Incidence of grade 3–4 adverse events, dose reduction, and treatment discontinuation in castration-resistant prostate cancer patients receiving PARP inhibitors: a meta-analysis

Background: PARP inhibitors (PARPi) have recently emerged as a new treatment option for several solid tumors, including metastatic castration-resistant prostate cancer (mCRPC). However, several grade 3–4 adverse events have been reported during PARPi administration, leading to limitations in treatment adherence. Methods: Herein, we conducted a meta-analysis aimed at analyzing the incidence rate of commonly reported grade 3–4 adverse events, dose reduction, and treatment discontinuation in mCRPC patients treated with PARPi monotherapy. Results: Incidence rate with 95% confidence intervals (CIs) of grade 3–4 toxicities, dose reduction, and treatment discontinuation were calculated. Six trials involving 752 mCRPC patients were available for the meta-analysis. According to our results, anemia was the most frequently observed grade 3–4 toxicity (24.1%), and dose reduction (26.9%) and treatment discontinuation (14.1%) were common events during PARPi treatment. Conclusions: Clinicians should carefully consider these risks, especially taking into account that the use of PARPi in mCRPC patients is expected to rise in the near future.