Core-binding factor acute myeloid leukemia in first relapse: a retrospective study from the French AML Intergroup.

Although core-binding factor-acute myeloid leukemia (CBF-AML) (t[8;21] or inv[16]/t[16;16]) represents a favorable cytogenetic AML subgroup, 30% to 40% of these patients relapse after standard intensive chemotherapy. The encouraging results of gemtuzumab ozogamicin (GO) in newly diagnosed AML, and particularly in CBF-AML, incited us to retrospectively investigate the impact of GO-based salvage in these patients. We retrospectively analyzed the outcome of 145 patients with CBF-AML (59 t[8;21], 86 inv[16]/t[16;16]) in first relapse. As salvage, 48 patients received GO-based chemotherapy and 97 patients received conventional chemotherapy. Median age was 43 years (range, 16-76). Median first complete remission duration was 12.1 months (range, 2.1-93.6). Overall, second complete remission (CR2) rate was 88%. With a median follow-up from relapse of 3.5 years, the estimated 5-year disease-free survival (DFS) was 50% and 5-year overall survival (OS) was 51%. Older age and shorter first complete remission duration was associated with a shorter OS. Patients treated with GO had similar CR2 rate but significantly higher 5-year DFS (68% vs 42%; P = .05) and OS (65% vs 44%; P = .02). In multivariate analysis, GO salvage was still associated with a significant benefit in DFS and OS. In the 78 patients who received allogeneic hematopoietic stem cell transplantation in CR2, GO before transplant significantly improved posttransplant DFS and OS without excess of treatment-related mortality.