P731: survival in lower-risk mds patients from eumds registry by two transplant selection criteria - implications for transplant decision

Background: Allogeneic hematopoietic stem cell transplantation is the only curative treatment for myelodysplastic syndrome (MDS). How to select lower-risk (LR) patients (pts) for transplantation is a matter of debate. The International Working Group for Prognosis in MDS (IWG) defined intermediate IPSS-R risk pts as a higher-risk if IPSS-R score is above 3.5. MDS-RIGHT criteria recommend transplantation in LR-MDS if: very/poor risk cytogenetics, >50% blasts increase from baseline or >15% BM blasts, neutrophils <0.3x109/l, platelets <30x109/l, high transfusion intensity ≥2 units/month for 6 months, progression to higher risk IPSS-R group or drop of platelets >25% in 6 months (MDS Europe. https://www.mds-europe.org). Aims: The primary aim of the study was to compare the survival of LR-MDS pts candidate for transplant by IWG and MDS-RIGHT criteria with non-candidate pts using registry data. The secondary aim was to compare the survival of IWG and MDS-RIGHT registry based cohorts with survival in published transplant cohort. Methods: 2284 pts from the EUMDS registry with LR-MDS (very/low and intermediate risk IPSS-R) were included in the registry based cohort. Survival analysis of pts meeting IWG and MDS-RIGHT criteria at baseline, 6 and 12 months was done in all candidates and those fit for transplantation, defined by Karnofsky ≥70, HCT-CI <3 according to MDS-RIGHT. Systematic review of transplantation studies in MDS was conducted. Published survival from transplant cohort were compared to the registry based cohorts. Results: Number of all and fit [Nall (Nfit, %)] candidates for transplant at baseline, 6 and 12 months was: IWG: 280 (146, 52%), 15 (5, 33%) and 22 (0, 0%); MDS-RIGHT: 182 (97, 53%), 428 (112, 26%) and 125 (39, 31%), respectively. Median OS, PFS and LFS survival in candidate and non-candidate patients at baseline were significantly different (p<0.01). Median OS was: IWG: 2.5 vs 4.6 years; MDS-RIGHT: 3.3 vs 4.6 years (Fig.1A and B). MDS-RIGHT pts with IPSS-R >3.5 (28% of IWG group) shown unfavorable median OS comparing with other pts (1.5 vs 4.8 years, p <0.001, Fig.1C). Published OS of transplanted intermediate IPSS-R risk pts (Scheid et al., BMT 2017) at 12, 24 and 36 months was: 59%, 48%, and 43%. Survival in IWG and MDS-RIGHT pts was better at all time points. MDS-RIGHT pts with IPSS-R >3.5 had higher survival at 1 year (68%) but worse survival at 2 and 3 years (42% and 33%) (p=0.07, Fig.1D). Summary/Conclusion: Both transplant selection criteria identify LR-MDS patients with unfavorable survival. MDS-RIGHT pts with IPSS-R above 3.5 have particularly unfavorable prognosis. There is no clear evidence for upfront transplantation in any of prognostic group.Keywords: Myelodysplastic syndrome, Prognosis, Allogeneic hematopoietic stem cell transplant