This experimental drug could change the field of cancer research

A tiny group of people with rectal cancer just experienced something of a scientific miracle: their cancer simply vanished after an experimental treatment.

In a very small trial done by doctors at New York's Memorial Sloan Kettering Cancer Center, patients took a drug called dostarlimab for six months. The trial resulted in every single one of their tumors disappearing. The trial group included just 18 people, and there's still more to be learned about how the treatment worked. But some scientists say these kinds of results have never been seen in the history of cancer research.

Dr. Hanna Sanoff of the University of North Carolina's Lineberger Comprehensive Cancer Center joined NPR's All Things Considered to outline how this drug works and what it could mean for the future of cancer research. Although she was not involved with the study, Dr. Sanoff has written about the results.

This interview has been lightly edited

On her first reaction to the results:
I mean, I am incredibly optimistic. Like you said in the introduction, we have never seen anything work in 100 percent of people in cancer medicine.

On how the drug works to treat cancer:
This drug is one of a class of drugs called immune checkpoint inhibitors. These are immunotherapy medicines that work not by directly attacking the cancer itself, but actually getting a person's immune system to essentially do the work. These are drugs that have been around in melanoma and other cancers for quite a while, but really have not been part of the routine care of colorectal cancers until fairly recently.

On the kinds of side effects patients experienced:
Very, very few in this study - in fact, surprisingly few. Most people had no severe adverse effects at all.

On how this study could be seen as 'practice-changing':
Our hope would be that for this subgroup of people - which is only about five percent to 10 percent of people who have rectal cancer - if they can go on and just get six months of immunotherapy and not have any of the rest of this - I don't even know the word to use. Paradigm shift is often used, but this really absolutely is paradigm-shifting.

On why the idea of being able to skip surgery for cancer treatment is so revolutionary:
In rectal cancer, this is part of the conversation we have with someone when they're diagnosed. We are very hopeful for being able to cure you, but unfortunately, we know our treatments are going to leave you with consequences that may, in fact, be life-changing. I have had patients who, after their rectal cancer, have barely left the house for years - and in a couple of cases, even decades - because of the consequences of incontinence and the shame that's associated with this.

On next steps for the drug:
What I'd really like us to do is get a bigger trial where this drug is used in a much more diverse setting to understand what the real, true response rate is going to be. It's not going to end up being 100 percent. I hope I bite my tongue on that in the future, but I can't imagine it will be 100 percent. And so when we see what the true response rate is, that's when I think we can really do this all the time.

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