UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549 

Amendment No. 1

FORM 10-K/A

(Mark One)

For the fiscal year ended December 31, 2013

OR

For the transition period from____ to ____

Commission File Number: 001-32295 

ADHEREX TECHNOLOGIES INC.

(Exact Name of Registrant as Specified in Its Charter) 

(919) 636-4530

(Registrant's telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act:  None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.  YES ¨   NO x

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.  YES ¨   NO x

Indicate by check mark whether the Registrant:  (1) has filed all reports required to be filed by section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.  YES x   NO ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).

Yes x   No¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of Registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.   x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):  

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).  YES ¨   NO x

The aggregate market value of the voting stock held by non-affiliates of the Registrant, computed by reference to the closing sales price of the Common Shares as reported by the OTCQB on June 30, 2013 (the last business day of the Registrant’s most recently completed second fiscal quarter) was $2,802,147 based upon a total of 9,340,489 shares held as of June 30, 2013 by persons believed to be non-affiliates of the Registrant (for purposes of this calculation, all of the Registrant’s officers, directors and 10% owners known to the Company are deemed to be affiliates of the Registrant).

As of March 14, 2014, there were 29,307,618 shares of Adherex Technologies Inc. common stock outstanding.

Explanatory Note

Adherex Technologies Inc. (the “Company”) is filing this Amendment No. 1 to its Annual Report on Form 10-K (the “Form 10-K/A”) to amend its Annual Report on Form 10-K for the year ended December 31, 2013, which was filed with the Securities and Exchange Commission (“SEC”) on March 31, 2014 (the “2013 10-K”). The sole purpose of this Amendment No. 1 is to (i) rename Exhibit 10.19 “Form of Subscription Agreement, dated November 15, 2013, between Adherex Technologies Inc. and Manchester” and (ii) file Exhibit 10.19, which was inadvertently omitted from the 2013 10-K. Other than the matters described above, no changes have been made to the 2013 10-K and this Amendment No. 1 does not otherwise amend, update or change the financial statements or disclosures in the 2013 10-K.

SIGNATURES

Pursuant to the requirements of Section 13 of 15(d) the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Supplemental Information to be Furnished With Reports Filed Pursuant to Section 15(d) of the Act by Registrants Which Have Not Registered Securities Pursuant to Section 12 of the Act

The registrant intends to furnish proxy materials to its security holders subsequent to the filing of this annual report on Form 10-K and shall furnish copies of such proxy materials to the Commission when such materials are sent to security holders.