<SEC-DOCUMENT>0001193125-17-263720.txt : 20170821
<SEC-HEADER>0001193125-17-263720.hdr.sgml : 20170821
<ACCEPTANCE-DATETIME>20170821164533
ACCESSION NUMBER:		0001193125-17-263720
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		4
CONFORMED PERIOD OF REPORT:	20170821
ITEM INFORMATION:		Entry into a Material Definitive Agreement
ITEM INFORMATION:		Other Events
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20170821
DATE AS OF CHANGE:		20170821

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ARCA biopharma, Inc.
		CENTRAL INDEX KEY:			0000907654
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				363855489
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		171043473

	BUSINESS ADDRESS:	
		STREET 1:		11080 CIRCLEPOINT ROAD
		STREET 2:		SUITE 140
		CITY:			WESTMINSTER
		STATE:			CO
		ZIP:			80020
		BUSINESS PHONE:		720-940-2200

	MAIL ADDRESS:	
		STREET 1:		11080 CIRCLEPOINT ROAD
		STREET 2:		SUITE 140
		CITY:			WESTMINSTER
		STATE:			CO
		ZIP:			80020

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NUVELO INC
		DATE OF NAME CHANGE:	20030203

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HYSEQ INC
		DATE OF NAME CHANGE:	19970610
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>d639616d8k.htm
<DESCRIPTION>8-K
<TEXT>
<HTML><HEAD>
<TITLE>8-K</TITLE>
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 <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P>
<P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="margin-top:4pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>UNITED STATES </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>WASHINGTON, D.C. 20549 </B></P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM <FONT
STYLE="white-space:nowrap">8-K</FONT> </B></P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>CURRENT
REPORT </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>Pursuant to Section&nbsp;13 or 15(d) </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>of the Securities Exchange Act of 1934 </B></P>
<P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>Date of Report (Date of earliest event reported):&nbsp;August&nbsp;21, 2017 </B></P>
<P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>ARCA biopharma, Inc. </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(Exact name of Registrant as Specified in Its Charter) </B></P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top" ALIGN="center"><B>Delaware</B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"><B><FONT STYLE="white-space:nowrap">000-22873</FONT></B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"><B><FONT STYLE="white-space:nowrap">36-3855489</FONT></B></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(State or Other Jurisdiction</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>of Incorporation)</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Commission</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>File Number)</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(IRS Employer</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification No.)</B></P></TD></TR>
</TABLE> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>11080 CirclePoint Road, Suite 140,</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Westminster, CO</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" ALIGN="center"><B>80020</B></TD></TR>
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<TD VALIGN="top" ALIGN="center"><B>(Address of Principal Executive Offices)</B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"><B>(Zip Code)</B></TD></TR>
</TABLE> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Registrant&#146;s Telephone Number, Including Area Code: (720)
<FONT STYLE="white-space:nowrap">940-2200</FONT> </B></P> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Not Applicable </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Former Name or Former Address, if Changed Since Last Report) </B></P>
<P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Check the appropriate box below if the Form <FONT STYLE="white-space:nowrap">8-K</FONT> filing is intended to simultaneously satisfy the filing obligation of
the registrant under any of the following provisions (see General Instructions A.2. below): </P> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">&#9744;</TD>
<TD ALIGN="left" VALIGN="top">Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) </TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">&#9744;</TD>
<TD ALIGN="left" VALIGN="top">Soliciting material pursuant to Rule <FONT STYLE="white-space:nowrap">14a-12</FONT> under the Exchange Act (17 CFR <FONT STYLE="white-space:nowrap">240.14a-12)</FONT> </TD></TR></TABLE>
<P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">&#9744;</TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="white-space:nowrap">Pre-commencement</FONT> communications pursuant to Rule <FONT STYLE="white-space:nowrap">14d-2(b)</FONT> under the Exchange Act (17 CFR
<FONT STYLE="white-space:nowrap">240.14d-2(b))</FONT> </TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">&#9744;</TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="white-space:nowrap">Pre-commencement</FONT> communications pursuant to Rule <FONT STYLE="white-space:nowrap">13e-4(c)</FONT> under the Exchange Act (17 CFR
<FONT STYLE="white-space:nowrap">240.13e-4(c))</FONT> </TD></TR></TABLE> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Indicate by check mark whether the registrant is an emerging growth company as
defined in Rule 405 of the Securities Act of 1933 (&#167;&nbsp;230.405 of this chapter) or Rule <FONT STYLE="white-space:nowrap">12b-2</FONT> of the Securities Exchange Act of 1934 <FONT STYLE="white-space:nowrap">(&#167;&nbsp;240.12b-2</FONT> of
this chapter). </P> <P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Emerging growth company&nbsp;&nbsp;&#9744; </P>
<P STYLE="margin-top:10pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or
revised financial accounting standards provided pursuant to Section&nbsp;13(a) of the Exchange Act. &nbsp;&nbsp;&#9744; </P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>

