Mylotarg combined with topotecan and cytarabine in patients with refractory acute myelogenous leukemia

Purpose: Mylotarg, a humanized anti-CD33 antibody linked to an antitumor antibiotic, is approved for the treatment of patients with relapsed acute myeloid leukemia (AML). Topotecan and cytarabine (ara-C) is an effective anti-AML regimen. A pilot study of Mylotarg combined with topotecan and ara-C (MTA) was conducted in patients with refractory AML. Methods: MTA consisted of Mylotarg 9 mg/m² intravenously (i.v.) over 2 h on day 1, ara-C 1 g/m² over 2 h i.v. on days 1 through 5, and topotecan 1.25 mg/m² by continuous infusion i.v. on days 1 through 5. Results: A group of 17 patients (9 primary resistant, 8 relapsed) with AML or advanced myelodysplastic syndrome (MDS) received 20 courses of MTA. The median age of the patients was 55 years (20-70 years). Two patients (12%) achieved complete remission. The median overall survival was 8.2 weeks. Five patients (29%) developed grade 3/4 hepatic transaminitis, including one patient (6%) who died with hepatic venoocclusive disease. Conclusions: MTA was moderately effective and associated with significant toxicity in patients with refractory AML.