Teva And OncoGenex Announce Joint Prostate Cancer Drug Fails Clinical Trial

Teva and OncoGenex have announced that their joint prostate cancer drug has failed its phase 3 clinical trial, as the drug did not show any significant improvement over standard chemotherapy treatments in patients. The drug, custirsen, was in a phase-3 trial. The drug was used to treat castrate-resistant prostate cancer patients in combination with chemotherapy, however the primary endpoint for the trial —significant improvement in overall survival over men treated with docetaxel/prednisone alone — was not achieved.

Custirsen works by blocking the production of the clusterin protein. The clusterin protein is believed to play an important role in the survival of cancer cells, and researchers believe that it also aids cancer cells in their ability to gain resistance to treatments over time. Researchers have linked faster clusterin protein production to faster rates of cancer progression.

The results of the clinical trial were unexpected by both the market and the pharmaceutical companies involved in the development of the drug. Scott Cormack, the president and CEO of OncoGenex, said that both companies would be studying the factors that resulted in the failed trial.

“The results of SYNERGY are unexpected, particularly given the wealth of scientific evidence supporting the targeting of clusterin to combat treatment resistance in first-line prostate cancer,” said Cormack. “A thorough analysis of the data is underway to understand the potential factors that may have contributed to the results. Importantly, we remain strong in our belief that targeting mechanisms of treatment resistance is a critical path forward in the fight against cancer and we continue to actively pursue this approach through the two ongoing Phase 3 trials of custirsen and the seven Phase 2 trials of apatorsen in four tumor types.”