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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Item&nbsp;1.01 Entry Into a Material Definitive Agreement. </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">On August&nbsp;21, 2017, ARCA biopharma, Inc. (the &#147;Company&#148;) entered into Amendment No.&nbsp;1 (the &#147;Amendment&#148;) to its Capital on Demand
Sales Agreement, dated as of January&nbsp;11, 2017 (the &#147;Original Agreement&#148; and, as amended by the Amendment, the &#147;Sales Agreement&#148;), with JonesTrading Institutional Services LLC, as agent (&#147;JonesTrading&#148;). The
Amendment, among other things, increased the maximum aggregate offering value of shares of the Company&#146;s common stock (the &#147;Additional Shares&#148;) which the Company may issue and sell from time to time under the Sales Agreement (the
&#147;Offering&#148;) by approximately $2.9&nbsp;million, from $7,300,000 to $10,242,863. The Company will file a prospectus supplement with the Securities and Exchange Commission (the &#147;SEC&#148;) in connection with the Offering (the
&#147;Prospectus Supplement&#148;) under its existing Registration Statement on Form <FONT STYLE="white-space:nowrap">S-3</FONT> (File No <FONT STYLE="white-space:nowrap">333-217459),</FONT> which became effective on May&nbsp;12, 2017 (the
&#147;Registration Statement&#148;). </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Under the Sales Agreement, JonesTrading may sell the Additional Shares by any method permitted by law and deemed to
be an &#147;at the market offering&#148; as defined in Rule 415 promulgated under the Securities Act of 1933, as amended. In addition, under the Sales Agreement, JonesTrading may sell the Additional Shares by any other method permitted by law,
including in negotiated transactions. The Company may instruct JonesTrading not to sell Additional Shares if the sales cannot be effected at or above the price designated by the Company from time to time. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The Company is not obligated to make any sales of the Additional Shares under the Sales Agreement. The Offering will terminate upon the earlier of
(a)&nbsp;the sale of all of the Additional Shares subject to the Sales Agreement or (b)&nbsp;the termination of the Sales Agreement by JonesTrading or the Company, as permitted therein. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The Company will pay JonesTrading a commission rate equal to 3.0% of the aggregate gross proceeds from each sale of Additional Shares and have agreed to
provide JonesTrading with customary indemnification and contribution rights. The Company will also reimburse JonesTrading for certain specified expenses in connection with entering into the Sales Agreement. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The foregoing description of the Sales Agreement is not complete and is qualified in its entirety by reference to the full text of such agreement, a copy of
which is filed herewith as Exhibit 10.1 to this Current Report on <FONT STYLE="white-space:nowrap">Form&nbsp;8-K&nbsp;and</FONT> is incorporated herein by reference. The Company previously filed the Sales Agreement as Exhibit 10.1 to its Current
Report on Form <FONT STYLE="white-space:nowrap">8-K</FONT> filed with the SEC on January&nbsp;11, 2017. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Cooley LLP, counsel to the Company, has issued a
legal opinion relating to the Additional Shares. A copy of such legal opinion, including the consent included therein, is attached as Exhibit 5.1 hereto. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The Additional Shares will be sold pursuant to the Registration Statement, and offerings of the Additional Shares will be made only by means of the Prospectus
Supplement and any accompanying prospectus. This Current Report on Form <FONT STYLE="white-space:nowrap">8-K</FONT> shall not constitute an offer to sell or solicitation of an offer to buy these securities, nor shall there be any sale of these
securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities law of such state or jurisdiction. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Item&nbsp;8.01. Other Events. </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">As of August&nbsp;21,
2017, the Company had sold 2,653,440 shares under the Original Agreement for an aggregate offering price of $6.5&nbsp;million, before deducting sales commissions and offering expenses. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Item&nbsp;9.01. Financial Statements and Exhibits. </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(d)
Exhibits. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:28.45pt; font-size:8pt; font-family:Times New Roman"><B>Exhibit<BR>Number</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:39.50pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Description</B></P></TD></TR>


