On February 23, 2026 Bristol Myers Squibb (NYSE: BMY) reported positive top-line results from the ongoing, ex-US, Phase 2 registrational study (NCT05664737) evaluating Reblozyl (luspatercept-aamt) versus placebo for anemia in adults with Alpha (α)-Thalassemia.
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The non‑transfusion‑dependent (NTD) and transfusion‑dependent (TD) cohorts of the study met their respective primary endpoints, with Reblozyl demonstrating a statistically significant and clinically meaningful increase in hemoglobin levels in NTD patients with α‑thalassemia, and a statistically significant and clinically meaningful decrease in red blood cell (RBC) transfusion burden in TD patients with α‑thalassemia. The study also met all key secondary endpoints. Safety findings were consistent with the known profile of Reblozyl in thalassemia.
"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. "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."
The data will be presented at an upcoming medical congress and will be discussed with the Center for Drug Evaluation in China.
About the Study (NCT05664737)
The Phase 2 trial is evaluating the efficacy and safety of luspatercept plus best supportive care versus placebo for anemia in adults and adolescents with α-thalassemia, including both red blood cell (RBC) transfusion-dependent (TD) and non-transfusion-dependent (NTD) cohorts. The primary endpoint of the NTD cohort measures an increase from baseline of ≥ 1 grams (g)/deciliter (dL) in mean hemoglobin (Hb) values over the continuous 12-week interval from Week 13 to Week 24 in the absence of RBC transfusion. The primary endpoint of the TD cohort measures ≥ 50% reduction from baseline in RBC transfusion burden with a reduction of at least 2 units during any continuous 12 weeks during Week 13-48 compared to 12-week interval immediately prior to date of first dose. The adolescent NTD and TD cohorts are ongoing.
About Reblozyl
Reblozyl, a first-in-class therapeutic option, promotes late-stage red blood cell maturation in animal models. Reblozyl is being developed and commercialized through a global collaboration with Merck as of November 2021. Reblozyl is indicated in the U.S. for the treatment of:
anemia in adult patients with beta thalassemia who require regular red blood cell (RBC) transfusions, and
anemia without previous erythropoiesis stimulating agent use (ESA-naïve) in adult patients with very low- to intermediate-risk myelodysplastic syndromes (MDS) who may require regular red blood cell (RBC) transfusions.
anemia failing an erythropoiesis stimulating agent and requiring 2 or more red blood cell (RBC) units over 8 weeks in adult patients with very low- to intermediate-risk myelodysplastic syndrome with ring sideroblasts (MDS-RS) or with myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T).
Reblozyl is not indicated for use as a substitute for RBC transfusions in patients who require immediate correction of anemia. In the U.S., Reblozyl is not indicated for use in patients with non-transfusion-dependent beta thalassemia.
Important Safety Information
WARNINGS AND PRECAUTIONS
Thrombosis/Thromboembolism
In adult patients with beta thalassemia, thromboembolic events (TEE) were reported in 8/223 (3.6%) of REBLOZYL-treated patients. TEEs included deep vein thrombosis, pulmonary embolus, portal vein thrombosis, and ischemic stroke. All patients with TEE were splenectomized and had at least 1 other risk factor for developing TEE, such as a history of thrombocytosis or concomitant use of hormone-replacement therapy. The occurrence of TEE was not correlated with elevated hemoglobin levels. Patients with known risk factors for thromboembolism (splenectomy or concomitant use of hormone replacement therapy) may be at further increased risk of thromboembolic conditions. Consider thromboprophylaxis in patients at increased risk of TEE. Monitor patients for signs and symptoms of thromboembolic events and institute treatment promptly.
Hypertension
Hypertension was reported in 11.4% (63/554) of REBLOZYL-treated patients. Across clinical studies, the incidence of Grade 3 to 4 hypertension ranged from 2% to 9.6%. In patients with beta thalassemia with normal baseline blood pressure, 13 (6.2%) patients developed systolic blood pressure (SBP) ≥130 mm Hg and 33 (16.6%) patients developed diastolic blood pressure (DBP) ≥80 mm Hg. In ESA-refractory or -intolerant adult patients with MDS with normal baseline blood pressure, 26 (30%) patients developed SBP ≥130 mm Hg and 23 (16%) patients developed DBP ≥80 mm Hg. In ESA-naïve adult patients with MDS with normal baseline blood pressure, 23 (36%) patients developed SBP ≥140 mm Hg and 11 (6%) patients developed DBP ≥80 mm Hg. Monitor blood pressure prior to each administration. Manage new or exacerbations of preexisting hypertension using anti-hypertensive agents.
