Japan Phase 2 Study of Niraparib (Maintenance Therapy) in Participants With Relapsed Ovarian Cancer

Inclusion Criteria

• Japanese female participants aged 20 years or older on the day of signing informed consent.
• Voluntary written consent must be given before performance of any study related procedure not part of standard medical care, with the understanding that consent may be withdrawn by the participant at any time without prejudice to future medical care.
• Participant must have a histologically diagnosed ovarian cancer, fallopian tube cancer, or primary peritoneal cancer.
• Participant must have a high-grade (or Grade 3) serous or high-grade predominantly serous histology or known to have germline breast cancer gene mutation (gBRCAmut).
• Participants must have completed at least 2 previous lines of platinum-containing therapy (eg, carboplatin, oxaliplatin, or cisplatin):

Note: The last platinum regimen did not necessarily have to immediately follow the next-to-last (penultimate) platinum regimen. For example, if a participant received a non-platinum regimen between the penultimate platinum regimen and last platinum regimen, she could have been eligible as long as she met all entry criteria.

• For the penultimate platinum-based chemotherapy prior to study enrollment, participants must have had platinum-sensitive disease after this treatment, defined as achieving a response (CR or PR) and disease progression >6 months after completion of her last dose of platinum therapy (documented 6 to 12 months or >12 months). Source documentation was required.
• For the last line of platinum-based chemotherapy prior to study enrollment:
• Participants must have received a platinum-containing regimen for a minimum of 4 cycles.
• Participants must have achieved a partial or complete tumor response.
• Following the last regimen, participants must have had either: CA-125 in the normal range, OR; CA-125 decrease by more than 90% during the last platinum regimen, and which was stable for at least 7 days (ie, no increase >15%).
• Following the last regimen, participants could not have had any measurable lesion >2 cm at the time of study enrollment.
• Participants must have been enrolled within 8 weeks after completion of their final dose of the platinum-containing regimen.
• Participants must have performance status of ≤1 on the Eastern Cooperative Oncology Group (ECOG) Performance Status Scale.
• Participants must have adequate organ function as indicated by the following laboratory values:
• Absolute neutrophil count (ANC) ≥1,500/μL.
• Platelet count ≥100,000/μL.
• Hemoglobin ≥9 g/dL.
• Serum creatinine ≤1.5× institutional upper limit of normal (ULN) OR calculated creatinine clearance ≥50 mL/minute, using the Cockcroft-Gault equation.
• Total bilirubin ≤1.5×ULN OR direct bilirubin ≤1×ULN.
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5×ULN unless liver metastases were present, in which case they had to be ≤5×ULN.
• Participants must be able to take oral medications.
• Female participants of childbearing potential must be negative for pregnancy test (beta-human chorionic gonadotropin [β-hCG]) within 7 days prior to receiving the first dose of study treatment.
• Female participants who:
• Are postmenopausal for at least 1 year before the screening visit, OR
• Are surgically sterile, OR
• If they are of childbearing potential, agree to practice 1 highly effective method of contraception and 1 additional effective (barrier) method at the same time, from the time of signing the informed consent through 180 days after the last dose of study drug, OR
• Agree to practice true abstinence, when this is in line with the preferred and usual lifestyle of the participant. (Periodic abstinence [eg, calendar, ovulation, symptothermal, postovulation methods], condoms only, withdrawal, spermicides only, and lactational amenorrhea are not acceptable methods of contraception. Female and male condoms should not be used together.)

Exclusion Criteria

• Participants who have had drainage of ascites dur