A case of a patient who successfully underwent allogeneic bone marrow transplantation for relapsed Philadelphia chromosome-positive acute lymphoblastic leukemia harboring T315I mutation

Abstract

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ALL) with tyrosine kinase domain mutations is highly resistant to therapy. Ph⁺ALL harboring T315I mutation shows a particularly poor prognosis. An 8-year-old boy diagnosed as having Ph⁺ALL at a previous hospital was transferred to our hospital after induction therapy. Because imatinib intolerance and hepatic dysfunction caused by dasatinib necessitated frequent discontinuation of tyrosine kinase inhibitors, he experienced recurrence. As T315I mutation was confirmed by genetic analysis, he underwent bone marrow transplantation (BMT) in the nonremission status from an HLA-identical sibling with a chemotherapy containing cytarabine, mitoxantrone, and prednisolone, followed by a myeloablative conditioning regimen containing melphalan and 12 Gy total body irradiation. Engraftment was obtained on day 17, and he is alive in complete remission without any complications for more than 7 years after BMT. It is necessary to investigate the efficacy of BMT in large numbers of patients with Ph⁺ALL harboring T315I mutation.