Clinical evaluation of combined programmed cell death protein 1 inhibitor and poly(ADP-ribose) polymerase inhibitor in metastatic castration-resistant prostate cancer patients: Insights from a real-world study.

Background: This study aimed to evaluate the clinical efficacy and safety of combining a programmed cell death protein 1 (PD-1) inhibitor with a poly(ADP-ribose) polymerase inhibitor (PARPi) in patients with metastatic castration-resistant prostate cancer (mCRPC) who progressed after multiple lines of treatment, from a real-world perspective. Materials and methods: This open-label, single-arm, prospective study enrolled patients with mCRPC who had experienced disease progression after docetaxel and at least 2 lines of next-generation hormonal agents to receive camrelizumab (PD-1 inhibitor) and fluzoparib (PARPi). The primary endpoints were radiographic progression-free survival and overall survival (OS), and the secondary endpoints were prostate-specific antigen progression-free survival and safety. Results: Eight patients with mCRPC who met the inclusion criteria were enrolled. The results showed that the median radiographic progression-free survival was 5.1 months, the median OS was 8.1 months, and the median prostate-specific antigen progression-free survival was 3.1 months. Safety analysis revealed that 87.5% of the patients experienced one or more treatment-related adverse events (AEs), with 37.5% reporting grade 3 or higher treatment-related AEs. None of the patients discontinued treatment because of treatment-related AEs. Conclusions: This real-world study demonstrated that the combination of a PD-1 inhibitor and PARPi exhibited sustained antitumor activity with an acceptable safety profile in the fourth-line treatment of patients with mCRPC.