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 /CNW/ - 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% of those treated with prednisone 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).