FDA Accepts Priority Review for GSK's Jemperli in dMMR/MSI-H Locally Advanced Rectal Cancer

GSK announced that the FDA has accepted for priority review a supplemental Biologics License Application (sBLA) for dostarlimab (Jemperli) in patients with previously untreated stage II and III mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer.¹ The agency has assigned a PDUFA action date of February 2027, and the application is also eligible for expedited review through the National Priority Voucher program, which could produce an earlier decision.¹

What is this filing based on?

The sBLA is supported by the registrational phase 2 AZUR-1 trial, which met its primary objective by demonstrating a sustained clinical complete response rate at 12 months in patients receiving Jemperli monotherapy.¹ GSK first reported these interim results in July, and BioPharm International^© covered that data readout in detail, including the trial's single-arm design and the questions that design leaves open ahead of full data disclosure; see our earlier coverage of the AZUR-1 results for the complete trial breakdown. GSK states the interim safety and tolerability profile remained consistent with Jemperli’s established profile across solid tumors, and full data are expected at a scientific congress later in 2026.¹

What would approval mean for patients?

If approved, GSK states Jemperli could become the first immunotherapy able to eliminate or delay the need for chemotherapy, radiation, and surgery for some patients in this population.¹ Standard treatment for locally advanced rectal cancer is often effective but can carry lasting effects on bowel, urinary, and sexual function, as well as fertility.¹ This builds on earlier research conducted with Memorial Sloan Kettering Cancer Center, which first showed dostarlimab alone could produce clinical complete responses in dMMR/MSI-H locally advanced rectal cancer without chemoradiation or surgery.¹

How common is this cancer subtype?

Rectal cancer affects an estimated 770,000 people globally each year, with roughly 5% to 10% of cases falling into the dMMR/MSI-H subtype.¹ Independent GLOBOCAN estimates from the International Agency for Research on Cancer put annual global rectal cancer incidence at approximately 778,600 cases, closely aligning with GSK's figure.² dMMR/MSI-H tumors carry a genetic defect that impairs DNA damage repair, leading to a high mutational burden that often makes them especially responsive to immunotherapies like Jemperli.¹ These biomarkers appear most frequently in endometrial, colorectal, and other gastrointestinal cancers.¹

What regulatory pathways apply here?

The application was accepted under Project Orbis, an FDA Oncology Center of Excellence initiative enabling coordinated reviews across international health authorities, potentially supporting earlier access in multiple countries, though regulatory decisions remain independent in each one.¹ Dostarlimab previously received Fast Track and Breakthrough Therapy designations in this setting.¹

What is dostarlimab's broader development history?

Dostarlimab was discovered by AnaptysBio and licensed to TESARO under a collaboration and exclusive license agreement signed in March 2014; GSK has been responsible for the drug's ongoing research, development, commercialization, and manufacturing since acquiring TESARO.¹ Jemperli is the backbone of GSK's immuno-oncology program, with an active clinical trial portfolio spanning gynecologic, colorectal, and head and neck cancers.¹ The drug's first FDA approval came via the accelerated pathway in April 2021 for dMMR endometrial cancer, later expanding to other dMMR solid tumors and gaining additional endometrial cancer approvals in 2023 and 2024.³ A locally advanced rectal cancer indication would mark dostarlimab's first approval outside endometrial and other previously approved dMMR solid tumor settings.

What's next?

GSK expects to present full AZUR-1 data at a scientific congress later in 2026, ahead of the FDA's February 2027 PDUFA date.¹ Jemperli is not currently approved anywhere for rectal cancer, and this remains an investigational use pending FDA review.¹

References

1. GSK plc. Jemperli (dostarlimab) accepted for priority review by the US FDA for dMMR/MSI-H locally advanced rectal cancer. Press release. Accessed August 24, 2026.
2. International Agency for Research on Cancer. Rectum Cancer Fact Sheet. GLOBOCAN 2022. Accessed August 24, 2026.
3. Shukla S, Patel H, Chen S, Sun R, Wei L, Chen ZS. Dostarlimab in the treatment of mismatch repair deficient recurrent or advanced endometrial cancer. Cancer Pathog Ther. 2023 Oct 18;2(3):135-141.