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<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;5.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Opinion of Cooley LLP.</TD></TR>
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<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top" NOWRAP>10.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Amendment No.&nbsp;1 to Capital on Demand<SUP STYLE="font-size:85%; vertical-align:top">TM</SUP>&nbsp;Sales Agreement, dated August&nbsp;21, 2017, by and between ARCA biopharma, Inc. and JonesTrading Institutional Services
LLC.</TD></TR>
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<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>23.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Consent of Cooley LLP (included in Exhibit 5.1).</TD></TR>
</TABLE>

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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>SIGNATURES </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned
hereunto duly authorized. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Dated: August&nbsp;21, 2017 </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><DIV ALIGN="right">
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<TD VALIGN="top" COLSPAN="5"><B>ARCA biopharma, Inc.</B></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="5">(Registrant)</TD></TR>
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<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="4"></TD></TR>
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<TD VALIGN="top">By:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" COLSPAN="3"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Brian L. Selby</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">Name:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">Brian L. Selby</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">Title:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Vice President, Finance and</P> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Chief Accounting
Officer</P></TD></TR>
</TABLE></DIV>

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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INDEX TO EXHIBITS </B></P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD WIDTH="92%"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:28.45pt; font-size:8pt; font-family:Times New Roman"><B>Exhibit<BR>Number</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:39.50pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Description</B></P></TD></TR>


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<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;5.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Opinion of Cooley LLP.</TD></TR>
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<TD VALIGN="top" NOWRAP>10.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Amendment No.&nbsp;1 to Capital on Demand<SUP STYLE="font-size:85%; vertical-align:top">TM</SUP>&nbsp;Sales Agreement, dated August&nbsp;21, 2017, by and between ARCA biopharma, Inc. and JonesTrading Institutional Services
LLC.</TD></TR>
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<TD VALIGN="top" NOWRAP>23.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Consent of Cooley LLP (included in Exhibit 5.1).</TD></TR>
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<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>d639616dex51.htm
<DESCRIPTION>EX-5.1
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Exhibit 5.1 </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="margin-top:0pt;margin-bottom:0pt; margin-left:1%;margin-right:1%">


