Ps1053 impact of cytomegalovirus reactivation on relapse rate after allogeneic stem cell transplantation in patients with acute myeloblastic leukemia

Background: Cytomegalovirus (CMV) infection is a major complication after allogeneic stem cell transplantation (ASCT). Aims: The aim of the study was to evaluate the impact of CMV reactivation on the relapse rate after ASCT in patients with acute myeloid leukemia (AML). Methods: Retrospective study conducted in patients with AML who underwent ASCT from HLA identical sibling donor between January 2011 and December 2018. Conditioning regimen consisted of Busulfex and Cyclophosphamide (Bu/Cy) or Fludarabine and Busulfex (F/Bu). Graft‐versus‐host disease (GVHD) prophylaxis consisted of cyclosporine and a short course of methotrexate. Antiviral prophylaxis for CMV infection was assured by Acyclovir from day +1 to day +180. CMV detection was carried out once‐a‐week from engraftment to day +100 by either pp 65 antigenemia test or real‐time quantitative PCR. Results: Ninety‐three patients were enrolled (55 men and 38 women). Median age was 33 years (range, 5 ‐ 49 y). At the time of transplant, 73 patients (78.5%) were in CR1, 16 patients (17.2%) were in CR2 and 4 patients (4.3%) were in response failure. CMV serostatus for donor (D) and recipient (R) was available for 44 cases (47.3%). Serostatus of R+/D+ and R+/D− was observed in 38 patients (86.4%). Stem cell source were BM in 49 cases (52.7%) and PBSC in 44 cases (47.3%). No graft failure was observed. Acute GVHD grade II‐IV occurred in 19 patients (20.4%). Chronic GVHD was observed in 40 patients (45.4%). Twenty‐nine patients (31.2%) developed CMV reactivation. With a median follow‐up of 2 years (range 49 days – 7 years), the overall survival (OS) and the non‐relapse mortality (NRM) were not statistically significant between patients with CMV reactivation and those without CMV reactivation (74% vs 63%, p = 0.3 and 20.7% vs 7.8%, p = 0.08, respectively). Twenty‐four patients (25.8%) relapsed at a median of 6 months (range 2 ‐ 67 months). the rate of relapse among patients with CMV reactivation was significantly lower than in those without CMV reactivation (10.3% vs 32.8%, p = 0.02). In univariate analysis, the CMV reactivation was the only factor associated with a decreased risk of relapse (OR = 0.23, 95% CI: 0.06–0.87, p = 0.02). Summary/Conclusion: CMV reactivation was associated with decreased relapse risk after ASCT for patients with AML without a benefit in OS.