FDA approves dostarlimab for MSI-H/dMMR rectal cancer

The FDA has granted accelerated approval to dostarlimab (brand name Jemperli) for adults with stage II or III locally advanced rectal cancer (LARC) that is microsatellite instability–high (MSI-H) or mismatch repair deficient (dMMR). This marks the first immunotherapy approved for this specific patient population.

Based on the phase 2 AZUR-1 trial, the treatment offers a nonoperative management pathway. In the study, 71% of 154 treated patients received dostarlimab alone without disease progression, and the sustained 12-month clinical complete response rate was 47%. This approach may allow eligible patients to avoid the standard combination of chemotherapy, radiation, and surgery, which can often lead to long-term impacts on bowel, urinary, and sexual function.

Patients who achieve a clinical complete response enter a multimodal surveillance period, requiring assessments every few months for several years. The FDA noted that while this approval brings a new approach to patients sooner, further studies are required to confirm lasting benefits.