Luspatercept Meets Primary Endpoints in Phase 2 Alpha-Thalassemia Trial

Luspatercept (Reblozyl®) met primary endpoints in both non-transfusion-dependent (NTD) and transfusion-dependent (TD) adults with Alpha (α)-Thalassemia in the first registrational phase 2 trial in this population.1

Bristol Myers Squibb announced the positive top-line results on February 23, 2026, including luspatercept increased hemoglobin in NTD and reduced transfusion burden in TD, along with meeting all secondary endpoints and exhibiting a consistent safety profile.1

“These positive data further support the potential of Reblozyl for patients around the world,” said Cristian Massacesi, MD, Executive Vice President, Chief Medical Officer, and Head of Development at Bristol Myers Squibb, in a statement. “This is the first and only registrational Phase 2 trial specifically designed to address the needs of patients, especially in China, with alpha-thalassemia, a lifelong disease with limited treatment options and the potential for serious long-term complications.”1

Alpha-thalassemia is a hereditary blood disorder characterized by reduced or absent alpha-globin chain production, leading to chronic anemia. Patients with transfusion-dependent disease often require lifelong RBC transfusions, which are associated with iron overload and other complications. Therapeutic options for non–transfusion-dependent alpha-thalassemia remain limited.1

Luspatercept is a recombinant fusion protein that binds select transforming growth factor-β superfamily ligands, inhibiting SMAD2/3 signaling and promoting late-stage RBC maturation. In the United States, Reblozyl is approved by the US Food and Drug Administration for anemia in adults with beta-thalassemia who require regular RBC transfusions and for certain lower-risk myelodysplastic syndromes. It is not currently approved for alpha-thalassemia.1,2

In the NTD cohort, luspatercept demonstrated a statistically significant and clinically meaningful increase in hemoglobin. The primary endpoint was a ≥1 g/dL increase from baseline in mean hemoglobin over a continuous 12-week interval from Week 13 to Week 24 in the absence of red blood cell (RBC) transfusion.1

In the TD cohort, luspatercept demonstrated a statistically significant and clinically meaningful reduction in RBC transfusion burden. The primary endpoint was a ≥50% reduction from baseline in transfusion burden with a ≥2-unit reduction during any continuous 12 weeks between Week 13 and Week 48 compared with the 12-week interval before the first dose.1

The ongoing study is evaluating luspatercept plus best supportive care versus placebo in adults and adolescents with alpha-thalassemia, including both TD and NTD cohorts. The adolescent cohorts remain ongoing. Data from the trial are expected to be presented at an upcoming medical congress and will be discussed with the Center for Drug Evaluation in China.1

References

1. Bristol Myers Squibb Announces Positive Top-Line Results from Registrational Phase 2 Study of Luspatercept in Adults with Alpha (α)-Thalassemia. Bms.com. Published 2020. Accessed February 23, 2026. https://news.bms.com/news/details/2026/Bristol-Myers-Squibb-Announces-Positive-Top-Line-Results-from-Registrational-Phase-2-Study-of-Luspatercept-in-Adults-with-Alpha--Thalassemia/default.aspx

2. Patel B, Moosavi L. Luspatercept. PubMed. Published 2023. https://www.ncbi.nlm.nih.gov/books/NBK560635/