On August 24, 2026 GSK plc (LSE/NYSE: GSK) reported the US Food and Drug Administration (FDA) has accepted for priority review a supplemental Biologics License Application (sBLA) for Jemperli (dostarlimab) for patients with previously untreated stage II and III mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer. The FDA has assigned a PDUFA action date of February 2027. The application is also eligible for expedited review through the National Priority Voucher program, which could result in an earlier FDA decision1.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

Rectal cancer, a type of bowel cancer, affects around 770,000 people globally each year2 and approximately 5-10% of cases have the dMMR/MSI-H subtype3. Chemotherapy, radiation and surgery are the standard of care and while often effective, they can have lasting adverse effects on bowel, urinary and sexual function, fertility and overall quality of life4,5,6.

The application is based on positive data from the registrational phase II, single-arm AZUR-1 trial, which met its primary objective by demonstrating a meaningful and sustained clinical complete response rate for 12 months (cCR12) with no detectable signs of cancer for at least one year. In interim data, the safety and tolerability profile of dostarlimab was generally consistent with its well-characterised and manageable safety profile observed across solid tumours. These data will be submitted for presentation at a scientific congress later in 2026.

AZUR-1 results represent a substantial improvement compared to the historical standard of care7. The data support the potential for dostarlimab, if approved, to become the first immunotherapy capable of eliminating or delaying the need for chemotherapy, radiation and surgery for some patients in this population. These findings build on earlier research conducted with Memorial Sloan Kettering Cancer Center (MSK), which first demonstrated the potential for dostarlimab to achieve clinical complete responses without other treatments in patients with dMMR/MSI-H locally advanced rectal cancer.

Dostarlimab was previously granted Fast Track and Breakthrough Therapy Designations in this setting8,9. The application has also been accepted under Project Orbis, an FDA Oncology Center of Excellence initiative that enables coordinated reviews by international health authorities and may support earlier regulatory decisions and patient access. Regulatory decisions remain independent in each country.

About stage II and III dMMR/MSI-H locally advanced rectal cancer
Rectal cancer affects around 770,000 people globally each year2. Around 5–10% of rectal cancers are mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H)3. These tumours have a specific genetic characteristic where they are unable to properly repair DNA damage, leading to an accumulation of mutations. This unique biological feature often makes them highly responsive to immunotherapies like dostarlimab10,11. These biomarkers are most commonly found in endometrial, colorectal and other gastrointestinal cancers, but can also be present in other solid tumours12.

About AZUR-1
AZUR-1 is a global, open-label, single-arm, registrational phase II trial evaluating dostarlimab monotherapy in patients (n=154) with previously untreated stage II and III dMMR/MSI-H locally advanced rectal cancer. The trial was designed to assess sustained clinical complete responses for 12 months (cCR12) and determine whether dostarlimab alone could enable patients to avoid chemotherapy, radiation and surgery. Patients received nine cycles of dostarlimab over six months, administered as a 500mg intravenous infusion every three weeks. In interim data, the safety and tolerability profile of dostarlimab was generally consistent with its well-characterised and manageable safety profile observed across solid tumours.

The AZUR-1 results represent a substantial improvement compared to the historical standard of care. They build on earlier research conducted in collaboration with Memorial Sloan Kettering Cancer Center, which first demonstrated the potential for dostarlimab to achieve clinical complete responses without other treatments in patients with dMMR/MSI-H locally advanced rectal cancer.

About Jemperli  
Jemperli, a programmed death receptor-1 (PD-1)-blocking antibody, is the backbone of GSK’s ongoing immuno-oncology based research and development programme. A robust clinical trial programme includes studies of Jemperli alone and in combination with other therapies in gynaecologic, colorectal and head and neck cancers, as well as where there are opportunities for transformational outcomes.

Jemperli was discovered by AnaptysBio, Inc. and licensed to TESARO, Inc., under a collaboration and exclusive license agreement signed in March 2014. Under this agreement, GSK is responsible for the ongoing research, development, commercialisation and manufacturing of Jemperli.

More information about the product and its indications is available at EU product information13 and US product information14.  Jemperli is not currently approved anywhere in the world for locally advanced rectal cancer.

(Press release, GlaxoSmithKline, AUG 24, 2026, View Source [SID1234670293])