GSK plc announced that the US Food and Drug Administration (FDA) has accepted for priority review its supplemental Biologics License Application (sBLA) for Jemperli (dostarlimab) in patients with previously untreated stage 2 and 3 Mismatch Repair Deficient (dMMR)/Microsatellite Instability-High (MSI-H) locally advanced rectal cancer. The FDA has assigned a Prescription Drug User Fee Act (PDUFA) action date of February 2027.

The application is also eligible for expedited review under the FDA’s National Priority Voucher programme, which could enable an earlier regulatory decision. It has additionally been accepted under Project Orbis, an FDA Oncology Center of Excellence initiative designed to facilitate coordinated reviews among participating international health authorities. Regulatory decisions, however, remain independent in each country.

The submission is supported by positive results from the registrational phase 2 AZUR-1 trial, which evaluated Jemperli as a standalone treatment in patients with previously untreated stage 2 and 3 dMMR/MSI-H locally advanced rectal cancer. The study met its primary objective by demonstrating a meaningful and sustained clinical complete response rate at 12 months (cCR12), indicating no detectable signs of cancer for at least one year.

The findings could represent a significant shift from the current treatment approach for this patient population. Standard treatment for locally advanced rectal cancer typically involves combinations of chemotherapy, radiation and surgery. While these approaches can be effective, they may result in lasting effects on bowel, urinary and sexual function, fertility and overall quality of life.

If approved for this indication, dostarlimab could potentially offer some eligible patients an opportunity to avoid or delay these interventions. The AZUR-1 findings build on earlier research conducted with Memorial Sloan Kettering Cancer Centre (MSK), which demonstrated the potential of dostarlimab to produce complete clinical responses without chemotherapy, radiation or surgery in patients with dMMR/MSI-H locally advanced rectal cancer.

Rectal cancer affects approximately 770,000 people worldwide each year, with around 5 percent to 10 percent of cases estimated to have the dMMR/MSI-H subtype. These tumours carry genetic characteristics that impair the ability of cancer cells to repair DNA damage, resulting in an accumulation of mutations. This biological profile can make such tumours particularly responsive to immune checkpoint inhibitors.

AZUR-1 is a global, open-label, single-arm phase 2 trial involving 154 patients with previously untreated stage 2 and 3 dMMR/MSI-H locally advanced rectal cancer. Participants received nine cycles of dostarlimab over six months, with a 500 mg intravenous infusion administered every three weeks. The study was designed to assess sustained clinical complete responses at 12 months and evaluate whether treatment with dostarlimab alone could allow patients to avoid chemotherapy, radiation and surgery.

Interim safety data showed that the safety and tolerability profile of dostarlimab was generally consistent with its established profile across solid tumours. GSK plans to present the AZUR-1 data at a scientific congress later in 2026.

Dostarlimab has previously received both Fast Track and Breakthrough Therapy Designations from the FDA for this treatment setting. The latest regulatory milestone further advances GSK’s efforts to explore the potential of Jemperli in gastrointestinal and other solid tumours.

Jemperli is a programmed death receptor-1 (PD-1) blocking antibody and serves as a key component of GSK’s immuno-oncology research and development programme. The company is evaluating the therapy both as a monotherapy and in combination with other treatments across gynaecological, colorectal, head and neck and other cancers.

Jemperli was originally discovered by AnaptysBio and licensed to TESARO under a collaboration and exclusive licensing agreement signed in 2014. GSK is responsible for its ongoing research, development, manufacturing and commercialisation.

The latest regulatory filing forms part of GSK’s broader oncology strategy, which aims to improve survival and quality of life while developing treatments capable of changing the course of cancer. The company is expanding its oncology focus across blood cancers, women’s cancers, lung cancer, gastrointestinal cancers and other solid tumours.