Successful Induction of Hematologic and Cytogenetic Remission with Gemtuzumab Ozogamicin (Mylotarg(R)) in Patients with Myeloid Blast Crisis of Chronic Myelogenous Leukemia in Refractory to Imatinib Mesylate and Chemotherapy.

Introduction The treatment options for patients with chronic myeloid leukaemia (CML) in blast crisis phase are limited, especially to those were refractory to imatinib mesylate. We report the achievement of hematologic and molecular completely remission after the use of gemtuzumab ozogamicin( mylotarg) in two patients with CD33-positive CML-BC who were refractory to chemotherapy and imatinib mesylate(Gleevec). Two patients(male,62yr; female, 40yr), Before received Mylotarg, they were administrated imatinib mesylate(600mg per day) more than three months and receiveed combination chemotherapy, but they were refractory and their disease progressed. Then, they received Mylotarg as a 2-hour intravenous infusion, at a dose of 9 mg/m², at 2-week intervals for three doses. One of the patient was treated with Mylotarg combinated MA(Mitoxantrone 5mg, d1–4; cytarabin 100mg/M²,d1–7). After the first cycle Mylotarg, two patients achieved a complete hematologic and molecular remission, bcr/abl fusion gene negative detected by FISH, real time PCR bcr/abl ratio 0.03. They have been alive and continuous complete remission.

CONCLUSION: Mylotarg alone or combinated with chemotherapy to patients with CD33-positive CML-BC in refractory to imatinib mesylate can obtain complete hematologic and molecular cytogenic remissions with what appears to be a favorable safety profile.