Best responses achieved in DDX41 mutated patients were complete remission (CR, n=1), marrow CR (n=1), hematologic improvement (HI, n=1), and stable disease (SD, n=2). Remarkably, of the 5 patients that received treatment (4 AZA, 1 AZA+LEN), the overall survival at 52 months (range 47–58) follow up was 100% (Figure 2)...our correlative molecular analysis of the ALLG MDS4 trial of AZA vs AZA+LEN in MDS/AML has identified, in addition to established molecular risk factors for inferior outcomes, that pts with DDX41 mutations are associated with highly favorable outcomes with either AZA or AZA+LEN.