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Clinical Data on OGX-427 Presented at the ASCO 2012 Genitourinary Cancers Symposium Provide Ongoing Evidence of Hsp27 as a Potential Therapeutic Target in Advanced Prostate Cancer

OncoGenex Announces Plans to Initiate a Phase 2 Study of OGX-427 in Combination with Zytiga® (abiraterone) in Castrate-Resistant Prostate Cancer
BOTHELL, Wash. and VANCOUVER, British Columbia, Feb. 2, 2012 /PRNewswire/ -- OncoGenex Pharmaceuticals, Inc. (NASDAQ: OGXI) announced today preliminary results from a Phase 2 prostate cancer study with its investigational compound OGX-427, which is designed to inhibit the production of Hsp27. Hsp27 is a cell-survival protein expressed in many types of cancers including prostate, bladder, breast and non-small cell lung cancer. Overexpression of Hsp27 is thought to be an important factor leading to the development of treatment resistance and is associated with negative clinical outcomes in patients with various tumor types.

In chemotherapy-naive patients with metastatic castrate-resistant prostate cancer (mCRPC), preliminary study results showed a higher number of patients without disease progression at 12 weeks, and greater declines in prostate-specific antigen (PSA) and circulating tumor cells (CTC) with OGX-427 plus prednisone treatment compared to prednisone alone. These data are being presented in conjunction with the American Society of Clinical Oncology (ASCO) 2012 Genitourinary Cancers Symposium held this weekend in San Francisco. Results of a Phase 1 study of OGX-427 in patients with superficial bladder cancer will also be presented at this meeting. 

In the first 32 patients randomized to the mCRPC Phase 2 study, 17 patients received OGX-427 plus prednisone and 15 patients received prednisone alone. Available preliminary data are as follows:

•In the OGX-427 plus prednisone arm, 71% of patients were progression-free at 12 weeks, compared to 33% in the prednisone alone arm. The primary efficacy endpoint of this study is defined as the proportion of patients without disease progression at 12 weeks where disease progression is based on any of the following parameters: PSA levels, measurable disease, bone lesions, global deterioration or requiring palliative radiation therapy.
•Among patients who received OGX-427 plus prednisone, 76% experienced an overall decline in PSA compared to 53% in the prednisone alone arm.
•Forty-one percent of patients who received OGX-427 plus prednisone experienced a >50% decline in PSA, versus 20% of patients who received prednisone alone.
•CTC declines from ≥5 to <5 occurred in 50% of patients receiving ogx-427 plus prednisone compared to 31% those treated with alone.
•Among the 17 patients with baseline measurable disease, 38% of patients who received OGX-427 plus prednisone (n=8) had a partial response compared to 0% in the prednisone alone arm (n=9).
•Adverse events reported in both arms were primarily grade 1 or 2 with grade 3 or higher adverse events reported in 31% of patients in the OGX-427 plus prednisone arm and 25% in the prednisone alone arm.
•OGX-427 infusion reactions occurred and were primarily grade 1 or 2 chills, nausea, vomiting, flushing or diarrhea. Other adverse events in 2 or more patients thought to be related to OGX-427 were fatigue, dizziness, decreased appetite, and pyrexia.
"The PSA declines, progression free survival at 12 weeks, and response rates observed thus far are supportive of OGX-427's ability to suppress androgen receptor activity and tumor cell survival through inhibition of Hsp27," said Dr. Kim Chi, a medical oncologist at BC Cancer Agency, British Columbia, Canada, and the primary investigator on the study. "This warrants further study, particularly in combination with other agents targeting the androgen pathway, such as abiraterone acetate."

OncoGenex is hosting an investigator panel today (February 2, 2012) to discuss these preliminary study results as well as on-going and future development plans including an investigator-initiated, randomized, controlled Phase 2 study evaluating OGX-427 in combination with abiraterone for the treatment of mCRPC, supported in part by grant funding.

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 statements regarding the potential benefits and potential development 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 that final trial results will not demonstrate the same or any potential benefit as observed in preliminary trial results, the risk that subsequent studies may not confirm earlier trial results, the risk of delays in our expected clinical trials, the risk that new developments in the rapidly evolving cancer therapy landscape require changes in our clinical trial plans 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 third quarter ended September 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.

Zytiga is a registered trademark of the Johnson & Johnson Corporation

SOURCE OncoGenex Pharmaceuticals, Inc.

Posted: February 2012