Extramedullary Hematopoietic (EMH) Masses
In adult patients with transfusion-dependent beta thalassemia, EMH masses were observed in 3.2% of REBLOZYL-treated patients, with spinal cord compression symptoms due to EMH masses occurring in 1.9% of patients (BELIEVE and REBLOZYL long-term follow-up study).
In a study of adult patients with non-transfusion-dependent beta thalassemia, a higher incidence of EMH masses was observed in 6.3% of REBLOZYL-treated patients vs. 2% of placebo-treated patients in the double-blind phase of the study, with spinal cord compression due to EMH masses occurring in 1 patient with a prior history of EMH. REBLOZYL is not indicated for use in patients with non-transfusion-dependent beta thalassemia.
Possible risk factors for the development of EMH masses in patients with beta thalassemia include history of EMH masses, splenectomy, splenomegaly, hepatomegaly, or low baseline hemoglobin (<8.5 g/dL). Signs and symptoms may vary depending on the anatomical location. Monitor patients with beta thalassemia at initiation and during treatment for symptoms and signs or complications resulting from the EMH masses and treat according to clinical guidelines. Discontinue treatment with REBLOZYL in case of serious complications due to EMH masses. Avoid use of REBLOZYL in patients requiring treatment to control the growth of EMH masses.
Embryo-Fetal Toxicity
REBLOZYL may cause fetal harm when administered to a pregnant woman. REBLOZYL caused increased post-implantation loss, decreased litter size, and an increased incidence of skeletal variations in pregnant rat and rabbit studies. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 3 months after the final dose.
ADVERSE REACTIONS
Beta-Thalassemia
Serious adverse reactions occurred in 3.6% of patients on REBLOZYL. Serious adverse reactions occurring in 1% of patients included cerebrovascular accident and deep vein thrombosis. A fatal adverse reaction occurred in 1 patient treated with REBLOZYL who died due to an unconfirmed case of acute myeloid leukemia (AML).
Most common adverse reactions (at least 10% for REBLOZYL and 1% more than placebo) were headache (26% vs 24%), bone pain (20% vs 8%), arthralgia (19% vs 12%), fatigue (14% vs 13%), cough (14% vs 11%), abdominal pain (14% vs 12%), diarrhea (12% vs 10%) and dizziness (11% vs 5%).
ESA-naïve adult patients with Myelodysplastic Syndromes
Grade ≥3 (≥2%) adverse reactions included hypertension and dyspnea. The most common (≥10%) all-grade adverse reactions included diarrhea, fatigue, hypertension, peripheral edema, nausea, and dyspnea.
ESA-refractory or -intolerant adult patients with Myelodysplastic Syndromes
Grade ≥3 (≥2%) adverse reactions included fatigue, hypertension, syncope and musculoskeletal pain. A fatal adverse reaction occurred in 5 (2.1%) patients. The most common (≥10%) adverse reactions included fatigue, musculoskeletal pain, dizziness, diarrhea, nausea, hypersensitivity reactions, hypertension, headache, upper respiratory tract infection, bronchitis, and urinary tract infection.
LACTATION
It is not known whether REBLOZYL is excreted into human milk or absorbed systemically after ingestion by a nursing infant. REBLOZYL was detected in milk of lactating rats. When a drug is present in animal milk, it is likely that the drug will be present in human milk. Because many drugs are excreted in human milk, and because of the unknown effects of REBLOZYL in infants, a decision should be made whether to discontinue nursing or to discontinue treatment. Because of the potential for serious adverse reactions in the breastfed child, breastfeeding is not recommended during treatment and for 3 months after the last dose.
DRUG ABUSE POTENTIAL
Abuse: Abuse of REBLOZYL may be seen in athletes for the effects on erythropoiesis. Misuse of drugs that increase erythropoiesis, such as REBLOZYL, by healthy persons may lead to polycythemia, which may be associated with life-threatening cardiovascular complications.
Please see accompanying U.S. Full Prescribing Information for REBLOZYL.
(Press release, Bristol-Myers Squibb, FEB 23, 2026, View Source;Thalassemia/default.aspx [SID1234662846])