In remission for 10 years: Long-term toxicity data on CAR T cells


When a patient with cancer hears there isn’t much left that doctors can do, it always stays fresh in the mind.

Doug Olson was first diagnosed with chronic lymphocytic leukemia (CLL) over 20 years ago, in 1996. For several years, his doctors used the watch-and-wait approach. But then his cancer progressed and needed treatment. By 2010, it had mutated so much that it no longer responded to standard therapy.

He was rapidly running out of options. Back then, the only treatment left was a bone marrow transplant. Without one, his doctors said, he would have 1 or 2 years left to live.

“I was really trying to avoid a bone marrow transplant. You’re playing your last card if that doesn’t work. It’s a pretty rough procedure,” Olson told Medscape Medical News.

Looking back, Olson counts himself as lucky – for being in the right place, at the right time, with the right doctor. His oncologist was David Porter, MD, the principal investigator on a trial at the University of Pennsylvania that was investigating a brand new approach to treating cancer: chimeric antigen receptor (CAR) T-cell therapy.

CAR T-cell therapy uses a patient’s own T cells engineered to express a receptor that targets proteins on cancer cells. CAR T cells are considered “living drugs” because they expand inside the body and stick around for years – maybe for a lifetime – to fight the cancer if it tries to come back.

“I was certainly intrigued by the approach. It had worked in mice, and it was the sort of thing that looked like it would work,” Olson recalled.

Science is not a foreign language to Olson. He holds a PhD in medicinal chemistry, spent most of his career in the in vitro diagnostics industry, and currently acts as chief executive officer of Buhlmann Diagnostics Corp.

So he read the clinical protocol for the first in-human trial of CAR T cells and agreed to become patient number two.

Olson’s T cells were harvested, engineered to attack the CD19 antigen found on malignant and normal B lymphocytes, and then were expanded into millions in the lab. After undergoing preconditioning with chemotherapy to minimize rejection and boost the CAR T cells’ expansion inside the body, he received several infusions of the new therapy over the course of 3 days.

Nothing really happened for 2 weeks. Then he developed severe flu-like symptoms – so bad that he was hospitalized.

Ironically, getting sick was a sign that the CAR T cells were working. Olson was experiencing one of the main short-term effects of CAR T-cell therapy: cytokine release syndrome. Symptoms include extremely high fevers and dangerous drops in blood pressure that can potentially cause end-organ damage.

In the early trials of these products, some patients experienced such a severe reaction that they needed intensive care, and some died. With increasing clinical experience, doctors have learned to control the reaction with the use of steroids and interleukein-6 inhibitors such as tocilizumab (Actemra).

Fortunately for Olson, the reaction passed, and he was eventually discharged.

Then the “aha moment” happened. Four weeks after receiving the CAR T cells, Olson found out that he was cancer free.

“It still gives me shivers,” he said. “Dr Porter said, ‘Your bone marrow’s completely free. We just can’t find a cancer cell anywhere.’ “

The remission has lasted, and it is now 10 years later.


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