<SEC-DOCUMENT>0001181431-15-008421.txt : 20150617
<SEC-HEADER>0001181431-15-008421.hdr.sgml : 20150617
<ACCEPTANCE-DATETIME>20150617194633
ACCESSION NUMBER:		0001181431-15-008421
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150616
FILED AS OF DATE:		20150617
DATE AS OF CHANGE:		20150617

ISSUER:		

	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

	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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sonsini Peter W.
		CENTRAL INDEX KEY:			0001559807

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		15938356

	MAIL ADDRESS:	
		STREET 1:		2855 SAND HILL ROAD
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>rrd425750.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2015-06-16</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000907654</issuerCik>
        <issuerName>ARCA biopharma, Inc.</issuerName>
        <issuerTradingSymbol>ABIO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001559807</rptOwnerCik>
            <rptOwnerName>Sonsini Peter W.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2855 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10221465</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 1</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.8716</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2015-12-13</value>
            </exerciseDate>
            <expirationDate>
                <value>2022-06-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4088586</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 1</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person is a manager of NEA 15 GP, LLC, (&quot;NEA 15 GP&quot;) which is the sole general partner of NEA Partners 15, L.P. (&quot;NEA Partners 15&quot;). NEA Partners 15 is the sole general partner of New Enterprise Associates 15, L. P. (&quot;NEA 15&quot;).  NEA 15 is the sole member of Growth Equity Opportunities Fund IV, LLC (&quot;GEO IV&quot;), which is the direct beneficial owner of the shares. The Reporting Person disclaims beneficial ownership within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the shares held by GEO IV in which the Reporting Person has no pecuniary interest.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Sasha Keough, attorney-in-fact</signatureName>
        <signatureDate>2015-06-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
