Anti-CD19 CAR T-Cells Cause “Highly Durable” Remissions of Relapsed B-Cell Lymphoma and CLL

Anti-CD19 chimeric antigen receptor (CAR) T-cells cause remission of relapsed B-cell lymphoma and chronic lymphocytic leukemia (CLL) with few long-term adverse events (Aes), according to a study presented as part of the 2020 ASCO Virtual Scientific Program.

In the longest follow-up study of patients who received anti-CD19 CAR T-cells, between 2009 and 2015, investigators treated 43 patients with anti-CD19 CAR T-cells followed by conditioning chemotherapy of cyclophosphamide plus fludarabine. Three patients were re-treated, for a total of 46 CAR T-cell treatments. The study population consisted of 28 patients with aggressive lymphoma, eight patients with low-grade lymphoma (five with follicular lymphoma and one each with splenic marginal zone lymphoma, mantle cell lymphoma, and unspecified low-grade non-Hodgkin lymphoma), and seven patients with CLL. Patients were treated in three cohorts that differed in the CAR T-cell production process and conditioning chemotherapy dose.

The study results showed that 63% of patients had chemotherapy-refractory lymphoma. Following an average of four lines of therapy (median CAR⁺ T-cell dose per kilogram was 2×10⁶), the overall remission rate was 76%, with 54% complete remissions (CRs) and 22% partial remissions. Researchers observed that patients with a CR had higher median peak blood CAR levels (86 CAR⁺ cells/µL) than those who did not achieve CR (16 CAR⁺ cells/µL; P=0.0041). They noted that long-term AEs were rare, except for B-cell depletion and hypogammaglobulinemia, “which both improved over time.”

The researchers noted, “Anti-CD19 CAR T-cells cause highly durable remissions of relapsed B-cell lymphoma and CLL, and long-term AEs of anti-CD19 CAR T-cells were rare and usually mild.”

Cappell K, et al. Long-Term Follow-up of anti-CD19 CAR T-cell Therapy for B-cell Lymphoma and Chronic Lymphocytic Leukemia. Presented at the 2020 ASCO Virtual Scientific Program; May 29-31, 2020.