FDA greenlights immunotherapy that may spare rectal cancer patients from surgery

The U.S. Food and Drug Administration approved the immunotherapy drug dostarlimab, marketed as Jemperli, for rectal cancers that are microsatellite instability-high or mismatch-repair deficient, a group that makes up roughly 5-10% of rectal tumors. A study involving 154 patients treated with nine three-weekly infusions reported a 68% rate of complete clinical response at one year, meaning imaging could not detect any tumor.

Memorial Sloan Kettering investigators, including Andrea Cercek and Luis Diaz, said the responses have persisted, suggesting a durable effect that could replace the conventional regimen of chemotherapy, radiation and radical surgery. Patients such as Kelly Spill and Sascha Roth avoided colostomies and preserved fertility, with Spill later giving birth to two children after being declared cancer-free. Side effects were limited, with about one-fifth of participants reporting fatigue, rash, diarrhea or itching. Dostarlimab is already used for endometrial cancer and is priced at $10,000-$12,000 per dose, though GSK offers a savings program for eligible patients.