THE
WARRANT WILL EXPIRE IF NOT EXERCISED ON OR BEFORE 5:00 PM., OTTAWA TIME, ON
________, 201__. THE TERMS AND CONDITIONS OF THE WARRANT ARE SET FORTH IN THE
COMPANY’S PROSPECTUS DATED
                  ,
2011 (THE “PROSPECTUS”) AND ARE INCORPORATED HEREIN BY REFERENCE, COPIES OF THE
PROSPECTUS ARE AVAILABLE UPON REQUEST FROM ADHEREX TECHNOLOGIES INC. OR THE
SUBSCRIPTION AGENT.

    

    


    
      
        
          
            
              	
                      
                        EVIDENCING
      WARRANTS TO PURCHASE COMMON SHARES OF ADHEREX TECHNOLOGIES
      INC.

                      

                    	 
      	
                       ADHEREX
      TECHNOLOGIES INC.

                    	 
      	
                      CUSIP         00686R176

                      ISIN         CA00686R1762

                    
	 
      	 
      	 
      	 
      	 
      
	
                      

                    	 
      	
                      
                        THIS
      CERTIFIES THAT, for value

                        received:

                      

                    	 
      	
                      

                    
	 
      	 
      	 
      	 
      	 
      
	
                      
                        ATTACHMENT
      1 – NOTICE OF EXERCISE

                         

                        TO:  ADHEREX
      TECHNOLOGIES INC. AND THE WARRANT REGISTRAR

                         

                        1.  The
      undersigned hereby elects to purchase _________ Common Shares of the
      Company pursuant to Section 5 of the Warrant, and tenders herewith payment
      of the purchase price of such shares in full.

                         

                        2.  Please
      issue a certificate or certificates representing said Warrant Shares in
      the name of the undersigned or in such other name as is specified
      below:

                         

                        _____________________________________

                        (Name
      in which certificate(s) are to be issued)

                         

                        _______________________________

                        (Address)

                         

                        3.  Upon
      any exercise of the Warrant for less than the total number of full Shares
      provided for herein, there shall be issued to the registered holder (or
      the registered holder’s transferee) a new Warrant covering the number of
      Shares for which the Warrant has not been exercised.

                         

                        _______________________

                        (Name of Warrant Holder) 

                                                                                                           By: ____________________

                                                                                                          Title: __________________

                                                                                                          Date
      signed: ____________

                      

                    	 
        	
                       
      

                       

                       

                       

                       

                    	 
        	
                      1.  Definitions.  As
      used in this Warrant, the following terms have the definitions ascribed to
      them below: 

                      (a)    “Commencement
      Date” means [INSERT DATE THAT IS SIX (6) MONTHS
      FROM ISSUANCE DATE].

                       (b)    “Issuance
      Date” means ___________. 

                      (c)  
       “person”
      means any individual, corporation, partnership, limited liability company,
      trust, incorporated or unincorporated association, joint venture, joint
      stock company, governmental authority or other entity of any kind, and
      shall include any successor (by merger or otherwise) of such
      entity.
      

                      (d)    “Warrant
      Price” means CDN$0.08 per share subject to adjustment under Section
      2.

                       
      

                      2.  Adjustments
      and Notices.  The Warrant Price and/or the Warrant Shares
      shall be subject to adjustment from time to time in accordance with this
      Section 2.  The Warrant Price and/or the Warrant Shares shall be
      adjusted to reflect all of the following events that occur on or after the
      Issuance
      Date. 

                       
      

                      (a)  Subdivision,
      Stock Dividends or Combinations.  In case the Company
      shall at any time subdivide the outstanding Common Shares or shall issue a
      stock dividend with respect to the Common Shares, the Warrant Price in
      effect immediately prior to such subdivision or the issuance of such
      dividend shall be proportionately decreased, and the number of Warrant
      Shares for which this Warrant may be exercised immediately prior to such
      subdivision or the issuance of such dividend shall be proportionately
      increased.  In case the Company shall at any time combine the
      outstanding Common Shares, the Warrant Price in effect immediately prior
      to such combination shall be proportionately increased, and the number of
      Warrant Shares for which this Warrant may be exercised immediately prior
      to such combination shall be proportionately decreased.  In each
      of the foregoing cases, the adjustment shall be effective at the close of
      business on such subdivision, dividend or combination, as the case may
      be.

