Dr. Chu on the Role of Pembrolizumab in dMMR/MSI-H mCRC

Edward Chu, MD, MMS, director and professor of medicine and molecular pharmacology at Albert Einstein Cancer Center, and vice president for cancer medicine at Montefiore Medicine, discusses the role of pembrolizumab (Keytruda) in patients with mismatch repair deficient (dMMR) or microsatellite instability–high (MSI-H) metastatic colorectal cancer (mCRC).

The phase 3 MK-3475-177/KEYNOTE-177 trial demonstrated a significantly improved overall response rate, duration of response, and progression-free survival with pembrolizumab versus investigator’s choice of standard-of-care chemotherapy, says Chu. Moreover, pembrolizumab demonstrated a favorable safety profile compared with chemotherapy.

On June 29, 2020, the FDA approved pembrolizumab as a first-line therapy for patients with unresectable dMMR or MSI-H mCRC based on results from the KEYNOTE-177 study. The regimen should now be considered a standard of care for this patient population, Chu adds.

Notably, patients with dMMR or MSI-H mCRC account for about 5% of the overall mCRC population. Although the subset is small, the activity of pembrolizumab in this space confirms the need for precision medicine and personalized therapeutic approaches for patients with CRC, concludes Chu.