Low doses of gemtuzumab ozogamicin in adults diagnosed with acute myeloid leukaemia

Background: Gemtuzumab ozogamicin (GO) is a monoclonal antibody with significant activity in CD33+acute myeloid leukaemia (AML). At doses of 9mg/m², its benefit was limited by hepatotoxicity and sinusoidal obstruction syndrome (SOS). Fractionated doses improved toxicity without compromising efficacy. We evaluated the efficacy and the toxicity of low doses of GO.

Methods: Twenty-four patients with AML received 3mg/m² of GO as a part of the induction or reinduction therapy.

Results: Fourteen patients diagnosed with de novo AML and 10 patients with relapsed or refractory (R/R) AML received GO as a part of the induction or reinduction therapy. Three and no cases of hepatotoxicity were observed, respectively. Thirteen patients received a subsequent haematopoietic stem cell transplantation (HSCT) after GO therapy. Hepatotoxicity was observed in 2 patients and no SOS was observed in any patient.

Conclusions: The administration of low dose GO is feasible and does not have impact on subsequent HSCT outcome. Although some degree of hepatotoxicity was observed, there were no cases of SOS, either before or after HSCT.