<SEC-DOCUMENT>0001104659-22-022787.txt : 20220214
<SEC-HEADER>0001104659-22-022787.hdr.sgml : 20220214
<ACCEPTANCE-DATETIME>20220214161150
ACCESSION NUMBER:		0001104659-22-022787
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20220214
DATE AS OF CHANGE:		20220214
GROUP MEMBERS:		PETER KOLCHINSKY
GROUP MEMBERS:		RAJEEV SHAH

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Silverback Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001671858
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				811489190
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-91894
		FILM NUMBER:		22631917

	BUSINESS ADDRESS:	
		STREET 1:		500 FAIRVIEW AVENUE NORTH, SUITE 600
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98109
		BUSINESS PHONE:		206-456-2900

	MAIL ADDRESS:	
		STREET 1:		500 FAIRVIEW AVENUE NORTH, SUITE 600
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98109

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RA CAPITAL MANAGEMENT, L.P.
		CENTRAL INDEX KEY:			0001346824
		IRS NUMBER:				830406777
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-778-2500

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RA CAPITAL MANAGEMENT, LLC
		DATE OF NAME CHANGE:	20051213
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>tm225316d7_sc13ga.htm
<DESCRIPTION>SILVERBACK THERAPEUTICS, INC
<TEXT>
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<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; text-align: center"><B>UNITED STATES</B>&nbsp;</P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SCHEDULE 13G/A</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>Under the Securities Exchange Act of 1934</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Amendment No.&nbsp; 1)*</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">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Silverback Therapeutics, Inc.</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(Name of Issuer)</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: center">Common Stock, par value $0.0001 per share</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center">(Title of Class&nbsp;of Securities)</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: center">82835W108</P>

<!-- Field: Rule-Page --><DIV STYLE="margin-left: auto; margin-right: auto; width: 40%"><DIV STYLE="border-top: Black 1pt solid; font-size: 1pt">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(CUSIP Number)</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: center">December 31, 2021</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(Date of Event Which Requires Filing of this Statement)</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-top: 0; margin-bottom: 0; margin-left: 0in; text-indent: 0in">Check the appropriate
box to designate the rule&nbsp;pursuant to which this Schedule is filed:</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0; width: 100%"><TR STYLE="vertical-align: top; text-align: justify">
    <TD STYLE="width: 0.5in">&nbsp;</TD>
<TD STYLE="width: 0.5in; text-align: left"><FONT STYLE="font-family: Wingdings">&#120;</FONT></TD><TD STYLE="text-align: justify">Rule&nbsp;13d-1(b)</TD>
</TR>
<TR STYLE="vertical-align: top; text-align: justify">
    <TD>&nbsp;</TD>
<TD STYLE="text-align: left"><FONT STYLE="font-family: Wingdings">&#168;</FONT></TD><TD STYLE="text-align: justify">Rule&nbsp;13d-1(c)</TD>
</TR>
<TR STYLE="vertical-align: top; text-align: justify">
    <TD>&nbsp;</TD>
<TD STYLE="text-align: left"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&#168;</FONT></TD><TD STYLE="text-align: justify">Rule&nbsp;13d-1(d)</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-top: 0; margin-bottom: 0; margin-left: 0in; text-indent: 0in">*The remainder
of this cover page&nbsp;shall be filled out for a reporting person&rsquo;s initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.</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-top: 0; margin-bottom: 0; margin-left: 0in; text-indent: 0in">The information
required in the remainder of this cover page&nbsp;shall not be deemed to be &ldquo;filed&rdquo; for the purpose of Section&nbsp;18 of
the Securities Exchange Act of 1934 (&ldquo;Act&rdquo;) or otherwise subject to the liabilities of that section of the Act but shall
be subject to all other provisions of the Act (however, see the Notes).</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">&nbsp;</P>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CUSIP No.&nbsp;82835W108</P>

