Luspatercept Data Expand Therapeutic Pathways in Alpha-Thalassemia

Positive top-line results from a registrational Phase II study indicate that luspatercept -aamt (brand name Reblozyl, Bristol Myers Squibb), a recombinant fusion protein, may address anemia across both transfusion-dependent and non-transfusion-dependent populations with alpha (α)-thalassemia, a genetic blood disorder associated with ineffective erythropoiesis and chronic anemia burden.¹

Bristol Myers Squibb announced on Feb. 23, 2026 that both cohorts of an ongoing ex-US trial evaluating luspatercept-aamt met their respective primary and secondary endpoints, demonstrating statistically significant clinical improvements compared with placebo. The therapy is being studied as a potential treatment option for adults living with α-thalassemia, a condition for which disease-modifying therapies remain limited.

Alpha-thalassemia results from impaired production of alpha-globin chains, leading to ineffective red blood cell maturation, chronic anemia, and, in severe cases, lifelong transfusion dependence. Treatment strategies have historically focused on supportive care rather than targeting underlying erythropoietic dysfunction.²

How did luspatercept-aamt affect anemia outcomes across patient populations?

The Phase II registrational study evaluated luspatercept-aamt plus best supportive care versus placebo in adults with α-thalassemia across two clinically distinct populations, non-transfusion-dependent (NTD) and transfusion-dependent (TD) patients.

In the NTD cohort, Bristol Myers Squibb reported that treatment resulted in a statistically significant and clinically meaningful increase in hemoglobin levels without the need for transfusion during the prespecified evaluation period. In parallel, patients in the TD cohort experienced a statistically significant reduction in red blood cell transfusion burden, meeting the study’s primary efficacy endpoint.¹

The company stated that key secondary endpoints were also achieved across both cohorts, reinforcing consistency of treatment benefit. Reported safety findings aligned with the established clinical profile of luspatercept-aamt observed in previously approved hematologic indications.

“These positive data further support the potential of Reblozyl for patients around the world,” said Cristian Massacesi, executive vice president, chief medical officer and head of Development, Bristol Myers Squibb, in a company press release.¹ “This is the first and only registrational [Phase II] 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.”

Why is targeting late-stage erythropoiesis emerging as a therapeutic strategy?

Luspatercept-aamt functions by promoting late-stage red blood cell maturation, addressing ineffective erythropoiesis, which is a central pathological mechanism underlying thalassemia-associated anemia. Unlike transfusion-based management approaches, therapies targeting erythroid maturation aim to reduce transfusion requirements while improving endogenous hemoglobin production.³

The trial’s dual success across NTD and TD populations may support broader application of erythroid maturation agents in genetically driven anemias, particularly where transfusion dependence contributes to iron overload and cumulative morbidity. Enrollment in adolescent cohorts remains ongoing, while study findings are expected to inform regulatory discussions with China’s Center for Drug Evaluation, according to Bristol Myers Squibb. Data from the trial are scheduled for presentation at an upcoming medical congress.¹

What could these findings mean for global thalassemia development programs?

Alpha-thalassemia represents a substantial unmet medical need in regions with high disease prevalence, including parts of Asia, where therapeutic options beyond transfusion support remain limited. Demonstration of efficacy in a registrational Phase II setting may help establish a regulatory pathway for targeted anemia therapies in genetically defined hemoglobinopathies.¹

Luspatercept-aamt is currently approved in multiple markets for anemia associated with beta-thalassemia and myelodysplastic syndromes, reflecting expanding interest in mechanisms that modulate erythropoiesis rather than replacing lost red blood cells. As global development of the therapy progresses, the study results highlight continued industry movement toward mechanism-based therapies designed to reduce long-term treatment burden in inherited hematologic diseases.

References

1. Bristol Myers Squibb. Bristol Myers Squibb Announces Positive Top-Line Results from Registrational Phase 2 Study of Luspatercept in Adults with Alpha (α)-Thalassemia. Press Release. Feb. 23, 2026.
2. Baird DC, Batten SH, Sparks SK. Alpha- and Beta-thalassemia: Rapid Evidence Review. Am Fam Physician. 2022;105(3):272-280. Accessed Feb. 23, 2026. https://www.aafp.org/pubs/afp/issues/2022/0300/p272.html
3. Harewood J, Azevedo AM. Alpha Thalassemia. [Updated 2023 Sep 4]. In: StatPearls [Internet]. StatPearls Publishing; 2025. https://www.ncbi.nlm.nih.gov/books/NBK441826/