<SEC-DOCUMENT>0001144204-18-009015.txt : 20180214
<SEC-HEADER>0001144204-18-009015.hdr.sgml : 20180214
<ACCEPTANCE-DATETIME>20180214170852
ACCESSION NUMBER:		0001144204-18-009015
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20180214
DATE AS OF CHANGE:		20180214
GROUP MEMBERS:		PETER KOLCHINSKY

SUBJECT COMPANY:	

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

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-51477
		FILM NUMBER:		18613485

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

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

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

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HYSEQ INC
		DATE OF NAME CHANGE:	19970610

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RA CAPITAL MANAGEMENT, LLC
		CENTRAL INDEX KEY:			0001346824
		IRS NUMBER:				830406777
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		20 PARK PLAZA, SUITE 1200
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-778-2500

	MAIL ADDRESS:	
		STREET 1:		20 PARK PLAZA, SUITE 1200
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>tv485673_sc13ga.htm
<DESCRIPTION>SCHEDULE 13G/A
<TEXT>
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<HEAD>
     <TITLE></TITLE>
</HEAD>
<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="margin-top: 0; text-align: center; margin-bottom: 0"></P>

<!-- Field: Rule-Page --><DIV ALIGN="LEFT" STYLE="margin-top: 12pt; margin-bottom: 3pt"><DIV STYLE="font-size: 1pt; border-top: Black 2pt solid; border-bottom: Black 1pt solid; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="margin-top: 0; text-align: center; margin-bottom: 0">&nbsp;</P>

<P STYLE="margin-top: 0; text-align: center; margin-bottom: 0"><B>UNITED STATES<BR>
SECURITIES AND EXCHANGE COMMISSION<BR>
Washington, D.C. 20549</B></P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>SCHEDULE 13G</B></P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center; text-indent: 0in"><B>(Amendment No. 3)*</B></P>

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

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><FONT STYLE="font-size: 14pt">ARCA biopharma,
Inc.</FONT></P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">(Name of Issuer)</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Common Stock, par value $0.001 per share</B>&nbsp;</P>

<!-- Field: Rule-Page --><DIV ALIGN="CENTER" STYLE="margin-top: 3pt; margin-bottom: 3pt"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>00211Y407</B></P>

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>December 31, 2017</B></P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">(Date of Event Which Requires Filing of this
Statement)</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Check the appropriate box to designate the rule pursuant to which
this Schedule is filed:</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"></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: 0.25in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">x</FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif">Rule
13d-1(b)</FONT></TD>
</TR></TABLE>

<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: 0.25in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&uml;</FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif">Rule
13d-1(c)</FONT></TD>
</TR></TABLE>

<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: 0.25in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&uml;</FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif">Rule
13d-1(d)</FONT></TD>
</TR></TABLE>



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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">*The remainder of this cover page 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: 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">The information required in the remainder of
this cover page shall not be deemed to be &ldquo;filed&rdquo; for the purpose of Section 18 of the Securities Exchange Act of 1934
(&ldquo;<B><I>Act</I></B>&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: 0">&nbsp;</P>

<!-- Field: Rule-Page --><DIV ALIGN="LEFT" STYLE="margin-top: 3pt; margin-bottom: 12pt"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid; border-bottom: Black 2pt solid; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

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


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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 67%"><FONT STYLE="font-size: 10pt">CUSIP No. </FONT><B>00211Y407</B></TD>
    <TD STYLE="width: 33%; text-align: right"><FONT STYLE="font-size: 12pt"><B>13G</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">1.</FONT></TD>
    <TD COLSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Names of Reporting Persons.<BR>
        I.R.S. Identification Nos. of above persons (entities only).</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>RA Capital Management, LLC</B></P></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top">&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">2.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">Check the Appropriate Box if a Member of a Group (See Instructions)</FONT></TD></TR>
<TR>
    <TD STYLE="width: 4%">&nbsp;</TD>
    <TD STYLE="width: 7%">&nbsp;</TD>
    <TD STYLE="width: 6%"><FONT STYLE="font-size: 10pt">(a)</FONT></TD>
    <TD STYLE="width: 83%"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">(b)</FONT></TD>
    <TD><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">3.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">SEC Use Only</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">4.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">Citizenship or Place of Organization&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <B>Massachusetts</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD ROWSPAN="7" STYLE="width: 18%"><FONT STYLE="font-size: 10pt">Number of</FONT><BR>
<FONT STYLE="font-size: 10pt">Shares</FONT><BR>
<FONT STYLE="font-size: 10pt">Beneficially</FONT><BR>
<FONT STYLE="font-size: 10pt">Owned by</FONT><BR>
<FONT STYLE="font-size: 10pt">Each Reporting</FONT><BR>
<FONT STYLE="font-size: 10pt">Person With</FONT></TD>
    <TD STYLE="width: 3%"><FONT STYLE="font-size: 10pt">5.</FONT></TD>
    <TD STYLE="width: 25%"><FONT STYLE="font-size: 10pt">Sole Voting Power</FONT></TD>
    <TD STYLE="width: 54%"><FONT STYLE="font-size: 10pt"><B>0 shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">6.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Shared Voting Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>324,490<SUP>1</SUP> shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">7.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Sole Dispositive Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>0 shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">8.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Shared Dispositive Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>324,490<SUP>1</SUP> shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 4%">&nbsp;</TD>
    <TD STYLE="width: 7%"><FONT STYLE="font-size: 10pt">9.</FONT></TD>
    <TD STYLE="width: 82%"><FONT STYLE="font-size: 10pt">Aggregate Amount Beneficially Owned by Each Reporting Person</FONT></TD>
    <TD STYLE="width: 9%">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 9pt"><FONT STYLE="font-size: 10pt"><B>324,490<SUP>1</SUP> shares</B></FONT></TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 9pt">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">10.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)</FONT></TD>
    <TD><P STYLE="margin: 0; text-align: right"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></P>