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse"><TR STYLE="vertical-align: top"><TD STYLE="padding: 3pt; vertical-align: top; border: black 1pt solid; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>1</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">NAMES OF REPORTING PERSONS</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)</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">RA Capital Management, L.P.</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>2</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)</P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">
        (a)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">(b)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>3</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; background-color: #F2F2F2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SEC USE ONLY</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">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>4</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CITIZENSHIP OR PLACE OF ORGANIZATION</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">Delaware</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"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD ROWSPAN="4" STYLE="text-align: center; padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; width: 20%; vertical-align: middle">
        <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">NUMBER OF</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARES</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">BENEFICIALLY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">OWNED BY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">EACH</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">REPORTING</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">PERSON</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">WITH:</P></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>5</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 70%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE VOTING POWER</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">0</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>6</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED VOTING POWER</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">1,742,186</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>7</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE DISPOSITIVE POWER</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">0</P>
        <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></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>8</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED DISPOSITIVE POWER</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">1,742,186</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>9</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON</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">1,742,186</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; padding: 3pt; text-align: center; font-size: 10pt; vertical-align: top"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>10</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Times New Roman, Times, Serif">CHECK
        BOX IF THE AGGREGATE AMOUNT IN ROW (9)&nbsp;EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)</FONT></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"><FONT STYLE="font-family: Wingdings">&#168;</FONT></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>11</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">PERCENT OF CLASS&nbsp;REPRESENTED BY AMOUNT IN ROW 9</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">4.97%</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>12</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)</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">IA, PN</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">CUSIP No.&nbsp;82835W108</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"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>1</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">NAMES OF REPORTING PERSONS</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)</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">Peter Kolchinsky</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>2</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)</P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">
        (a)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">(b)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>3</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; background-color: #F2F2F2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SEC USE ONLY</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">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>4</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CITIZENSHIP OR PLACE OF ORGANIZATION</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">United States of America</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD ROWSPAN="4" STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; width: 20%">
        <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; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">NUMBER OF</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">SHARES</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">BENEFICIALLY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">OWNED BY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">EACH</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">REPORTING</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">PERSON</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">WITH:</P></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>5</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 70%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE VOTING POWER</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">0</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>6</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED VOTING POWER</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">1,742,186</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>7</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE DISPOSITIVE POWER</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">0</P>
        <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></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>8</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED DISPOSITIVE POWER</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">1,742,186</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; padding: 3pt; vertical-align: top; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>9</B></FONT></TD>
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; padding: 3pt; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON</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">1,742,186</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; padding: 3pt; text-align: center; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>10</B></FONT></TD>
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; padding: 3pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Times New Roman, Times, Serif">CHECK
        BOX IF THE AGGREGATE AMOUNT IN ROW (9)&nbsp;EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)</FONT></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"><FONT STYLE="font-family: Wingdings">&#168;</FONT></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; padding: 3pt; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>11</B></FONT></TD>
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; padding: 3pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">PERCENT OF CLASS&nbsp;REPRESENTED BY AMOUNT IN ROW 9</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">4.97%</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; padding: 3pt; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>12</B></FONT></TD>
    <TD STYLE="border-right: black 1pt solid; border-bottom: black 1pt solid; padding: 3pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)</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">HC, IN</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>

<!-- Field: Page; Sequence: 3 -->
    <DIV STYLE="margin-top: 12pt; margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt; margin-bottom: 12pt"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

<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">CUSIP No.&nbsp;82835W108</P>

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse"><TR STYLE="vertical-align: top"><TD STYLE="padding: 3pt; border: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>1</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">NAMES OF REPORTING PERSONS</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)</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">Rajeev Shah</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>2</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)</P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">
        (a)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="text-align: right; font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 5.5in; text-indent: 18.15pt"><FONT STYLE="font-family: Times New Roman, Times, Serif">(b)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><FONT STYLE="font-family: Wingdings"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>3</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-top: black 1pt solid; border-right: black 1pt solid; border-bottom: black 1pt solid; background-color: #F2F2F2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SEC USE ONLY</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">&nbsp;</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>4</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">CITIZENSHIP OR PLACE OF ORGANIZATION</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">United States of America</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD ROWSPAN="4" STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; width: 20%">
        <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; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">NUMBER OF</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">SHARES</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">BENEFICIALLY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">OWNED BY</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">EACH</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">REPORTING</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">PERSON</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">WITH:</P></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>5</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 70%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE VOTING POWER</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">0</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>6</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED VOTING POWER</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">1,742,186</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>7</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SOLE DISPOSITIVE POWER</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">0</P>
        <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></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>8</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">SHARED DISPOSITIVE POWER</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">1,742,186</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 0pt">&nbsp;</FONT></P>

<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 STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt; width: 10%"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>9</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; width: 90%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON</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">1,742,186</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; text-align: center; font-size: 10pt; vertical-align: top"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>10</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Times New Roman, Times, Serif">CHECK
        BOX IF THE AGGREGATE AMOUNT IN ROW (9)&nbsp;EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)</FONT></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"><FONT STYLE="font-family: Wingdings">&#168;</FONT></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>11</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">PERCENT OF CLASS&nbsp;REPRESENTED BY AMOUNT IN ROW 9</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">4.97%</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid; border-left: black 1pt solid; vertical-align: top; text-align: center; font-size: 10pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif"><B>12</B></FONT></TD>
    <TD STYLE="padding: 3pt; border-right: black 1pt solid; border-bottom: black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)</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">HC, IN</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>

