required to make any determination to issue any preferred
stock based on its judgment as to the best interests of our stockholders, our board of directors could act in a manner that would discourage an acquisition attempt or other transaction that some, or a
majority, of our stockholders might believe to be in their best interests or </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>10</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2><A
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<P style="font-family:arial;"><FONT SIZE=2>in
which stockholders might receive a premium for their stock over prevailing market prices of such stock. Our board of directors does not at present intend to seek stockholder approval prior to any
issuance of currently authorized stock, unless otherwise required by law or applicable stock exchange requirements. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><B><I> Terms of the Preferred Stock That We May Offer and Sell to You  </I></B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We summarize below some of the provisions that will apply to the preferred stock that we may offer to you unless the applicable prospectus supplement
provides otherwise. This summary may not contain all information that is important to you. You should read the prospectus supplement, which will contain additional information and which may update or
change some of the information below. Prior to the issuance of a new series of preferred stock, we will further amend our third restated certificate of incorporation, as amended, designating the stock
of that series and the terms of that series. We will file&nbsp;a copy of the certificate of designation that contains the terms of each new series of preferred stock with the SEC each time we issue
a new series of preferred stock. Each certificate of designation will establish the number of shares included in a designated series and fix the designation, powers, privileges, preferences and rights
of the shares of each series as well as any applicable qualifications, limitations or restrictions. You should refer to the applicable certificate of designation as well as our third restated
certificate of incorporation, as amended, before deciding to buy shares of our preferred stock as described in the applicable prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Our
board of directors has the authority, without further action by the stockholders, to issue preferred stock in one or more series and to fix the number of shares, dividend rights, conversion
rights, voting rights, redemption rights, liquidation preferences, sinking funds, and any other rights, preferences, privileges and restrictions applicable to each such series of preferred stock. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>The
issuance of any preferred stock could adversely affect the rights of the holders of common stock and, therefore, reduce the value of the common stock. The ability of our board of directors to
issue preferred stock could discourage, delay or prevent a takeover or other corporate action. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
terms of any particular series of preferred stock will be described in the prospectus supplement relating to that particular series of preferred stock, including, where
applicable:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the designation, stated value and liquidation preference of such preferred
stock; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the number of shares within the series; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the offering price; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the dividend rate or rates (or method of calculation), the date or dates
from which dividends shall accrue, and whether such dividends shall be cumulative or noncumulative and, if cumulative, the dates from which dividends shall commence to cumulate; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether interests in the shares of preferred stock will be represented by
depositary shares as more fully described below under "Description of Depositary Shares"; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any redemption or sinking fund provisions; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the amount that shares of such series shall be entitled to receive in the
event of our liquidation, dissolution or winding-up; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the terms and conditions, if any, on which shares of such series shall be
convertible or exchangeable for shares of our stock of any other class or classes, or other series of the same class; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the voting rights, if any, of shares of such series; the status as to
reissuance or sale of shares of such series redeemed, purchased or otherwise reacquired, or surrendered to us on conversion or exchange; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the conditions and restrictions, if any, on the payment of dividends or on
the making of other distributions on, or the purchase, redemption or other acquisition by us or any subsidiary, of the common stock or of any other class of our shares ranking junior to the shares of
such series as to dividends or upon liquidation; </FONT></DD></DL>
</UL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>11</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><A
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<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the conditions and restrictions, if any, on the creation of indebtedness by
us or by any subsidiary, or on the issuance of any additional stock ranking on a parity with or prior to the shares of such series as to dividends or upon liquidation;
and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any additional dividend, liquidation, redemption, sinking or retirement fund
and other rights, preferences, privileges, limitations and restrictions of such preferred stock. </FONT></DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>The
description of the terms of a particular series of preferred stock in the applicable prospectus supplement will not be complete. You should refer to the applicable amendment to our third restated
certificate of incorporation, as amended, for complete information regarding a series of preferred stock. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
preferred stock will, when issued against payment of the consideration payable therefor, be fully paid and nonassessable. Unless otherwise specified in the applicable prospectus supplement, each
series of preferred stock will, upon issuance, rank senior to the common stock and on a parity in all respects with each other outstanding series of preferred stock. The rights of the holders of our
preferred stock will be subordinate to that of our general creditors. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>12</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="de16901_description_of_warrants"> </A>
<A NAME="toc_de16901_2"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTION OF WARRANTS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We summarize below some of the provisions that will apply to the warrants unless the applicable prospectus supplement provides otherwise. This summary
may not contain all information that is important to you. The complete terms of the warrants will be contained in the applicable warrant certificate and warrant agreement. These documents have been or
will be included in or incorporated by reference as exhibits to the registration statement of which this prospectus is a part. You should read the warrant certificate and the warrant agreement. You
should also read the prospectus supplement, which will contain additional information and which may update or change some of the information below. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><B> General  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We may issue, together with other securities or separately, warrants to purchase common stock, preferred stock or other securities. We may issue the
warrants under warrant agreements to be entered into between us and a bank or trust company, as warrant agent, all as set forth in the applicable prospectus supplement. The warrant agent would act
solely as our agent in connection with the warrants of the series being offered and would not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of
warrants. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
applicable prospectus supplement will describe the following terms, where applicable, of warrants in respect of which this prospectus is being
delivered:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the title of the warrants; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the designation, amount and terms of the securities for which the warrants
are exercisable and the procedures and conditions relating to the exercise of such warrants; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the designation and terms of the other securities, if any, with which the
warrants are to be issued and the number of warrants issued with each such security; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the price or prices at which the warrants will be issued; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the aggregate number of warrants; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any provisions for adjustment of the number or amount of securities
receivable upon exercise of the warrants or the exercise price of the warrants; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the price or prices at which the securities purchasable upon exercise of the
warrants may be purchased; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>if applicable, the date on and after which the warrants and the securities
purchasable upon exercise of the warrants will be separately transferable; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>if applicable, a discussion of the material U.S. federal income tax
considerations applicable to the warrants; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any other terms of the warrants, including terms, procedures and limitations
relating to the exchange and exercise of the warrants; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the date on which the right to exercise the warrants shall commence and the
date on which the right shall expire; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>if applicable, the maximum or minimum number of warrants which may be
exercised at any time; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the identity of the warrant agent; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any mandatory or optional redemption provision; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether the warrants are to be issued in registered or bearer form; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether the warrants are extendible and the period or periods of such
extendibility; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>information with respect to book-entry procedures, if any;
and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any other terms of the warrants. </FONT></DD></DL>
</UL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>13</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2>Before
exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including the right to receive dividends, if any, or
payments upon our liquidation, dissolution or winding-up or to exercise voting rights, if any. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><B> Exercise of Warrants  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Each warrant will entitle the holder thereof to purchase such number of shares of common stock or preferred stock or other securities at the exercise
price as will in each case be set forth in, or be determinable as set forth in, the applicable prospectus supplement. Warrants may be exercised at any time up to the close of business on the
expiration date set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void. Warrants may be exercised as set forth in
the applicable prospectus supplement relating to the warrants offered thereby. Upon receipt of payment and proper completion and due execution at the corporate trust office of the warrant agent or any
other office indicated in the applicable prospectus supplement of the warrant certificate, we will, as soon as practicable, forward the purchased securities. If less than all of the warrants
represented by the warrant certificate are exercised, a new warrant certificate will be issued for the remaining warrants. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> Enforceability of Rights of Holders of Warrants  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or
trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any
default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a
warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon
exercise of, that holder's warrant(s). </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B> Modification of the Warrant Agreement  </B></FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>The warrant agreement will permit us and the warrant agent, without the consent of the warrant holders, to supplement or amend the agreement in the
following circumstances:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>to cure any ambiguity; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>to correct or supplement any provision which may be defective or
inconsistent with any other provisions; or</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>to add new provisions regarding matters or questions that we and the warrant
agent may deem necessary or desirable and which do not adversely affect the interests of the warrant holders. </FONT></DD></DL>
</UL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>14</FONT></P>