</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="text-align: left; vertical-align: top"><FONT STYLE="font-size: 10pt">11.</FONT></TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Percent of Class Represented by Amount in Row (9)</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>2.7%<SUP>2</SUP></B></P></TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="text-align: left; vertical-align: top"><FONT STYLE="font-size: 10pt">12.</FONT></TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Type of Reporting Person (See Instructions)</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>IA</B></P></TD>
    <TD>&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 12pt"><SUP>1</SUP> The shares reported herein for the Reporting
Person represent 324,490 shares of the Issuer&rsquo;s Common Stock the reporting person has the right to acquire through the exercise
of warrants dated June 16, 2015 (&ldquo;Warrant Shares&rdquo;).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><SUP>2</SUP> The percentage calculation assumes (i) 11,750,977
outstanding shares of Common Stock of the Issuer, based on the Issuer&rsquo;s Form 10-Q as filed with the Securities and Exchange
Commission (&ldquo;SEC&rdquo;) on November 9, 2017, plus (ii) 324,490 shares of the Issuer&rsquo;s Common Stock the reporting
person has the right to acquire through the exercise of Warrant Shares.</P>

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

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

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    <!-- Field: /Page -->

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 67%"><FONT STYLE="font-size: 10pt">CUSIP No. </FONT><B>00211Y407</B></TD>
    <TD STYLE="text-align: right; width: 33%"><FONT STYLE="font-size: 12pt"><B>13G</B></FONT></TD></TR>
</TABLE>

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

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">1.</FONT></TD>
    <TD COLSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Names of Reporting Persons.<BR>
        I.R.S. Identification Nos. of above persons (entities only).</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>Peter Kolchinsky</B></P></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top">&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">2.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">Check the Appropriate Box if a Member of a Group (See Instructions)</FONT></TD></TR>
<TR>
    <TD STYLE="width: 4%">&nbsp;</TD>
    <TD STYLE="width: 7%">&nbsp;</TD>
    <TD STYLE="width: 6%"><FONT STYLE="font-size: 10pt">(a)</FONT></TD>
    <TD STYLE="width: 83%"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">(b)</FONT></TD>
    <TD><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">3.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">SEC Use Only</FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">4.</FONT></TD>
    <TD COLSPAN="2"><FONT STYLE="font-size: 10pt">Citizenship or Place of Organization&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <B>United States</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"></P>

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD ROWSPAN="7" STYLE="width: 18%"><FONT STYLE="font-size: 10pt">Number of</FONT><BR>
<FONT STYLE="font-size: 10pt">Shares</FONT><BR>
<FONT STYLE="font-size: 10pt">Beneficially</FONT><BR>
<FONT STYLE="font-size: 10pt">Owned by</FONT><BR>
<FONT STYLE="font-size: 10pt">Each Reporting</FONT><BR>
<FONT STYLE="font-size: 10pt">Person With</FONT></TD>
    <TD STYLE="width: 3%"><FONT STYLE="font-size: 10pt">5.</FONT></TD>
    <TD STYLE="width: 25%"><FONT STYLE="font-size: 10pt">Sole Voting Power</FONT></TD>
    <TD STYLE="width: 54%"><FONT STYLE="font-size: 10pt"><B>0 shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">6.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Shared Voting Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>324,490<SUP>1</SUP> shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">7.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Sole Dispositive Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>0 shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD><FONT STYLE="font-size: 10pt">8.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Shared Dispositive Power</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>324,490<FONT STYLE="font-family: Times New Roman, Times, Serif"><SUP>1</SUP></FONT> shares</B></FONT></TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 4%">&nbsp;</TD>
    <TD STYLE="width: 7%"><FONT STYLE="font-size: 10pt">9.</FONT></TD>
    <TD STYLE="width: 82%"><FONT STYLE="font-size: 10pt">Aggregate Amount Beneficially Owned by Each Reporting Person</FONT></TD>
    <TD STYLE="width: 9%">&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 9pt"><FONT STYLE="font-size: 10pt"><B>324,490<SUP>1</SUP> shares</B></FONT></TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 9pt">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">10.</FONT></TD>
    <TD><FONT STYLE="font-size: 10pt">Check if the Aggregate Amount in Row (9) Excludes</FONT> Certain Shares (See Instructions)</TD>
    <TD><P STYLE="margin: 0; text-align: right"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></P>