<!-- Field: Page; Sequence: 4 -->
    <DIV STYLE="margin-top: 12pt; margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt; margin-bottom: 12pt"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top; text-align: justify">
<TD STYLE="width: 0.75in; text-align: left"><B>Item 1(a).</B></TD><TD STYLE="text-align: justify"><B><U>Name of Issuer</U>:</B></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; text-indent: 0.75in">Silverback Therapeutics,&nbsp;Inc. (the &ldquo;Issuer&rdquo;)</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;1(b).</B></FONT></TD><TD><B><U>Address of Issuer&rsquo;s Principal Executive Offices</U>:</B></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 0pt 0.75in">500 Fairview Ave N, Suite&nbsp;600, Seattle, WA 98109</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;2(a).</B></FONT></TD><TD><B><U>Names of Persons Filing</U>:</B></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 0pt 0.75in">The names of the persons filing this report (collectively,
the &ldquo;Reporting Persons&rdquo;) are:</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 0pt 0.75in">RA Capital Management, L.P. (&ldquo;RA Capital&rdquo;)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.75in">Peter Kolchinsky</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.75in">Rajeev Shah</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;2(b).</B></FONT></TD><TD><B><U>Address of Principal Business Office or, if None, Residence</U>:</B></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 0pt 0.75in">The address of the principal business office of each of
the Reporting Persons is:</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 0pt 0.75in">c/o RA Capital Management, L.P., 200 Berkeley Street, 18<SUP>th</SUP>
Floor, Boston MA 02116</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;2(c).</B></FONT></TD><TD><B><U>Citizenship</U>:</B></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 0pt 0.75in">RA Capital is a Delaware limited partnership. Dr.&nbsp;Kolchinsky
and Mr.&nbsp;Shah are United States citizens.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;2(d).</B></FONT></TD><TD><B><U>Title of Class&nbsp;of Securities</U>:</B></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 0pt 2in; text-indent: -1.25in">Common stock, par value $0.0001 per
share (&ldquo;Common Stock&rdquo;)</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;2(e).</B></FONT></TD><TD><B><U>CUSIP Number</U>:</B></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 0pt 0.25in; text-indent: 0.5in">82835W108</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;3.</B></FONT></TD><TD><B><U>If this statement is filed pursuant to &sect;&sect; 240.13d-1(b)&nbsp;or 240.13d-2(b)&nbsp;or (c), check <B><U>whether the person filing is
a:</U></B></U></B></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 0pt 0.75in">(e)&nbsp;RA Capital Management, L.P. is a registered investment
adviser and is filing this statement in accordance with &sect;240.13d-1(b)(1)(ii)(E);</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 0pt 0.75in">(g)&nbsp;Peter Kolchinsky and Rajeev Shah are control persons
and are filing this statement in accordance with &sect;240.13d-1(b)(1)(ii)(G).</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"></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">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;4.</B></FONT></TD><TD><B><U>Ownership</U>.</B></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 0pt 0.75in">The information required by this item with respect to each
Reporting Person is set forth in Rows 5 through 9 and 11 of the cover pages&nbsp;to this Schedule 13G.&nbsp;&nbsp;The ownership percentages reported
are based on 35,076,083 outstanding Common Stock, as reported in the Issuer&rsquo;s Form&nbsp;10-Q filed with the SEC on November&nbsp;10,
2021.</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 0pt 0.75in">RA Capital Healthcare Fund, L.P. (the &ldquo;Fund&rdquo;)
directly holds 1,500,977 shares of Common Stock. RA Capital Nexus Fund, L.P. (the &ldquo;Nexus Fund&rdquo;) holds 241,209 shares of Common
Stock.</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 0pt 0.75in">RA Capital Healthcare Fund GP, LLC is the general partner
of the Fund and RA Capital Nexus Fund GP, LLC is the general partner of the Nexus Fund.&nbsp;&nbsp;The general partner of RA Capital is RA Capital
Management GP, LLC, of which Dr.&nbsp;Kolchinsky and Mr.&nbsp;Shah are the controlling persons. RA Capital serves as investment adviser
for the Fund and the Nexus Fund and may be deemed a beneficial owner, for purposes of Section&nbsp;13(d)&nbsp;of the Securities Exchange
Act of 1934 (the &ldquo;Act&rdquo;), of any securities of the Issuer held by the Fund or the Nexus Fund.&nbsp;&nbsp;The Fund and the Nexus Fund have
delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in the Fund&rsquo;s and the Nexus
Fund&rsquo;s portfolio, including the shares of the Issuer&rsquo;s Common Stock reported herein.&nbsp; Because the Fund and the Nexus
Fund have divested themselves of voting and investment power over the reported securities they hold and may not revoke that delegation
on less than 61 days&rsquo; notice, the Fund and the Nexus Fund&nbsp;disclaim beneficial ownership of the securities they hold for purposes
of Section&nbsp;13(d)&nbsp;of the Act and therefore disclaim any obligation to report ownership of the reported securities under Section&nbsp;13(d)&nbsp;of
the Act.&nbsp;&nbsp;As managers of RA Capital, Dr.&nbsp;Kolchinsky and Mr.&nbsp;Shah may be deemed beneficial owners, for purposes of Section&nbsp;13(d)&nbsp;of
the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr.&nbsp;Kolchinsky, and Mr.&nbsp;Shah disclaim
beneficial ownership of the securities reported in this Schedule 13D Statement (the &ldquo;Statement&rdquo;) other than for the purpose
of determining their obligations under Section&nbsp;13(d)&nbsp;of the Act, and the filing of the Statement shall not be deemed an admission
that either RA Capital, Dr.&nbsp;Kolchinsky, or Mr.&nbsp;Shah is the beneficial owner of such securities for any other purpose.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;5.</B></FONT></TD><TD><B><U>Ownership of Five Percent or Less of a Class</U>.</B></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 0pt 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">If
