OBJECTIVES: Prostate cancer represents the second most common cancer in men worldwide and the fifth most common cause of cancer death in the United States. Castration-resistant prostate cancer (CRPC) is a form of advanced prostate cancer. With mCRPC, the cancer stops responding to hormone treatment, and metastasizes

The phase-3 KEYNOTE-641 trial (NCT03834493) data indicates in-effectiveness of pembrolizumab in combination with hormonal therapy for mCRPC patients as it failed to reach its primary end points (progression free survival and overall survival) and the trial was discontinued. In this review, we aim to evaluate the rate of adverse events (AEs) with pembrolizumab either alone or in combination with some other drug in mCRPC patients.

METHODS: A comprehensive search was conducted between 2018-2023 using biomedical databases (MEDLINE®, EMBASE®, PubMed) and supplementary searches were performed to summarize evidence from grey literature. Two independent researchers performed the analysis of the included studies, and third researcher resolved any kind of conflict.

RESULTS: A total of 118 studies were identified, of those 12 studies were included. Most of the included studies were phase 1/2 (n=08) among which the most common grade 3-5 treatment related adverse events (TRAEs) were anemia (27%), febrile neutropenia (12%), fatigue (5.9%) and decreased neutrophil count (5.8%). Most reported any grade or grade 1-2 TRAEs were chills (89.2%), pyrexia (54.1%), and nausea (45.9%).

For the remaining 04 studies, the most common grade 3-5 TRAEs were anemia (19.6%), fatigue (3%), and asthenia (2.3%). Most reported any grade TRAEs were anemia (46%), nausea (35.6%), fatigue (25.7%). Grade 1-2 AEs were fatigue (66.7%) and hot flashes (50%).

CONCLUSIONS: Pembrolizumab was associated with a significant incidence of AEs, although most of the AEs were of mild to severe grades (grade 1-3). Fatigue was the commonly reported AE. The AEs were tolerable in most cases and did not require hospitalization or treatment discontinuation.