Defining The Dose Of Gemtuzumab Ozogamicin In Combination With Induction Chemotherapy In Acute Myeloid Leukemia: A Comparison Of 3 Mg/M2 With 6 Mg/M2 In The NCRI AML17 Trial

Abstract

Arecent source data meta-analysis of randomized trials in adults assessing the immunoconjugate gemtuzumab ozogamicin combined with standard chemotherapy in acute myeloid leukemia showed a significant survival benefit in patients without an adverse karyotype. It is not clear whether the optimal dose should be 3 mg/m2 or 6 mg/m2. In this study, we randomized 788 patients to a single dose of gemtuzumab ozogamicin 3 mg/m2 or 6 mg/m2 with the first course of induction therapy. We found that the rate of complete remission was higher with 3 mg/m2 [82% vs. 76%; odds ratio 1.46 (1.04–2.06); P=0.03], but this was balanced by a higher rate of complete remission with incomplete peripheral blood count recovery in the 6 mg/m2 treatment (10% vs. 7%) resulting in similar overall response rate [89% vs. 86%; hazard ratio 1.34 (0.88–2.04); P=0.17]. There was no overall difference in relapse or survival at four years between the arms: 46% vs. 54%; hazard ratio 1.17 (0.94–1.45), P=0.5, and 50% versus 47%; hazard ratio 1.10 (0.90–1.34), P=0.3, respectively. The 30- and 60-day mortality was significantly higher in the 6 mg/m2 recipients: 7% versus 3%; hazard ratio 2.07 (1.11–3.87), P=0.02, and 9% versus 5%; hazard ratio 1.99 (1.17–3.39), P=0.01, respectively, which in addition was associated with a higher rate of veno-occlusive disease (5.6% vs. 0.5%; P<0.0001). Our conclusion from this trial is that there is no advantage in using a single dose of 6 mg/m2 of gemtuzumab ozogamicin in combination with induction chemotherapy when compared with a 3 mg/m2 dose, with respect to response, disease-free and overall survival, either overall, or in any disease subgroup. (AML17 was registered as ISRCTN55675535.