Fractionated doses of gemtuzumab ozogamicin combined with 3 + 7 induction chemotherapy as salvage treatment for young patients with acute myeloid leukemia in first relapse.

Current salvage therapies for relapsed acute myeloid leukemia (AML) are unsatisfactory. We retrospectively evaluated the efficacy and toxicity of fractionated doses of gemtuzumab ozogamicin (GO) combined with a standard 3 + 7 induction regimen in young patients with AML in first relapse. Salvage regimen consisted of GO 3 mg/m² on days  1, 4, and 7; cytarabine, 200 mg/m² on days 1-7; and daunorubicine, 60 mg/m²; or idarubicine, 12 mg/m² on days 1-3. Fourteen patients were treated between April 2008 and April 2011. Median age was 46 years (29-58), median white blood cell count is 3.4 10⁹/L (0.9-19), and median first complete remission (CR) duration is 11 months (1-42). All the patients had previously received high or intermediate doses of cytarabine as consolidation therapy. Salvage treatment was performed as scheduled for the 14 patients, using daunorubicine in 12 patients and idarubicine in two. Overall response rate was 79 % with six CR and five CR with incomplete platelet recovery. Median times to neutrophil (>0.5 10⁹/L) and platelet (>20 10⁹/L) recovery were 29 days (23-32) and 36 days (28-48), respectively. Allogeneic transplantation was performed in the 11 responding patients within a median time of 4 months (3-10). Three mild and one moderate veno-occlusive disease (VOD) occurred after salvage and two moderate VOD after transplantation. Median and 2-year overall survival (OS) were 10 months and 42 %, respectively. For responders, estimated 2-year OS was 53 % (median OS not reached). This salvage regimen seems safe and effective in younger patients with AML in first relapse allowing allogeneic transplantation in CR2 for most patients.