OncoGenex Announces Publication of Custirsen Phase II Clinical and Pre-Clinical Data in Leading Cancer Journals

BOTHELL, Wash. and VANCOUVER, British Columbia, Sept. 6, 2011 /PRNewswire/ -- OncoGenex Pharmaceuticals, Inc. (NASDAQ: OGXI) announced today that data from two studies, a Phase II clinical study and a pre-clinical study, evaluating the investigational compound custirsen (OGX-011/TV-1011), were published in the September issues of the journals Clinical Cancer Research and Cancer Research.

Custirsen inhibits the production of clusterin, a protein commonly over-produced in cancer cells and a cause of treatment resistance. Two Phase III studies evaluating custirsen in men with castrate-resistant prostate cancer (CRPC) are ongoing: the SYNERGY clinical trial - designed to evaluate an overall survival benefit for custirsen in combination with first-line docetaxel treatment, and the Prostate Cancer SATURN Trial - which will evaluate a durable pain palliation benefit in patients receiving second-line chemotherapy. Both studies are currently enrolling CRPC patients.

Phase II Data Published in Clinical Cancer Research

Data from a Phase II clinical study of custirsen in combination with docetaxel retreatment or mitoxantrone as second-line chemotherapy in patients with metastatic castrate-resistant prostate cancer (mCRPC) was published in the September 1, 2011 issue of Clinical Cancer Research.

In the clinical study, custirsen combined with docetaxel retreatment resulted in overall survival of 15.8 months. When custirsen was combined with mitoxantrone, overall survival was 11.5 months. The Phase II study also evaluated pain responses in patients with mCRPC. Overall, the pain response was durable (greater than or equal to three months) in 88 percent of patients who had pain or were on opioids for pain at study entry.

"These are encouraging results because we observed durable pain responses in many patients who had disease progression while on or shortly after first-line docetaxel treatment," said Dr. Fred Saad, Professor of Surgery/Urology at the University of Montreal and lead investigator on the study. "These data suggest that custirsen may restore docetaxel sensitivity and potentially provide improvements in pain control for this difficult-to-treat patient population."

The authors concluded that the study's results, which demonstrated feasibility, safety and pain relief, as well as an association of low serum clusterin levels with longer survival, provides a consistent signal that warrants further testing of custirsen combined with second-line chemotherapy in mCRPC.

The abstract can be found at the following link:

http://clincancerres.aacrjournals.org/content/17/17/5765.abstract

Pre-Clinical Data Published in Cancer Research

Pre-clinical data published in the September 1, 2011 issue of Cancer Research, demonstrated that clusterin inhibition using custirsen synergistically enhanced Heat-shock 90 (Hsp90) inhibitor activity by suppressing the heat shock response in CRPC.

Heat-shock 90 (Hsp 90) inhibitors trigger the elevation of compensatory survival mechanisms that result in the production of clusterin, leading to cancer cell survival and treatment resistance. Results of this study demonstrated that when custirsen was combined with the Hsp90 inhibitor PF-04929113 or 17-AAG, the compounds worked synergistically to inhibit CPRC tumor cell growth in mice.

"These data support the broad, potential applicability of custirsen in combination with various anti-cancer treatments," said Dr. Martin Gleave, Director of The Vancouver Prostate Centre at The University of British Columbia and researcher on the study. "This study is an example of how we continue to develop a greater understanding of cancer treatment resistance and identify opportunities to block these mechanisms in order to delay tumor progression."

The abstract can be found at the following link:

http://cancerres.aacrjournals.org/content/71/17/5838.abstract

About Custirsen

Custirsen is the only compound currently in development designed to inhibit the production of clusterin, a protein commonly over-produced in cancer cells, and one cause of treatment resistance. Unlike opioids or agents that target the androgen receptor, custirsen is mechanistically unique in its ability to impact pain responses via the regulation of NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity.  This is a potential attribute that could contribute to custirsen's clinical benefit in combination with numerous anti-cancer treatments.

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

More information is available at www.OncoGenex.com and www.tevapharm.com/research.

About OncoGenex Pharmaceuticals

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 diverse oncology pipeline, with each product candidate having a distinct mechanism of action and representing a unique opportunity for cancer drug development. OncoGenex and Teva Pharmaceutical Industries Ltd. (NASDAQ: TEVA) have entered a global collaboration and license agreement to develop and commercialize OncoGenex' lead drug candidate, custirsen. Custirsen is currently in Phase III clinical development as a treatment in men with metastatic castrate-resistant prostate cancer. The companies plan to begin Phase III development of custirsen in first-line treatment of advanced, unresectable non-small cell lung cancer. OGX-427 is in Phase II clinical development; CSP-9222 and OGX-225 are currently in pre-clinical development.

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, such as expected clinical trial initiation and completion dates, patient enrollment targets, proposed amendments to our ongoing clinical trial design and the timing and possibility for approval by the FDA thereof, the timing and costs of our product development 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, the risk of delays in our expected clinical trials and the uncertainties regarding patient enrollment rates, the risk that the FDA does not approve our proposed amendment to the Saturn trial design in a timely fashion or at all, the risk that our product candidates do not obtain the requisite regulatory approvals to commercialize, the risk that new developments in the rapidly evolving prostate cancer therapy landscape require additional changes in our clinical trial design or limit the potential benefits of our product and the other factors described in our risk factors set forth in our filings with the Securities and Exchange Commission from time to time, including the Company's Quarterly Report on Form 10-Q for second quarter ended June 30, 2011. 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 by applicable law.

SOURCE OncoGenex Pharmaceuticals, Inc.