If bowel cancer is detected early the prognosis is usually good and, in fact, nine out of 10 patients treated for stage one bowel cancer survive five years or more. However, certain specific subtypes of tumors do not respond well to treatment and are more likely to come back. In these cases, five-year survival drops to 65% in stage three and 10% in stage four bowel cancer.
Now, results from a clinical trial presented at the 2024 Annual Meeting of the American Society of Clinical Oncology (ASCO) have shown that giving the immunotherapy drug pembrolizumab before surgery, instead of chemotherapy, made a A significantly greater number of patients with a certain genetic profile were cancer-free after the intervention.
The findings are preliminary results from the Phase II NEOPRISM-CRC clinical trial testing whether pembrolizumab is able to improve outcomes for patients with stage 2 or 3 colon tumors with a genetic profile known as MMR-deficient/MSI-high. . The trial is a collaboration between UCL – London’s Global University, UCLH, Christie NHS Foundation Trust in Manchester, St James’s University Hospital in Leeds, University Hospital Southampton and the University of Glasgow.
Bowel cancer is the fourth most common cancer in the UK, with around 42,900 cases a year. In Spain, the cancers that will be diagnosed the most in 2024 will be those of the colon and rectum (44,294 new cases). Although these tumors continue to especially affect older people, cases among those under 50 years of age have increased in recent decades.
The drug pembrolizumab is more effective than chemotherapy
UCL researchers recruited 32 patients with stage two or three bowel cancer and a certain genetic profile (MMR-deficient/MSI-high upper bowel cancer) from five UK hospitals. Patients received pembrolizumab for nine weeks before surgery instead of the usual treatment of chemotherapy and surgery, and were monitored for a period of time afterwards. The results indicate that 59% of patients had no signs of cancer after treatment with pembrolizumab, and in the remaining 41% of patients the cancer was removed during surgery.
All patients in the trial were cancer-free after treatment and remain cancer-free many months later. The median cancer-free period was 9.7 months and ranged from 5.3 to 19 months among individual patients. When conventional chemotherapy is administered to patients with this genetic profile, less than 5% have no signs of cancer after surgery. This strategy also prevented patients from needing postoperative chemotherapy, which has side effects and is difficult to endure.
“Our results indicate that pembrolizumab is a safe and highly effective treatment to improve outcomes in patients with high-risk bowel cancers”
In the coming years researchers will evaluate overall survival and relapse rates. Dr Kai-Keen Shiu, chief investigator of the trial at the UCL Cancer Institute and consultant medical oncologist at UCLH, said: “Our results indicate that pembrolizumab is a safe and highly effective treatment for improving outcomes in patients with high-risk bowel cancers, increasing the chances of curing the disease at an early stage.” “We need to wait to see if the patients in our trial remain cancer-free for a longer period of time, but the initial indications are extremely positive,” he added.
Professor Mark Saunders, consultant clinical oncologist at The Christie, said: “This is a really exciting new treatment for the 10-15% of patients who have the right genetic makeup. Immunotherapy prior to surgery could well become a ‘game changer’ for these patients with this type of cancer. Not only is the outcome better, but it also prevents patients from receiving more conventional chemotherapy, which often has more side effects.”
“In the future, immunotherapy may even replace the need for surgery. However, further trials are needed to confirm these exciting early results and The Christie is delighted to collaborate in this way so that we can offer this new form of therapy to our patients as part of the NEOPRISM trial.”
“More work needs to be done to evaluate pembrolizumab before it can be considered a standard treatment, but given the quality of the results from this trial, I think it’s possible we could see it in the clinic within a couple of years if subsequent trials have the same success,” concludes Dr Marnix Jansen, clinical scientist and consultant histopathologist leading the translational research for the UCL Cancer Institute and UCLH trial.