</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="text-align: left; vertical-align: top"><FONT STYLE="font-size: 10pt">11.</FONT></TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Percent of Class Represented by Amount in Row (9)</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>2.7%<SUP>2</SUP></B></P></TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR>
    <TD>&nbsp;</TD>
    <TD STYLE="text-align: left; vertical-align: top"><FONT STYLE="font-size: 10pt">12.</FONT></TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Type of Reporting Person (See Instructions)</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 9pt"><B>IN</B></P></TD>
    <TD>&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 12pt"><SUP>1</SUP> The shares reported herein for the Reporting
Person represent 324,490 shares of the Issuer&rsquo;s Common Stock the reporting person has the right to acquire through the exercise
of warrants dated June 16, 2015 (&ldquo;Warrant Shares&rdquo;).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><SUP>2</SUP> The percentage calculation assumes (i) 11,570,977
outstanding shares of Common Stock of the Issuer, based on the Issuer&rsquo;s Form 10-Q as filed with the Securities and Exchange
Commission (&ldquo;SEC&rdquo;) on November 14, 2016, plus (ii) 324,490 shares of the Issuer&rsquo;s Common Stock the reporting
person has the right to acquire through the exercise of Warrant Shares.</P>

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


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

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 67%"><FONT STYLE="font-size: 10pt">CUSIP No. </FONT><B>00211Y407</B></TD>
    <TD STYLE="width: 33%; text-align: right"><FONT STYLE="font-size: 12pt"><B>13G</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>Item 1.</B></P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">(a)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Name
of Issuer:</B> ARCA biopharma, Inc. (the &ldquo;Issuer&rdquo;).</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">(b)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Address
of the Issuer&rsquo;s Principal Executive Offices:</B> 11080 CirclePoint Road, Suite 140, Westminster, CO 80020.</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>Item 2.</B></P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0in">(a)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Name
of Person Filing: </B> This joint statement on Schedule 13G is being filed by RA Capital Management, LLC (&ldquo;Capital&rdquo;)
and Peter Kolchinsky. Capital and Mr. Kolchinsky are collectively referred to herein as the &ldquo;Reporting Persons.&rdquo; Capital
is the general partner of the RA Capital Healthcare Fund, L.P. (the &ldquo;Fund&rdquo;) and serves as investment adviser for a
separately managed account (the &ldquo;Account&rdquo;). Mr. Kolchinsky is the manager of Capital. As the investment adviser to
the Fund and the Account, Capital may be deemed a beneficial owner, for purposes of Section 13(d) of the Securities Exchange Act
of 1934 (the &ldquo;Act&rdquo;), of any securities of the Issuer owned by the Fund or the Account. As the manager of Capital, Mr.
Kolchinsky may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially
owned by Capital. Capital and Mr. Kolchinsky disclaim beneficial ownership of the securities reported in this Schedule 13G Statement
(the &ldquo;Statement&rdquo;) other than for the purpose of determining their obligations under Section 13(d) of the Act, and neither
the filing of the Statement nor the filing of this Amendment shall be deemed an admission that either Capital or Mr. Kolchinsky
is or was the beneficial owner of such securities for any other purpose.</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0in">(b)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Address
of Principal Business Office:</B> The principal business office of the Reporting Persons is c/o RA Capital Management, LLC, 20
Park Plaza, Suite 1200, Boston, MA 02116.</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0in">(c)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Citizenship:</B> Capital
is a Massachusetts limited liability company. Mr. Kolchinsky is a United States citizen.</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0in">(d)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Title
and Class of Securities: </B>Common stock (&ldquo;Common Stock&rdquo;)</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0in">(e)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>CUSIP
Number: </B>00211Y407</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"><B>&nbsp;</B></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"></TD><TD STYLE="width: 0.75in; text-align: left"><B>Item&nbsp;3.</B></TD><TD STYLE="text-align: justify"><B>If this statement is filed pursuant to &sect;&sect;240.13d-1(b)
or 240.13d-2(b) or (c), check whether the person filing is a:</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">(e) RA Capital Management LLC 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: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">(g) Peter Kolchinsky is a control person and is 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: 0">&nbsp;</P>


