Impact of the Presence of An Internal Tandem Duplicate of FlT3 Receptor (ITD) on the Outcome of Adult Patients with Acute Myelocytic Leukemia (AML) Autografted In First Remission (CR1)Norbert-Claude Gorin, Myriam Labopin, Jordi Esteve, and Mohamad Mohty, on Behalf of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Abstract 3556

The prognosis of patients with AML harbouring the FlT3 ITD is known to be poor in patients treated with chemotherapy only. However it remains uncertain whether it also has an impact on outcome following high dose intensification and autologous stem cell transplantation (ASCT).We adressed the question using the EBMT data base. Information on the presence or the absence of FlT3ITD was available in 134 adult patients with AML who were autografted in CR1 in the period of January 1999 to December 2009. 76 patients (42 with normal karyotypes) were ITD negative and 58 (36 with normal karyotypes) were ITD positive. 90% of the patients received peripheral blood as a source of stem cells. The follow up was 30 mo (1-139).Patients ITD positive were older than patients ITD negative (52.8 vs 47.4 years; p=0.009)and their White cell counts at diagnosis were higher (52 vs 10.9 10⁹/l; p<0.0001).For the 134 patients, the 3 year leukemia free survival (LFS) was 42 ± 5%, the relapse incidence (RI) 53 ± 4% and the non relapse mortality (NRM) 6 ±3%.Patients positive for Flt3ITD had a 3 year LFS of 34±7% vs 46±6% in those with no ITD (p=0.12), and a RI of 62±7% vs 45±6% (p=0.051). In Patients with ITD, age was the only significant poor risk factor with a LFS of 20 ± 9% in those older than 53 years (median) vs 46±10% in those younger. Further studies are needed with a larger patient population to draw valuable conclusions. However, these results suggest that while ASCT is of little benefit to older patients, it remains valuable in younger patients with AML harbouring the FlT3ITD, in whom the outcome does not differ from the ITD negative population.