UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G 

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 68230A106

Item 1.

(a)          Name of Issuer: OncoGenex Pharmaceuticals Inc. (the “Issuer”).

(b)          Address of the Issuer’s Principal Executive Offices: 1522 217th Place S.E., Bothell, Washington 98021.

Item 2.

(a)          Name of Person Filing: This joint statement on Schedule 13G is being filed by Peter Kolchinsky, RA Capital Management, LLC (“Capital”), and RA Capital Healthcare Fund, L.P. (the “Fund”). Mr. Kolchinsky, Capital and the Fund are collectively referred to herein as the “Reporting Persons.”

(b)          Address of Principal Business Office: The principal business office of the Reporting Persons is c/o RA Capital Management, LLC, 20 Park Plaza, Suite 1200, Boston, MA 02116.

(c)          Citizenship: Capital is a Massachusetts limited liability company. The Fund is a Delaware limited partnership. Mr. Kolchinsky is a United States citizen.

(d)          Title and Class of Securities: Common stock (“Common Stock”).

(e)          CUSIP Number: 68230A106.

Item 3.          If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

Not applicable.

Item 4.          Ownership:

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

CUSIP No. 68230A106

** The Reporting Persons have the right to purchase an additional 205,000 shares of Common Stock pursuant to the terms of common stock purchase warrants issued on October 22, 2010, which are not exercisable except upon sixty-one (61) days prior written notice to the Issuer. Capital serves as investment adviser for the Fund. Mr. Kolchinsky serves as the manager of Capital. Each of the Reporting Persons disclaims beneficial ownership of the shares reported herein except to the extent of its or his pecuniary interest therein.

Item 5.          Ownership of Five Percent or Less of a Class:

If this statement is being filed to report the fact that as of the date hereof the Reporting Person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following x.

Item 6.          Ownership of More than Five Percent on Behalf of Another Person:

Not applicable.

Item 7.          Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person:

Not applicable.

CUSIP No. 68230A106

Item 8.          Identification and Classification of Members of the Group:

Not applicable.

Item 9.          Notice of Dissolution of Group:

Not applicable.

Item 10.         Certification:

By signing below I hereby certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Exhibits

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.