<SEC-DOCUMENT>0001104659-20-069457.txt : 20200603
<SEC-HEADER>0001104659-20-069457.hdr.sgml : 20200603
<ACCEPTANCE-DATETIME>20200603163050
ACCESSION NUMBER:		0001104659-20-069457
CONFORMED SUBMISSION TYPE:	DEFA14A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20200603
DATE AS OF CHANGE:		20200603
EFFECTIVENESS DATE:		20200603

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SELLAS Life Sciences Group, Inc.
		CENTRAL INDEX KEY:			0001390478
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		DEFA14A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33958
		FILM NUMBER:		20940423

	BUSINESS ADDRESS:	
		STREET 1:		15 WEST 38TH STREET
		STREET 2:		10TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10018
		BUSINESS PHONE:		(917) 438-4353

	MAIL ADDRESS:	
		STREET 1:		15 WEST 38TH STREET
		STREET 2:		10TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10018

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Galena Biopharma, Inc.
		DATE OF NAME CHANGE:	20110926

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RXi Pharmaceuticals Corp
		DATE OF NAME CHANGE:	20110926

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	GALENA BIOPHARMA, INC.
		DATE OF NAME CHANGE:	20110922
</SEC-HEADER>
<DOCUMENT>
<TYPE>DEFA14A
<SEQUENCE>1
<FILENAME>tm2021708d1_defa14a.htm
<DESCRIPTION>DEFA14A
<TEXT>
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<P STYLE="margin: 0"></P>

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="margin: 0"></P>

<!-- Field: Rule-Page --><DIV ALIGN="LEFT" STYLE="margin-top: 0pt; margin-bottom: 0pt"><DIV STYLE="border-top: Black 2pt solid; border-bottom: Black 1pt solid; font-size: 1pt; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>UNITED STATES</B></P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>Washington, D.C. 20549</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: center; margin-top: 0pt; margin-bottom: 0pt">&nbsp;</P>

<!-- Field: Rule-Page --><DIV STYLE="text-align: center; margin-top: 1pt; margin-bottom: 1pt"><DIV STYLE="border-top: black 1pt solid; text-align: center; font-size: 1pt; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>SCHEDULE 14A</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>Proxy Statement Pursuant to Section&nbsp;14(a)</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>of the Securities Exchange Act of 1934</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center"><B>&nbsp;</B></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Times New Roman, Times, Serif">Filed
by the Registrant&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings">x</FONT><FONT STYLE="font-family: Times New Roman, Times, Serif">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Filed by a Party other than the Registrant&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings">&uml;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 6pt 0 0pt">Check the appropriate box:</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt; width: 0.25in"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Preliminary Proxy Statement</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&#168;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Definitive Proxy Statement</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&#120;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Definitive Additional Materials</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Soliciting Material Pursuant to &sect;&nbsp;240.14a-12</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-size: 22pt"><B>SELLAS
LIFE SCIENCES GROUP, INC.</B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Name of Registrant as Specified In Its
Charter)</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Name of Person(s) Filing Proxy Statement
if Other Than the Registrant)</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Payment of Filing Fee (Check the appropriate box)</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt; width: 0.25in"><FONT STYLE="font: 10pt Wingdings">x</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">No fee required.</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR>
    <TD STYLE="padding-top: 6pt; width: 0.25in">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; width: 0.25in; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(1)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Title of each class of securities to which transaction applies:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(2)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Aggregate number of securities to which transaction applies:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(3)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Per unit price or other underlying value of transaction computed
        pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the filing fee is calculated and state how it was determined):</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(4)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Proposed maximum aggregate value of transaction:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(5)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Total fee paid:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; width: 0.25in; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Fee paid previously with preliminary materials.</FONT></TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt; vertical-align: top; font-size: 10pt"><FONT STYLE="font: 10pt Wingdings">&uml;</FONT></TD>
    <TD STYLE="padding-top: 6pt; vertical-align: bottom; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR>
    <TD STYLE="padding-top: 6pt; width: 0.25in">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; width: 0.25in; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(1)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Amount Previously Paid:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(2)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Form, Schedule or Registration Statement No.:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(3)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Filing Party:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
<TR>
    <TD STYLE="padding-top: 6pt">&nbsp;</TD>
    <TD STYLE="padding-top: 6pt; text-align: left; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(4)</FONT></TD>
    <TD STYLE="border-bottom: Black 1pt solid; padding-top: 6pt; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Date Filed:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>
</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>



<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<P STYLE="text-align: center; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center; background-color: white"><B>SUPPLEMENT TO<BR>
NOTICE OF ANNUAL MEETING OF STOCKHOLDERS<BR>
AND PROXY STATEMENT, DATED APRIL&nbsp;22, 2020<BR>
FOR THE VIRTUAL ANNUAL MEETING OF STOCKHOLDERS<BR>
TO BE HELD ON JUNE 9, 2020</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>&nbsp;</B></P>

<P STYLE="text-align: justify; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This
supplement (the&nbsp;&ldquo;Supplement&rdquo;) provides updated information with respect to the 2020 Annual Meeting of Stockholders
(the&nbsp;&ldquo;Annual Meeting&rdquo;) of SELLAS Life Sciences Group,&nbsp;Inc. (&ldquo;SELLAS&rdquo;) to be held on June 9,&nbsp;2020.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;</P>