                       
      

                      (b)  Reclassification,
      Exchange, Substitution, In-Kind Distribution.  Upon any
      reclassification, exchange, substitution or other event that results in a
      change of the number and/or class of the securities issuable upon exercise
      or conversion of this Warrant or upon the payment of a dividend in
      securities or property other than Common Shares, the Holder shall be
      entitled to receive, upon exercise of this Warrant, the number and kind of
      securities and property that Holder would have received if this Warrant
      had been exercised immediately before the record date for such
      reclassification, exchange, substitution, or other event or immediately
      prior to the record date for such dividend.  The Company or its
      successor shall promptly issue to Holder a new warrant for such new
      securities or other property.  The new warrant shall provide for
      adjustments which shall be as nearly equivalent as may be practicable to
      the adjustments provided for in this Section 2 including, without
      limitation, adjustments to the Warrant price and to the number of
      securities or property issuable upon exercise or conversion of the new
      warrant.  The provisions of this Section 2(b) shall similarly
      apply to successive reclassifications, exchanges, substitutions, or other
      events and successive dividends. 
 

                      (c)  Reorganization,
      Merger etc.  In case of any merger or consolidation of
      the Company into or with another corporation where the Company is not the
      surviving corporation, or sale, transfer or lease (but not including a
      transfer or lease by pledge or mortgage to a bona fide lender) of all or
      substantially all of the assets of the Company, the Company, or such
      successor or purchasing corporation, as the case may be, shall, as a
      condition to closing any such reorganization, merger or sale, duly execute
      and deliver to the Holder hereof a new warrant so that the Holder shall
      have the right to receive, at a total purchase price not to exceed that
      payable upon the exercise or conversion of the unexercised portion of this
      Warrant, and in lieu of the Warrant Shares theretofore issuable upon
      exercise or conversion of this warrant, the kind and amount of shares of
      stock, other securities, money and property that would have been
      receivable upon such reorganization, merger or sale by the Holder with
      respect to the Warrant Shares if this Warrant had been exercised
      immediately before the consummation of such transaction.  Such
      new warrant shall provide for adjustments that shall be as nearly
      equivalent as may be practicable to the adjustments provided for in this
      Section 2.  The provisions of this subparagraph (c) shall
      similarly apply to successive transactions of the type described in this
      subparagraph (c).

                       
      

                      
                        Terms
      continued on
      reverse.

                      

                    
	 
      	
                      
                        or
      registered assigns (the “Holder”),
      from and after the Commencement Date (as defined herein), and subject to
      the terms and conditions herein set forth, is entitled to purchase from
      Adherex Technologies Inc., a Canadian corporation (the “Company”),
      at any time before 5:00p.m. Ottawa, Ontario time on __________________
      (the “Termination
      Date”) _________ common shares in the capital of the Company
      (“Common
      Shares”), at a price per share equal to the Warrant Price (as
      defined herein) upon exercise of this Warrant pursuant to Section 5 hereof
      and subject to any conditions set forth in the agreement between the
      Company and the Warrant Registrar (the “Warrant
      Registrar Agreement”).  The
      number of Common Shares issuable pursuant to this Warrant (the “Warrant
      Shares”)
      is subject to adjustment under Section 2.

                      

                    	 
      
	 
      	 
      	 
      	 
      
	
                      
                        ATTACHMENT
      2 – FORM OF TRANSFER

                         

                        FOR
      VALUE RECEIVED, the undersigned (“Transferor”) hereby sells, assigns and
      transfers unto _________________________________ (the “Transferee”)
      (include name and address of Transferee) Warrants exercisable for common
      shares of Adherex Technologies Inc. (the “Company”) registered in the name
      of the Transferor on the register of the Company maintained therefore, and
      hereby irrevocably appoints ______________________________ the attorney of
      the undersigned to transfer the said securities on the books maintained by
      the Company, with full power of substitution.

                         

                                         Dated
      this ___ day of _________, 20___

                         

                        Signature
      of Transferor guaranteed by:

                        __________________    
            _________________

                                                         
                    Signature
      of Transferor

                                                
                            _________________

                                                                       _________________

                                                                       Address
      of Transferor

                         

                        THE
      TRANSFEROR’S SIGNATURE MUST CORRESPOND WITH THE NAME OF THE HOLDER WRITTEN
      UPON THE FACE OF THIS WARRANT IN EVERY PARTICULAR, WITHOUT ANY CHANGES
      WHATSOEVER, AND MUST BE GUARANTEED BY A MAJOR CANADIAN SCHEDULE I
      CHARTERED BANK OR BY AN ELIGIBLE GUARANTOR INSTITUTION (BANK, STOCK
      BROKER, SAVINGS & LOAN ASSOCIATION OR CREDIT UNION) WITH MEMBERSHIP IN
      AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM PURSUANT TO SECURITIES
      EXCHANGE ACT OF 1934 RULE 17 AD-15

                      

                    	 
      	
                      ADHEREX
      TECHNOLOGIES INC.

