Secondary analysis of phase III data for OGX 011 (custirsen) in prostate cancer shows some benefit- OncoGenex Pharmaceuticals

OncoGenex Pharmaceuticals announced results from additional exploratory analyses of the Phase III SYNERGY trial demonstrating that OGX 011 (custirsen) treatment significantly lowered serum clusterin (sCLU) levels from baseline in men with metastatic castrate-resistant prostate cancer (mCRPC). In addition, these data showed that sCLU reductions after custirsen treatment resulted in higher two-year survival rates in patients who were at increased risk for poor outcomes. Of those patients with lower sCLU levels, the data also showed a correlation to an overall survival benefit for custirsen-treated patients who were at increased risk for poor outcomes.

A previous retrospective analysis from the SYNERGY trial showed a benefit with custirsen therapy in men with metastatic CRPC who had at least two of five common risk factors for poor prognosis. For those men, a 27 percent lower risk of death occurred when custirsen was used in combination with first-line docetaxel compared to docetaxel alone. Data were presented at the 2015 European Cancer Congress in Vienna.

Comment: The treatment has not performed well in previous trials. In the Phase III SYNERGY trial, top-line survival results indicated that the addition of custirsen to standard first-line docetaxel / prednisone therapy did not meet the primary endpoint of a statistically significant improvement in overall survival in men with metastatic castrate-resistant prostate cancer (CRPC), compared to docetaxel / prednisone alone (median survival 23.4 months vs 22.2 months, respectively).