this statement is being filed to report the fact that as of the date hereof the Reporting Persons have ceased to be the beneficial owner
of more than five percent of the class of securities, check the following </FONT><FONT STYLE="font-family: Wingdings">x</FONT>.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;6.</B></FONT></TD><TD><B><U>Ownership of More than Five Percent on Behalf of Another Person</U>.</B></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; text-indent: 0.75in">Not applicable.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;7.</B></FONT></TD><TD><B><U>Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company
or Control Person</U>.</B></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; text-indent: 0.75in">Not applicable.</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"></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">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;8.</B></FONT></TD><TD><B><U>Identification and Classification of Members of the Group</U>.</B></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; text-indent: 0.75in">Not applicable.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;9.</B></FONT></TD><TD><B><U>Notice of Dissolution of Group</U>.</B></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; text-indent: 0.75in">Not applicable.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.75in"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Item&nbsp;10.</B></FONT></TD><TD><B><U>Certification</U>.</B></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 0pt 0.75in">By signing below I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are
not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired
and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely
in connection with a nomination under &sect; 240.14a-11.</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"><B><U>Exhibit&nbsp;List</U></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">Exhibit&nbsp;1: Joint filing agreement</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"></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; text-align: center"><U>SIGNATURE</U></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-indent: 0.5in">After reasonable inquiry and to the best of its
knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="border-collapse: collapse; width: 100%">
<TR STYLE="vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">Date: February 14, 2022</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">RA CAPITAL MANAGEMENT, L.P.</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">By: </FONT></TD>
    <TD COLSPAN="2" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 4%">&nbsp;</TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 5%"><FONT STYLE="font-size: 10pt">Name: </FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 41%"><FONT STYLE="font-size: 10pt">Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt; width: 50%"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif">&nbsp;</TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">Title: </FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">Authorized Signatory</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">PETER KOLCHINSKY</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">RAJEEV SHAH</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Rajeev Shah</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></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; text-align: right"><B>EXHIBIT&nbsp;1</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: center">AGREEMENT</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">This Joint Filing Agreement, dated as of February&nbsp;14, 2022, is
by and among RA Capital Management, L.P., Peter Kolchinsky, and Rajeev Shah (the foregoing are collectively referred to herein as the
 &ldquo;Filers&rdquo;).</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">Each of the Filers may be required to file with the United States Securities
and Exchange Commission a statement on Schedule 13G and/or 13D with respect to Common Stock, par value $0.0001 per share of Silverback
Therapeutics,&nbsp;Inc. beneficially owned by them from time to time.</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">Pursuant to and in accordance with Rule&nbsp;13(d)(1)(k)&nbsp;promulgated
under the Securities Exchange Act of 1934, as amended, the Filers hereby agree to file a single statement on Schedule 13G and/or 13D (and
any amendments thereto) on behalf of each of such parties, and hereby further agree to file this Joint Filing Agreement as an exhibit
to such statement, as required by such rule.</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">This Joint Filing Agreement may be terminated by any of the Filers
upon one week&rsquo;s prior written notice or such lesser period of notice as the Filers may mutually agree.</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">Executed and delivered as of the date first above written.</P>

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

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="border-collapse: collapse; width: 100%">
<TR STYLE="vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">RA CAPITAL MANAGEMENT, L.P.</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">By:</FONT></TD>
    <TD COLSPAN="2" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 4%"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 5%"><FONT STYLE="font-size: 10pt">Name:</FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif; width: 41%"><FONT STYLE="font-size: 10pt">Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt; width: 50%"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">Title:</FONT></TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">Authorized Signatory</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">PETER KOLCHINSKY</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Peter Kolchinsky</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">RAJEEV SHAH</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD COLSPAN="3" STYLE="border-bottom: Black 1pt solid; font: 10pt Times New Roman, Times, Serif"><FONT STYLE="font-size: 10pt">/s/ Rajeev Shah</FONT></TD>
    <TD STYLE="font-size: 10pt"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD></TR>
</TABLE>
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