The FDA granted accelerated approval to dostarlimab (Jemperli) for adults with stage II or III locally advanced rectal cancer that is MSI-H or dMMR, based on results from the multicenter, single-arm AZUR-1 trial. In AZUR-1, 154 previously untreated patients received dostarlimab 500 mg IV every three weeks for nine cycles. Independent central review showed a 12-month clinical complete response rate of 47% among evaluable patients, with an objective response rate of 79%. After a median 26.3-month follow-up, no disease progression was reported among patients who achieved clinical complete response at 12 months, with responders entering a monitored nonoperative management period. About 71% received dostarlimab alone with no additional treatment required. The approval underscores regulators’ continued reliance on response-based endpoints in biomarker-defined oncology, while the trial’s framework keeps surgery and standard-of-care options available for those who do not meet response criteria.