Chimeric antigen receptor T-cell targeting CD-19 (CAR T-19) may be more effective at a higher dose (5 x 108) than a standard lower dose (5 x 107) in patients with relapsed or refractory chronic lymphocytic leukemia (CLL), according to a recent study.
Toxicity may also be tolerable for patients receiving the higher dose, the study also found.
In an attempt to describe long-term outcomes of CAR T-19 in patients with relapsed or refractory CLL, David L Porter, MD, Abramson Cancer Center, University of Pennsylvania (Philadelphia, PA), and colleagues enrolled 42 patients from January 2013 to June 2016. Thirty-eight of these patients were infused with CAR T-19, and among these 28 were initially randomized to receive a low (5 x 107) or high (5 x 108) dose of therapy. Researchers noted that 24 patients were evaluable for response assessment.
After an interim analysis, 10 additional patients received the high CAR T-19 dose. Among these patients, eight were evaluable for response.
Patients were followed for a median of 31.5 months, Dr Porter and colleagues noted. Results of the study were published in the Journal of Clinical Oncology (online April 16, 2020; doi:10.1200/JCO.19.03237).
After 4 weeks, the complete and overall response rates for the 32 total evaluable patients were 28% (90% CI, 16% to 44%) and 44% (90% CI, 29% to 60%), respectively. Median overall survival for all patients was 64 months, and researchers reported that there was no statistically significant difference between the low- and high-dose groups (P = .84).
Additionally, they found that prolonged survival was observed in patients who achieved a complete response vs those who did not, regardless of dose (P = .035). Median overall survival was not reached in patients with a complete response vs 64 months in those without a complete response. Median progression-free survival was 40.2 months vs 1 month, respectively (P < .0001).
Furthermore, researchers acknowledged that toxicity was comparable in both dose groups.
“We conclude that a single course of treatment with CAR T-19 can induce durable remissions with an acceptable toxicity profile in some patients with advanced CLL,” authors of the study wrote.—Zachary Bessette
