First experience with gemtuzumab ozogamicin plus cytarabine as continuous infusion for elderly acute myeloid leukaemia patients.

Gemtuzumab ozogamicin (GO), an anti-CD33 monoclonal antibody conjugated to calicheamicin, is effective as single agent in the treatment of poor risk acute myeloid leukaemia (AML) patients. We treated with GO in combination with cytarabine as continuous perfusion nine elderly AML patients, either untreated (five cases), or with relapsed/refractory disease (four cases). Five patients achieved a complete remission (CR), four were resistant. One patient died while in CR due to CNS haemorrhage, two relapsed and two are still in CR. The median CR duration was 10 months. The median overall survival was 6 months (1-19 months). The most common adverse event was myelosuppression, as expected. No hepatic veno-occlusive disease was recorded. Notably, in four cases we observed a grade III/IV bleeding, including gasto-intestinal bleeding, epistaxis, CNS haemorrhage, and ocular bleeding. Larger prospective studies are now warranted in order to better define the possible role of this regimen in the treatment of elderly AML patients.