Bristol Myers Squibb Announces Positive Top-Line Results from Registrational Phase 2 Study of Luspatercept in Adults with Alpha (α)-Thalassemia

Key Terms

hemoglobin medical

Hemoglobin is a protein inside red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide for disposal, like trucks transporting fuel to factories. Investors care because hemoglobin levels are a basic indicator of health that affect demand for drugs, diagnostics and treatments, influence outcomes in clinical trials, and can impact workforce productivity and healthcare costs—factors that affect company revenues and valuations.

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The body's process for making red blood cells in the bone marrow, driven by signals such as a hormone that tells immature cells to mature and enter the bloodstream. Think of it as a factory assembly line that builds the blood’s oxygen delivery trucks; when the line speeds up or breaks down it changes demand for drugs, diagnostics and treatments. Investors watch it because therapies that boost or regulate this process can reshuffle market value in hematology, transfusion services and related drugs.

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Myelodysplastic syndromes are a group of disorders in which the bone marrow — the body’s blood cell factory — makes blood cells that are abnormal or too few, leading to anemia, infections, or bleeding and sometimes progressing to leukemia. Investors monitor them because demand for effective drugs, clinical trial results, and regulatory approvals can materially affect the revenues and valuations of healthcare companies and influence projected treatment costs and market opportunities.

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Both non-transfusion-dependent and transfusion dependent cohorts met their respective primary and secondary endpoints

PRINCETON, N.J.--(BUSINESS WIRE)-- Bristol Myers Squibb (NYSE: BMY) today announced 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.

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.

Bristol Myers Squibb: Creating a Better Future for People with Cancer

Bristol Myers Squibb is inspired by a single vision — transforming patients’ lives through science. The goal of the company’s cancer research is to deliver medicines that offer each patient a better, healthier life and to make cure a possibility. Building on a legacy across a broad range of cancers that have changed survival expectations for many, Bristol Myers Squibb researchers are exploring new frontiers in personalized medicine and, through innovative digital platforms, are turning data into insights that sharpen their focus. Deep understanding of causal human biology, cutting-edge capabilities and differentiated research platforms uniquely position the company to approach cancer from every angle.

Cancer can have a relentless grasp on many parts of a patient’s life, and Bristol Myers Squibb is committed to taking actions to address all aspects of care, from diagnosis to survivorship. As a leader in cancer care, Bristol Myers Squibb is working to empower all people with cancer to have a better future.

About Bristol Myers Squibb: Transforming Patients' Lives Through Science

At Bristol Myers Squibb, our mission is to discover, develop and deliver innovative medicines that help patients prevail over serious diseases. We are pursuing bold science to define what's possible for the future of medicine and the patients we serve. For more information about Bristol Myers Squibb, visit us at BMS.com or follow us on LinkedIn, X, YouTube, Facebook and Instagram.

Cautionary Statement Regarding Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 regarding, among other things, the research, development and commercialization of pharmaceutical products. All statements that are not statements of historical facts are, or may be deemed to be, forward-looking statements. Such forward-looking statements are based on current expectations and projections about our future financial results, goals, plans and objectives and involve inherent risks, assumptions and uncertainties, including internal or external factors that could delay, divert or change any of them in the next several years, that are difficult to predict, may be beyond our control and could cause our future financial results, goals, plans and objectives to differ materially from those expressed in, or implied by, the statements. These risks, assumptions, uncertainties and other factors include, among others, that future study results may not be consistent with the results to date, that Reblozyl (luspatercept-aamt), may not receive regulatory approval for the additional indication described in this release in the currently anticipated timeline or at all, any marketing approvals, if granted, may have significant limitations on their use, and, if approved, whether Reblozyl for such indication will be commercially successful. No forward-looking statement can be guaranteed. Forward-looking statements in this press release should be evaluated together with the many risks and uncertainties that affect Bristol Myers Squibb’s business and market, particularly those identified in the cautionary statement and risk factors discussion in Bristol Myers Squibb’s Annual Report on Form 10-K for the year ended December 31, 2025, as updated by our subsequent Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the Securities and Exchange Commission. The forward-looking statements included in this document are made only as of the date of this document and except as otherwise required by applicable law, Bristol Myers Squibb undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise.

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