The FDA granted accelerated approval to dostarlimab (Jemperli) for adults with stage II or III locally advanced rectal cancer whose tumors are MSI-H or mismatch repair deficient (dMMR). The decision is based on results from the multicenter, single-arm, open-label AZUR-1 Phase 2 trial, which enrolled 154 previously untreated patients. In patients evaluable by independent central review, the FDA cited a 12-month clinical complete response rate of 47% and an objective response rate of 79%. Tango-like durability signals were also part of the regulatory narrative: after a median follow-up of 26.3 months, the report states that patients with clinical complete response at early assessments did not experience disease progression. The regimen evaluated dostarlimab 500 mg intravenously every three weeks for nine cycles, with treatment response assessed by endoscopy plus rectal MRI and CT imaging at prespecified intervals. For cCR responders, the protocol included a nonoperative management phase with multimodal monitoring. Clinically and commercially, the approval expands the use of a PD-1 inhibitor into a biomarker-defined rectal cancer setting, reinforcing the broader shift toward nonoperative strategies in selected MSI-H/dMMR patients and creating new urgency around how oncology teams operationalize response assessment workflows.