Prostate cancers initially need the male hormone testosterone for growth. Hormone therapies that lower the level of testosterone are among the most effective treatments for prostate cancers that have spread to other organs (metastasized). The benefits of hormone treatments do not last, however. Over time, many prostate cancers continue to grow despite hormonal therapies; these are called “castration-resistant prostate cancers” (CRPC).
Abiraterone acetate and cabazitaxel are drugs that are both approved for treating CRPC. Abiraterone, which is given with prednisone, works by blocking the production of cancer-fueling testosterone by inhibiting an enzyme called CYP17. Cabazitaxel makes the “skeleton” in some cancer cells very stiff, so the cells can no longer grow or divide. Both abiraterone and cabazitaxel are given to men whose cancer has progressed despite docetaxel chemotherapy.
In this study, researchers are assessing the safety and effectiveness of combining abiraterone, prednisone, and cabazitaxel in men with CRPC who have not yet received docetaxel. This approach is considered investigational. Patients will be randomly assigned to one of two groups:
- One group will receive abiraterone and prednisone, but will not receive cabazitaxel unless the cancer continues to grow despite abiraterone/prednisone therapy.
- The second group will receive all three drugs together.
Abiraterone and prednisone are taken orally (by mouth), while cabazitaxel is given intravenously (by vein).