A Phase I/II Study of Ipilimumab Given with Abiraterone and Prednisone in Men with Metastatic Castration-Resistant Prostate Cancer

Prostate cancer needs the male hormone testosterone for growth. Hormone therapies that lower the level of testosterone are among the most effective treatments for prostate cancer that have spread to other organs (metastasized). The benefit of hormone treatments does not last, however. Over time, many patients with metastatic prostate cancer develop disease progression despite hormonal therapies (“castration-resistant” prostate cancer).

Abiraterone acetate and prednisone are drugs used together to treat metastatic castration-resistant prostate cancer. The purpose of this study is to evaluate the safety and effectiveness of adding ipilimumab to abiraterone and prednisone in men with metastatic castration-resistant prostate cancer who have not yet been treated with chemotherapy or immunotherapy.

Ipilimumab is an antibody against CTLA-4, a molecule that controls a part of the immune system by shutting it down. Researchers believe that one way cancers can escape the immune system could be through this shut-down mechanism. Ipilimumab stops CTLA-4 from turning off the immune system. This may allow an immune reaction help the body to destroy remaining cancer cells. Ipilimumab is approved for treating melanoma, but its use in men with prostate cancer is considered investigational.