<IMG SRC="g639616g0819071515241.jpg" ALT="LOGO">
 </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Matthew P. Dubofsky </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">+1 720
566 4244 </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">mdubofsky@cooley.com </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">August&nbsp;21, 2017 </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">ARCA biopharma, Inc. </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">11080 CirclePoint Road, Suite 140 </P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Westminster, CO 80020 </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Ladies and Gentlemen: </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">We have acted as counsel to ARCA biopharma, Inc., a Delaware corporation (the &#147;<B>Company</B>&#148;), and you have requested our opinion with respect to
certain matters in connection with the offering by the Company of the number of authorized but unissued shares having aggregate sale proceeds of up to $3,568,486 (the &#147;<B>Shares</B>&#148;) of the Company&#146;s common stock, par value $0.001
(the &#147;<B>Common Stock</B>&#148;), to be issued pursuant to the Registration Statement on Form <FONT STYLE="white-space:nowrap">S-3</FONT> (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-217459)</FONT> originally filed with the Securities
and Exchange Commission (the &#147;<B>Commission</B>&#148;) under the Securities Act of 1933, as amended (the &#147;<B>Act</B>&#148;), on May&nbsp;10, 2017 and declared effective by the Commission on May&nbsp;12, 2017, (the &#147;<B>Registration
Statement</B>&#148;), the related prospectus dated May&nbsp;10, 2017, included in the Registration Statement (the &#147;<B>Base Prospectus</B>&#148;), and the prospectus supplement to be filed with the Commission pursuant to Rule 424(b) of the rules
and regulations of the Act (the &#147;<B>Prospectus Supplement</B>&#148;). The Base Prospectus and the Prospectus Supplement are collectively referred to as the &#147;<B>Prospectus.</B>&#148; The Shares are to be sold by the Company in accordance
with the Capital on Demand&#153;<B> </B>Sales Agreement, dated January&nbsp;11, 2017 and as amended August&nbsp;21, 2017, by and between the Company and JonesTrading Institutional Services LLC (the &#147;<B>Agreement</B>&#148;), as described in the
Prospectus Supplement. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">In connection with this opinion, we have examined and relied upon the Registration Statement, the Prospectus, the Agreement, the
Company&#146;s Amended and Restated Certificate of Incorporation, as amended, and Second Amended and Restated Bylaws, as amended, each as currently in effect, and originals or copies certified to our satisfaction of such records, documents,
certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have
not sought independently to verify such matters. We have assumed the genuineness and authenticity of all signatures on original documents; the authenticity of all documents submitted to us as originals; the conformity to originals of all documents
submitted to us as copies thereof; and the accuracy, completeness and authenticity of certificates of public officials. Further, we have assumed that, upon the issuance of any of the Shares, the total number of shares of Common Stock issued and
outstanding and committed to be issued will not exceed the total number of shares of Common Stock that the Company is then authorized to issue under its Amended and Restated Certificate of Incorporation, as it is then in effect and that the proceeds
from the sale of each of the Shares will be equal to at least its par value and that the Company&#146;s Board of Directors or a duly authorized committee thereof has approved the specific issuance of the Shares. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Our opinion is limited to the matters stated herein, and no opinion is implied or may be inferred beyond the matters expressly stated. Our opinion herein is
expressed solely with respect to the General Corporation Law of the State of Delaware. Our opinion is based on the law as in effect on the date hereof, and we disclaim any obligation to advise you of facts, circumstances, events or developments
which hereafter may be brought to our attention and which may alter, affect or modify the opinion expressed herein. We express no opinion as to whether the laws of any particular jurisdiction other than those identified above are applicable to the
subject matter hereof. </P> <P STYLE="font-size:12pt; margin-top:0pt; margin-bottom:0pt">&nbsp;</P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Cooley
LLP&nbsp;&nbsp;&nbsp;&nbsp;380 Interlocken Crescent&nbsp;&nbsp;&nbsp;&nbsp;Suite 900&nbsp;&nbsp;&nbsp;&nbsp;Broomfield, CO&nbsp;&nbsp;&nbsp;&nbsp;80021-8023 </P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">t: (720) <FONT STYLE="white-space:nowrap">566-4000</FONT> f: (720) <FONT STYLE="white-space:nowrap">566-4099</FONT> cooley.com </P>


