The FDA granted accelerated approval to dostarlimab (Jemperli) for adults with stage II or III locally advanced rectal cancer with MSI-H or dMMR, based on data from the single-arm AZUR-1 trial. Treatment was given as dostarlimab 500 mg every three weeks for nine cycles, with tumor response assessed via endoscopy, rectal MRI, and CT. For evaluable patients assessed by independent central review, the 12-month clinical complete response rate (cCR12) was 47%, while objective response rate reached 79%. After a median follow-up of 26.3 months, the report said no patients with cCR12, cCR, or nonoperative clinical complete response experienced disease progression, with ongoing monitoring through multimodal assessments. The FDA’s biomarker gate—MSI-H/dMMR—keeps attention on how immune checkpoint inhibitor strategies are expanding beyond cancers with larger randomized evidence bases. The accelerated path also raises the bar for confirmatory studies and long-term durability tracking. Clinicians will now weigh how nonoperative management protocols may change for MSI-H/dMMR patients versus standard chemoradiation and surgery sequencing.