A groundbreaking immunotherapy drug, pembrolizumab, has been hailed as a 'gamechanger' for certain bowel cancer patients, with a clinical trial showing it can dramatically increase the chances of a cure and potentially replace the need for surgery. The drug, also known as Keytruda, works by blocking a specific protein on immune cells, enabling them to seek out and destroy cancer cells.
The trial, led by University College London and involving five UK hospitals, recruited 32 patients with stage two or three bowel cancer who had a specific genetic profile known as MMR deficient/MSI-High. This genetic makeup is present in about 10-15% of bowel cancer patients. Instead of standard chemotherapy followed by surgery, patients received nine weeks of pembrolizumab before surgery.
Results presented at the American Society of Clinical Oncology conference showed that 59% of patients had no signs of cancer after treatment with pembrolizumab, with any remaining cancer removed during surgery. All patients were cancer-free after treatment. In contrast, fewer than 5% of patients with the same genetic profile who received standard chemotherapy had no signs of cancer after surgery.
Dr Kai-Keen Shiu, the trial's chief investigator, said: 'Our results indicate that pembrolizumab is a safe and highly effective treatment to improve outcomes in patients with high-risk bowel cancers, increasing the chances of curing the disease at an early stage.' He added that the drug can 'melt away' tumours before surgery, tripling survival chances for those who respond completely.
Patients in the trial did not require post-operative chemotherapy, avoiding its side effects. Prof Mark Saunders of the Christie NHS foundation trust said: 'Immunotherapy prior to surgery could well become a gamechanger for these patients. Not only is the outcome better, but it saves patients from having more conventional chemotherapy.'
Bowel cancer is the second leading cause of cancer-related deaths worldwide, with over 1.9m new cases and 900,000 deaths annually. Further trials are needed, but researchers are optimistic that pembrolizumab could become standard treatment within a few years.
