Updated results from the NEOPRISM-CRC clinical trial show that patients with a specific subtype of bowel cancer who received preoperative immunotherapy have remained cancer-free after almost three years of follow-up, with no relapses recorded among treated participants. The findings were presented at the American Association for Cancer Research (AACR) Annual Meeting 2026 and were led by researchers from University College London (UCL) and University College London Hospitals (UCLH).
The trial enrolled 32 patients with stage two or three bowel cancer carrying a mismatch repair-deficient (MMR-d) or microsatellite instability-high (MSI-high) genetic profile, a subgroup representing approximately 10 to 15% of stage two and three bowel cancer cases, or around 2,000 to 3,000 cases per year in the UK. Participants received up to nine weeks of pembrolizumab before surgery, in place of the standard approach of surgery followed by three to six months of chemotherapy.
Earlier results had shown that 59% of patients had no detectable signs of disease following treatment and surgery. At 33 months of follow-up, none of the participants had experienced a cancer recurrence, including those who still had residual disease after treatment. By comparison, approximately 25% of patients receiving standard surgery and postoperative chemotherapy are expected to relapse within three years.
Alongside survival data, researchers developed personalised blood tests capable of detecting circulating tumour DNA, enabling early assessment of treatment response and disease status. Immune profiling of tumour tissue taken before treatment also showed potential for predicting which patients are most likely to respond, which could inform more tailored treatment decisions in the future.
Bowel cancer is the fourth most common cancer in the UK, with around 44,000 new cases diagnosed annually.
Source: University College London. NEOPRISM-CRC trial results presented at AACR Annual Meeting 2026, April 2026.
The trial enrolled 32 patients with stage two or three bowel cancer carrying a mismatch repair-deficient (MMR-d) or microsatellite instability-high (MSI-high) genetic profile, a subgroup representing approximately 10 to 15% of stage two and three bowel cancer cases, or around 2,000 to 3,000 cases per year in the UK. Participants received up to nine weeks of pembrolizumab before surgery, in place of the standard approach of surgery followed by three to six months of chemotherapy.
Earlier results had shown that 59% of patients had no detectable signs of disease following treatment and surgery. At 33 months of follow-up, none of the participants had experienced a cancer recurrence, including those who still had residual disease after treatment. By comparison, approximately 25% of patients receiving standard surgery and postoperative chemotherapy are expected to relapse within three years.
Alongside survival data, researchers developed personalised blood tests capable of detecting circulating tumour DNA, enabling early assessment of treatment response and disease status. Immune profiling of tumour tissue taken before treatment also showed potential for predicting which patients are most likely to respond, which could inform more tailored treatment decisions in the future.
Bowel cancer is the fourth most common cancer in the UK, with around 44,000 new cases diagnosed annually.
Source: University College London. NEOPRISM-CRC trial results presented at AACR Annual Meeting 2026, April 2026.
