Gemtuzumab ozogamicin in combination with attenuated doses of standard induction chemotherapy can successfully induce complete remission without increasing toxicity in patients with acute myeloid leukemia aged 55 or older

Background: In this study, the effectiveness and safety of combining gemtuzumab ozogamicin (GO) with an abbreviated schedule of standard induction chemotherapy were assessed in 37 patients (aged ≥55) yr with previously untreated acute myeloid leukemia (AML). Methods: GO was administered at a dose of 6 mg/m² as a single 2-h intravenous infusion on day 1. Following GO, an abbreviated schedule of induction chemotherapy consisting of idarubicin (12 mg/m²/d, days 2-4), and N4-behenoyl-1-β-arabinofuranosyl cytosine (300 mg/m²/d, days 2-6) was given. Results: Thirty-seven patients were treated with GO in combination with chemotherapy. Complete remission (CR) and CR with incomplete platelet recovery were achieved in 28 patients (75.7%) and one patient (2.7%) respectively. Two patients (5.4%) died during induction and two patients (5.4%) with grade 4 treatment emergent adverse effects during chemotherapy did not complete induction chemotherapy. The majority of toxicities were mild and manageable. Severe myelosuppresion was universal with significantly prolonged thrombocytopenic period. In total, 25 patients who received consolidation treatment, 19 patients remain alive at the time of analysis. Thirteen patients had undergone hematopoietic stem cell transplantation, three are preparing for transplantation and seven are receiving their consolidation chemotherapy course. Conclusion: Although only a relatively small number of cases were included in this preliminary study and the follow-up duration was short, frontline GO in combination with attenuated conventional chemotherapy was found to be effective and feasible in elderly patients with AML.