Key Takeaways
- The FDA granted accelerated approval on October 19, 2026, for eligible adults with stage II or III MSI-H or dMMR rectal cancer.
- In the AZUR-1 trial, 68% of 144 evaluable patients achieved a clinical complete response sustained for 12 months, according to GSK.
- The approval requires continued study, and Jemperli can cause serious immune-related side effects.
What Happened
The US Food and Drug Administration (FDA) has approved GSK's Jemperli immunotherapy for certain adults with locally advanced rectal cancer. Announced on October 19, 2026, the accelerated approval offers a new treatment option for patients whose tumours have specific genetic characteristics.
The approval covers previously untreated stage II or III rectal cancer that is microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR). These biomarkers can help identify tumours that may respond to immunotherapy.
What the Clinical Trial Found
The decision was supported by interim results from AZUR-1, a phase II clinical trial involving 154 patients with previously untreated dMMR or MSI-H locally advanced rectal cancer. Patients received up to nine doses of Jemperli every three weeks over six months.
After a median follow-up of more than two years, almost three-quarters of participants had not needed surgery, radiation or chemotherapy. Further monitoring is needed to establish how durable these responses will be and how often the cancer returns.
An earlier study at Memorial Sloan Kettering Cancer Center evaluated Jemperli alone in 50 patients with previously untreated dMMR or MSI-H locally advanced rectal cancer. None had detectable signs of cancer after treatment, and 93% maintained that status for at least 12 months, according to the FDA.
Who Could Benefit?
Jemperli is not intended for every patient with rectal cancer. Eligibility depends on the cancer's stage, biomarker status and individual clinical circumstances. Testing with an FDA-authorised diagnostic test is required to identify suitable patients.
The treatment also carries risks. Jemperli can cause serious immune-related reactions that damage healthy organs and may sometimes be fatal. The most common side effects reported in at least 15% of patients treated for this type of rectal cancer were fatigue, rash, diarrhoea and itching.
TwikUp's Perspective
The approval uses tumour biomarkers to identify patients who may benefit from an alternative to conventional treatment pathways. For eligible patients, this approach may create alternatives to chemotherapy, radiation and surgery.
However, promising interim results should not be confused with a guaranteed cure. Longer-term evidence will be important in determining whether responses remain durable and how often the cancer returns. The approval is a significant development, but continued monitoring remains essential.