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 </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">August 21, 2017 </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Page Two </P>
<p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P>
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares have been duly
authorized and when sold and issued against payment therefor in accordance with the terms of the Agreement, the Registration Statement and the Prospectus, will be validly issued, fully paid and nonassessable. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">We consent to the reference to our firm under the caption &#147;<B>Legal Matters</B>&#148; in the Prospectus Supplement and to the filing of this opinion as
an exhibit to a current report on Form <FONT STYLE="white-space:nowrap">8-K</FONT> of the Company and to the incorporation by reference of this opinion in the Registration Statement. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Sincerely, </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>C<SMALL>OOLEY</SMALL> LLP </B></P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top">By: <U>/s/ Matthew P. Dubofsky&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</U></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Matthew P.
Dubofsky</P></TD></TR>
</TABLE> <P STYLE="font-size:12pt; margin-top:0pt; margin-bottom:0pt">&nbsp;</P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Cooley
LLP&nbsp;&nbsp;&nbsp;&nbsp;380 Interlocken Crescent&nbsp;&nbsp;&nbsp;&nbsp;Suite 900&nbsp;&nbsp;&nbsp;&nbsp;Broomfield, CO&nbsp;&nbsp;&nbsp;&nbsp;80021-8023 </P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">t: (720) <FONT STYLE="white-space:nowrap">566-4000</FONT> f: (720) <FONT STYLE="white-space:nowrap">566-4099</FONT> cooley.com </P>

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<TYPE>EX-10.1
<SEQUENCE>3
<FILENAME>d639616dex101.htm
<DESCRIPTION>EX-10.1
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Exhibit 10.1 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B><U>AMENDMENT NO. 1 TO CAPITAL ON DEMAND&#153; SALES AGREEMENT</U> </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right">August&nbsp;21, 2017 </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">JonesTrading Institutional
Services LLC </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">757 Third Avenue, 23<SUP STYLE="font-size:85%; vertical-align:top">rd</SUP> Floor </P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">New York, NY 10017 </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Ladies and Gentlemen: </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">ARCA biopharma, Inc., a Delaware corporation (the &#147;<U>Company</U>&#148;), and JonesTrading Institutional Services LLC (the
&#147;<U>Agent</U>&#148;), are parties to that certain Capital on Demand&#153; Sales Agreement dated January&nbsp;11, 2017 (the &#147;<U>Original Agreement</U>&#148;). All capitalized terms not defined herein shall have the meanings ascribed to them
in the Original Agreement. The parties, intending to be legally bound, hereby amend the Original Agreement pursuant to the terms of this amendment No.&nbsp;1 to the Original Agreement (this &#147;<U>Amendment No.&nbsp;1</U>&#148;) as follows (to be
effective as set forth in paragraph 4 below): </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">1. The first paragraph of Section&nbsp;1 of the Original Agreement is hereby deleted in its
entirety and replaced with the following: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; text-indent:8%; font-size:10pt; font-family:Times New Roman">&#147;<U>Issuance and Sale of Shares</U>. The Company agrees that, from time to
time during the term of this Agreement, on the terms and subject to the conditions set forth herein, it may issue and sell through the Agent, shares (the &#147;<U>Placement Shares</U>&#148;) of common stock of the Company, $0.001 par value per share
(the &#147;<U>Common Stock</U>&#148;) having an aggregate offering price of up to $10,242,863, provided, however, that in no event shall the Company issue or sell through Agent such number of Placement Shares that (a)&nbsp;exceeds the number or
dollar amount of shares of Common Stock that may be sold pursuant to the Registration Statement (as defined below), or (b)&nbsp;exceeds the number of authorized but unissued shares of Common Stock of the Company (the &#147;Maximum Amount&#148;).
Pursuant to this Agreement, shares of our common stock were previously sold for $6,514,961 in aggregate gross proceeds under a separate prospectus and prospectus supplement. Under this Agreement, as amended by Amendment No.&nbsp;1 to Capital on
Demand&#153; Sales Agreement, dated August&nbsp;21, 2017, the Company, through the Agent, may offer and sell further shares of common stock having an aggregate offering price of up to $3,727,902 pursuant to the Prospectus (as defined below).
Notwithstanding anything to the contrary contained herein, the parties hereto agree that compliance with the limitations set forth in this Section&nbsp;1 on the amount of Placement Shares issued and sold under this Agreement shall be the sole
responsibility of the Company and that Agent shall have no obligation in connection with such compliance. The issuance and sale of Placement Shares through Agent will be effected pursuant to the Registration Statement (as defined below) filed by the
Company and at no earlier time than such time as the Registration Statement shall have been declared effective by the Securities and Exchange Commission (the &#147;<U>Commission</U>&#148;), although nothing in this Agreement shall be construed as
requiring the Company to use the Registration Statement to issue Placement Shares.&#148; </P>

