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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 IQiO00jCA1i2E/FYmlS82lE4GGJk9jp0tY5EBfZmm7wGcDCuGomeQPmsxRJV5XeS
 SS/6T+5y0UAVQiXPdxjQzw==

<SEC-DOCUMENT>0001140361-08-027711.txt : 20081212
<SEC-HEADER>0001140361-08-027711.hdr.sgml : 20081212
<ACCEPTANCE-DATETIME>20081212150019
ACCESSION NUMBER:		0001140361-08-027711
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081210
FILED AS OF DATE:		20081212
DATE AS OF CHANGE:		20081212

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			REGENERX BIOPHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000707511
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				521253406
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3 BETHESDA METRO CENTER
		STREET 2:		SUITE 700
		CITY:			BETHESDA
		STATE:			MD
		ZIP:			20814
		BUSINESS PHONE:		3019611992

	MAIL ADDRESS:	
		STREET 1:		3 BETHESDA METRO CENTER
		STREET 2:		SUITE 700
		CITY:			BETHESDA
		STATE:			MD
		ZIP:			20814

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALPHA 1 BIOMEDICALS INC
		DATE OF NAME CHANGE:	19950719

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chaumiere Consultadoria & Servicos SDC Unipessoal LDA
		CENTRAL INDEX KEY:			0001330564
		STATE OF INCORPORATION:			S1

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-15070
		FILM NUMBER:		081246436

	BUSINESS ADDRESS:	
		STREET 1:		77-6F AVENIDA ARRIAGA
		STREET 2:		EDIFICIO MARINA FORUM
		CITY:			FUNCHAL-MADEIRA
		STATE:			S1
		ZIP:			P-9000
		BUSINESS PHONE:		351 291 20 24 00

	MAIL ADDRESS:	
		STREET 1:		77-6F AVENIDA ARRIAGA
		STREET 2:		EDIFICIO MARINA FORUM
		CITY:			FUNCHAL-MADEIRA
		STATE:			S1
		ZIP:			P-9000
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-12-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000707511</issuerCik>
        <issuerName>REGENERX BIOPHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>RGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001330564</rptOwnerCik>
            <rptOwnerName>Chaumiere Consultadoria &amp; Servicos SDC Unipessoal LDA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>77-6F AVENIDA ARRIAGA</rptOwnerStreet1>
            <rptOwnerStreet2>EDIFICIO FORUM, P-900 FUNCHAL</rptOwnerStreet2>
            <rptOwnerCity>MADEIRA</rptOwnerCity>
            <rptOwnerState>S1</rptOwnerState>
            <rptOwnerZipCode>10209</rptOwnerZipCode>
            <rptOwnerStateDescription>PORTUGAL</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1034482</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.45</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5590467</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.74</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-12-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-12-10</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-12-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>372552</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These 1,034,482 shares (the ?Shares?) were acquired on December 10, 2008 pursuant to a purchase agreement with the Issuer that provides that the Issuer, rather than the Reporting Person, has all voting rights in respect of the Shares through December 31, 2011, and that the Reporting Person may not transfer the Shares through December 31, 2011 except for transfers to Affiliates (as defined therein).</footnote>
        <footnote id="F2">2,500,000 of these shares were acquired on February 29, 2008 pursuant to a purchase agreement with the Issuer that provides that the Issuer shall have the right to repurchase the shares at any time until December 31, 2009, for $2.00 per share, or at any time between January 1, 2010 and December 31, 2010, for $2.50 per share.  Furthermore, the purchase agreement provides that the Issuer, rather than the Reporting Person, has all voting rights in respect to the shares through December 31, 2010, and that the Reporting Person may not transfer the shares through December 31, 2010 except for transfers to Affiliates (as defined therein).</footnote>
        <footnote id="F3">This warrant was issued by the Issuer to the Reporting Person in consideration of the Reporting Person?s purchase of the Shares.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Fabio Poma, Attorney-in-fact</signatureName>
        <signatureDate>2008-12-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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