Clinical outcomes of gemtuzumab ozogamicin for relapsed acute myeloid leukemia: single-institution experience

We retrospectively evaluated the clinical efficacy and toxicity of gemtuzumab ozogamicin (GO) in patients with relapsed acute myeloid leukemia (AML). Nineteen patients (median 70 years) received GO (9 mg/m², days 1 and 15) as salvage therapy in our institution between 2006 and 2017. The primary endpoint was the response rate. The secondary endpoint was the occurrence of adverse events. Thirteen patients had de novo AML, and 6 patients had secondary AML. Most of the patients had received salvage treatments more than once prior to GO. Six patients responded to the treatment (31.6%) with 3 complete remissions (15.8%). Five patients had stable disease, and 8 patients did not show any response. GO was more efficacious among the patients with fewer numbers of prior salvage treatments. CD33 positivity of leukemic cells was higher in responders than in nonresponders. Peripheral WT1 mRNA levels mostly decreased over time in the responders. The adverse event most commonly seen was febrile neutropenia (84%). No patient presented with veno-occlusive disease. Three patients died by day 30 (mortality rate 15.8%), one due to acute respiratory distress syndrome and the other two due to sepsis. GO remains an effective salvage treatment.