Clinical outcomes by SF3B1 mutation status in patients (pts) with lower-risk myelodys-plastic syndrome (LR-MDS) retreated with erythropoiesis-stimulating agents (ESAs).

7071 Background: Pts with SF3B1-mutated LR-MDS often have a more favorable prognosis versus those with SF3B1 wildtype. A sizeable number of pts with LR-MDS undergo ESA treatment even after experiencing ESA failure in first line. This study evaluated the outcomes of pts with LR-MDS retreated with ESAs in routine clinical practice, stratified by SF3B1 status. Methods: This retrospective cohort study included pts with LR-MDS in the US community setting who initiated ESAs as first-line therapy between January 1, 2016 and June 30, 2019, and were followed through June 30, 2021. Eligible pts discontinued ESAs (treatment gap ≥ 3 wk for epoetin alfa or ≥ 6 wk for darbepoetin alfa) and subsequently reinitiated ESA therapy at least once during follow-up. Ring sideroblasts (RS) ≥ 15% served as a surrogate for pts with unknown SF3B1 mutation status. Outcomes included ESA switches, dose reductions and escalations, ESA failure, and overall survival (OS). Primary ESA failure was defined as no rise in hemoglobin (Hb) ≥ 1.5 g/dL or no decrease in RBC transfusion requirement by 8 wk of treatment. Transfusion-dependent (TD) status was evaluated for pts who were transfusion independent (TI) at baseline. Results: A total of 82 pts with LR-MDS and repeat ESA treatment were included. Median age at start of ESA treatment was 79 y (interquartile range [IQR], 72–85). Diagnosis of MDS-RS, MDS with isolated del(5q), MDS with multilineage dysplasia, and MDS with single lineage dysplasia was reported in 30 (36%), 7 (9%), 9 (11%), and 9 (11%) pts, respectively; 27 (33%) had unknown classification. Median follow-up was 26 mo (IQR, 13–38) with 65% failing ESA therapy by 8 wk. Table shows pts’ SF3B1 mutation status, median OS, pts who had an ESA switch, dose reduction or escalation, experienced ESA failure, and pts who were TI at baseline and became TD during follow-up. Results were similar when RS was not used as a surrogate, and when analyses were limited to pts who were treated with ESAs only throughout follow-up. Conclusions: In this study of pts with LR-MDS retreated with ESAs, primary ESA failure was high with nearly half of TI pts becoming TD during follow-up. OS was poor regardless of SF3B1 status – 2–4 times lower than the remaining life expectancy for a 79-y-old (108 mo for men; 125 mo for women). Although treatment options were limited during the study period, the high primary failure rate suggests that pts with LR-MDS may benefit from alternatives to ESAs. [Table: see text]