Clinical Trial Success

Data from a clinical trial shows that a dual immunotherapy regimen plus short-course radiation for the treatment of rectal cancer that is microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) can be effective enough to avoid chemotherapy and colostomy-requiring surgery. 

The data from the EA2201 study was so promising that the clinical trial is being redesigned to investigate whether radiation treatment can also be avoided. Most patients in the study — 57% — had a complete clinical response according to scan results, or a complete surgical response. Of those who had rectal surgery, which was the standard of care when the clinical trial began, 100% had no cancer cells left, according to pathology reports. The study participants, who had Stage 2 or Stage 3 MSI-H/dMMR rectal cancer, were treated with nivolumab plus ipilimumab before and after receiving short-course radiation therapy. 

Kristen Ciombor, MD, MSCI, Ingram Associate Professor of Cancer Research and co-leader of the Translational Research and Interventional Oncology Research Program at Vanderbilt-Ingram Cancer Center, presented the data in Munich during the European Society for Medical Oncology Gastrointestinal Cancers Congress  2024. 

She is the principal investigator of the EA2201 study, which is sponsored by the National Cancer Institute and being administered through the ECOG-ACRIN Cancer Research Group. Around 5% of rectal cancer patients have MSI-H tumors, characterized by a higher number of repeated DNA base sequences.