There has been a lot of enthusiasm in the news for CAR-T treatments for blood cancers, based on a presentation at the American Association for the Advancement of Science conference earlier this month. The presentation looked at the results of a clinical trial of CAR-T therapy -- some very good results. But this seems like one of those things that has been overblown a little bit by the media. The strong numbers can't be denied, but they need to be looked at a little more carefully. I'm going with my usual mix of hope and caution with this one.
The presentation, called "Engineering T Cells for Safe and Effective Cancer Immunotherapy,"
took place at the AAAS conference, and described the process for creating the CAR-T cells. The abstract, which is where the link will take you, doesn't get into the results of the clinical trial. Instead, it described the process for creating the T cells. Which makes sense, since the AAAS isn't a cancer-related organization. The speaker, Stanley Riddell from Fred Hutchinson Cancer Center in Seattle, was speaking to scientists, not necessarily cancer researchers.
The Fred Hutchinson News Service sent out a press release about the presentation. It includes a very enthusiastic video describing CAR-T therapy and the success of the trial, and then a more measured text with more detail. The video really is exciting; it shows Dr. Riddell discussing the treatment, and I love to see researchers get excited about their work.
The text, though, quotes Dr. Riddell as saying things like "Much like chemotherapy and radiotherapy, it’s not
going to be a save-all," adding, "Some patients may require other treatments." The article also makes clear that 27 of 29 patients with Acute Lymphoblastic Leukemia (ALL) had a complete response, as did 19 of 30 NHL patients (no breakdown of which types of NHL they had). Good numbers, but not a "save-all," as Dr. Riddell makes clear.
There are some other problems, too, with the treatment, including the possibility of Cytokine Release Syndrome, which occurs when too many cancer cells are killed off at once and the body cannot process them all. Two patients in the trial actually died from this. (Some trials are halted when patients die from the treatment or its side effects.) A couple of months ago, I wrote about a CAR-T trial for Follicular Lymphoma, and heard from a reader named Ben who had gone through the trial, and who experienced CRS. (Ben mentioned wanting to start a blog -- maybe we'll hear from him with a link so we can read more about his experiences.)
There are other issues, too. Clearly, with the NHL arm of the trial, it had some good results, also didn't work for about 1/3 of the patients. And it's worth remembering that this was presented at a conference, so it hasn't been peer reviewed (before a medical journal publishes the results, other experts in the area will look it over and make sure the data says what the authors claim it says).
Some other articles take a critical look at the study (and at the overly positive reaction that the media has had to it): The Washington Post's "Why it’s too early to get excited about this ‘unprecedented’ new cancer treatment," and Cancer Research UK's "Immunotherapy cancer ‘cure’ headlines distract from fascinating science." Both of them acknowledge that the research is very promising, but also say, for a bunch of reasons, that we have a while before we know for sure just how exciting this is.
So, as I said, I'm going with "hopeful, but cautious." There's a lot that can happen between a conference presentation and an oncologist's prescription. I hope it all works out as well as it promises.