ESSA Pharma Inc. (EPIX) has decided to halt its Phase 2 clinical trial that compared masofaniten combined with enzalutamide against enzalutamide alone, in patients with metastatic castration-resistant prostate cancer who are yet to be treated with second-generation antiandrogens.
This decision followed a protocol-mandated interim review examining safety, pharmacokinetics, and efficacy data. The review indicated a significantly higher rate of PSA90 response in patients treated solely with enzalutamide than anticipated when considering historical data. Furthermore, the combination of masofaniten and enzalutamide did not demonstrate any clear efficacy advantage compared to enzalutamide monotherapy. A futility analysis indicated a low probability of achieving the study's predefined primary endpoint.
The combination of masofaniten with enzalutamide was found to be well-tolerated, producing no new safety issues and maintaining a safety profile consistent with observations from Phase 1 studies.
The company has announced plans to pursue a strategic review process to examine a variety of options aimed at maximizing shareholder value. In line with refocusing its resources, ESSA also intends to discontinue other ongoing company-sponsored and investigator-sponsored clinical trials involving masofaniten, whether as a standalone treatment or in conjunction with other agents.
