Anti-CD19 CAR T-Cells Effective for Acute Lymphocytic Leukemia

A meta-analysis found that anti-CD19 chimeric antigen receptor (CAR) T-cell therapy induces high response rates in patients with acute lymphocytic leukemia (ALL). The results of the study were published in The Lancet Haematology.

Researchers conducted a literature review to systematically analyze the outcomes of patients with ALL treated with anti-CD19 CAR T-cells and identify factors associated with differences in outcomes. They used published and unpublished clinical trial data reporting on outcomes of adult (n=263) or pediatric (n=346) patients treated with anti-CD19 CAR T-cells for relapsed/refractory B-cell ALL. They included studies reported between January 1, 2012, and April 14, 2020. Studies including two patients or fewer were excluded. A total of 35 studies met the eligibility criteria, comprising 953 patients. Heterogeneity between studies was moderate. The risk of bias was low in 17 studies and moderate in 18 studies.

The pooled complete remission (CR; primary endpoint) was 80% (95% confidence interval, 75.5-84.8). In the prespecified subgroup analyses, 195 adult patients (75%) and 242 pediatric patients (81%) achieved CR (P=0.24). The pooled CR did not significantly differ with anti-CD19 CAR T-cell construct type or single-chain variable fragment clone but was higher with autologous T-cell origin (n=727/901; 83%) compared with allogeneic T-cell origin (n=29/52; 55%; P=0.018).

Grade ≥3 cytokine release syndrome (CRS) occurred in 26% of patients (n=242/854), and grade ≥3 neurotoxicity occurred in 12% of patients (n=97/532). There was no difference in the proportion of patients who achieved CR or who had CRS or neurotoxicity between different anti-CD19 CAR T-cell constructs.

“The high response rates after anti-CD19 CAR T-cell therapy can be used to guide the use of therapy in patients with relapsed or refractory ALL,” the researchers concluded. “Comparison studies are required to further determine differences in efficacy between different anti-CD19 CAR T-cell constructs in the setting of relapsed or refractory ALL.”