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HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="de16901_description_of_depositary_shares"> </A>
<A NAME="toc_de16901_3"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTION OF DEPOSITARY SHARES    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We summarize below some of the provisions that will apply to depositary shares unless the applicable prospectus supplement provides otherwise. This
summary may not contain all information that is important to you. The complete terms of the depositary shares will be contained in the depositary agreement and depositary receipt applicable to any
depositary shares. These documents have been or will be included in or incorporated by reference as exhibits to the registration statement of which this prospectus is a part. You should read the
depositary agreement and the depositary receipt. You should also read the prospectus supplement, which will contain additional information and which may update or change some of the information below. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><B> General  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We may, at our option, elect to offer fractional or multiple shares of common stock or preferred stock, rather than single shares of common stock or
preferred stock (to be set forth in the prospectus supplement relating to such depositary shares). In the event we elect to do so, depositary receipts evidencing depositary shares will be issued to
the public. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
shares of common stock or any class or series of preferred stock represented by depositary shares will be deposited under a deposit agreement among us, a depositary selected by us, and the holders
of the depositary receipts. The depositary will be a bank or trust company having its principal office in the United States and
having a combined capital and surplus of at least $50,000,000. Subject to the terms of the deposit agreement, each owner of a depositary share will be entitled, in proportion to the applicable
fraction of a share of common stock or preferred stock represented by such depositary share, to all the rights and preferences of the shares of common stock or preferred stock represented by the
depositary share, including dividend, voting, redemption and liquidation rights. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
depositary shares will be evidenced by depositary receipts issued pursuant to the deposit agreement. Depositary receipts will be distributed to those persons purchasing the fractional shares of
common stock or the related class or series of preferred shares in accordance with the terms of the offering described in the related prospectus supplement. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>15</FONT></P>

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HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="de16901_description_of_units"> </A>
<A NAME="toc_de16901_4"> </A>
<BR></FONT><FONT SIZE=2><B>  DESCRIPTION OF UNITS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We may issue units comprised of one or more of the other securities described in this prospectus in any combination. Each unit will be issued so that
the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit
agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date. The
applicable prospectus supplement may describe:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the designation and terms of the units and of the securities comprising the
units, including whether and under what circumstances those securities may be held or transferred separately; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any provisions for the issuance, payment, settlement, transfer or exchange
of the units or of the securities comprising the units; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the terms of the unit agreement governing the units; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>United States federal income tax considerations relevant to the units;
and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>whether the units will be issued in fully registered global form. </FONT></DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>This
summary of certain general terms of units and any summary description of units in the applicable prospectus supplement do not purport to be complete and are qualified in their entirety by
reference to all provisions of the applicable unit agreement and, if applicable, collateral arrangements and depositary arrangements relating to such units. The forms of the unit agreements and other
documents relating to a particular issue of units will be filed with the SEC each time we issue units, and you should read those documents for provisions that may be important to you. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>16</FONT></P>

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<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> <A NAME="Plan_of"></A>PLAN OF DISTRIBUTION  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We may sell the securities covered hereby from time to time pursuant to underwritten public offerings, direct sales to the public, negotiated
transactions, block trades or a combination of these methods. A distribution of the securities offered by this prospectus may also be effected through the issuance of derivative securities, including
without limitation, warrants and subscriptions. We or any selling securityholders may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers.
We or any selling securityholders may distribute securities from time to time in one or more transactions:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>at a fixed price or prices, which may be changed; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>at market prices prevailing at the time of sale; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>at prices related to such prevailing market prices; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>at varying prices determined at the time of sale; or </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>at negotiated prices. </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>A prospectus supplement or supplements will describe the terms of the
offering of the securities, including:</FONT><FONT SIZE=2>
<BR><BR></FONT>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the name or names of the underwriters, dealers, agents or selling
securityholders participating in the offering, if any; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>the purchase price of the securities sold by us to any underwriter or dealer
and the net proceeds we expect to receive from the offering; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any over-allotment options under which underwriters may purchase additional
securities from us; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any agency fees or underwriting discounts or commissions and other items
constituting agents' or underwriters' compensation; </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any public offering price; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any discounts or concessions allowed or reallowed or paid to dealers;
and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>any securities exchange or market on which the securities may be listed. </FONT></DD></DL>
</DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>Only
underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>If
underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering
price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting
agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the
underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any
discounts or commissions or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the
prospectus supplement, naming the underwriter, the nature of any such relationship. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
or any selling securityholders may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will
describe any commissions and other compensation we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for
the period of its appointment. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
or any selling securityholders may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set
forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>17</FONT></P>

