FDA approves immunotherapy that may replace standard rectal cancer treatment for some
The FDA approved dostarlimab for certain adults with previously untreated stage 2 or stage 3 rectal cancer whose tumors have a defective DNA repair system. In a trial of 154 patients, nearly three in four remained free of surgery, radiation, and chemotherapy after more than two years. The approval offers an option that may avoid lasting bowel, bladder, sexual, and fertility effects associated with standard treatment.
The approval applies to adults with previously untreated stage 2 or 3 rectal cancer whose tumors carry a faulty DNA repair process. Such cancers accumulate copying errors that can make them more visible to the immune system, though only a minority of rectal cancers have this feature.
In the 154-patient trial, dostarlimab was given intravenously every three weeks for six months, for as many as nine doses. After more than two years, almost three-quarters had not needed surgery, radiation, or chemotherapy. An earlier 50-patient study found no cancer signs; among 27 followed at least three years, one recurred. Accelerated approval requires continued follow-up.
For patients with this uncommon tumor profile, the approval could reshape early treatment decisions by offering a nonsurgical path and reducing exposure to long-term bowel, bladder, sexual, and fertility effects. It may also increase demand for tumor testing to identify eligible people. Because the evidence comes from early data and long-term recurrence remains uncertain, clinicians and patients may weigh convenience and organ preservation against incomplete durability information. Health systems could face new questions about access, monitoring, and follow-up.