[Sustained molecular remission with a tyrosine kinase inhibitor alone for seven months in a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia].

: Herein, we report the case of a 28-year-old man with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+)ALL). The patient received induction chemotherapy, including imatinib (IM) therapy, which required early cessation because of a severe infection. After the resolution of the infection, general flaccid paralysis was observed, which was diagnosed as critical illness myopathy (CIM). Ph(+)ALL showed molecular remission (MR) on day 42. We intended to maintain MR with only IM therapy for several months until the improvement of CIM; however, owing to the patient's intolerance to IM, therapy was changed to dasatinib. Because the symptoms of myopathy gradually improved and disappeared completely, the patient was able to undergo one course of intensive chemotherapy and allogeneic stem cell transplantation from an HLA-matched sibling donor, 8 months after admission (7 months after the re-administration of IM). Thus, this case report suggests that a tyrosine kinase inhibitor is an alternative therapy for maintaining the response of Ph(+)ALL patients who refrain from conventional chemotherapy.