Responses to Anti-CD19 CAR-T Therapy Tied to Longer Survival in Relapsed CLL

Study findings suggest that, among patients with relapsed chronic lymphocytic leukemia (CLL), achieving a complete response (CR) after infusion with anti-CD19 CAR-T cells (CART-19) is tied to longer overall survival (OS) and progression-free survival (PFS), regardless of cell dose (J Clin Oncol. 2020 Apr 16. Online ahead of print).

The purpose of the study by Noelle V. Frey, MD, MS, Cell Therapy and Transplant Program, Division of Hematology-Oncology, Department of Medicine, Philadelphia, Pennsylvania, was to describe the long-term outcomes of anti-CD19 chimeric antigen receptor (CAR)-T cells in patients with relapsed or refractory CLL.

A total of 42 patients were enrolled in the study between January 2013 and June 2016, with 38 receiving CART-19 infusions. Of these patients, 28 were initially randomized to receive a low (5×10⁷) or high (5×10⁸) CART-19 dose, and 24 were evaluable for response assessment.

An additional 10 patients received the high dose following interim analysis, 8 of whom were evaluable for response.

The median follow-up time frame was 31.5 months, and at 4 weeks, the CR and overall response rates for the 32 evaluable patients were 28% (90% CI, 16%-44%) and 44% (90% CI, 29%-60%), respectively.

Findings showed a median OS of 64 months for all patients, and no statistically significant differences between recipients of low and high doses (P = .84).

Furthermore, Dr Frey et al observed extended survival in patients who did versus did not achieve a CR (P = .035), regardless of dose.

The median OS was not reached for patients with CR versus 64 months for those without CR, and the median PFS was 40.2 months versus 1 month, respectively (P <.0001).

Toxicity was found to be comparable among recipients of both doses.

“In patients with advanced CLL, a 5 × 10⁸ dose of CART-19 may be more effective than 5 × 10⁷ CART-19 at inducing CR without excessive toxicity,” Dr Frey and colleagues said.

“Attainment of a CR after CART-19 infusion, regardless of cell dose, is associated with longer OS and progression-free survival in patients with relapsed CLL,” they concluded.—Hina Porcelli