Sequential combination of gemtuzumab ozogamicin and standard chemotherapy in older patients with newly diagnosed acute myeloid leukemia: results of a randomized phase III trial by the EORTC and GIMEMA consortium (AML-17).

Purpose: This randomized trial evaluated the efficacy and toxicity of sequential gemtuzumab ozogamicin (GO) and standard chemotherapy in older patients with newly diagnosed acute myeloid leukemia (AML).
Patients and Methods: Patients (n = 472) age 61 to 75 years were randomly assigned to induction chemotherapy with mitoxantrone, cytarabine, and etoposide preceded, or not, by a course of GO (6 mg/m(2) on days 1 and 15). In remission, patients received two consolidation courses with or without GO (3 mg/m(2) on day 0). The primary end point was overall survival (OS).
Results: The overall response rate was comparable between the two arms (GO, 45%; no GO, 49%), but induction and 60-day mortality rates were higher in the GO arm (17% v 12% and 22% v 18%, respectively). With median follow-up of 5.2 years, median OS was 7.1 months in the GO arm and 10 months in the no-GO arm (hazard ratio, 1.20; 95% CI, 0.99 to 1.45; P = .07). Other survival end points were similar in both arms. Grade 3 to 4 hematologic and liver toxicities were greater in the GO arm. Treatment with GO provided no benefit in any prognostic subgroup, with the possible exception of patients age < 70 years with secondary AML, but outcomes were significantly worse in the oldest age subgroup because of a higher risk of early mortality.
Conclusion: As used in this trial, the sequential combination of GO and standard chemotherapy provides no benefit for older patients with AML and is too toxic for those age ≥ 70 years.