Serum Creatinine Elevation as a Risk Factor for Niraparib-induced Hematologic Toxicity.

BACKGROUND/AIM:Niraparib dosages can be individualized to reduce the starting dose based on body weight and baseline platelet count. However, even with individualized dosing, scattered cases of ≥Grade 3 hematologic toxicity occur. This study explored markers predictive of serious hematologic toxicity in niraparib therapy. PATIENTS AND METHODS:This retrospective observational study investigated patients who started niraparib therapy at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research between December 2020 and March 2022. Associations between hematologic toxicities and serum creatinine ratio (percentage increase in serum creatinine between baseline and after niraparib initiation) were investigated. RESULTS:Out of 50 ovarian cancer patients who initiated niraparib, 45 patients were included in the final analysis. Twenty-three patients (51.1%) developed ≥Grade 3 hematologic toxicity, with neutropenia in 17 (37.8%), anemia in 9 (20.0%), and thrombocytopenia in 4 (8.9%). Patients with Grade 4 hematologic toxicity showed higher serum creatinine ratios than those with ≤Grade 2. Thrombocytopenia ≥Grade 3 occurred only within 2 months of niraparib initiation and was preceded by an increase in serum creatinine in all affected patients. CONCLUSION:Serum creatinine ratio offers a potential marker for predicting severe hematologic toxicity following niraparib therapy.