                       

                       

                       

                       

                       

                      Secretary                 
           Chief Executive Officer

                       

                      OLYMPIA
      TRANSFER SERVICES INC.

                       

                       

                       

                       

                      Authorized
      Signatory

                       

                      Date:
      _______________________

                       

                      
                        SEE
      TERMS CONTINUED ON REVERSE AND

                        COMPLETE
      APPROPRIATE FORMS HEREOF

                      

                    	 
      


            

          

        

      

    


    
      
         


      

      
        
        

        
          

        

      

      
         


      

    


    (d)           Certificate of
Adjustment.  In each case of an adjustment or readjustment of
the Warrant Price, the Company, at its own expense, shall cause its chief
financial officer (or other most senior financial officer at the time) to
compute such adjustment or readjustment in accordance with the provisions hereof
and prepare a certificate showing such adjustment or readjustment, and shall
mail such certificate, by first class mail, postage prepaid, to the
Holder.  The certificate shall set forth such adjustment or
readjustment, showing in detail the facts upon which such adjustment or
readjustment is based.  No adjustment of the Warrant Price shall be
required to be made unless it would result in an increase or decrease of at
least CDN$0.01, but any adjustments not made because of this sentence shall be
carried forward and taken into account in any subsequent adjustment otherwise
required hereunder.

     

    (e)           No
Impairment.  The Company shall not, by amendment of its
charter, by-laws or other organizational documents, or through a reorganization,
transfer of assets, consolidation, merger, dissolution, issue, or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
or performance of any of the terms to be observed or performed under this
Warrant by the Company, but shall at all times in good faith assist in carrying
out all of the provisions of this Section 2 and in taking all such action as may
be necessary or appropriate to protect the Holder’s rights under this Section 2
against impairment.

     

    (f)           Fractional
Shares.  No fractional shares shall be issuable upon exercise
or conversion of the Warrant and in no event will the Company be required to net
cash settle the warrant exercise.  If a fractional share interest
arises upon any exercise or conversion of the Warrant, the Company shall
eliminate such fractional share interest by rounding up or down to the nearest
whole number the number of shares to be issued to such holder.

     

    3.           No Shareholder
Rights.  This Warrant, by itself, as distinguished from any
shares purchased hereunder, shall not entitle the Holder to any of the rights of
a shareholder of the Company.

    


    4.           Reservation of
Shares.  The Company will reserve from its authorized and
unissued share capital a sufficient number of Common Shares to provide for the
issuance of the Warrant Shares upon the exercise of this
Warrant.  Issuance of this Warrant shall constitute full authority to
the Company’s officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares issuable upon the exercise of this Warrant.

    


    
      
        5.         Exercise of
Warrant.   This Warrant may be exercised by the Holder
hereof, in whole or in part, at any time from and after the Commencement Date
and on or prior to the Termination Date, at the election of the Holder hereof
(with the notice of exercise substantially in the form attached hereto as Attachment 1 duly
completed and executed for an exercise under this Section 5), by the surrender
of this Warrant at the principal office of the Company or the Warrant
Registrar and the
payment to the Company, by certified or bank check, or by wire transfer to an
account designated by the Company of an amount equal to the then applicable
Warrant Price multiplied by the number of Warrant Shares then being
purchased.  This Warrant shall be deemed to have been exercised
immediately prior to the close of business on the date of its surrender for
exercise as provided above, and the person entitled to receive the Warrant
Shares issuable upon such exercise shall be treated for all purposes as the
holder of such shares of record as of the close of business on such
date.  As promptly as practicable after such date, the Company shall
issue and deliver to the person or persons entitled to receive the same a
certificate or certificates for the number of full Warrant Shares issuable upon
such exercise.

      

       

    

    6.           Transfer of
Warrant.   This Warrant is issued upon the following terms
respecting transferability, to which Holder consents and agrees:

    


    (a)           Until
this Warrant is transferred on the books of the Company, the Company will, and
shall be entitled to, treat the Holder of this Warrant registered as such on the
books of the Company as the absolute owner hereof for all purposes without being
affected by any notice to the contrary.

    


    (b)           This
Warrant may not be exercised, and this Warrant and the Warrant Shares shall not
be transferable, except in compliance with all applicable provincial, state and
federal securities laws, regulations and orders, and with all other applicable
laws, regulations and orders.

