-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 OpchymSmBR32Is5pas0YlptwZHSlkqJP6sYbIY2lvlt1X3vtbglxiyglTReA+q5Y
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<SEC-DOCUMENT>0001140361-10-025044.txt : 20100610
<SEC-HEADER>0001140361-10-025044.hdr.sgml : 20100610
<ACCEPTANCE-DATETIME>20100610133646
ACCESSION NUMBER:		0001140361-10-025044
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100608
FILED AS OF DATE:		20100610
DATE AS OF CHANGE:		20100610

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Clark John Smith II
		CENTRAL INDEX KEY:			0001378379

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32295
		FILM NUMBER:		10889818

	MAIL ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ADHEREX TECHNOLOGIES INC
		CENTRAL INDEX KEY:			0001211583
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				000000000

	BUSINESS ADDRESS:	
		STREET 1:		4620 CREEKSTONE DRIVE
		STREET 2:		SUITE 200
		CITY:			DURHAM
		STATE:			NC
		ZIP:			27703
		BUSINESS PHONE:		919-484-8484

	MAIL ADDRESS:	
		STREET 1:		4620 CREEKSTONE DRIVE
		STREET 2:		SUITE 200
		CITY:			DURHAM
		STATE:			NC
		ZIP:			27703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Southpoint Capital Advisors LP
		CENTRAL INDEX KEY:			0001319998
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32295
		FILM NUMBER:		10889822

	BUSINESS ADDRESS:	
		STREET 1:		237 PARK AVENUE
		STREET 2:		SUITE 900
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		212.692.6350

	MAIL ADDRESS:	
		STREET 1:		237 PARK AVENUE
		STREET 2:		SUITE 900
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Southpoint GP, LP
		CENTRAL INDEX KEY:			0001378376
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32295
		FILM NUMBER:		10889820

	BUSINESS ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212.692.6349

	MAIL ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Southpoint Capital Advisors LLC
		CENTRAL INDEX KEY:			0001378377
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32295
		FILM NUMBER:		10889821

	BUSINESS ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212.692.6349

	MAIL ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Southpoint GP, LLC
		CENTRAL INDEX KEY:			0001378378
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32295
		FILM NUMBER:		10889819

	BUSINESS ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212.692.6349

	MAIL ADDRESS:	
		STREET 1:		623 FIFTH AVENUE
		STREET 2:		SUITE 2503
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
</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>2010-06-08</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001211583</issuerCik>
        <issuerName>ADHEREX TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>ADHXF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001319998</rptOwnerCik>
            <rptOwnerName>Southpoint Capital Advisors LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>623 FIFTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 2601</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378377</rptOwnerCik>
            <rptOwnerName>Southpoint Capital Advisors LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>623 FIFTH AVENUE, SUITE 2601</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378376</rptOwnerCik>
            <rptOwnerName>Southpoint GP, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>623 FIFTH AVENUE, SUITE 2601</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378378</rptOwnerCik>
            <rptOwnerName>Southpoint GP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>623 FIFTH AVENUE, SUITE 2601</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378379</rptOwnerCik>
            <rptOwnerName>Clark John Smith II</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>623 FIFTH AVENUE, SUITE 2601</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></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>2010-06-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>41504000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>200000000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.08</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-06-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>41504000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-10-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2015-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>41504000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>158496000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reported securities are included within 41,504,000 units sold by the reporting persons for CDN$0.03 per unit.  Each unit consists of one share of common stock of Adherex Technologies Inc. and one warrant to purchase one share of common stock of Adherex Technologies Inc.</footnote>
        <footnote id="F2">Southpoint Capital Advisors LP, and its general partner Southpoint Capital Advisors LLC, hold the reported securities indirectly on behalf of Southpoint Fund LP, Southpoint Qualified Fund LP, Southpoint Master Fund, LP and Southpoint Offshore Fund, Ltd., for which Southpoint Capital Advisors LP serves as investment manager.  Southpoint GP, LP, and its general partner Southpoint GP, LLC, hold the reported securities indirectly on behalf of Southpoint Fund LP, Southpoint Qualified Fund LP, and Southpoint Master Fund, LP, of which Southpoint GP, LP is the general partner.  John S. Clark II reports the securities held indirectly by Southpoint GP, LLC and Southpoint Capital Advisors LLC as the manager of each.</footnote>
        <footnote id="F3">Each of the reporting persons disclaims beneficial ownership of the reported securities except to the extent of his or its pecuniary interest therein, and this report shall not be deemed an admission that such reporting person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
        <footnote id="F4">The exercise price of the warrants reported is listed in Canadian Dollars.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>SOUTHPOINT CAPITAL ADVISORS LP, By: Southpoint Capital Advisors LLC, its General Partner, By: John S. Clark II, Managing Member</signatureName>
        <signatureDate>2010-06-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SOUTHPOINT CAPITAL ADVISORS LLC,  By: John S. Clark, II, Managing Member</signatureName>
        <signatureDate>2010-06-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SOUTHPOINT GP, LP, By: Southpoint GP, LLC, its General Partner, By: John S. Clark, II, Managing Member</signatureName>
        <signatureDate>2010-06-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SOUTHPOINT GP, LLC, By: John S. Clark, II, Managing Member</signatureName>
        <signatureDate>2010-06-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>John S. Clark, II</signatureName>
        <signatureDate>2010-06-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----