Dr Hill on Efficacy of Dostarlimab in dMMR Locally Advanced Rectal Cancer

Joshua Hill, MD, MS, oncologist, co-chair, the Quality Assurance Improvement Committee, Atrium Health Levine Cancer Institute, assistant professor of surgery, Atrium Health Carolinas Medical Center, program director, the National Accreditation Program in Rectal Cancer (NAPRC), discussed the early efficacy of dostarlimab-gxly (Jemperli) in mismatch repair–deficient (dMMR) locally advanced rectal cancer.

From a surgical perspective, the biggest recent news across the rectal cancer landscape came from a single arm phase 2 trial (NCT04165772) that examined single-agent dostarlimab in a small group of patients with stage II/III dMMR locally advanced rectal cancer, Hill says.

Data presented at the 2022 ASCO Annual Meeting and in the New England Journal of Medicine showed that among the 12 patients who completed at least 6 months of treatment with dostarlimab, the complete response rate was 100%, and there was no evidence of tumor on subsequent imaging. At the time of data cutoff, no patients had received chemoradiotherapy or undergone surgery, and there were no reports of progression or recurrence during follow-up. Additionally, no adverse effects of grade 3 or higher were reported.

Although only 5% to 10% of rectal tumors are dMMR, this subset of patients has been associated with poor responses to chemotherapy, including neoadjuvant chemotherapy for locally advanced rectal cancer. Given the responses generated by dostarlimab and the lack of a need for surgery in this small set of patients, these data were promising in the rectal cancer space, Hill concludes.