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

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 67%"><FONT STYLE="font-size: 10pt">CUSIP No. </FONT><B>00211Y407</B></TD>
    <TD STYLE="width: 33%; text-align: right"><FONT STYLE="font-size: 12pt"><B>13G</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B></B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></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"></TD><TD STYLE="width: 0.75in; text-align: left"><B>Item&nbsp;4.</B></TD><TD STYLE="text-align: justify"><B>Ownership:</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">Provide the following information regarding
the aggregate number and percentage of the class of securities of the issuer identified in Item 1.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">&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="width: 6%; text-align: left; vertical-align: top">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">(a)</P></TD>
    <TD STYLE="width: 94%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Amount Beneficially Owned:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 9 on the attached cover page(s).</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>(b)</TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Percent of Class:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 11 on the attached cover page(s).</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>(c)</TD>
    <TD>Number of shares as to which such person has:</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 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="width: 6%"><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD STYLE="width: 6%">(i)</TD>
    <TD STYLE="width: 88%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">sole power to vote or to direct the vote:</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 5 on the attached cover page(s).</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>(ii)</TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">shared power to vote or to direct the vote</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 6 on the attached cover page(s).</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>(iii)</TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">sole power to dispose or to direct the disposition of</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 7 on the attached cover page(s).</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">&nbsp;</FONT></TD>
    <TD>(iv)</TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">shared power to dispose or to direct the disposition of</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">See the response(s) to Item 8 on the attached cover page(s).</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"><B>&nbsp;</B></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"></TD><TD STYLE="width: 0.75in; text-align: left"><B>Item&nbsp;5.</B></TD><TD STYLE="text-align: justify"><B>Ownership of Five Percent or Less of a Class:</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">If this statement is being filed to report the fact that as of the
date hereof the Reporting Person has ceased to be the beneficial owner of more than five percent of the class of securities, check
the following <FONT STYLE="font-family: Wingdings; font-size: 10pt">x</FONT>.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 1in; text-align: justify; text-indent: -1in"><B>&nbsp;</B></P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.75in"><B>Item 6.</B></TD><TD STYLE="text-align: justify"><B>Ownership of More than Five Percent on Behalf of Another Person:</B></TD></TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"><B>&nbsp;</B></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"></TD><TD STYLE="width: 0.75in; text-align: left"><B>Item&nbsp;7.</B></TD><TD STYLE="text-align: justify"><B>Identification and Classification of the Subsidiary
Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person:</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"><B>&nbsp;</B></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"></TD><TD STYLE="width: 0.75in; text-align: left"><B>Item&nbsp;8.</B></TD><TD STYLE="text-align: justify"><B>Identification and Classification of Members of the
Group:</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"><B>&nbsp;</B></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"></TD><TD STYLE="text-align: left; width: 0.75in"><B>Item&nbsp;9.</B></TD><TD STYLE="text-align: justify"><B>Notice of Dissolution of Group:</B></TD>
</TR>
</TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">Not applicable.</P>

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


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

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%">
<TR>
    <TD STYLE="width: 67%"><FONT STYLE="font-size: 10pt">CUSIP No. </FONT><B>00211Y407</B></TD>
    <TD STYLE="width: 33%; text-align: right"><FONT STYLE="font-size: 12pt"><B>13G</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B></B></P>

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


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

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.75in"><B>Item 10.</B></TD><TD STYLE="text-align: justify"><B>Certification:</B></TD></TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify">By signing below I hereby certify that, to
the best of my knowledge and belief, the securities referred to above 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.</P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 0.5in; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.5in">1</TD><TD>Joint Filing Agreement by and among the Reporting Persons is incorporated herein by reference to Exhibit 1 to the Schedule
13G filed by the Reporting Persons with the Securities and Exchange Commission on June 25, 2015.</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 0.5in; text-indent: -0.5in">&nbsp;</P>


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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in">After reasonable inquiry
and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.</P>

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    <TD STYLE="width: 50%">&nbsp;</TD>
    <TD STYLE="width: 50%"><FONT STYLE="text-transform: uppercase">Date: F</FONT>ebruary 14<FONT STYLE="text-transform: uppercase">, 2018</FONT></TD></TR>
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    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>RA CAPITAL MANAGEMENT, LLC</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
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    <TD>&nbsp;</TD>
    <TD STYLE="border-bottom: Black 1pt solid">By: /s/ Rajeev Shah</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>Rajeev Shah</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>Authorized Signatory</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>PETER KOLCHINSKY</TD></TR>
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    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
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    <TD>&nbsp;</TD>
    <TD STYLE="border-bottom: Black 1pt solid">/s/ Peter Kolchinsky</TD></TR>
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