Reduced intensity allogeneic stem cell transplantation in patients with myelodysplastic syndrome: Does the conditioning matter? A retrospective study of the SFGM-TC on 61 patients

Abstract

6547 Background: Reduced-intensity allogeneic stem cell transplantation (RIT) has emerged as an alternative to myeloablative transplantation in pts with myelodysplastic syndrome (MDS). Given the uncertainty regarding the appropriate conditioning, SFGM-TC conducted a retrospective multicenter study with the attempt to evaluate the impact of conditioning on pts’ outcome. Methods: The record of 61 pts (37 males) with MDS who received a RIT between 1998 and 2003, from 22 French transplantation centres, were reviewed. According to the FAB classification, 11 pts had RA at diagnosis, of whom one had progressed to REAB and one to AML before transplantation. Thirty-two pts had REAB, of whom 2 had progressed to REAB-T and 7 to AML. Twelve pts had REAB-T and 6 CMML, of whom 8 progressed to AML. The median time from diagnosis to RIT was 12 months (6–129). Conditioning regimen consisted of fludarabin (Flu) plus busulfan ( n=29), Flu plus 2-Gy TBI ( n=20) and idarubicin plus aracytine and Flu (n=12). Donors were HLA-identical siblings (n=52) and HLA-matched unrelated (n=9). All pts received peripheral blood stem cells. The median of CD34+ infused cell dose was 5 × 106/kg (0.5–17.3). Results: At the reference date of 1 July 2005, median follow-up was 44.7 months (21–85). Estimated 3-year overall survival (OS), progression free survival (PFS), relapse and transplant-relapse mortality (TRM) were 35%, 27%, 66% and 30%, respectively. Neither of the 3 conditioning regimens used had impact on pts’ outcome. In multivariable analyses, while acute III/IV grade GVHD development was the only factor found to adversely influencing OS (HR=3.6; 95% CI: 1.1–12.2), chronic GVHD development was the only favourably influencing PFS and relapse ratios (HR=0.3; 95% CI: 0.1–0.7 and HR=0.2; 95% CI: 0.1–0.6, respectively). TRM was adversely influenced by male sex of pt (HR=9.2; 95% CI: 1.5–66.6). Conclusions: RIT seems to be an effective treatment in MDS pts irrespective of conditioning type. While acute III/IV grade GVHD appeared to be detrimental, the benefit effect of chronic GVHD was to be bound to GVL effect. New approaches with focus on immunosuppressive treatment are needed to enhance the GVL effect with an acceptable risk of GVHD. No significant financial relationships to disclose.