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.