LONDON, October 14 — The NEOPRISM-CRC trial showed zero cancer recurrences in patients with high-risk bowel cancer who received pembrolizumab before surgery, with 33 months of follow-up data presented at the AACR Annual Meeting 2026. By the numbers, patients with stage two or three bowel cancer and MMR deficient/MSI-high genetic profile who received nine weeks of pembrolizumab pre-operatively had no observed relapses, compared to an expected 25% relapse rate within three years for those receiving standard surgery followed by chemotherapy.
The trial enrolled 32 patients across five UK hospitals, including University Hospital Southampton, St. James’s University Hospital in Leeds, and the Christie NHS Foundation Trust in Manchester. Investors will note that pembrolizumab, an immunotherapy drug, was administered before surgery instead of the usual post-operative chemotherapy regimen.
Researchers developed personalized blood tests with biotechnology company Personalis to detect circulating tumor DNA, which closely correlated with treatment response and long-term outcomes. Immune profiling from tumor tissue prior to treatment also helped predict which patients would benefit most. Dr. Kai-Keen Shiu, Chief Investigator from UCL Cancer Institute and Consultant Medical Oncologist at UCLH, emphasized the durability of response and potential for personalized testing to guide therapy intensity.
Professor Marnix Jansen, leading translational research at UCL Cancer Institute and UCLH, highlighted the biological insights gained from the trial. Yanrong Jiang, first author of the latest abstract and clinical PhD student at UCL Cancer Institute, noted the value of personalized blood tests in monitoring treatment efficacy.
Patient Christopher Burston, a 73-year-old from Portland, Dorset, diagnosed in February 2023 via routine screening, participated in the trial after a positive bowel screening kit led to colonoscopy-confirmed cancer. The approach may reduce long-term treatment burden and healthcare costs by avoiding unnecessary chemotherapy in responders, while identifying high-risk patients who need additional intervention. The trial’s focus on biomarker-driven treatment selection aligns with precision oncology trends that could influence future reimbursement models, drug development investment, and cost-effectiveness assessments in cancer care within the UK’s NHS and comparable health systems.
Bowel cancer is the fourth most common cancer in the UK, with approximately 44,000 new cases annually; around 10-15% of stage two or three cases have the MMR deficient/MSI-high profile, equating to roughly 2,000-3,000 cases per year in the UK. Five-year survival for stage three bowel cancer is 65%, dropping to 10% for stage four. The findings were presented at the American Association for Cancer Research (AACR) Annual Meeting 2026 in April, with the latest phase presented in San Diego, California.
Watch for regulatory submissions and NHS evaluation of neoadjuvant immunotherapy pathways based on this biomarker-selected approach.
