Toxicity Associated with Pembrolizumab Monotherapy in Patients with Gastrointestinal Cancers: A Systematic Review of Clinical Trials.

Pembrolizumab, an immune checkpoint inhibitor targeting programmed death 1 (PD-1), is a widely employed therapy for various gastrointestinal (GI) cancers. We conducted a systematic review of clinical trials investigating pembrolizumab monotherapy in GI cancer patients to assess the spectrum and incidence of immune-related adverse events (irAEs) associated with pembrolizumab. A comprehensive search of PubMed/MEDLINE was performed to identify clinical trials investigating pembrolizumab monotherapy in GI cancer patients. Primary endpoints included the incidence of grade 3 or higher irAEs and the rate of treatment discontinuation due to irAEs. Secondary endpoints encompassed the incidence of any-grade irAEs, as well as specific irAEs. Data extraction and analysis were performed on 25 articles. The analysis included 3101 patients with a median age of 62 years (range 53-68), with 30.2% being female. Tumor types encompassed were colorectal (12%), esophagogastric (46%), hepatocellular carcinoma (24%), and other GI tumor types (18%). The rate of treatment discontinuation due to irAEs was 6.8%. The most prevalent grade 3 or higher irAEs were hepatitis (3.6%), pneumonitis (0.8%), and colitis (0.7%). Death attributed to irAEs was infrequent (0.9%). In patients with GI cancers treated with pembrolizumab monotherapy, severe toxicities are infrequent, and irAEs leading to treatment discontinuation or death are uncommon.