High dose cytarabine plus gemtuzumab ozogamicin for patients with relapsed or refractory acute myeloid leukemia: Cancer and Leukemia Group B study 19902

Gemtuzumab ozogamicin (GO), an anti-CD33 immunoconjugate, was combined with high dose cytarabine (HiDAC; cytarabine 3 g/m2 over 3 h daily for 5 days) for adults with relapsed or refractory AML. HiDAC plus GO 9 mg/m2 on day 7 and 4.5 mg/m2 on day 14 was not tolerated, but HiDAC followed by GO 9 mg/m2 on day 7 was safe: 12/37 (32%) patients with relapsed AML achieved complete remission. Median overall survival was 8.9 months. No grade 4 hepatic veno-occlusive disease was observed. This regimen merits further study, both in this setting and as a remission consolidation therapy.