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HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>the
future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments
that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>All
securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any agents or underwriters may make a market in these securities, but will
not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities. There is currently no market
for any of the offered securities, other than our common stock which is listed on the NASDAQ Global Market. We have no current plans for listing of the preferred stock, warrants or subscription rights
on any securities exchange or quotation system; any such listing with respect to any particular preferred stock, warrants or subscription rights will be described in the applicable prospectus
supplement or other offering materials, as the case may be. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Any
underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation&nbsp;M under the Exchange Act. Overallotment
involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a
specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters
to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or short covering transaction to cover short positions. Those activities
may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Any
agents and underwriters who are qualified market makers on the NASDAQ Global Market may engage in passive market making transactions in the securities on the NASDAQ Global Market in accordance
with Regulation&nbsp;M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable
volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such
security; if all independent bids are lowered below the passive market maker's bid, however, the passive market maker's bid must then be lowered when certain purchase limits are exceeded. Passive
market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>18</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><A
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<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> <A NAME="Legal"></A>LEGAL MATTERS  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Unless otherwise indicated in the applicable prospectus supplement, the validity of the securities offered hereby will be passed upon for us by
Lowenstein Sandler LLP, Roseland, New Jersey. If the validity of the securities offered hereby in connection with offerings made pursuant to this prospectus are passed upon by counsel for the
underwriters, dealers, agents or selling securityholders, if any, such counsel will be named in the prospectus supplement relating to such offering. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> <A NAME="Experts"></A>EXPERTS  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The financial statements and management's assessment of the effectiveness of internal control over financial reporting (which is included in
Management's Report on Internal Control over Financial Reporting) incorporated in this prospectus by reference to our Annual Report on Form&nbsp;10-K for the year ended December&nbsp;31, 2012 have
been so incorporated in reliance on the report of PricewaterhouseCoopers&nbsp;LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and
accounting. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> <A NAME="More_Info"></A>WHERE YOU CAN FIND MORE INFORMATION  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We have filed with the SEC a registration statement on Form&nbsp;S-3, including exhibits, under the Securities Act of which this prospectus
forms&nbsp;a part. This prospectus does not contain all of the information set forth in the registration statement. This prospectus contains descriptions of certain agreements or documents that are
exhibits to the registration statement. The statements as to the contents of such exhibits, however, are brief descriptions and are not necessarily complete, and each statement is qualified in all
respects by reference to such agreement or document. For further information about us, please refer to the registration statement and the documents incorporated by reference in this prospectus. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC's website at
http://www.sec.gov. The SEC's website contains reports, proxy statements and other information regarding issuers, such as Celldex Therapeutics,&nbsp;Inc., that
file electronically with the SEC. You may also read and copy any document we file with the SEC at the SEC's Public Reference Room, located at 100&nbsp;F Street, N.E., Washington, D.C. 20549. Please
call the SEC at 1-800-SEC-0330 for further information on the operation of its Public Reference Room. We make available free of charge through our web site our Annual Report on Form&nbsp;10-K,
Quarterly Reports on Form&nbsp;10-Q, Current Reports on Form&nbsp;8-K, Proxy Statements on Schedule&nbsp;14A and all amendments to those reports as soon as reasonably practicable after such
material is electronically filed with or furnished to the SEC. Our website address is http://www.celldextherapeutics.com. Please note that our website address is provided as an inactive textual
reference only. Information contained on or accessible through our website is not part of this prospectus or the prospectus supplement, and is therefore not incorporated by reference unless such
information is otherwise specifically referenced elsewhere in this prospectus or the prospectus supplement. </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>19</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> <A NAME="Incorporation"></A>INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The SEC allows us to incorporate by reference in this prospectus much of the information we file with the SEC, which means that we can disclose
important information to you by referring you to those publicly available documents. The information that we incorporate by reference in this prospectus is considered to be part of this prospectus.
Because we are incorporating by reference future filings with the SEC, this prospectus is continually updated and those future filings may modify or supersede some of the information included or
incorporated in this prospectus. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus or in any document
previously incorporated by reference have been modified or superseded. This prospectus incorporates by reference the documents listed below (File No.&nbsp;000-15006) and any future filings we make
with the SEC under Sections&nbsp;13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act (in each case, other than those documents or the portions of those
documents not deemed to be filed) until the offering of the securities under the registration statement is terminated or completed:</FONT></P>

<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Our Annual Report on Form&nbsp;10-K for the fiscal year ended
December&nbsp;31, 2012, filed with the SEC on March&nbsp;8, 2013 (including the portions of our Proxy Statement on Schedule&nbsp;14A, filed with the SEC on April&nbsp;23, 2013, incorporated by
reference therein); </FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Our Quarterly Reports on Form&nbsp;10-Q for the fiscal quarters ended
March&nbsp;31, 2013, June&nbsp;30, 2013 and September&nbsp;30, 2013, filed on May&nbsp;3, 2013, August&nbsp;6, 2013 and November&nbsp;8, 2013, respectively; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Our Current Reports on Form&nbsp;8-K filed with the SEC on
February&nbsp;4, 2013, February&nbsp;6, 2013, March&nbsp;7, 2013 (with respect to Item&nbsp;8.01 only), May&nbsp;20, 2013 and June&nbsp;13, 2013; </FONT> <FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The description of our Common Stock contained in our registration statement
on Form&nbsp;8-A, filed with the SEC on September&nbsp;22, 1986 under Section&nbsp;12 of the Securities Exchange Act, and any amendments or reports filed for the purpose of updating such
description; and</FONT><FONT SIZE=2>
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=3>&#149;</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The description of the rights to purchase our
Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock contained in our registration statement on Form&nbsp;S-4, filed with the SEC on December&nbsp;21, 2007, our registration
statement on Form&nbsp;8-A filed with the SEC on November&nbsp;8, 2004, our registration statement on Form&nbsp;8-A/A filed with the SEC on October&nbsp;22, 2007, our registration statement on
Form&nbsp;8-A/A filed with the SEC on March&nbsp;7, 2008, and any amendment or report filed with the SEC for the purposes of updating such descriptions. </FONT></DD></DL>
</UL>

<P style="font-family:arial;"><FONT SIZE=2>Nothing
in this prospectus shall be deemed to incorporate information furnished but not filed with the SEC pursuant to Item&nbsp;2.02 or 7.01 of Form&nbsp;8-K. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
will furnish without charge to each person, including any beneficial owner, to whom this prospectus is delivered, upon written or oral request, a copy of any documents incorporated by reference
other than exhibits to those documents. Requests should be addressed to: </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B>Celldex Therapeutics,&nbsp;Inc.</B></FONT><FONT SIZE=2><BR>
Attention: Investor Relations<BR>
119 Fourth Avenue<BR>
Needham, Massachusetts 02494<BR>
Telephone number: (781)&nbsp;433-0771 </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>20</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2>
<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="ja16901_part_ii_information_not_required_in_the_prospectus"> </A>
<A NAME="toc_ja16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  PART II<BR>  <BR>    INFORMATION NOT REQUIRED IN THE PROSPECTUS    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><A
NAME="ja16901_item_14._other_expense__ja101991"> </A>
<A NAME="toc_ja16901_2"> </A></FONT> <FONT SIZE=2><B>  Item&nbsp;14.&nbsp;&nbsp;&nbsp;&nbsp;Other Expenses of Issuance and Distribution.    <BR>    </B></FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>The following table sets forth the estimated costs and expenses payable by the Registrant in connection with the registration of the securities being
registered under this Registration Statement. All amounts shown are estimates: </FONT></P>
 <DIV style="padding:0pt;position:relative;width:80%;margin-left:10%;">
<p style="font-family:arial;"></FONT></P>

