Journal of Clinical Oncology Publishes Data from Randomized Phase 2 Custirsen Trial Randomized Phase 2 Study of Docetaxel and Prednisone With or Without OGX-011 in Patients With Metastatic Castration-Resistant Prostate C

Journal of Clinical Oncology Publishes Data from

Randomized Phase 2 Custirsen Trial

Randomized Phase 2 Study of Docetaxel and Prednisone With or Without OGX-011 in Patients With Metastatic

Castration-Resistant Prostate Cancer. Chi K.N., et al. JCO Sep 20, 2010: 4247-4254

BOTHELL, WA and VANCOUVER, CANADA, September 22, 2010 OncoGenex Pharmaceuticals, Inc. (NASDAQ: OGXI) announced today

publication of results from a randomized Phase 2 trial in the Journal of Clinical Oncology. The trial results showed a

survival benefit with the investigational agent OGX-011/TV1011 (custirsen) in patients with advanced prostate cancer.

The median overall survival for patients who were treated with custirsen plus first-line docetaxel/prednisone was 23.8

months compared to 16.9 months for patients treated with docetaxel/prednisone alone. The manuscript was published in

the September 20, 2010 issue of the journal.

The survival analysis provides a strong suggestion of clinical benefit with a hazard ratio consistent with a 50%

reduction in the rate of death favoring custirsen treatment, said Dr. Kim Chi, Principal Investigator and medical

oncologist at BC Cancer Agency. These data provide the foundation and rationale for the upcoming SYNERGY Phase 3 trial

evaluating custirsen in approximately 800 men with metastatic CRPC.

The study investigators concluded custirsen in combination with docetaxel was well tolerated. Furthermore, they noted

that adverse events associated with custirsen, including lymphopenia, rigors and fever have been reported with other

antisense therapeutics.

Analysis of trial results also showed:

Despite the number of new treatment options for patients with advanced prostate cancer, many patients will eventually

experience disease progression. We believe custirsen has the potential to reduce treatment resistance thereby

increasing the efficacy of various therapeutic agents such as docetaxel, and are hopeful this will be confirmed through

the Phase 3 development program, said Scott Cormack, president and CEO of OncoGenex.

In 2009, Teva Pharmaceutical Industries Ltd. and OncoGenex Pharmaceuticals, Inc. entered into a global license and

collaboration agreement to develop and commercialize custirsen.

Phase 2 Study Design

In this Phase 2 study, 82 patients were randomized to one of two treatment arms to receive either 640 mg per week of

custirsen by intravenous infusion in combination with docetaxel/prednisone or docetaxel/prednisone alone. Patients in

both treatment arms received therapy until disease progression, toxicity or completion of ten 3-week cycles of therapy.

The primary endpoint of the trial was to achieve a 50% reduction in PSA from baseline in over 50% of the patients

treated with custirsen plus docetaxel. Secondary endpoints included determining objective response and duration of

response in those patients with measurable disease at baseline, determining the tolerability and toxicity of weekly

custirsen in combination with docetaxel/prednisone, measuring the effect of custirsen on serum clusterin levels and

describing time to progression and overall patient survival. Baseline characteristics were well balanced between the

Custirsen is designed to inhibit the production of clusterin, a protein that is associated with cancer treatment

resistance. In 2009, Teva Pharmaceutical Industries Ltd. and OncoGenex Pharmaceuticals, Inc. entered into a global

license and collaboration agreement to develop and commercialize custirsen. The global Phase 3 clinical programs

include both the ongoing SATURN Phase 3 trial assessing durable pain palliation as the primary endpoint for second-line

chemotherapy in men with metastatic CRPC and the upcoming SYNERGY Phase 3 trial assessing survival as the primary

endpoint in men with metastatic CRPC receiving first-line chemotherapy. A third Phase 3 trial assessing survival as the

primary endpoint in first-line treatment of advanced, unresectable non-small cell lung cancer (NSCLC) is also planned

as part of the global clinical program to commercialize custirsen.

More information on the SATURN trial is available on the OncoGenex website at

http://oncogenex.com/clinicalTrials/index.html.

Custirsen has received Fast Track designation from the U.S. Food and Drug Administration (FDA). Both the Prostate

Cancer SATURN trial and the SYNERGY trial are being conducted through the Special Protocol Assessment (SPA) process. In

addition, the European Medicines Agency indicated that the Committee for Medicinal Products for Human Use was in

overall agreement with the custirsen development plan for commercialization.

OncoGenex is a biopharmaceutical company committed to the development and commercialization of new cancer therapies

that address treatment resistance in cancer patients. OncoGenex has a deep oncology pipeline, with each product

candidate having a distinct mechanism of action and representing a unique opportunity for cancer drug development. OncoGenex and Teva

Pharmaceuticals have entered a global collaboration and license agreement to develop and commercialize OncoGenex lead

drug candidate, custirsen. Custirsen is currently in Phase 3 clinical development as a treatment in men with metastatic

castrate-resistant prostate cancer. The companies plan to begin Phase 3 development of custirsen in first-line

treatment of advanced, unresectable non-small cell lung cancer in 2011. OGX-427 is entering Phase 2 clinical

development; SN2310 has completed a Phase 1 clinical trial; and CSP-9222 and OGX-225 are currently in pre-clinical

Custirsen utilizes second-generation antisense technology, licensed from Isis Pharmaceuticals (NASDAQ: ISIS), to target

and inhibit production of clusterin. OncoGenex and Isis partnered in the successful discovery and initial development

of custirsen. Teva and OncoGenex are responsible for the development and commercialization of custirsen, subject to

their global collaboration and license agreement and subject to OncoGenex s financial obligations to Isis. Key

intellectual property related to custirsen, OGX-427 and OGX-225 were discovered by the University of British Columbia

and the Vancouver Prostate Centre, and were exclusively licensed to OncoGenex.

More information is available at www.OncoGenex.com.

OncoGenex Forward Looking Statements

This press release contains forward-looking statements within the meaning of the safe harbor provisions of the

Private Securities Litigation Reform Act of 1995, including, but not limited to, statements concerning our anticipated

product development activities, the timing and costs of these activities and the potential benefits of our product

candidates. All statements other than statements of historical fact are statements that could be deemed forward-looking

statements. These statements are based on management s current expectations and beliefs and are subject to a number of

risks, uncertainties and assumptions that could cause actual results to differ materially from those described in the

forward-looking statements. Such forward-looking statements are subject to risks and uncertainties, including, among

others, uncertainties regarding our future operating results, the risk that our product candidates will not obtain the

requisite regulatory approvals to commercialize or that the future sales of our product candidates may be less than

expected, and the risk factors set forth in the Company s filings with the Securities and Exchange Commission,

including the Company s Annual Report on Form 10-K for fiscal year 2009 and the Company s Quarterly Report on Form 10-Q

for the quarter ended June 30, 2010. The Company undertakes no obligation to update the forward-looking statements

contained herein or to reflect events or circumstances occurring after the date hereof, other than as may be required