Learning from late-stage trial failures in higher-risk myelodysplastic syndromes: towards adaptive and...

Higher-risk myelodysplastic syndromes (HR-MDS) remain an area of high unmet need in which multiple randomized late-stage trials have failed to improve outcomes beyond hypomethylating agent monotherapy, despite encouraging early-phase signals.

Key randomized late-stage HR-MDS trials that failed to meet primary endpoints are evaluated for recurring design and interpretive challenges. Key themes include endpoint limitations, optimistic effect-size assumptions, underpowering for modest but clinically meaningful hazard ratios, and signal dilution from biological and operational heterogeneity. We discuss adaptive methodologies applicable to HR-MDS to improve trial efficiency and preserve statistical integrity. Regulatory perspectives including contemporary guidance and emerging international principles for confirmatory adaptive trials are considered. Randomized Phase 2/3 HR‑MDS trials and relevant literature were identified through searches of PubMed, ClinicalTrials.gov, and major conference proceedings (2010-2025).

Many new HR-MDS therapies are likely to deliver incremental survival gains rather than large overall survival improvements, particularly given an apparent survival plateau around 2 years. Future confirmatory programs should, therefore, plan for incremental improvements, prespecify handling of transplantation and post-protocol therapies, and integrate molecular stratification/enrichment to reduce variance. Adaptive designs should be used to stop futile programs earlier and to expand adequately powered trials when emerging data support clinically meaningful benefit.