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<TD WIDTH="" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="49pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
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<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD COLSPAN=4 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Registration Statement filing fee</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>**</FONT></TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Printing fees</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>5,000</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>*</FONT></TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Legal fees and expenses</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>20,000</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>*</FONT></TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Accounting fees</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>15,000</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>*</FONT></TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Miscellaneous</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>5,000</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>*</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2><B>Total</B></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>***</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD COLSPAN=4 VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
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<DIV style="padding:0pt;position:relative;text-align:left;margin-left:10%;">
 <DL compact>
<DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;">*</FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Estimated
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;">**</FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Payable
in accordance with Rules 456(b) and 457(r).
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;">***</FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">This
information is unknown at the time of filing </FONT></DD></DL>
 </DIV>
 <P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><A
NAME="ja16901_item_15._indemnification_of_directors_and_officers."> </A>
<A NAME="toc_ja16901_3"> </A></FONT> <FONT SIZE=2><B>  Item&nbsp;15.&nbsp;&nbsp;&nbsp;&nbsp;Indemnification of Directors and Officers.    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Celldex is a Delaware corporation. In accordance with the Delaware General Corporation Law (the "DGCL"), Article Six of the
Registrant's Third Restated Certificate of Incorporation, as amended, provides that no director of the Registrant shall be personally liable to the Registrant or its stockholders for breach of
fiduciary duty as a director, except for liability (i)&nbsp;for any breach of the director's duty of loyalty to Celldex or its stockholders, (ii)&nbsp;for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii)&nbsp;under Section&nbsp;174 of the DGCL, or (iv)&nbsp;for any transaction from which the director derived an improper
personal benefit. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
DGCL permits, but does not require, a corporation to indemnify its directors, officers, employees or agents and expressly provides that the indemnification provided for under the DGCL shall not be
deemed exclusive of any indemnification right under any bylaw, agreement, vote of stockholders or disinterested directors, or otherwise. The DGCL permits indemnification against expenses and certain
other liabilities arising out of legal actions brought or threatened against such persons for their conduct on behalf of the corporation, provided that each such person acted in good faith and in a
manner that he or she reasonably believed was in or not opposed to the corporation's best interests and in the case of a criminal proceeding, had no reasonable cause to believe his or her conduct was
unlawful. The DGCL does not allow indemnification of directors in the case of an action by or in the right of the corporation (including stockholder derivative suits) unless the directors successfully
defend the action or indemnification is ordered by the court. The Amended and Restated Bylaws of Celldex (the "Bylaws") provide for indemnification to the directors, officers, employees and agents of
Celldex consistent with that authorized by the DGCL. Insofar as indemnification for liabilities arising under the Securities Act of 1933, as amended, may be permitted to directors and officers of
Celldex pursuant to the foregoing provision or otherwise, Celldex has been advised that, in the opinion of the Securities and Exchange Commission, such indemnification is against public policy as
expressed in the Securities Exchange Act of 1934, as amended, and is therefore, unenforceable. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Celldex
currently carries a directors' and officers' liability insurance policy which provides for payment of expenses of Celldex's directors and officers in connection with threatened, pending or
completed actions, </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-1</FONT></P>

<HR NOSHADE>
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<P style="font-family:arial;"><FONT SIZE=2>suits
or proceedings against them in their capacities as directors and officers, in accordance with the Bylaws and the DGCL.  </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2><A
NAME="ja16901_item_16._exhibits."> </A>
<A NAME="toc_ja16901_4"> </A></FONT> <FONT SIZE=2><B>  Item&nbsp;16.&nbsp;&nbsp;&nbsp;&nbsp;Exhibits.    <BR>    </B></FONT></P>
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<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>No. </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Description </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Location </B></FONT></TH>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>2.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Agreement and Plan of Merger, dated as of May&nbsp;28, 2009, by and among Celldex, Cottrell Merger Sub,&nbsp;Inc. and CuraGen Corporation.</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;2.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. N. 333-160257), filed June&nbsp;26, 2009.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.2</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.3</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Second Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.2 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.4</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Third Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Quarterly Report on Form&nbsp;10-Q, filed May&nbsp;10, 2002</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.5</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Amended and Restated By-Laws of Celldex as of March&nbsp;14, 2007</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.5 of Celldex's Annual Report on Form&nbsp;10-K, filed March&nbsp;18, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.6</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Designations, Preferences and Rights of a Series of Preferred Stock of Celldex classifying and designating the Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;8-A filed November&nbsp;8, 2004</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.7</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Elimination of Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.6 of Celldex's Annual Report on Form&nbsp;10-K, filed March&nbsp;16, 2005</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.8</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Fourth Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Current Report on Form&nbsp;8-K, filed March&nbsp;11, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.9</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Fifth Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.2 of Celldex's Current Report on Form&nbsp;8-K, filed March&nbsp;11, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.10</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Shareholder Rights Agreement dated November&nbsp;5, 2004 between Celldex and EquiServe Trust Company, N.A. as Rights Agent</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;4.1 of Celldex's Registration Statement on Form&nbsp;8-A, filed November&nbsp;8, 2004</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.11</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Amendment No.&nbsp;1 to Shareholder Rights Agreement dated October&nbsp;19, 2007 between Celldex and Computershare Trust Company, N.A. (formerly EquiServe Trust Company, N.A.) as Rights Agent</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;10.1 of Celldex's Registration Statement on Form&nbsp;8-A/A, filed October&nbsp;22, 2007</FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-2</FONT></P>

<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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<P style="font-family:arial;"><FONT SIZE=2><A
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<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>No. </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Description </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Location </B></FONT></TH>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>4.12</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Amendment No.&nbsp;2 to Shareholder Rights Agreement dated March&nbsp;7, 2008, between Celldex and Computershare Trust Company, N.A. (formerly EquiServe Trust Company, N.A.), as Rights Agent.</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;10.1 of Celldex's Registration Statement on Form&nbsp;8-A12G/A, filed on March&nbsp;7, 2008.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.13</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Specimen of Common Stock Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;4.13 of Celldex's Registration Statement on Form&nbsp;S-3, filed on December&nbsp;21, 2012.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.14</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Warrant Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.15</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Warrant Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>(included in Exhibit&nbsp;4.14)</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.16</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Specimen of Preferred Stock Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.17</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Depositary Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.18</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Depositary Receipt</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>(included in Exhibit&nbsp;4.17)</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.19</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Unit Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>5.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Opinion of Lowenstein Sandler LLP as to the legality of the securities being registered</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>12.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Computation of Ratio of Combined Fixed Charges and Preferred Stock Dividends to Earnings</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>23.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Consent of PricewaterhouseCoopers&nbsp;LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
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<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>23.2</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Consent of Lowenstein Sandler LLP</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Included in Exhibit&nbsp;5.1</FONT></TD>
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<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>24.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Powers of Attorney</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Included in the signature page</FONT></TD>
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 <P style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><A
NAME="ja16901_item_17._undertakings."> </A>
<A NAME="toc_ja16901_5"> </A></FONT> <FONT SIZE=2><B>  Item&nbsp;17.&nbsp;&nbsp;&nbsp;&nbsp;Undertakings.    <BR>    </B></FONT></P>

<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(a)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The
undersigned registrant hereby undertakes:
<BR><BR></FONT>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(1)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>To
file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:
<BR><BR></FONT>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(i)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>To
include any prospectus required by Section&nbsp;10(a)(3) of the Securities Act; </FONT></DD></DL>
</DD></DL>
</DD></DL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-3</FONT></P>

<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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<P style="font-family:arial;"><FONT SIZE=2><A
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<UL>
<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(ii)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>To
reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective
amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or
decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated
maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule&nbsp;424(b) if, in the aggregate, the changes in volume and price represent no more than
a 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective registration statement; and
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(iii)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>To
include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change
to such information in the registration statement; </FONT></DD></DL>
</UL>
</UL>
<UL>

<P style="font-family:arial;"><FONT SIZE=2><I>provided, however</I></FONT><FONT SIZE=2>, Paragraphs&nbsp;(a)(1)(i), (a)(1)(ii) and (a)(1)(iii) of this section do not apply if the registration statement is on
Form&nbsp;S-3 or Form&nbsp;F-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by
the registrant pursuant to section&nbsp;13 or section&nbsp;15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form
of prospectus filed pursuant to Rule&nbsp;424(b) that is part of the registration statement.  </FONT></P>

