Bristol Myers Squibb (NYSE:BMY) announced Monday that its Phase 2 registrational study of Reblozyl (luspatercept-aamt) achieved its primary and key secondary endpoints, potentially expanding the drug’s use to patients with alpha-thalassemia.
The ex-U.S. study (NCT05664737) evaluated two distinct cohorts of adult patients.
In the non-transfusion-dependent (NTD) group, Reblozyl demonstrated a statistically significant increase in hemoglobin levels.
In the transfusion-dependent (TD) group, the drug significantly reduced the red blood cell (RBC) transfusion burden.
While Reblozyl is already approved in the U.S. and Europe for beta-thalassemia and myelodysplastic syndromes, there are currently no approved therapies specifically for alpha-thalassemia, a lifelong genetic blood disorder that causes the body to produce less hemoglobin than normal.
The primary endpoint for the NTD cohort was a mean hemoglobin increase of at least 1 g/dL over a 12-week interval (weeks 13–24).
For the TD cohort, the goal was a 50% or greater reduction in transfusion units during any continuous 12-week period between weeks 13 and 48.
The safety profile in the trial was consistent with previous Reblozyl studies, which have noted side effects such as fatigue, hypertension, and bone pain.
Bristol Myers plans to present the detailed data at a future medical congress and will begin discussions with regulatory authorities in China.
Reblozyl is a cornerstone of Bristol Myers’ growth strategy as it faces patent cliffs for older blockbusters like Revlimid.
The drug generated $1.6 billion in global revenue in 2025, and an expansion into alpha-thalassemia—particularly in high-prevalence regions like Southeast Asia and China—could significantly bolster its long-term sales trajectory.