On 19 October 2026 the US Food and Drug Administration (FDA) granted accelerated approval to the immunotherapy dostarlimab (Jemperli, made by GSK) for adults with previously untreated stage II or stage III locally advanced rectal cancer whose tumours are mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H), as determined by an FDA-authorised test.
The FDA says published estimates suggest about 3% of locally advanced rectal cancers are dMMR or MSI-H. Its decision was based on interim results from AZUR-1, a phase 2 study of 154 patients who received up to nine doses of dostarlimab, given every 3 weeks over 6 months. After a median follow-up of more than 2 years, almost three-quarters of patients had not needed surgery, radiotherapy or chemotherapy.
The FDA says longer follow-up is needed to understand how long responses last and how often the cancer returns, and the prescribing information states that continued approval may depend on confirmatory trials. This is a decision by the US regulator. It is not a UK approval, and it does not mean the medicine is available for this use on the NHS.