<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(2)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>That,
for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new Registration
Statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial </FONT><FONT SIZE=2><I>bona fide</I></FONT><FONT SIZE=2>
offering thereof.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(3)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>To
remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the
offering.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(4)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>That,
for the purpose of determining liability under the Securities Act to any purchaser, (A)&nbsp;each prospectus filed by the registrant pursuant to
Rule&nbsp;424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and (B)&nbsp;each
prospectus required to be filed pursuant to Rule&nbsp;424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule&nbsp;430B relating to an offering made pursuant to
Rule&nbsp;415(a)(1)(i), (vii), or (x)&nbsp;for the purpose of providing the information required by section&nbsp;10(a) of the Securities Act of 1933 shall be deemed to be part of and included in
the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in
the prospectus. As provided in Rule&nbsp;430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the
registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial
bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed
incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date,
supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective
date. </FONT></DD></DL>
</UL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-4</FONT></P>

<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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<UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(5)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>That,
for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities: </FONT></DD></DL>
</UL>
<UL>
<UL>

<P style="font-family:arial;"><FONT SIZE=2>The
undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell
the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser
and will be considered to offer or sell such securities to such purchaser: </FONT></P>

<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(i)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Any
preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule&nbsp;424;
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(ii)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Any
free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned
registrant;
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(iii)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The
portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its
securities provided by or on behalf of the undersigned registrant; and
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(iv)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Any
other communication that is an offer in the offering made by the undersigned registrant to the purchaser.
<BR><BR></FONT></DD></DL>
</UL>
</UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(b)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The
undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant's
annual report pursuant to Section&nbsp;13(a) or 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section&nbsp;15(d) of the
Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial </FONT><FONT SIZE=2><I>bona fide</I></FONT><FONT SIZE=2> offering thereof.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(c)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>Insofar
as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the
Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director,
officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the
securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question
whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(d)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>The
undersigned Registrant hereby undertakes that:
<BR><BR></FONT>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(1)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>For
purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this
registration statement in reliance upon Rule&nbsp;430A and contained in a form of prospectus filed by the registrant pursuant to Rule&nbsp;424(b)(1) or (4)&nbsp;or 497(h) under the Securities
Act shall be deemed to be part of this registration statement as of the time it was declared effective.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>(2)</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>For
the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be
deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. </FONT></DD></DL>
</DD></DL>
<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-5</FONT></P>

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<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="jc16901_signatures"> </A>
<A NAME="toc_jc16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  SIGNATURES    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form&nbsp;S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Town of Needham,
Commonwealth of Massachusetts, on December&nbsp;3rd, 2013. </FONT></P>
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<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD COLSPAN=3 style="font-family:arial;"><FONT SIZE=2><B>CELLDEX THERAPEUTICS,&nbsp;INC.</B></FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>  By:</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="BOTTOM" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;ANTHONY S. MARUCCI<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Anthony S. Marucci<BR></FONT> <FONT SIZE=2><I>President and Chief Executive Officer</I></FONT></TD>
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NAME="jc16901_signatures_and_power_of_attorney_1"> </A>
<A NAME="toc_jc16901_2"> </A>
<BR></FONT><FONT SIZE=2><B>  SIGNATURES AND POWER OF ATTORNEY    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Anthony S. Marucci and Avery W. Catlin, or
any one of them, as his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, to sign any
and all amendments (including pre-effective and post-effective amendments) to this registration statement on Form&nbsp;S-3 and any subsequent registration filed pursuant to Rule&nbsp;462(b) under
the Securities Act of 1933, as amended, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his substitutes or substitute, may
lawfully do or cause to be done by virtue hereof. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Pursuant
to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated. </FONT></P>
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<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
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 </B></FONT></DIV></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH NOWRAP  ALIGN="CENTER" style="font-family:arial;"><DIV style="border-bottom:solid #000000 1.0pt;margin-bottom:0pt;width:17pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Date

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 </B></FONT></DIV></TH>
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<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>/s/&nbsp;ANTHONY S. MARUCCI<BR>



<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Anthony S. Marucci</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Director, Chief Executive Officer and President (Principal Executive Officer)</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;AVERY W. CATLIN<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Avery W. Catlin</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Senior Vice President, Treasurer and Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
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<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;LARRY ELLBERGER<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Larry Ellberger</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-6</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><A
HREF="#bg16901a_main_toc">Table of Contents</A></FONT></P>
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<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
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<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH NOWRAP  ALIGN="CENTER" style="font-family:arial;"><DIV style="border-bottom:solid #000000 1.0pt;margin-bottom:0pt;width:17pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Date

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 </B></FONT></DIV></TH>
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<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
</TR>
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<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>/s/&nbsp;HERBERT J. CONRAD<BR>



<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Herbert J. Conrad</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;GEORGE O. ELSTON<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> George O. Elston</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
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<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;HARRY H. PENNER, JR.<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Harry H. Penner, Jr.</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;TIMOTHY M. SHANNON<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Timothy M. Shannon, M.D.</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>/s/&nbsp;KAREN L. SHOOS<BR>


<HR NOSHADE SIZE="1.0pt" WIDTH="100%" COLOR="#000000">

</FONT> <FONT SIZE=2> Karen L. Shoos</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>Director</FONT></TD>
<TD VALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="CENTER" VALIGN="CENTER" style="font-family:arial;"><BR><FONT SIZE=2>December&nbsp;3, 2013</FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-7</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2>
<A HREF="#bg16901a_main_toc">Table of Contents</A> </FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><A
NAME="ka16901_exhibit_index"> </A>
<A NAME="toc_ka16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  EXHIBIT INDEX    <BR>    </B></FONT></P>
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<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>No. </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Description </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Location </B></FONT></TH>
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<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>2.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Agreement and Plan of Merger, dated as of May&nbsp;28, 2009, by and among Celldex, Cottrell Merger Sub,&nbsp;Inc. and CuraGen Corporation.</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;2.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. N. 333-160257), filed June&nbsp;26, 2009.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.2</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.3</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Second Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.2 of Celldex's Registration Statement on Form&nbsp;S-4 (Reg. No.&nbsp;333-59215), filed July&nbsp;16, 1998</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.4</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Third Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Quarterly Report on Form&nbsp;10-Q, filed May&nbsp;10, 2002</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.5</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Amended and Restated By-Laws of Celldex as of March&nbsp;14, 2007</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.5 of Celldex's Annual Report on Form&nbsp;10-K, filed March&nbsp;18, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.6</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Designations, Preferences and Rights of a Series of Preferred Stock of Celldex classifying and designating the Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Registration Statement on Form&nbsp;8-A filed November&nbsp;8, 2004</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.7</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Certificate of Elimination of Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.6 of Celldex's Annual Report on Form&nbsp;10-K, filed March&nbsp;16, 2005</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.8</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Fourth Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.1 of Celldex's Current Report on Form&nbsp;8-K, filed March&nbsp;11, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.9</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Fifth Certificate of Amendment of Third Restated Certificate of Incorporation of Celldex</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;3.2 of Celldex's Current Report on Form&nbsp;8-K, filed March&nbsp;11, 2008</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.10</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Shareholder Rights Agreement dated November&nbsp;5, 2004 between Celldex and EquiServe Trust Company, N.A. as Rights Agent</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;4.1 of Celldex's Registration Statement on Form&nbsp;8-A, filed November&nbsp;8, 2004</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.11</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Amendment No.&nbsp;1 to Shareholder Rights Agreement dated October&nbsp;19, 2007 between Celldex and Computershare Trust Company, N.A. (formerly EquiServe Trust Company, N.A.) as Rights Agent</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;10.1 of Celldex's Registration Statement on Form&nbsp;8-A/A, filed October&nbsp;22, 2007</FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-8</FONT></P>

