Validation of International Working Group response criteria in higher‐risk myelodysplastic syndromes: A report on behalf of the MDS Clinical Research Consortium

The utility of the International Working Group (IWG) 2006 response criteria for myelodysplastic syndromes (MDS) as a surrogate endpoint for outcomes is unclear. We assessed the validity of the IWG 2006 response criteria in a large cohort of higher‐risk MDS patients (pts) treated at centers from the MDS Clinical Research Consortium. The best overall response rate (ORR) by IWG 2006 criteria to first‐line therapy among 597 evaluable pts was 38% and include complete response (CR) 16%, marrow CR (mCR) 2%, partial response (PR) 10%, hematological improvement (HI) 10%, stable disease (SD) 33%, and progressive disease (PD) 24%. CR was associated with a better overall survival (OS) compared to all other response groups (P