Dr. Marshall on Single-Agent and Combination Immunotherapy Applications in MSI-H mCRC

John L. Marshall, MD, chief, Division of Hematology/Oncology, Medstar Georgetown University Hospital director, Otto J. Ruesch Center for the Cure of Gastrointestinal Cancer, Georgetown-Lombardi Comprehensive Cancer Center, discusses the progression of immunotherapy in colon cancer.

Immunotherapy was once believed to have no impact on colon cancers. Since then, researchers have looked at immunotherapy in microsatellite instability-high (MSI-H) colon cancers, or mismatch repair deficient colon cancers. Results showed that checkpoint inhibitors work very well in that subgroup.

The FDA has since approved 2 checkpoint inhibitors as single agents in refractory metastatic colon cancers if they are MSI-H. Physicians know from melanoma and other cancers that combining immunotherapies can result in even greater benefit. The most recent study compared nivolumab (Opdivo) plus ipilimumab (Yervoy) in MSI-H colon cancers. Although physicians saw more toxicity and cost, there was a higher benefit rate, further increasing the number of patients who are benefiting from immunotherapy.