An immunotherapy the FDA just approved let almost three-fourths of 154 rectal cancer patients avoid surgery, radiation and chemo

The Food and Drug Administration has approved a drug that, in a clinical trial of 154 patients with one specific kind of rectal cancer, left almost three-fourths of them with no need for surgery, radiotherapy or chemotherapy. The medicine is Jemperli (dostarlimab-gxly), made by GSK, and the agency announced the accelerated approval on Oct. 19, 2026.

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The approval covers a narrow group of adults, not rectal cancer broadly. Doctors will need a tumor test to decide who qualifies, and the agency has told GSK to keep following patients because the evidence so far is interim. For the patients it fits, the appeal is plain: standard care for locally advanced rectal cancer is a demanding sequence of chemotherapy, radiation and surgery, and this option aims to spare at least some people from all three.

Who qualifies for Jemperli

According to the FDA press announcement, the new use is for adults with previously untreated stage II or stage III locally advanced rectal cancer, meaning the tumor has grown into nearby tissue or reached nearby lymph nodes but has not spread to distant organs. The tumor must also be mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H), as determined by an FDA-authorized test. The agency estimates that only about 3% of locally advanced rectal cancers carry that profile, so the group of eligible patients is small.

Jemperli works by targeting PD-1, a protein on immune cells, and blocking a signal that cancer cells use to evade the immune system. Tumors with the dMMR or MSI-H profile tend to respond to that kind of release of the immune brake, which is why the drug can be used alone, without the chemotherapy and radiation that usually come first. Before the first dose, the tumor has to be tested, and the result decides whether the treatment is an option at all. Patients whose tumors are mismatch repair proficient are outside this approval, however much they might wish to skip surgery.

AZUR-1 trial results and the numbers behind them

The approval rests on interim results from AZUR-1, a phase 2 study registered as NCT05723562, which tested Jemperli alone in 154 patients. Patients received up to nine doses, one every three weeks over six months. After a median follow-up of more than two years, the FDA reports that almost three-fourths of patients had not needed surgery, radiotherapy or chemotherapy. The agency’s release does not give a formal response rate, and it says longer follow-up is needed to learn how long responses last and how often the cancer returns.

The prescribing summary on the FDA’s Jemperli approval page adds more conservative measures. By independent central review, 47% of 116 evaluable patients had a sustained clinical complete response at 12 months, and the objective response rate was 79%. Investigator assessment was higher: 68% of 144 evaluable patients. Of 15 patients who went on to surgery after dostarlimab alone, 12 had a pathologic complete response, and none of the patients with a complete or near-complete response had disease progression. The figures differ because they answer different questions: the press announcement counts patients who had not needed other treatment at the data cutoff, while the label tallies measured tumor responses under defined criteria, and independent reviewers applied a stricter standard than the treating investigators did.

An earlier Memorial Sloan Kettering study

The agency also drew on an investigator-led, single-arm study at Memorial Sloan Kettering (NCT04165772) in 50 patients with previously untreated dMMR or MSI-H locally advanced rectal cancer, all treated with Jemperli alone. The FDA says no patient had detectable cancer after treatment, and 93% stayed cancer-free for at least 12 months. Of 27 patients followed for at least three years, one had a recurrence, in the same area. The label lists a 12-month sustained clinical complete response of 93% and an objective response rate of 100% for that study.

Angelo de Claro, director of the FDA Oncology Center of Excellence, said the approval “represents a groundbreaking option that avoids surgery, radiation and chemotherapy.” Acting FDA Commissioner Kyle Diamantas said completing the review nearly four months ahead of schedule means some patients who might otherwise be preparing for surgery may have another path. Both statements come from the agency’s own announcement, and both are framed around the patients who respond, not around every patient who starts the drug.

What standard treatment costs patients

The agency frames the approval against the usual course of care, which is chemotherapy and radiation before surgery. Those treatments can affect bowel, urinary and sexual function and fertility, and surgery carries its own risks, including poor healing, leaks where the bowel is reconnected and, for some patients, a permanent colostomy. Avoiding even part of that sequence is the practical appeal for patients whose tumors qualify.

Jemperli has risks too. It can cause the immune system to attack healthy organs and tissues, sometimes severely or fatally, and the most common side effects in this cancer were fatigue, rash, diarrhea and itching. Because accelerated approval depends on interim results, GSK must keep following patients to show the responses translate into lasting clinical benefit. The review used the Commissioner’s National Priority Voucher pilot program, and the agency says this was its 11th approval under that program. The drug already carried Priority Review and Breakthrough Therapy designations, which are meant to speed promising treatments for serious conditions.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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