Risk Factors for Niraparib-induced Severe Anemia in Japanese Patients With Ovarian Cancer: A Multicenter Study

Background/Aim: Niraparib is an effective maintenance therapy after platinum-based chemotherapy for ovarian cancer. However, niraparib-induced anemia, particularly when severe, often leads to treatment discontinuation and reduced quality of life. Although its incidence and time to onset have been reported, specific risk factors remain unclear, and little real-world data have been published for Japanese patients. Herein, we aimed to identify risk factors for grade ≥3 anemia to support earlier intervention and optimized management.

Patients and Methods: This multicenter, retrospective, observational cohort study included patients initiated on niraparib from November 2020 to November 2023 for ovarian, fallopian tube, or primary peritoneal cancer. For the primary endpoint, we identified baseline risk factors for the initial occurrence of grade ≥3 anemia by using multivariable logistic regression. Secondary endpoints were the time to onset, symptom occurrence, and management strategies.

Results: Among 252 patients, 18.2% developed grade ≥3 anemia. None of the evaluated baseline factors were independently associated with such anemia. The proportion of participants free from grade ≥3 anemia was 92.6% by day 56 and 78.7% by day 168. Fatigue and dyspnea were reported by 19.6% and 10.9% of participants, respectively. Management for niraparib-induced anemia included red blood cell transfusion (32.6%) and niraparib discontinuation (23.9%).

Conclusion: Although no baseline risk factors for niraparib-induced severe anemia were identified, our real-world data clarified its incidence, timing, symptoms, and management in Japanese patients. These findings suggest that continuous monitoring for anemia-related symptoms, in addition to hemoglobin levels, is essential for earlier intervention and optimized niraparib therapy.