Abstract
Access to chimeric antigen receptor (CAR) T cell therapy remains limited in many developing countries. We conducted a single-arm, open-label, phase 1 trial (NCT05333302) at two Belarusian centers, evaluating an in-house manufactured CD19 CAR T cell product (BY19) in pediatric and adult patients with relapsed/refractory B cell malignancies. Lymphodepletion included fludarabine/cyclophosphamide, with or without decitabine. Twenty-three patients received therapy: seventeen B cell acute lymphoblastic leukemia, one chronic lymphocytic leukemia, and five non-Hodgkin lymphomas. Cytokine release syndrome (CRS) occurred in 67% of infusions, mostly grade 1-2, with severe CRS in 19%. Immune effector cell-associated neurotoxicity occurred in 44%, with severe cases in 18.5%. The overall response rate was 80% (16/20 evaluable), with complete remission achieved in 75% at day 28. Median progression-free survival (PFS) was 23 months; 12-month PFS was 83.3% in lymphoma and 48.3% in B cell acute lymphoblastic leukemia (B-ALL). Higher Cmax levels tended to correlate with better response rates (p = 0.0416); however, no clear advantage in PFS was observed. BY19's safety and efficacy profiles were comparable to approved CD19 CAR T cell products. This study underscores the translational potential of localized CAR T cell manufacturing to expand global access to advanced immunotherapies, especially in middle-income countries. Decitabine-containing lymphodepletion showed potential benefit and warrants further study.