Dr. Kim on Immunotherapy in CRC

Richard Kim, MD, assistant professor of oncology, University of South Florida College of Medicine, and medical oncologist, Department of Gastrointestinal Oncology, Moffitt Cancer Center, discusses the use of immunotherapy in colorectal cancer (CRC).

Currently, immunotherapy is limited to patients with mismatch repair deficiency or microsatellite instability—high (MSI-H) disease, explains Kim.

Clinical data have demonstrated efficacy with single-agent checkpoint inhibitors and combinations of PD-L1 and CTLA-4 inhibitors in patients who are MSI-H; however, this subgroup accounts for about 5% of patients with stage IV CRC, says Kim.

Ongoing research is investigating the utility of immunotherapy in patients with microsatellite stable (MSS) disease. The phase 1b REGONIVO trial (NCT03406871) results presented at the 2019 ASCO Annual Meeting demonstrated an overall response rate of 40% with the combination of regorafenib (Stivarga) and nivolumab (Opdivo) in patients with previously treated CRC or gastric cancer. Importantly, 98% of the 50 patients enrolled in the study had MSS disease.

These results suggest a potential role for immunotherapy in patients with MSS diseasewhere the traditional response rates is approximately 0% with single-agent checkpoint inhibition, concludes Kim.