One of the Biggest CAR-T Therapy Successes of All Time

Doug Olson was one of the first cancer patients to ever receive what was a new, experimental treatment back in 2010. The treatment was ‘chimeric antigen receptor’ T-cell therapy, or CAR-T therapy. 12 years later, Olson is cancer-free and his specific case may very well have been one of the biggest medical breakthroughs in recent decades.

In CAR-T therapy, some of a cancer patient’s T-cells are removed from their body to be genetically altered. The therapy transforms regular immune system T-cells into cells that recognize, hunt down and sometimes destroy cancer cells or even tumors. Those altered T-cells are then reinfused into the patient’s body.

Just a few weeks after Doug Olson received the treatment, his doctors informed him that they couldn’t find a single cancer cell in his body. Olson, along with one other patient, were two of the first people in the world to receive CAR-T therapy for chronic lymphocytic leukemia. When the protocols for Olson’s treatment were crafted back in 2010, doctors originally hoped that the CAR-T cells would remain active in his body for four weeks. It’s been 12 years, and he still has active altered T-cells swimming through his system and protecting against recurrence of cancer.

Olson’s doctors told Nature magazine in February of 2022 that they now believe CAR-T therapy has the possibility to cure leukemia.

Since Olson was first treated more than a decade ago, five different CAR-T therapy treatments have been approved by the US Food and Drug Administration (FDA). Those treatments are for various forms of myelomas, leukemias and lymphomas. It’s been estimated that patients numbering in the tens of thousands have been treated since then, with mixed success.

In the early days of CAR-T therapy, only 25 to 35 percent of patients with the same form of leukemia as Olson experienced durable remission. That statistic has improved with time, although the treatment still remains a “last resort.” People who do experience a full remission can still relapse within a short time. Cancer researchers still haven’t figured out which factors lead to long-term success with these treatments. Three problems with CAR-T therapy are that it remains technically difficult to perform, it’s very expensive and it is risky.

Doctors have been tracking the progress of Olson and the other patient ever since the initial trial, and both remain cancer-free. Shortly after they were initially treated, both experienced a sudden population of CD8+ cells, which are also known simply as “cancer killers.” As time passed, a different type of CAR-T cell emerged in both patients: CD4+. Researchers believe those new altered cells are the ones killing leukemia cells in both patients’ bodies.

There are two theories about what happened in the two patients. First, it’s possible that the first infusion of CAR-T cells killed all signs of leukemia permanently. The other theory is that the CAR-T cells that continue to patrol their immune systems are killing leukemia cells before they can increase to detectable levels. Either way, they now have proof of concept that CAR-T therapy can destroy cancer, and can provide long-lasting protection against the recurrence of cancers.

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