A Phase III Study of Abiraterone Acetate and Prednisone with and without Niraparib to Treat Metastatic Prostate Cancer


Full Title

A Phase 3 Randomized, Placebo-controlled, Double-blind Study of Niraparib in Combination with Abiraterone Acetate and Prednisone Versus Abiraterone Acetate and Prednisone for Treatment of Subjects with Metastatic Prostate Cancer (WIRB)


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 is a drug given with prednisone to treat CRPC, but the cancer eventually continues to grow. In this study, researchers want to see if adding the drug niraparib to treatment with abiraterone acetate and prednisone is more effective than abiraterone acetate and prednisone on their own.

Niraparib works by inhibiting PARP, a protein that helps cancer cells repair DNA that has been damaged by cancer treatments. When cancer cells repair damaged DNA, they can continue growing and multiplying, so depriving them of this power with a PARP inhibitor may be an effective approach to treatment. It is approved for treating ovarian cancer; its use in this study is considered investigational.

Patients in this study will be randomly assigned to receive abiraterone acetate/prednisone/niraparib or abiraterone acetate/prednisone/placebo. All of the medications used in this study are taken orally (by mouth).


To be eligible for this study, patients must meet several criteria, including but not limited to the following:

  • Patients must have CRPC and may not have previously received a PARP inhibitor.
  • Patients should recover from the serious side effects of prior therapies before entering the study.
  • Patients must be physically well enough that they are fully ambulatory, capable of all self-care, and capable of all but physically strenuous activities. As an example, patients must be well enough that they would be able to carry out office work or light housework.
  • This study is for men age 18 and older.

For more information about this study and to inquire about eligibility, please contact Dr. Dana Rathkopf at 646-422-4379.





Disease Status

Newly Diagnosed & Relapsed/Refractory