    


    (c)           Subject
to the provisions of this Section 6, the Warrant may be transferred by the
Holder completing and delivering to the Company a notice of transfer
substantially in the form attached hereto as Attachment
2.

    


    (d)           Upon
due presentment for registration of transfer of this Warrant at the office or
agency of the Warrant Registrar, a new Warrant or Warrants of like tenor and
evidencing in the aggregate a like number of Warrants shall be issued to the
Assignee in exchange for this Warrant, subject to the limitations provided
herein and in the Warrant Registrar Agreement, without charge except for any
applicable tax or other governmental charge.

    


    (e)           The
Company and the Warrant Registrar may deem and treat the registered holder as
the absolute owner of this Warrant (notwithstanding any notation of ownership or
other writing hereon made by anyone), for the purpose of any exercise hereof, of
any distribution to the registered holder, and for all other purposes, and
neither the Company nor the Warrant Registrar shall be affected by any notice to
the contrary.

    


    7.           Covenants, Representations
and Warranties.  The Company hereby represents and warrants
that it is authorized to create and issue the Warrants and covenants and agrees
that it will cause the Common Shares from time to time subscribed for and
purchased in the manner provided in this Warrant and the certificate or
certificates representing such Common Shares to be issued and that, at all times
prior to 5:00 p.m. (Ottawa, Ontario time) on the Termination Date, it will
reserve and there will remain unissued a sufficient number of Common Shares to
satisfy the right of purchase provided for in this Warrant.  The
Company hereby further covenants and agrees that it will at its expense
expeditiously use its best efforts to obtain the listing of this Warrant and the
underlying Common Shares (subject to issue or notice of issue) on each stock
exchange or over-the-counter market on which the Common Shares may be listed
from time to time.  All Common Shares which are issued upon the
exercise of the right of purchase provided in this Warrant, upon payment
therefor of the amount at which such Common Shares may be purchased pursuant to
the provisions of this Warrant, shall be and be deemed to be validly issued,
fully paid and non-assessable shares and free from all taxes, liens and charges
with respect to the issue thereof.  The Company hereby represents and
warrants that this Warrant is a valid and enforceable obligation of the Company,
enforceable in accordance with the provisions of this Warrant.

    


    8.           Further
Assurances.  The Company hereby covenants and agrees that it
will do, execute, acknowledge and deliver, or cause to be done, executed,
acknowledged and delivered, all and every such other act, deed and assurance as
the Holder shall reasonably require for the better accomplishing and
effectuating of the intentions and provisions of this Warrant.

    


    9.           Successors and
Assigns.  This Warrant shall enure to the benefit of the Holder
and the successors and assignees thereof and shall be binding upon the Company
and the successors thereof.

    


    10.         Termination.  This
Warrant shall terminate at 5:00 p.m. (Ottawa, Ontario time) on the Termination
Date.

    


    11.         Miscellaneous.  This
Warrant shall be governed by the laws of the Province of Ontario, as such laws
are applied to contracts to be entered into and performed entirely in Ontario by
Ontario residents. The headings in this Warrant are for purposes of convenience
and reference only, and shall not be deemed to constitute a part
hereof.  Neither this Warrant nor any term hereof may be changed or
waived orally, but only by an instrument in writing signed by the Company
and the
Holder.  All notices and other communications from the Company to the
Holder of this Warrant shall be delivered personally or by facsimile
transmission or mailed by first class mail, postage prepaid, to the address or
facsimile number furnished to the Company in writing by the last Holder of this
Warrant who shall have furnished an address or facsimile number to the Company
in writing, and if mailed shall be deemed given three days after deposit in the
United States mail.  Upon receipt of evidence satisfactory to the
Company of the ownership of and the loss, theft, destruction or mutilation of
any Warrant and, in the case of any such loss, theft or destruction, upon
receipt of indemnity or security satisfactory to the Company or, in the case of
any such mutilation, upon surrender and cancellation of such Warrant, the
Company will make and deliver, in lieu of such lost, stolen, destroyed or
mutilated Warrant, a new Warrant of like tenor and representing the right to
purchase the same aggregate number of Common Shares.  Time shall be of
the essence of this Warrant. The parties hereto have expressly required that
this agreement and all documents, agreements and notices related hereto be
drafted in the English language. Les parties aux présentes ont expressément
exigé que le présent contrat et tous les autres documents, conventions ou avis
qui y sont afférents soient rédigés en langue anglaise.