Chimeric Antigen Receptor-T Cell Therapy in Adults with B-Cell Acute Lymphoblastic Leukemia: A Systematic Review.

Chimeric antigen receptor T-cell (CAR-T) therapy has transformed treatment paradigms for relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL) in children and younger adults. We performed a systematic review to investigate the published literature on efficacy and toxicity of CAR-T therapy in adults with r/r B-ALL. We searched MEDLINE, Embase and Cochrane Library for prospective, interventional studies and included published studies of ≥5 patients with median age at enrollment of ≥ 18 years. Risk of bias was assessed using a modified Institute of Health Economics tool. A total of 2566 records were assessed; 16 studies involving 489 patients were included in the final analysis. The mean CR rate was 81% and MRD negative remission rate was 81% at 4 weeks post CAR-T infusion. With median follow-up across studies of 24 months the cumulative 12-month probability of PFS and OS were 37% (95% CI 26-48%) and 57% (95% CI 49-65%), respectively. Relapse occurred in 40.3%; target antigen was retained in 73.2% of relapses. Across studies, any grade of CRS occurred in 82% (95% CI 61-95%) and grade 3 or higher CRS in 27% (95% CI 18-36%). Neurotoxicity of any grade occurred in 34% (95% CI 24-47%) and grade 3 or higher in 14% (95% CI 1-25%). In summary, CAR-T therapy achieves high early remission rates in adults with r/r B-ALL and represents a significant improvement over traditional salvage chemotherapy. Relapses are common and durable response remains a challenge.