Clinical Significance of Inotuzumab Ozogamicin in Non-transplant Patients with Relapsed Acute Lymphoblastic Leukemia: A Report of Four Cases.

: Relapsed acute lymphoblastic leukemia (ALL) has a poor prognosis. Inotuzumab Ozogamicin (InO) is a novel therapeutic drug for the treatment of relapsed ALL. InO has received attention as a bridging therapy before transplantation due to its high complete remission (CR) rate. However, the significance of InO in non-transplant patients remains unclear. We retrospectively evaluated four non-transplant patients treated with InO. All cases achieved CR after receiving at least two cycles of InO. Three of the four cases survived for more than 11 months without relapse. Moreover, all patients received InO as outpatients, because the adverse events were well-controlled. InO therefore appears to be a beneficial treatment even for non-transplant patients.