Prognostic impact of genetic characterization in the GIMEMA LAM99P multicenter study for newly diagnosed acute myeloid leukemia

Background: Recent advances in genetic characterization of acute myeloid leukemia indicate that combined cytogenetic and molecular analyses provide better definition of prognostic groups. The aim of this study was to verify this prospectively in a large group of patients. Design and Methods: Genetic characterization was prospectively carried out in 397 patients with acute myeloid leukemia (median age, 46 years) receiving uniform treatment according to the LAM99P protocol of the Italian GIMEMA group. The impact of genetic markers on response to therapy and outcome was assessed by univariate and multivariate analyses. Results: For induction response, conventional karyotyping identified three groups with complete remission rates of 92%, 67% and 39% (p<0.0001). Complete remission rates in NPM1 mutated (NPM1+) and wild-type (NPM1-) groups were 76% and 60%, respectively, for the whole populations and 81% and 61% in the group with normal karyotype (p<0.001 and p=0.026, respectively). Multivariate analysis indicated that low risk karyotype and NPM1+ were independent factors favorably affecting complete remission. Multivariate analysis of overall and disease-free survival among 269 patients who achieved complete remission showed a significant impact of karyotype on both estimates and of FLT3 status on disease free-survival (FLT3-ITD vs. FLT3 wildtype, p=0.0001). NPM1 status did not significantly influence disease free-survival in either the whole population or in the patients with a normal karyotype in this series, probably due to the low number of cases analyzed.