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<P style="font-family:arial;"><FONT SIZE=2><A
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<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>No. </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Description </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Location </B></FONT></TH>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>4.12</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Amendment No.&nbsp;2 to Shareholder Rights Agreement dated March&nbsp;7, 2008, between Celldex and Computershare Trust Company, N.A. (formerly EquiServe Trust Company, N.A.), as Rights Agent.</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;10.1 of Celldex's Registration Statement on Form&nbsp;8-A12G/A, filed on March&nbsp;7, 2008.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.13</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Specimen of Common Stock Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Incorporated by reference to Exhibit&nbsp;4.13 of Celldex's Registration Statement on Form&nbsp;S-3, filed on December&nbsp;21, 2012.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.14</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Warrant Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.15</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Warrant Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>(included in Exhibit&nbsp;4.14)</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.16</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Specimen of Preferred Stock Certificate</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.17</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Depositary Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.18</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Depositary Receipt</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>(included in Exhibit&nbsp;4.17)</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>4.19</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Form of Unit Agreement</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>To be filed subsequently by an amendment to the Registration Statement or by a Current Report of the Registrant on a Current Report on Form&nbsp;8-K and incorporated by reference therein.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>5.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Opinion of Lowenstein Sandler LLP as to the legality of the securities being registered</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>12.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Computation of Ratio of Combined Fixed Charges and Preferred Stock Dividends to Earnings</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
</TR>
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<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>23.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Consent of PricewaterhouseCoopers&nbsp;LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Filed herewith</FONT></TD>
</TR>
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<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>23.2</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Consent of Lowenstein Sandler LLP</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Included in Exhibit&nbsp;5.1</FONT></TD>
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<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><BR><FONT SIZE=2>24.1</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Powers of Attorney</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><BR><FONT SIZE=2>Included in the Signature page</FONT></TD>
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 <P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2>Part II-9</FONT></P>

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<BR></FONT><FONT SIZE=2><B>  Exhibit 5.1    <BR>    </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>December&nbsp;3,
2013 </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Celldex
Therapeutics,&nbsp;Inc.<BR>
119 Fourth Avenue<BR>
Needham, Massachusetts 02494 </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2><B>Re: Shelf Registration Statement of Celldex Therapeutics,&nbsp;Inc. on Form&nbsp;S-3</B></FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>Ladies
and Gentlemen: </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
have acted as counsel to Celldex Therapeutics,&nbsp;Inc., a Delaware corporation (the "Company"), in connection with its filing of a shelf registration statement on Form&nbsp;S-3 (the
"Registration Statement"), including the prospectus constituting a part thereof (the "Prospectus"), to which this opinion is attached, filed with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Securities Act"). We have been requested by the Company to render this opinion in connection with the filing of the Registration
Statement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>The
Prospectus provides that it will be supplemented in the future by one or more supplements to the Prospectus (each a "Prospectus Supplement"). The Prospectus, as supplemented by various Prospectus
Supplements, will
provide for the registration and sale, from time to time, of (i)&nbsp;shares of preferred stock, par value $0.001 per share, in one or more series or classes (the "Preferred Stock"),
(ii)&nbsp;shares of common stock, par value $0.001 per share, (and associated rights to purchase the registrant's Series&nbsp;C-1&nbsp;Junior Participating Cumulative Preferred Stock) (the
"Common Stock"), (iii)&nbsp;warrants to purchase Common Stock or Preferred Stock (the "Warrants"), (iv)&nbsp;depositary shares (evidenced by depositary receipts) representing fractional interests
in shares of Common Stock or Preferred Stock (the "Depositary Shares"), or (v)&nbsp;units composed of the foregoing (the "Units"). The Preferred Stock, Common Stock, Warrants, Depositary Shares and
the Units are collectively referred to herein as the "Securities." The Preferred Stock may be exchangeable for and/or convertible into shares of Common Stock or another series of Preferred Stock. The
Units may be exchangeable and/or settled into the Securities comprising the Units. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>In
rendering our opinion, we have reviewed the Registration Statement and the exhibits thereto. We have also reviewed such corporate documents and records of the Company, such certificates of public
officials and officers of the Company and such other matters as we have deemed necessary or appropriate for purposes of this opinion. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Except
to the extent we opine as to the binding effect of certain documents as set forth in paragraphs&nbsp;3, 4 and 5 below, we have assumed that all documents referenced below are the valid and
binding obligations of and enforceable against the parties thereto. We have also assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures, the
conformity to authentic original documents of all documents submitted to us as certified, conformed or photostatic copies and the legal capacities of all natural persons. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Based
on the foregoing, and subject to the assumptions, limitations and qualifications set forth herein, we are of the opinion that: </FONT></P>

<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>1.</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>(a)
When a new class or series of Preferred Stock has been duly established in accordance with the terms of the restated certificate of incorporation of the
Company, as amended ("Charter"), the by-laws of the Company ("Bylaws") and applicable law (in the event that the Preferred Stock is a new class or series of Preferred Stock), and upon adoption by the
Board of Directors of the Company of a resolution in form and content as required by applicable law, and (b)&nbsp;assuming that appropriate certificates of amendment to the Company's Charter
relating to such class or series of Preferred Stock have been duly approved by the Company's Board of Directors and been filed with and accepted for record by the State of Delaware, and
(c)&nbsp;assuming that the Registration Statement and any required post-effective amendment(s) thereto and any and all Prospectus Supplement(s) required by applicable laws have become effective
under the Securities Act, and (d)&nbsp;assuming that upon the issuance of such Preferred Stock, the total number of issued and outstanding shares of the applicable class or series of Preferred </FONT></DD></DL>
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<P style="font-family:arial;"><FONT SIZE=2>Stock
will not exceed the total number of shares of Preferred Stock or the number of shares of such class or series of Preferred Stock that the Company is then authorized to issue under its Charter,
then upon issuance, sale and delivery of and payment for such shares in the manner contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement(s) and by such
resolution, such shares of such class or series of Preferred Stock (including any Preferred Stock duly issued upon (i)&nbsp;the exchange or conversion of any shares of Preferred Stock that are
exchangeable or convertible into another class or series of Preferred Stock, (ii)&nbsp;the exercise of any duly issued Warrants exercisable for Preferred Stock, or (iii)&nbsp;the exchange or
settlement of Units that are exchangeable or able to be settled for Preferred Stock), will be validly issued, fully paid and non-assessable.  </FONT></P>

</UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>2.</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>(a)
Upon adoption by the Board of Directors of the Company of a resolution in form and content as required by applicable law authorizing the issuance and
sale of Common Stock, and (b)&nbsp;assuming that the Registration Statement and any required post-effective amendment(s) thereto and any and all Prospectus Supplement(s) required by applicable laws
have become effective under the Securities Act, and (c)&nbsp;assuming that upon the issuance of such Common Stock, the total number of issued and outstanding shares of Common Stock will not exceed
the total number of shares of Common Stock that the Company is then authorized to issue under its Charter, then upon issuance, sale and delivery of and payment for such shares in the manner
contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement(s) and by such resolution, such shares of Common Stock being issued by the Company (including any
Common Stock duly issued upon (i)&nbsp;the exchange or conversion of any shares of Preferred Stock that are exchangeable or convertible into Common Stock, (ii)&nbsp;the exercise of any duly issued
Warrants exercisable for Common Stock, or (iii)&nbsp;the exchange or settlement of Units that are exchangeable or able to be settled for Common Stock), will be validly issued, fully paid and
non-assessable.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>3.</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>(a)
When a warrant agreement relating to the Warrants has been duly authorized (the "Warrant Agreement"), executed and delivered and the Warrants and the
securities of the Company for which the Warrants will be exercisable have been duly authorized by the Company's Board of Directors, and (b)&nbsp;assuming that the terms of the Warrants and of their
issuance and sale have been duly established in conformity with the Company's Charter and Bylaws and the Warrant Agreement, and (c)&nbsp;assuming that the Registration Statement and any required
post-effective amendment thereto and any and all Prospectus Supplement(s) required by applicable laws have all become effective under the Securities Act, and (d)&nbsp;assuming that the terms of the
Warrants as executed and delivered are as described in the Registration Statement, the Prospectus and the related Prospectus Supplement(s), and (e)&nbsp;assuming that the Warrants, as executed and
delivered, do not violate any law applicable to the Company or result in a default under or breach of any agreement or instrument binding upon the Company, and (f)&nbsp;assuming that the Warrants as
executed and delivered comply with all requirements and restrictions, if any, applicable to the Company, whether imposed by any court or governmental or regulatory body having jurisdiction over the
Company, and (g)&nbsp;assuming that the Warrants are then issued and sold as contemplated in the Registration Statement, the Prospectus and the Prospectus Supplement(s), then upon issuance, sale and
delivery of and payment for such Warrants in the manner contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement and the Warrant Agreement and by such
resolution, the Warrants (including any Warrants issued upon the exchange or settlement of Units that are exchangeable or able to be settled for Warrants) will constitute valid and legally binding
obligations of the Company.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>4.</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>(a)
When a depositary agreement relating to the Depositary Shares has been duly authorized (the "Depositary Agreement"), executed and delivered and the
Depositary Shares have been duly authorized by the Company's Board of Directors, and (b)&nbsp;assuming that the terms of the Depositary Shares and of their issuance and sale have been duly
established in conformity with the Company's Charter and Bylaws and the Depositary Agreement, and (c)&nbsp;assuming that the Registration Statement and any required post-effective amendment thereto
and any and all Prospectus Supplement(s) required by applicable laws have all become effective under the Securities Act, and (d)&nbsp;assuming that the terms of the Depositary Shares as executed and
delivered are as described in the Registration Statement, the Prospectus and the related Prospectus Supplement(s), and (e)&nbsp;assuming that the Depositary Shares, as </FONT></DD></DL>
<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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<UL>

<P style="font-family:arial;"><FONT SIZE=2>executed
and delivered, do not violate any law applicable to the Company or result in a default under or breach of any agreement or instrument binding upon the Company, and (f)&nbsp;assuming that
the Depositary Shares as executed and delivered comply with all requirements and restrictions, if any, applicable to the Company, whether imposed by any court or governmental or regulatory body having
jurisdiction over the Company, and (g)&nbsp;assuming the depositary receipts evidencing the Depositary Shares have been duly issued against the deposit of the Common Stock or Preferred Stock in
accordance with the Depositary Agreement and issued and sold as contemplated in the Registration Statement, the Prospectus and the Prospectus Supplement(s), then upon issuance, sale and delivery of
and payment for such Depositary Shares in the manner contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement and by such resolution, the depositary receipts
evidencing Depositary Shares (including any depositary receipts evidencing Depositary Shares issued upon the exchange or
settlement of Units exchangeable or able to be settled for Depositary Shares) will entitle holders thereof to the rights specified in the Depositary Agreement.  </FONT></P>

</UL>
<DL compact>
<DT style='font-family:arial;margin-bottom:-11pt;'><FONT SIZE=2>5.</FONT></DT><DD style="font-family:arial;"><FONT SIZE=2>(a)
When a unit agreement relating to the Units has been duly authorized (the "Unit Agreement"), executed and delivered and the Units have been duly
authorized by the Company's Board of Directors, and (b)&nbsp;assuming that the terms of the Units and of their issuance and sale have been duly established in conformity with the Unit Agreement, and
(c)&nbsp;assuming that the Registration Statement and any required post-effective amendment thereto and any and all Prospectus Supplement(s) required by applicable laws have all become effective
under the Securities Act, and (d)&nbsp;assuming that the terms of the Units as executed and delivered are as described in the Registration Statement, the Prospectus and the related Prospectus
Supplement(s), and (e)&nbsp;assuming that the Units, as executed and delivered, do not violate any law applicable to the Company or result in a default under or breach of any agreement or instrument
binding upon the Company, and (f)&nbsp;assuming that the Units as executed and delivered comply with all requirements and restrictions, if any, applicable to the Company, whether imposed by any
court or governmental or regulatory body having jurisdiction over the Company, and (g)&nbsp;assuming that the Units are then issued and sold as contemplated in the Registration Statement, the
Prospectus and the Prospectus Supplement(s), then upon issuance, sale and delivery of and payment for such Units in the manner contemplated by the Registration Statement, the Prospectus and the
related Prospectus Supplement and the Unit Agreement and by such resolution, the Units will constitute valid and legally binding obligations of the Company. </FONT></DD></DL>

<P style="font-family:arial;"><FONT SIZE=2>The
opinions set forth above are subject to the following exceptions, limitations and qualifications: (i)&nbsp;the effect of bankruptcy, insolvency, reorganization, arrangement, moratorium,
fraudulent conveyance, fraudulent transfer and other similar laws relating to or affecting the rights of creditors; (ii)&nbsp;the effect of general principles of equity (including, without
limitation, concepts of materiality, reasonableness, good faith and fair dealing and the possible unavailability of specific performance, injunctive relief and other equitable remedies), regardless of
whether considered in a proceeding at law or in equity, (iii)&nbsp;the effect of public policy considerations that may limit the rights of the parties to obtain further remedies, (iv)&nbsp;we
express no opinion with respect to the enforceability of provisions relating to choice of law, choice of venue, jurisdiction or waivers of jury trial, and (v)&nbsp;we express no opinion with respect
to the enforceability of any waiver of any usury defense. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>To
the extent that the obligations of the Company with respect to the Securities may be dependent on such matters, we assume for purposes of this opinion that the other party under the Warrant
Agreement for any Warrants, under the Unit Agreement for any Units and under the Deposit Agreement for any Depository Shares, namely the warrant agent, the unit agent or the depositary, respectively,
is duly organized, validly existing and in good standing under the laws of its jurisdiction of organization; that such other party is duly qualified to engage in the activities contemplated by such
Warrant Agreement, Unit Agreement or Deposit Agreement, as applicable; that such Warrant Agreement, Unit Agreement or Deposit Agreement has been duly authorized, executed and delivered by such other
party and constitutes the legally valid, binding and enforceable obligation of such other party, enforceable against such other party in accordance with its terms; that such other party is in
compliance, generally and with respect to performance of its obligations under such Warrant Agreement, Unit Agreement, or Deposit Agreement, as applicable, with all applicable laws and regulations;
and that such other party has the requisite organizational and legal power and </FONT></P>

