‘Potentially game-changing’ trial results suggests immunotherapy could be used to fight bowel cancer, says ARU professor
Immunotherapy could successfully be used to treat the most common form of colorectal cancer, also known as bowel cancer, a new study has shown.
The study’s co-author, Prof Justin Stebbing of Anglia Ruskin University (ARU), described the results as “potentially game changing”.
The phase I trial involved using the immunotherapy drug botensilimab in conjunction with balstilimab on a group of patients in the United States.
It focused on the microsatellite stable metastatic colorectal cancer - also known as MSS or mCRC - the most common type of colorectal tumours.
The results represent the first time that consistent and durable responses to immunotherapy have been reported in difficult-to-treat patients with this cancer.
Immunotherapy has previously been shown to work on patients with specific mismatch repair deficient (dMMR) tumours, but only a small percentage of colorectal cancer patients have this type of tumour, and immunotherapy has so far been ineffective in patients with more common MSS mCRC tumours.
The drugs are monoclonal antibodies and work by triggering the body’s immune system to attack the cancer.
Of the patients in the trial, 101 took part in a six-month follow-up and of these, 61 per cent had seen their tumour shrink or remain stable after receiving a combination of botensilimab (BOT) and balstilimab (BAL). The most common side-effects, or treatment-related adverse events, were diarrhoea and fatigue.
Prof Stebbing, professor of biomedical sciences at ARU and communicating author of the study published in the journal Nature Medicine, said: “These results are incredibly exciting. Colorectal or bowel cancer is one of the most common forms of cancer worldwide and this is the first time there has been convincing evidence that immunotherapy can work in all forms of colorectal tumours, so this is potentially game-changing.
“This is now progressing into later phase clinical trials and we hope the FDA in the United States approves its use very soon. And because this is such an important area, affecting so many people, we hope authorities in the UK are also able to move quickly.”
Joint first author Dr Andrea Bullock, assistant professor in medicine at Beth Israel Deaconess Medical Center, said: "This study sheds light on the potential of the BOT/BAL combination to treat microsatellite stable metastatic colorectal cancer, the most common form of colorectal cancer, which has historically not responded to immunotherapy, and we hope our results will offer new hope for those diagnosed."
Joint last author Dr Anthony El-Khoueiry, associate director of clinical research and chief of section of developmental therapeutics at the USC Norris Comprehensive Cancer Center, said: “This phase I study of botensilimab highlights its promising anti-tumour activity that encompasses immunologically cold tumours such as MSS colorectal cancer. The efficacy noted highlights the potential of botensilimab through its broader engagement of anti-tumour immunity.”
