GSK’s Jemperli shows sustained clinical complete responses in dMMR/MSI‑H locally advanced rectal cancer

Key highlights
  • Phase II AZUR‑1 interim analysis met primary objective showing sustained clinical complete responses at 12 months (cCR12).
  • 154 participants received nine cycles of dostarlimab (500 mg IV every three weeks) over six months in a single‑arm trial.
  • Results suggest potential to eliminate or delay chemotherapy, radiation and surgery for some patients with stage II/III dMMR/MSI‑H rectal cancer.
  • Dostarlimab has FDA Breakthrough Therapy and Fast Track designations; GSK will share interim data with regulators for review.

Interim results

GSK announced positive interim results from the registrational phase II AZUR‑1 trial of dostarlimab (Jemperli) in patients with stage II/III mismatch repair‑deficient/microsatellite instability‑high (dMMR/MSI‑H) locally advanced rectal cancer. The single‑arm trial met its primary objective, demonstrating a clinically meaningful and sustained clinical complete response rate at 12 months (cCR12).

Trial design and dosing

AZUR‑1 is a global, open‑label, single‑arm registrational phase II trial. A total of 154 participants received nine cycles of dostarlimab over six months, administered as a 500 mg intravenous infusion every three weeks.

Clinical context

Rectal cancer affects around 730,000 people globally each year, and approximately 5–10% of rectal cancers are dMMR/MSI‑H. Current standard care typically includes chemotherapy, radiation and surgery, which can cause substantial long‑term quality‑of‑life impacts.

Safety, regulatory status and next steps

Safety and tolerability in the interim analysis were consistent with dostarlimab’s established profile across solid tumours. Dostarlimab has received Breakthrough Therapy and Fast Track designations from the US FDA in this setting. GSK plans to share interim AZUR‑1 data with global regulatory authorities, including for accelerated review in the US, and to present detailed results at a future scientific congress.

Source: GSK

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