Japan Phase 2 Study of Niraparib in Participants With Advanced, Relapsed Ovarian Cancer

The drug being tested in this study is called niraparib. Niraparib is being tested to treat people who have the homologous recombination deficiency (HRD)-positive, advanced, relapsed, high-grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer. This study will look at the efficacy and safety of niraparib in Japanese participants. The study will enroll approximately 16 participants. Participants will be enrolled to one group and after that will be asked to take niraparib capsules at the same time each day throughout the study: \- Niraparib 300 mg This multi-center trial will be conducted in Japan. The overall time to participate in this study is approximately 23 months. Participants will make multiple visits to the clinic in the treatment period, and the post-treatment period including follow-up assessments after the last dose of the study drug.