Two years ago, medical oncologist Myriam Chalabi and her colleagues witnessed unprecedented results of immunotherapy in 20 colon cancer patients. All patients were diagnosed with microsatellite-instable colon cancer (MSI), a cancer type that involves an extraordinarily large number of mutations in the tumor cells. Fifteen per cent of patients diagnosed with non-metastatic colon cancer have this microsatellite-instable form. Chalabi: "All 20 patients benefited from the treatment; we had never seen anything like that before."
This led to a larger follow-up study, the first results of which Chalabi has presented during the European congress. The results of this study (NICHE-2) are equally undeniable: almost all of the 107 patients with MSI colon cancer responded very well to pre-treatment with immunotherapy. In 95% of patients, even less than 10% of the cancer cells remained by the time they had their surgery. In two-thirds of the patients, there wasn’t even a single living cancer cell left by then. All patients had received two courses of immunotherapy in the month before surgery (nivolumab and ipilimumab).
"None of these patients has experienced recurrence to date, even though most of them had been diagnosed with high-risk tumors", Chalabi says. It has 2 to 61 months since these patients received their treatment. "These results are unprecedented. Every single time it’s so amazing to hear that a patient’s cancer is gone. The effects as well as the side effects of this treatment are much better than, for example, chemotherapy prior to surgery, to which only 1 in 20 patients responds."
This treatment is not currently available to patients in the Netherlands. "This extension of the NICHE study is intended to help make the treatment available to all patients, and we are working hard towards that goal. A follow-up study involving a slightly different combination of immunotherapy among 60 patients at the Netherlands Cancer Institute will also be starting soon."
The results have not gone unnoticed abroad. "Researchers in other countries are looking for ways to use this treatment based on our data, by setting up their own comparative trial, for example."
Physicians are also seeing great results in patients with other cancer types, including skin cancer, after this type of pre-treatment – also known as neoadjuvant immunotherapy. Chalabi: "We are slowly approaching the point where colorectal cancer patients who respond well to the neoadjuvant immunotherapy won’t even need to be treated with chemotherapy after their surgery. And eventually we hope to be able to omit surgery entirely in patients who respond well."
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