An Accelerated FDA Approval May Let Some Rectal Cancer Patients Skip Surgery

The U.S. Food and Drug Administration granted accelerated approval on Oct. 19, 2026, to the immunotherapy Jemperli (dostarlimab-gxly), used alone, for adults with previously untreated stage II or stage III locally advanced rectal cancer whose tumors carry a defect in the way they repair DNA.

In its announcement, the FDA said the approval may let some of these patients avoid the usual treatment for those stages, chemotherapy and radiation before surgery. The agency said that course can affect bowel, urinary and sexual function as well as fertility, and that surgery carries risks of serious complications, including, in some patients, a permanent colostomy.

The FDA said a patient's tumor must be mismatch repair deficient or microsatellite instability-high, meaning the cell's system for correcting DNA copying errors does not work, and that an FDA-authorized test must confirm it. The agency said such tumors produce proteins the immune system can recognize, and that published estimates put about 3% of locally advanced rectal cancers in this group.

The FDA said it based the decision on interim results from AZUR-1, a phase 2 study of Jemperli alone in 154 patients with the same diagnosis, who received a six-month course of the drug. After a median follow-up of more than two years, almost three-fourths of them had not needed surgery, radiotherapy or chemotherapy.

The agency also drew on an earlier study of 50 patients at Memorial Sloan Kettering Cancer Center that tested Jemperli the same way, and it said longer follow-up is needed to understand how long responses last and how often the cancer returns.

The FDA said Jemperli can cause the immune system to attack healthy organs and tissues, and that those reactions can be severe or fatal. The most common side effects in patients treated for this type of rectal cancer were fatigue, rash, diarrhea and itching.

The agency said that because this is an accelerated approval based on interim results, GSK, which holds it, must keep following patients to show the responses produce lasting clinical benefit.