Equivalent Outcome Between Reduced Intensity Versus Conventional Myeloablative Conditioning Hematopoietic Stem Cell Transplantation for Patients Older Than 35 Years with Acute Myeloid Leukemia

Abstract 3103 Introduction: Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) provides the best chance of long-term survival for patients with intermediate or high-risk acute myeloid leukemia (AML). The major limitation of this procedure is the risk of treatment related mortality (TRM). Use of reduced intensity conditioning (RIC) regimen has become standard practice among older candidates with comorbidities. Although RIC regimen have been used for over a decade in older patients, the benefit of this approach in younger patients with AML compared with the risk of toxicity of standard regimen (MAC) is still discussed. We compared the outcomes for patients with AML over 35 years using RIC or MAC HSCT. Patients, methods, and transplantation characteristics: From January 2000 to December 2010, 132 consecutive patients older than 35 years with AML (18 secondary AML) received HSCT in our center, either from siblings (n=87) or HLA 10/10 allele-matched donors (n=45). MAC (n=72) and RIC (n=60) regimens were defined as previously described (Bacigalupo, 2009). Seventy-three patients were in first complete remission (CR1); 30% of patients had poor risk cytogenetics (MRC classification). Karnofsky performance status was scored at time of HSCT. Engraftment, acute and chronic graft-versus-host disease (GvHD), transplantation-related mortality (TRM), relapse rate as well as overall survival (OS) at 4 years were compared according to the intensity of the conditioning regimen. First a classical multivariable Cox analysis was conducted. In a second step, baseline confounding factors were adjusted for using inverse probability-of-treatment weighting (IPTW). Results of the comparison: Patient characteristics according to the intensity of the conditioning regimen were similar for AML type (de novo versus secondary), gender, karnofsky performance status, CR#, donor type and number of CD34+ infused. Particularly, cytogenetic risks were comparable in both groups. Patients were younger in the MAC group (median age 44 years [range 35 to 56 years] vs 54[37 to 66] for RIC, p Conclusion: In patients with AML over 35 years, MAC regimen lead to a non significant higher rate of treatment related mortality with no benefit in terms of relapse when compared with RIC regimen. Until prospective trials are completed, this study supports the use of a RIC regimen for patients with AML older than 35 years who are transplanted either from siblings or matched unrelated donors. Disclosures: Fenaux: Amgen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.