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 <P STYLE="margin-top:0pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">2. Section&nbsp;3 of the Original Agreement is hereby deleted in its entirety and replaced with
the following: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; text-indent:4%; font-size:10pt; font-family:Times New Roman">&#147;<U>Sale of Placement Shares by Agent</U>. Subject to the provisions of <U>Section&nbsp;5(a)</U>, the
Agent, for the period specified in the Placement Notice, will use its commercially reasonable efforts consistent with its normal trading and sales practices and applicable state and federal laws, rules and regulations and the rules of The NASDAQ
Stock Market LLC. (the &#147;<U>Exchange</U>&#148;), to sell the Placement Shares up to the amount specified, and otherwise in accordance with the terms of such Placement Notice. The Agent will provide written confirmation to the Company no later
than the opening of the Trading Day (as defined below) immediately following the Trading Day on which it has made sales of Placement Shares hereunder setting forth the number of Placement Shares sold on such day, the compensation payable by the
Company to the Agent pursuant to <U>Section&nbsp;2</U> with respect to such sales, and the Net Proceeds (as defined below) payable to the Company, with an itemization of the deductions made by the Agent (as set forth in <U>Section&nbsp;5(b))</U>
from the gross proceeds that it receives from such sales. Subject to the terms of the Placement Notice, the Agent may sell Placement Shares by any method permitted by law deemed to be an &#147;at the market offering&#148; as defined in Rule
415(a)(4) of the Securities Act Regulations. Subject to the terms of a Placement Notice, the Agent may also sell Placement Shares by any other method permitted by law, including but not limited to in negotiated transactions if expressly authorized
by the Company in a Placement Notice.&#148; </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">3. Section&nbsp;8 of the Original Agreement is hereby deleted in its entirety and replaced
with the following: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; text-indent:4%; font-size:10pt; font-family:Times New Roman">&#147;<U>Payment of Expenses</U>. The Company will pay all expenses incident to the performance of its
obligations under this Agreement, including (i)&nbsp;the preparation, filing, including any fees required by the Commission, and printing of the Registration Statement including financial statements and exhibits) as originally filed and of each
amendment and supplement thereto, in such number as the Agent shall reasonably deem necessary, (ii)&nbsp;the printing and delivery to the Agent of this Agreement and such other documents as may be required in connection with the offering, purchase,
sale, issuance or delivery of the Placement Shares, (iii)&nbsp;the fees and disbursements of the counsel, accountants and other advisors to the Company, (iv)&nbsp;the reasonable and documented out-of-pocket expenses of Agent, including reasonable
and documented fees and disbursements of counsel to the Agent, (v)&nbsp;the printing and delivery to the Agent of copies of any Permitted Issuer Free Writing Prospectus (defined below) and the Prospectus and any amendments or supplements thereto in
such number as the Agent shall deem reasonably necessary, (vi)&nbsp;the preparation, printing and delivery to the Agent of copies of the blue sky survey and any Canadian &#147;wrapper&#148; and any supplements thereto, in such number as the Agent
shall deem reasonably necessary, (vii)&nbsp;the documented fees and expenses of the transfer agent and registrar for the Common Stock, (viii)&nbsp;the reasonable and documented fees and expenses incident to any review by FINRA of the terms of the
sale of the Placement Shares, including fees and expenses of counsel </P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">2 </P>


