Chimeric antigen receptor T-cell therapy for relapsed/refractory acute B-cell lymphoblastic leukemia with T315I mutation: report of one case and review of literature

Objective To explore the safety and efficacy of chimeric antigen receptor T-cell (CAR-T) therapy for relapsed/refractory acute B-cell lymphoblastic leukemia (B-ALL) with T315I mutation. Methods The clinical data of a patient with relapsed/refractory B-ALL with T315I mutation who underwent CAR-T therapy in the Second Affiliated Hospital of Anhui Medical University was analyzed, and the related literature was reviewed. Results The patient was a 34-year-old man. He was diagnosed with chronic myelogenous leukemia (CML) in January 2017 and started to take imatinib orally. However, the primary affection transformed to B-ALL 4 months later. Because of the E355G gene mutation, the treatment drug was adjusted to dasatinib, and induction chemotherapy was given at the same time. The sequential consolidation chemotherapy was given for 3 times after complete remission (CR). After half a year of remission, T315I mutation was detected and re-induced chemotherapy was given, but ineffective. The patient was treated with CAR-T 3 days after FC regimen (fludarabine 30 mg/m2 per day, day 1 to day 3; cyclophosphamide 200 mg/m2, day 1 to day 3). The number of CD19 CAR-T was 1.0×109, 98% activity degree. Grade 1 cytokine-releasing syndrome appeared after infusion, and was resolved after symptomatic treatment. No serious adverse reactions were observed. CR was achieved half-month after CAR-T treatment, and umbilical cord blood transplantation was successfully performed 1 month later. At the last follow-up, the relapse-free survival time of the patient was 396 days. Conclusion CAR-T therapy may be a new, safe and effective therapy for patients with relapsed/refractory B-ALL with T315I mutation. Key words: Leukemia, B lymphocyte, acute; T315I mutation; Chimeric antigen receptor T-cell