Humanized anti‐CD19 chimeric antigen receptor‐T cell therapy is safe and effective in lymphoma and leukemia patients with chronic and resolved hepatitis B virus infection

Chimeric antigen receptor‐T (CAR‐T) cell therapy is a promising treatment for CD19(+) B‐cell malignancies. However, elimination of B cells by anti‐CD19 CAR‐T cells may lead to the reactivation of hepatitis B virus (HBV) and related hepatitis in patients with HBV infection. This study aims to evaluate the safety and efficacy of humanized anti‐CD19 CAR‐T (hCAR‐T) therapy in B‐cell malignancies with HBV infection. Twenty relapsed/refractory (r/r) diffuse large B‐cell lymphoma (DLBCL) and acute lymphoblastic leukemia (ALL) patients with HBV infection were treated with hCAR‐T therapy. Among them, five hepatitis B antigen‐positive patients who received antiviral prophylaxis did not develop HBV reactivation, including two patients who received both hCAR‐T and allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Among 15 patients with resolved HBV infection, two received antiviral prophylaxis, and the other 13 did not experience HBV reactivation without antiviral prophylaxis. One patient with resolved HBV infection experienced HBV reactivation 6 months after hCAR‐T therapy and sequential allo‐HSCT. Moreover, HBV infection did not affect in vivo expansion of hCAR‐T cells or increase the risk of severe cytokine release syndrome. In conclusion, hCAR‐T therapy is safe and effective in DLBCL and ALL patients with chronic and resolved HBV infection under proper antiviral prophylaxis.