Clinical outcomes of patients with lower risk myelodysplastic syndrome from EUMDS registry eligible for transplantation: Implications for transplantation strategies

Selecting eligible allogeneic haematopoietic stem cell transplantation (allo-HSCT) candidates with low-risk and intermediate-risk myelodysplastic syndrome (MDS) remains controversial. The International Working Group (IWG) for MDS prognosis identified a Revised International Prognostic Scoring System (IPSS-R) score >3.5 for benefits from early transplantation; the MDS-RIGHT group uses a broader set of poor risk features. We analysed 1145 lower risk MDS (lower risk and intermediate-risk IPSS-R) patients aged <75 years, using real-world European Myelodysplastic Syndromes registry data and identifying those meeting IWG or MDS-RIGHT criteria for allo-HSCT at baseline and 6-month follow-up. Fit patients were characterised by Karnofsky score ≥70 and Haematopoietic Cell Transplantation-specific Comorbidity Index <3. We evaluated clinical outcomes of transplant candidates, including survival, disease progression risk, new comorbidity risk and performance status decline. The IWG criterion, and not MDS-RIGHT criteria, identified patients with lower risk and intermediate-risk MDS with poorer baseline survival. Fit lower risk patients showed 2-year cumulative risks of incident comorbidity and performance status deterioration of 20% and 5% respectively. In summary, IWG and MDS-RIGHT features identify patients with lower or intermediate-risk MDS as candidates for early transplantation. Lower risk patients fit for transplantation have a cumulative incidence of adverse outcomes possibly jeopardising transplantation eligibility and should be carefully selected when planning delayed transplantation strategies.