Niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer: final results of a multicenter phase 2 study.

Objective: This study evaluated the long-term safety and efficacy of niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer.
Methods: This was a follow-up analysis of a phase 2, multicenter, open-label, single-arm study in Japanese women with platinum-sensitive, relapsed ovarian cancer. Participants received niraparib (starting dose 300 mg) once daily in continuous 28-day cycles. The primary endpoint was the incidence of Grade 3 or 4 thrombocytopenia-related events (defined as the overall incidence of the MedDRA Preferred Terms "thrombocytopenia" and "platelet count decreased") occurring in the 30 days after initial administration of niraparib, and secondary endpoints included evaluation of treatment-emergent adverse events and progression-free survival.
Results: Nineteen patients (median age, 62 years; median body weight, 53.9 kg) were enrolled. As previously reported, the incidence of Grade 3 or 4 thrombocytopenia-related events during the first 30 days of treatment was 31.6%. At data cutoff, median (range) treatment exposure was 504.0 (56-1,054) days and mean ± standard deviation dose intensity was 154.4±77.5 mg/day. The most common treatment-emergent adverse events were nausea (n=14, 73.7%), decreased platelet count (n=12, 63.2%), decreased neutrophil count (n=11, 57.9%), anemia, vomiting, and decreased appetite (all n=9, 47.4%). One patient was diagnosed with treatment-related leukemia, which resulted in death. Median (95% confidence interval) progression-free survival was 18.0 (5.6-26.7) months.
Conclusion: Overall, the safety profile of niraparib was considered manageable in this study population of Japanese patients with platinum-sensitive, relapsed ovarian cancer and was consistent with that observed in studies of non-Japanese patients.
Trial Registration: ClinicalTrials.gov Identifier: NCT03759587.
Competing Interests: Kosei Hasegawa declares the receipt of research grants from Daiichi Sankyo, Eisai, MSD, and Takeda Pharmaceuticals Company Ltd, honoraria from AstraZeneca, Chugai, Daiichi Sankyo, Eisai, Genmab, Kaken, Kyowa Kirin, MSD, Sanofi, and Takeda Pharmaceuticals Company Ltd, and travel expenses from Regeneron. Kosei Hasegawa is also on the advisory board of Chugai, Eisai, Genmab, MSD, Roche, Sanofi, and Takeda Pharmaceuticals Company Ltd. Shoji Nagao declares the receipt of grants from AstraZeneca, consulting fees from AstraZeneca, and honoraria from AstraZeneca, Chugai, Eisai, MSD, and Takeda Pharmaceuticals Company Ltd. Kazuhiro Takehara declares the receipt of speaker bureaus fees from AstraZeneca, MSD, and Takeda Pharmaceutical Company Ltd, and manuscript writing fees from MSD. Hidekatsu Nakai and Hidemichi Watari declare the receipt of lecture fees from Takeda Pharmaceutical Company Ltd. Shuuji Sumino is an employee of Takeda Pharmaceutical Company Ltd. Yoichi Kase and Ai Kato are employees of, and hold stocks in Takeda Pharmaceutical Company Ltd. Ajit Suri is an employee of Millennium Pharmaceuticals, part of Takeda Pharmaceutical Company Ltd, and holds stocks in Takeda Pharmaceutical Company Ltd. Other authors have no conflict of interest to disclose.
(© 2024. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology, and Japan Society of Gynecologic Oncology.)