<P STYLE="text-align: justify; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;On
April&nbsp;22, 2020, SELLAS commenced distributing to its stockholders a Notice of the 2020 Annual Meeting of Stockholders and
Definitive Proxy Statement (the&nbsp;&ldquo;Notice and Proxy Statement&rdquo;) for the Annual Meeting. This Supplement, including
the press release dated May&nbsp;22, 2020 included below which describes a change in the location of the Annual Meeting from an
in-person to a virtual-only meeting, should be read in conjunction with the Notice and Proxy Statement. Except as specifically
revised by the information contained herein, this Supplement does not revise or update any of the other information set forth in
the Notice and Proxy Statement.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; background-color: white; text-indent: 0.25in"></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SELLAS to Host Virtual Annual Meeting
of Stockholders</B></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">NEW YORK, May 22, 2020 -- SELLAS Life Sciences
Group, Inc. (Nasdaq: SLS) (&ldquo;SELLAS&rdquo; or the &ldquo;Company&rdquo;), a late-stage clinical biopharmaceutical company
focused on the development of novel cancer immunotherapies for a broad range of cancer indications, today announced that it will
hold its 2020 Annual Meeting of Stockholders (the &ldquo;Annual Meeting&rdquo;) virtually due to the public health impact of the
coronavirus (COVID-19) pandemic and to prioritize the health and well-being of meeting participants.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">The Annual Meeting will be held in a virtual-only
format on Tuesday, June 9, 2020, at 8:30 a.m., Eastern Time. The date and time of the Annual Meeting, as disclosed in the previously
distributed Notice of the Annual Meeting and Definitive Proxy Statement (the &ldquo;Notice and Proxy Statement&rdquo;), has not changed.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Stockholders of record and registered beneficial
owners as of the close of business on April 13, 2020 will be able to vote and ask questions during the meeting through the online
platform. Online access to the Annual Meeting will begin at 8:15 a.m. Eastern Time. Stockholders will not be able to attend the
Annual Meeting in person.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">SELLAS encourages stockholders to vote
and submit their proxies in advance of the Annual Meeting by one of the methods described in the proxy materials for the Annual
Meeting.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Attending the Virtual Annual Meeting</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Stockholders of record as of April 13,
2020 can attend the meeting by accessing www.meetingcenter.io/257687071 and entering the 15-digit control number found on their
proxy card, voting instruction form, notice of internet availability of proxy materials, or email previously received. Stockholders
may vote during the Annual Meeting by following the instructions available on the meeting website during the meeting.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Participating, Voting Electronically
and Submitting Questions at the Virtual Annual Meeting</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><I>Stockholders of Record</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Stockholders of record will be able to
participate in the Annual Meeting, vote electronically and submit questions during the live webcast of the meeting, without advance
registration. The two items of information needed to access the live webcast of the meeting are the following:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">The 15-digit control number found on the
proxy card, voting instruction form, notice of internet availability of proxy materials, or email previously received</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Meeting password: <I>SLS2020</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><I>Beneficial Owners</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Beneficial stockholders as of April 13,
2020 who hold shares through an intermediary, such as a bank, broker or nominee, and who want to attend the Annual Meeting, must
register in advance to participate in the Annual Meeting, vote electronically and submit questions during the live webcast of the
meeting. To register in advance, beneficial stockholders must obtain a legal proxy from the bank, broker or other nominee that
holds their shares giving them the right to vote the shares and must forward a copy of the legal proxy along with their email address
to Computershare Trust Company, N.A. (&ldquo;Computershare&rdquo;).</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Requests for registration should be directed
to Computershare by email at legalproxy@computershare.com no later than <I>5:00 p.m. Eastern Time, on June 4, 2020</I>. Stockholders
will receive a confirmation of their registration and instructions on how to attend the meeting by email after Computershare receives
registration materials.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Questions</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Stockholders may submit questions in advance
of the Annual Meeting by emailing the question, along with proof of ownership, to questions2020@sellaslife.com prior to 8:30 a.m.
Eastern Time on June 8, 2020. Stockholders may also submit questions during the Annual Meeting through the online platform in accordance
with the instructions above. The Company will, subject to time constraints, answer all questions that are pertinent to the business
of the Annual Meeting and will give priority to questions submitted in advance.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">The proxy materials, including the proxy
card and Notice of Internet Availability of Proxy Materials, previously distributed along with the Notice and Proxy Statement,
will not be updated to reflect the change in location and may continue to be used to vote shares in connection with the Annual
Meeting.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>About SELLAS Life Sciences Group, Inc.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">SELLAS is a late-stage clinical biopharmaceutical
company focused on the development of novel cancer immunotherapeutics for a broad range of cancer indications. SELLAS&rsquo; lead
product candidate, galinpepimut-S (GPS), is licensed from Memorial Sloan Kettering Cancer Center and targets the Wilms Tumor 1
(WT1) protein, which is present in an array of tumor types. GPS has potential as a monotherapy or in combination to address a broad
spectrum of hematologic malignancies and solid tumor indications. SELLAS&rsquo; second product candidate, nelipepimut-S (NPS),
is a HER2-directed cancer immunotherapy with potential for the treatment of patients with early stage breast cancer with low to
intermediate HER2 expression, otherwise known as HER2 1+ or 2+, which includes triple negative breast cancer patients, following
standard of care. For more information on SELLAS, please visit&nbsp;www.sellaslifesciences.com.</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Investor Contacts</B><BR>
Adam Holdsworth<BR>
PCG Advisory<BR>
646-862-4607<BR>
<U>adamh@pcgadvisory.com</U></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><BR>
SELLAS Life Sciences Group, Inc.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Investor Relations<BR>
917-438-4353<BR>
<U>info@sellaslife.com</U></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Source: SELLAS Life Sciences Group</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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