Efficacy a nd S afety o f G emtuzumab O zogamicin i n P atients With C D33-Positive A cute M yeloid L eukemia i n F irst Relapse

Purpose: Three open-label, multicenter trials were conducted to evaluate the efficacy and safety of singleagent Mylotarg (gemtuzumab ozogamicin; CMA-676; Wyeth Laboratories, Philadelphia, PA), an antibodytargeted chemotherapy agent, in patients with CD33positive acute myeloid leukemia (AML) in untreated first relapse. Patients and Methods: The study population comprised 142 patients with AML in first relapse with no history of an antecedent hematologic disorder and a median age of 61 years. All patients received Mylotarg as a 2-hour intravenous infusion, at a dose of 9 mg/m 2 , at 2-week intervals for two doses. Patients were evaluated for remission, survival, and treatment-emergent adverse events. Results: Thirty percent of patients treated with Mylotarg obtained remission as characterized by 5% or less blasts in the marrow, recovery of neutrophils to at least 1,500/mL, and RBC and platelet transfusion independence. Although patients treated with Mylotarg had relatively high incidences of myelosuppression, grade 3 or 4 hyperbilirubinemia (23%), and elevated hepatic transaminase levels (17%), the incidences of grade 3 or 4 mucositis (4%) and infections (28%) were relatively low. There was a low incidence of severe nausea and vomiting (11%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Many patients received Mylotarg on an outpatient basis (38% and 41% of patients for the first and second doses, respectively). Among the 142 patients, the median total duration of hospitalization was 24 days; 16% of patients required 7 days of hospitalization or less. Conclusion: Administration of the antibody-targeted chemotherapy agent Mylotarg to patients with CD33positive AML in first relapse induces complete remissions with what appears to be a favorable safety profile. J Clin Oncol 19:3244-3254. © 2001 by American Society of Clinical Oncology.