The impact of post transplant use of G-CSF on event free survival in AML patients undergoing allogeneic stem cell transplantation from unrelated donors and in vivo T-cell depletion with ATG

Abstract

6637 Background: Allogeneic hematopoietic cell transplantation from matched unrelated donors (MUD-HSCT) may be curative for high risk AML patients. However, it carries a considerable risk of treatment related mortality. This study was performed to identify risk factors (RF) impairing event free survival (EFS) in patients (pts) with AML undergoing MUD-HSCT and in vivo T-cell depletion with ATG. Methods: In a retrospective analysis of all pts with AML undergoing MUD-HSCT we identified RF by Log-Rank analysis and performed a multivariate analysis of all RF being significant in univariate analysis. RF included were: disease status at transplant (DS); pts age; donor sex; transplant era; stem cell source; number of cells transplanted; HLA-match; ATG source; risk of cytomegalovirus infection; acute (a) and chronic graft vs host disease (GvHD); cytogenetics (CG); post transplant application of granulocyte colony stimulating factor (G-CSF). Results: Eighty-nine pts (47 m, 42 f), median age 42 y (18 –62 y), who underwent MUD-HSCT in the period from 1996 to 2003 were included. All pts received rabbit ATG (Fresenius: n=29, Merieux/Sangstat: n=60) during conditioning. 50 pts died after HSCT. Median EFS was 186 d (9 –2125 d). As significant risk factors we identified by univariate analysis: the occurrence of aGvHD (p=0.0000), CG (p=0.0375) and use of G-CSF (p=0.0001). The only RF remaining after cox regression analysis were aGvHD (p = 0.003, RR 1,544, CI 95%, 1,160 –2,056) and use of G-CSF (p = 0,000, RR 3,401, CI 95%, 1,712 –6,757). The mortality of pts receiving G-CSF was 77% as compared to 37% in pts not receiving G-CSF. This higher mortality was due to a higher transplant related mortality but also due to a higher relapse rate. Conclusions: In this cohort the occurence of acute GvHD and the application of G-CSF were independent negative predictors for EFS. Therefore the selection of pts for use of post transplant G-CSF should be done with due care, especially in AML pts receiving MUD-HSCT and in vivo T-cell depletion with ATG. No significant financial relationships to disclose.