Diarrhea and colitis are among the most commonly encountered immune-mediated adverse events among patients receiving antiprogrammed cell death protein/ligand-1 (PD-1/L1) as well as anticytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies.
A whole-blood RNA transcript-based gene signature is associated with the development of CTLA-4 blockade-related diarrhea in patients with advanced melanoma treated with the checkpoint inhibitor tremelimumab.
Anti-CTLA4 therapy was associated with a significantly higher risk of overall immune-related adverse events: diarrhea, immune-related colitis, pruritus, and rash compared to control therapies (relative risk (RR) = 2.43, 2.10, 11.39, 3.88, 3.87, 95% confidence interval (CI) = 1.77-3.34, 1.52-2.45, 6.30-20.59, 2.37-6.37, 2.39-6.27, P < 0.001 for all outcomes).