<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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<P style="font-family:arial;"><FONT SIZE=2>authority
to perform its obligations under such Warrant Agreement, Unit Agreement or Deposit Agreement, as applicable. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Our
opinion is limited to the federal laws of the United States and to the Delaware General Corporation law. We express no opinion as to the effect of the law of any other jurisdiction. Our opinion is
rendered as of the date hereof, and we assume no obligation to advise you of changes in law or fact (or the effect thereof on the opinions expressed herein) that hereafter may come to our attention. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We
hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement in accordance with the requirements of Item&nbsp;601(b)(5) of Regulation&nbsp;S-K
under the Securities Act and to the use of our name therein and in the related Prospectus and any Prospectus Supplement under the caption "Legal Matters." In giving such consent, we do not thereby
admit that we are in the category of persons whose consent is required under Section&nbsp;7 of the Securities Act or the Rules and Regulations of the Commission promulgated thereunder. </FONT></P>


<P style="font-family:arial;"><FONT SIZE=2>Very
truly yours, </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>/s/
Lowenstein Sandler&nbsp;LLP </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>LOWENSTEIN
SANDLER&nbsp;LLP </FONT></P>

<HR NOSHADE>
<P style='font-family:arial;page-break-before:always'></p>
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NAME="kg16901_exhibit_12.1"> </A>
<A NAME="toc_kg16901_1"> </A>
<BR></FONT><FONT SIZE=2><B>  Exhibit&nbsp;12.1    <BR>    </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> CELLDEX PHARMACEUTICALS,&nbsp;INC.<BR>
COMPUTATION OF RATIO OF EARNINGS TO COMBINED FIXED CHARGES  </B></FONT></P>
 <DIV style="padding:0pt;position:relative;width:54%;margin-left:10%;">
<p style="font-family:arial;"></FONT></P>

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<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="98pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="53pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="53pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="46pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="53pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
<TD WIDTH="7pt" ALIGN="RIGHT" style="font-family:arial;"></TD>
<TD WIDTH="53pt" style="font-family:arial;"></TD>
<TD WIDTH="12pt" style="font-family:arial;"></TD>
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<TR VALIGN="BOTTOM">
<TH ALIGN="LEFT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="LEFT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT><BR></TH>
<TH ROWSPAN=2 style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=14 ROWSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Year Ended December&nbsp;31, </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
<TR VALIGN="BOTTOM">
<TH ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH ROWSPAN=2 style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ROWSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>Nine Months Ended<BR>
September 30,<BR>
2013 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
<TR VALIGN="BOTTOM">
<TH ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2012 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2011 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2010 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2009 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="CENTER" style="font-family:arial;border-bottom:solid #000000 1.0pt;"><FONT  style="font-size:8pt;line-height:9pt;"><B>2008 </B></FONT></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
<TR VALIGN="BOTTOM">
<TH ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=2 ALIGN="LEFT" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
<TH COLSPAN=14 ALIGN="CENTER" style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;"><B>(In thousands)</B></FONT><BR></TH>
<TH style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">&nbsp;</FONT></TH>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Loss from continuing operations before taxes</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(59,328</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(58,077</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(43,399</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(6,455</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(36,850</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(48,756</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Fixed Charges:</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:18pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Interest expensed and amortization of debt discount</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>842</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>1,576</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>1,796</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>1,337</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>452</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>156</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:18pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Estimate of interest within rental expense<SUP>(2)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>661</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>838</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>841</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>821</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>825</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>726</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Total fixed charges</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>1,503</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>2,414</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>2,637</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>2,158</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>1,277</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>882</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:solid #000000 1.0pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
<TR BGCOLOR="White" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Loss as defined for ratio to fixed charges</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(57,825</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(55,663</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(40,762</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(4,297</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(35,573</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
<TD ALIGN="RIGHT"  style="font-family:arial;"><FONT SIZE=2>$</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>(47,874</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>)</FONT></TD>
</TR>
<TR style="font-size:1.5pt;" VALIGN="TOP">
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
<TD COLSPAN=2 ALIGN="RIGHT" VALIGN="BOTTOM" style="font-family:arial;border-bottom:double #000000 2.25pt;">&nbsp;</TD>
<TD VALIGN="BOTTOM" style="font-family:arial;">&nbsp;</TD>
</TR>
<TR BGCOLOR="#CCEEFF" VALIGN="BOTTOM">
<TD style="font-family:arial;"><p style="font-family:arial;margin-left:9pt;text-indent:-9pt;"><FONT SIZE=2> </FONT><FONT SIZE=2>Ratio of earnings to fixed charges</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD ALIGN="RIGHT" style="font-family:arial;"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD style="font-family:arial;"><FONT SIZE=2><SUP>(1)</SUP></FONT></TD>
</TR>
</TABLE></DIV>
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<DIV style="padding:0pt;position:relative;text-align:left;margin-left:10%;">
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<DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;"><font
style="font-size:6pt;position:relative;top:-2pt;add_sup:2pt;">(1)</font></FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Due
to the Company's loss from continuing operations for the nine months ended September&nbsp;30, 2013 and the years ended
December&nbsp;31, 2012, 2011, 2010, 2009 and 2008 earnings were insufficient to cover fixed charges by $59.3 million, $58.1&nbsp;million, $43.4&nbsp;million, $6.5&nbsp;million,
$36.9&nbsp;million, and $48.8&nbsp;million, respectively.
<BR><BR></FONT></DD><DT style='font-family:arial;margin-bottom:-9pt;'><FONT  style="font-size:8pt;line-height:9pt;"><font
style="font-size:6pt;position:relative;top:-2pt;add_sup:2pt;">(2)</font></FONT></DT><DD style="font-family:arial;"><FONT  style="font-size:8pt;line-height:9pt;">Interest
component on rentals estimated to be one-third of rentals. </FONT></DD></DL>
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<TYPE>EX-23.1
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<BR></FONT><FONT SIZE=2><B>  EXHIBIT 23.1    <BR>    </B></FONT></P>

<P ALIGN="CENTER" style="font-family:arial;"><FONT SIZE=2><B> CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM  </B></FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>We hereby consent to the incorporation by reference in this Registration Statement on Form&nbsp;S-3, of our report dated March&nbsp;8, 2013
relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in Celldex Therapeutics&nbsp;Inc.'s Annual Report on Form&nbsp;10-K for the
year ended December&nbsp;31, 2012. We also consent to the reference to us under the heading "Experts" in such Registration Statement. </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>/s/
PricewaterhouseCoopers&nbsp;LLP </FONT></P>

<P style="font-family:arial;"><FONT SIZE=2>Boston,
Massachusetts<BR>
December&nbsp;3, 2013 </FONT></P>

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