The U.S. Food and Drug Administration has approved Jemperli (dostarlimab), developed by GSK, for the treatment of adults with stage II and III microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) locally advanced rectal cancer, according to a statement from AnaptysBio, Inc. (NASDAQ: ANAB).

AnaptysBio manages financial collaborations for Jemperli with Tesaro, a GSK company. The FDA granted Jemperli Fast Track and Breakthrough Therapy designations for this indication, along with Priority Review and a National Priority Voucher, resulting in approval ahead of the February 2027 PDUFA date.

The approval is supported by data from the AZUR-1 trial. Investigator-assessed results showed 68% of evaluable patients (98/144; 95% CI: 60%, 76%) achieved sustained clinical complete responses at 12 months without surgery. In an exploratory analysis, 76% of evaluable patients showed no evidence of cancer one year or more after treatment. No disease recurrences have been reported among responders after a median follow-up of more than two years.

Serious adverse reactions occurred in 20% of patients. The most common adverse reactions were fatigue (32%), rash (22%), diarrhea (18%), and pruritus (17%). Jemperli was permanently discontinued due to adverse reactions in 3% of patients.

GSK plans to present full data from the AZUR-1 interim analysis at the ESMO Congress 2026 in Madrid, Spain, on October 25, 2026.

MSI-H/dMMR tumors are found in approximately 5–10% of rectal cancers. The application is being reviewed under Project Orbis, an FDA Oncology Center of Excellence initiative enabling concurrent review by international health authorities, with regulatory reviews ongoing in participating countries.