HEALTH – The results of this clinical trial would be “unprecedented”. In the New England Journal of Medicine, an article published on June 5 revealed a clinical study conducted on 12 patients with colorectal cancer. For six months, these patients received a dose of dostarlimab every three weeks. Thanks to this treatment, they would be completely cured.
What conclusions can be drawn? Caroline Moyret-Lalle, doctor in molecular biology, lecturer at the University Claude Bernard Lyon 1, and researcher at the Cancer Research Center of Lyon, helps us to see more clearly.
The researcher recognizes first of all that the results presented are “spectacular.” “These are metastatic cancers, at advanced stages and we observe a real healing, which to my knowledge is unprecedented for colorectal cancers”, she underlines.
20% maximum of colorectal cancers
Dostarlimab, which was administered to patients in the clinical study, is part of what are called immunotherapy treatments, that is to say “that target the immune system”. They are relatively recent: they have been tested since 2013 in the United States and 2016 in France.
“In many types of cancer, cancer cells neutralize immune cells, which cannot attack them, explains Dr. Moyret-Lalle. Immunotherapies, combined with chemotherapy, allow immune cells to attack tumor cells again.”
However, they are not effective on all types of colorectal cancers. In the case of this clinical trial, the test was carried out on a particular type of colorectal cancer, which represents a maximum of 20% of cases, depending on the country.
“These are colorectal cancers that have a particular genetic instability, which is called micro-satellite instability, explains the researcher. Which is not the case for 80 to 90% of colorectal cancers, so the vast majority.”
On other colorectal cancers, it would not be as effective for the moment. “For the vast majority of colorectal cancers, immunotherapies do not seem to give this type of result, emphasizes Dr. Moyret-Lalle. Even if studies are still in progress, in France in particular.”
Larger clinical trials
If the researcher wants to be optimistic, she remains cautious, therefore. “I’m waiting for what’s next. The number of patients is low, so this requires confirmation, she believes. We have to wait for slightly larger cohorts of patients and also have results on the 80 to 90% of patients who do not have this particular genetic instability.”
We will therefore have to wait for trials on more patients. “If we have the same results on one or several hundred patients, it will be really interesting, she hopes. Because we know that with immunotherapies, when we change scale, sometimes we realize that it only concerns a few patients and not the majority.”
According to New York Times, the price of this drug would be 11,000 dollars per dose. A price that seems “in the norm” for researcher Caroline Moyret-Lalle. “In France, it is supported, she recalls. But on average, immunotherapies cost 5,000 or 6,000 euros per injection.”
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