In July 2010, 2 patients with advanced chronic lymphocytic leukemia (CLL) received autologous CD19 chimeric antigen receptor (CAR) T-cell (CAR-T) therapy (tisagenlecleucel) at the University of Pennsylvania and their diseases went into complete remission. 

Now, 8 years later (and counting), both patients’ diseases remain in remission and the patients have detectable levels of CAR-T cells, according to a study presented during the 2019 American Society of Gene and Cell Therapy (ASGCT) annual meeting, held April 29 to May 2, 2019, in Washington, D.C.1 

These 2 patients were the first 2 CLL patients enrolled in the pilot trial (ClinicalTrials.gov identifier: NCT01029366) and represent the most durable examples of complete remissions to CD19 CAR-T for CLL to date.2 

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The second patient has already received significant attention because the complete remission was achieved with an infusion dose of only 14 million CAR-T cells — well below the target dose of 1.1 billion CAR-T cells, which was what the first patient received.3

The study findings included a deep dive into the behavior and features of the infused CAR-T cells as they evolved in the body during 8 years. The results offered up insights for future CAR-T cell development, as well as sparked questions about how much remains to be learned about CAR-T cells. 

“It’s a good study and it provides a lot of very interesting data about the expansion and contraction of these CD4+ and CD8+ cells over a very long period of time,” David Maloney, MD, PhD, Fred Hutchinson Cancer Research Center, Seattle, Washington, told Cancer Therapy Advisor. Although he was not involved in the current study, Dr Maloney said that based on what he’s seen, this study has the longest follow-up into the function and persistence of both CD4+ and CD8+ T-cell clones over time, at least in CLL.