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 <P STYLE="margin-top:0pt; margin-bottom:0pt; margin-left:4%; font-size:10pt; font-family:Times New Roman">
to the Agent, and (ix)&nbsp;the documented fees and expenses incurred in connection with the listing of the Placement Shares on the Exchange. Notwithstanding the foregoing, in no event shall the
amount of expenses reimbursed to Agent hereunder exceed $45,000, further the parties hereto agree that, as of the effective date of Amendment No.&nbsp;1 to Capital on Demand&#153; Sales Agreement, the Company has reimbursed $35,000 of such expenses
to Agent.&#148; </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">4. All references to &#147;January 11, 2017&#148; set forth in Schedule I and Exhibit 7(l) of the Original Agreement are
revised to read &#147;January 11, 2017 (as amended by Amendment No.&nbsp;1 to Capital on Demand&#153; Sales Agreement, dated August&nbsp;21, 2017)&#148;. </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">5. Except as specifically set forth herein, all other provisions of the Original Agreement shall remain in full force and effect. </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">6. This Amendment No.&nbsp;1 together with the Original Agreement (including all schedules and exhibits attached hereto and thereto and
Placement Notices issued pursuant hereto and thereto) constitutes the entire agreement and supersedes all other prior and contemporaneous agreements and undertakings, both written and oral, among the parties hereto with regard to the subject matter
hereof. All references in the Original Agreement to the &#147;Agreement&#148; shall mean the Original Agreement as amended by this Amendment No.&nbsp;1; <I>provided, however</I>, that all references to &#147;date of this Agreement&#148; in the
Original Agreement shall continue to refer to the date of the Original Agreement. </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">7. This Amendment shall be governed by, and construed in
accordance with, the internal laws of the State of New York without regard to the principles of conflicts of laws. Each party hereby irrevocably submits to the non-exclusive jurisdiction of the state and federal courts sitting in the City of New
York, borough of Manhattan, for the adjudication of any dispute hereunder or in connection with any transaction contemplated hereby, and hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not
personally subject to the jurisdiction of any such court, that such suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit, action or proceeding is improper. Each party hereby irrevocably waives personal
service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof (certified or registered mail, return receipt requested) to such party at the address in effect for notices to it under this
Amendment and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">8. The Company and the Agent each hereby irrevocably waives any right it may have to a trial by jury in respect of any claim based upon or
arising out of this amendment or any transaction contemplated hereby. </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">9. This Amendment may be executed in two or more counterparts, each
of which shall be deemed an original, but all of which together shall constitute one and the same instrument. Delivery of an executed amendment by one party to the other may be made by facsimile transmission. </P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">3 </P>


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 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">4 </P>


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 <P STYLE="margin-top:0pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">If the foregoing correctly sets forth the understanding among the Company and the Agent, please
so indicate in the space provided below for that purpose, whereupon this letter shall constitute a binding amendment to the Agreement between the Company and the Agent. </P>
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<TD VALIGN="top" COLSPAN="3">Very truly yours,</TD></TR>
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<TD VALIGN="top" COLSPAN="3"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>JONESTRADING INSTITUTIONAL</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman"><B>SERVICES LLC</B></P></TD></TR>
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<TD VALIGN="top">By:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Trent McNair</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3">Name: Trent McNair</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3">Title: CFO</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16" COLSPAN="3"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>ACCEPTED as of the date</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman"><B>first-above written:</B></P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16" COLSPAN="3"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3"><B>ARCA BIOPHARMA, INC.</B></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top">By:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Brian&nbsp;L. Selby</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3">Name: Brian&nbsp;L. Selby</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3">Title: Vice President, Finance</TD></TR>
</TABLE></DIV>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">[<I>Signature Page to
Amendment No. 1</I>] </P>

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