MDS-191: Long-Term Efficacy and Safety of Luspatercept in Lower-Risk Myelodysplastic Syndromes (MDS): Phase 2 PACE-MDS Study

Background: Luspatercept, a first-in-class erythroid maturation agent, has been investigated in patients with LR-MDS and ring sideroblasts (RS) (MEDALIST; Fenaux and Platzbecker NEJM 2020) and in an ongoing Phase 3 trial regardless of RS status (COMMANDS, NCT03682536 ). The previously reported Phase 2 trial of luspatercept (Platzbecker Lanc Onc 2017) includes subtypes of LR-MDS with and without RS, regardless of prior ESA exposure, and various EPO levels. Aims: Evaluate the long-term safety and efficacy of luspatercept in LR-MDS. Methods: Patients were IPSS low/int-1, age ≥ 18 years, Hgb NCT01749514 ; NCT02268383 ). Results: As of 13July2019, 115 patients were enrolled, of whom 108 were treated with ≥0.75 mg/kg. 44/108 (41%) were non-RS; 47/108 (44%) had prior ESA; 45/108 (42%) had baseline transfusion burden of ≥4U RBC/8 weeks. Median duration of treatment (n=108) was 10.4 (0.7-57.3) months. IWG HI-E RR was 54% (58/108) overall; 36% (16/44) in non-RS, 68% (42/62) in RS+ (2 patients had unknown RS status); 53% (25/47) prior ESA, 54% (33/61) in ESA-naive; 54% (34/63) in 2 patients) were fatigue, headache, hypertension, arthralgia, bone pain, diarrhea, injection site erythema, myalgia, and peripheral edema. Conclusions: Consistent with previous reports, data from the long-term Phase 2 study of luspatercept in LR-MDS continues to show efficacy in a variety of subtypes and safety similar to previous and ongoing studies.