Reduced Relapse Risk In Patients With AML After Hhcmv-Replication Post Transplantation-First Results Of a Prospective Registration Trial

Abstract 5503 Introduction Early detection of inapparent replicative human cytomegalovirus (HCMV) infection together with its preemptive antiviral treatment has led to a marked reduction of life-threatening HCMV disease after allogeneic hematopoietic stem cell transplants (alloSCT). A new aspect of HCMV reactivation and pretransplant HCMV serostatus has recently emerged by an earlier retrospectively performed report from us showing that the occurrence of a HCMV-reactivation after transplant reduces the risk for relapse in patients with AML and NHL. This idea was supported by a study by Scheper and co-worker (Leukemia, 2013) reporting recently, that gamma-delta T cells elicited by HCMV reactivation after alloSCT cross-recognize HCMV and leukemia. Here we evaluate the potential impact of early HCMV replication in a prospectively performed observational study about the occurrence of a HCMV- reactivation after T cell repleted alloSCT on the risk for leukemic relapse in patients with AML (Registration Trial DRKS00004300). Patients and Method Between January 2012 and March 2013 we enrolled in this trial 83 patients with AML who were consecutively transplanted at the University Hospital of Essen. 48 of 83 patients received a myeloablative (TBI based conditioning n=27, chemotherapy based conditioning n=23) and 35 patients a RIC regimen. Patients were transplanted in 1.CR (n=40), 2.CR (n=23) or more progressive disease stages (n=20) from HLA-identical sibling donor (n=17) or HLA-identical unrelated donor (URD) (n=42) or mismatched unrelated donor (n=24). The median age of patients was 53 years (range 18-72) and that of the donors 38 years (range 12-61). GVHD prophylaxis was performed with MTX and CSA, or CSA and MMF with or without ATG (n=64) (30-60mg total dose). The incidence of acute GVHD grade 2-4 was statistically not different in both groups (78% versus 85%). Results HCMV status of recipient (R) or donors (D) were in 29% R-/D-, 8% R-/ D+; 34% D+/R- and 29% R+/D+. Patients with a documented HCMV-reactivation (HCMV-R) had an estimated relapse incidence (CIR) at 1-year after transplant of only 8% compared to 43% in patients without a HCMV-R (p=0.03). Patients in more progressive disease phase of AML (N=43) benefit more from a HCMV-R in regard of CIR than patients in 1.CR of AML (0% versus 55% estimate for relapse at 1-year after transplant for patients with HCMV-R compared to patients without HCMV –R, p=0.028). One-year overall survival was statistically not different in both groups. Non relapse mortality was greater in patients with HCMV reactivation 37.8% versus 12.5%, p=0.1) Conclusion The first result of this prospective study confirms an independent advantageous effect of early HCMV replication on the leukemic relapse risk in patients with AML after transplant, which was more pronounced in patients in progressive disease phase of AML than patients in 1.CR of AML. Disclosures: Off Label Use: The off-label use of HCG will be presented here for the first tiem for treatment of chronic GVHD and will clearly marked as off-label use.