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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000935836-09-000796.txt : 20090401
<SEC-HEADER>0000935836-09-000796.hdr.sgml : 20090401
<ACCEPTANCE-DATETIME>20090401182646
ACCESSION NUMBER:		0000935836-09-000796
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090401
FILED AS OF DATE:		20090401
DATE AS OF CHANGE:		20090401

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IDM PHARMA, INC.
		CENTRAL INDEX KEY:			0000822206
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				330245076
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		9 PARKER, SUITE 100
		CITY:			IRVINE
		STATE:			CA
		ZIP:			92618-1605
		BUSINESS PHONE:		949-470-4751

	MAIL ADDRESS:	
		STREET 1:		9 PARKER, SUITE 100
		CITY:			IRVINE
		STATE:			CA
		ZIP:			92618-1605

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	EPIMMUNE INC
		DATE OF NAME CHANGE:	19990715

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CYTEL CORP/DE
		DATE OF NAME CHANGE:	19940324

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PALO ALTO HEALTHCARE MASTER FUND, L.P.
		CENTRAL INDEX KEY:			0001444357

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19591
		FILM NUMBER:		09724765

	BUSINESS ADDRESS:	
		STREET 1:		C/O CITCO FUND SERVICES (BERMUDA) LTD.
		STREET 2:		WASHINGTON MALL WEST, 2ND FL., 7 REID ST
		CITY:			HAMILTON
		STATE:			D0
		ZIP:			HM 11
		BUSINESS PHONE:		441-295-7149

	MAIL ADDRESS:	
		STREET 1:		C/O CITCO FUND SERVICES (BERMUDA) LTD.
		STREET 2:		WASHINGTON MALL WEST, 2ND FL., 7 REID ST
		CITY:			HAMILTON
		STATE:			D0
		ZIP:			HM 11
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>idmiform4_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-04-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000822206</issuerCik>
        <issuerName>IDM PHARMA, INC.</issuerName>
        <issuerTradingSymbol>IDMI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001444357</rptOwnerCik>
            <rptOwnerName>PALO ALTO HEALTHCARE MASTER FUND, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CITCO FUND SERVICES (BERMUDA) LTD.</rptOwnerStreet1>
            <rptOwnerStreet2>WASHINGTON MALL WEST, 2ND FL., 7 REID ST</rptOwnerStreet2>
            <rptOwnerCity>HAMILTON</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>HM 11</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-04-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>54000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.77</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2931029</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Palo Alto Healthcare Master Fund, L.P., By Palo Alto Investors, LLC, General Partner, by Palo Alto Investors, Manager, by Mark Shamia, Chief Operating Officer</signatureName>
        <signatureDate>2009-04-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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