Pembrolizumab (Keytruda)
Immunotherapy · Approved since 2014
Description
Pembrolizumab is a humanized monoclonal antibody and immune checkpoint inhibitor approved for treatment of microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) metastatic colorectal cancer. It is indicated as a tumor-agnostic therapy for patients whose tumors have progressed on or after fluoropyrimidine, oxaliplatin, and irinotecan-based chemotherapy. The drug has also been studied in neoadjuvant settings for locally advanced colorectal cancer and as combination therapy with other agents in microsatellite stable (MSS) metastatic disease.
Mechanism of Action
Pembrolizumab binds to the programmed cell death protein-1 (PD-1) receptor on T-cells, blocking its interaction with ligands PD-L1 and PD-L2. By inhibiting this immune checkpoint pathway, pembrolizumab prevents T-cell exhaustion and enhances the immune system's ability to recognize and eliminate cancer cells. This mechanism is particularly effective in MSI-H/dMMR tumors which have high tumor mutational burden and increased neoantigen expression.
Molecular Targets
Side Effects
Not all side effects are listed. Side effects vary by individual. Always consult your oncologist.