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Leukemia Patients 'Cured’ 10 Years After Breakthrough Treatment

illustration of CAR T-cell attacking cancer cell

This story first appeared on WebMD's sister site, MDEdge. 

Feb. 3, 2022 -- Two patients with chronic lymphocytic leukemia who 10 years ago were among the first to receive a groundbreaking new therapy were still in remission a decade later. .

The treatment, known as CAR T, “can actually cure patients with leukemia based on these results,” senior author Carl H. June, MD, said in a news briefing on the study, which was published this week in Nature.

Besides the patients’ cancer disappearing, scientists were also pleased to find that the CAR T-cells are still seen in the patients’ blood.

In CAR T-cell therapy, patients’ own T cells are removed, reprogrammed in a lab to recognize and attack cancer cells, and then infused back into the patients. It has transformed treatment of various blood cancers and shows often-remarkable results in leading to remission.

While the treatment has become a routine therapy for certain leukemias, long-term results on the fate and function of the cells over time has been highly anticipated.

The study details how the two patients were first treated in 2010 at the University of Pennsylvania in Philadelphia

Speaking in the press briefing, one of the patients, Doug Olson, described how several weeks after his treatment in 2010, he became very ill with what has become known as the common, short-term side effect of cytokine release syndrome, an over-reaction of the immune system.

However, after Olson recovered a few days later, Porter gave him the remarkable news that “we cannot find a single cancer cell. You appear completely free of [leukemia].”

Sadly, the other CLL patient, Bill Ludwig, who was first to receive the CAR T-cell treatment, died in 2021 from COVID-19.

A decade after the treatment began, the CAR T-cells have remained detectable in both patients, who been in remission since their first year of treatment.

“The killer T cells did the initial heavy lifting of eliminating the tumor, “ first author J. Joseph Melenhorst, PhD, says in an interview.

Melenhorst established the lab at the University of Pennsylvania to follow patients treated with CAR T-cell therapy. “[This] delayed phase of immune response against cancer is a novel insight, and we were surprised to see it.”

Another promising outcome: When Olson, donated his cells back to the center after more than 9 years, the researchers found that his cells were still capable of destroying leukemia cells in the lab.

“Ten years [post infusion], we can’t find any of the leukemia cells and we still have the CAR T cells that are on patrol and on surveillance for residual leukemia,” June, director of the Center for Cellular Immunotherapies, University of Pennsylvania, Philadelphia said at the briefing.

Effects in other blood diseases similar?

CAR T-cell therapy is approved in the United States for several blood cancers, and whether similar long-term patterns of the cells may be observed in other patients and cancer types remains to be seen, Melenhorst says.

While the prospect of some patients being “cured” is exciting, responses to the therapy have generally been mixed. In leukemia patients , for instance, full remissions have been maintained in about 25% of patients, with higher rates in some lymphomas and pediatric patients,. Melenhorst says.

The effects of CAR T-cell therapy in solid cancers have so far been more disappointing, with no studies reproducing the kinds of results that have been seen with blood cancers.

“There appear to be a number of reasons, including that the [solid] tumor is more complex, and these solid cancers have ways to evade the immune system that need to be overcome,” June said.

And despite the more encouraging findings in blood cancers, even with those, “the biggest disappointment is that CAR T-cell therapy doesn’t work all the time. It doesn’t work in every patient,” coauthor David Porter, MD, the University of Pennsylvania oncologist who treated the two patients, said in the news briefing.

“I think the importance of the Nature study is that we are starting to learn the mechanisms of why and how this works, so that we can start to get at how to make it work for more people,”. Porter said. “But what we do see is that, when it works, it really is beyond what we expected 10 or 11 years ago.”