Dr. Bekaii-Saab on the Response Rate of Pembrolizumab in MSI-H CRC

Tanios Bekaii-Saab, MD, professor of medicine, Mayo Clinic, discusses the response rate of pembrolizumab (Keytruda) for patients with microsatellite instability-high (MSI-H) colorectal cancer (CRC).

According to Bekaii-Saab, when looking at the patient population that has this MSI-H phenotype, response rates are up to 50% to 60%. In recent publications that looked at pembrolizumab in patients with MSI-H, many of the patients who had either stable disease or a partial response (PR) ended up with complete response (CR).

However, it was an average of about 24 to 26 weeks before they had better responses. Some of these benefits can be seen earlier, but they also accumulate with time, explains Bekaii-Saab. Many of these patients end up with a CR or a very solid PR after 6 months on the therapy.