Luspatercept
Pronunciation: loo-SPA-ter-sept.
- Generic name
- luspatercept
- Drug class
- Erythroid maturation agent (activin receptor type IIB ligand trap fusion protein)
- Form
- Lyophilized powder for reconstitution and subcutaneous injection (25 mg, 75 mg vials)
- Route
- Subcutaneous injection
- Legal status
- Prescription-only; haematologist/oncologist-administered
Availability and supply rules vary by country
Trade names by country: United States · United Kingdom · Canada · Australia
Australia: Reblozyl (4) · Full directory
What luspatercept is and how it works
Luspatercept is a prescription-only injectable medicine (an erythroid maturation agent) used to treat anaemia in adults with beta thalassaemia or certain myelodysplastic syndromes (MDS), conditions in which the body does not make enough healthy red blood cells. (1)
You receive luspatercept as an injection under the skin, usually given by a healthcare professional once every 3 weeks. It should only be prescribed and managed by a specialist experienced in treating blood disorders, because it carries risks including blood clots and high blood pressure, and requires regular monitoring, including blood pressure checks before every dose.
Mechanism of action: how luspatercept works
Luspatercept is a recombinant fusion protein consisting of a modified extracellular domain of the human activin receptor type IIB linked to the Fc portion of human immunoglobulin G1 (IgG1). It acts as a ligand trap, binding select members of the TGF-beta superfamily to reduce Smad2/3 signalling, which promotes late-stage maturation of red blood cell precursors (erythroid maturation), improving anaemia in beta thalassaemia and certain MDS subtypes. (1)
What luspatercept is used for
Anaemia in beta thalassaemia
Used to treat anaemia in adults with beta thalassaemia who require regular red blood cell transfusions, and, per more recent European approvals, in adults with non-transfusion-dependent beta thalassaemia. (1) (5)
Anaemia in myelodysplastic syndromes (MDS)
Used to treat anaemia in adults with very low- to intermediate-risk MDS who have not previously received an erythropoiesis-stimulating agent (ESA), and in adults with MDS with ring sideroblasts (MDS-RS) or a related overlap condition (MDS/MPN-RS-T) who have had an unsatisfactory response to, or are not suitable for, ESA therapy and need frequent red blood cell transfusions. (1) (5)
Before taking luspatercept
Do not take / not appropriate for
- Do not take luspatercept if you have had an allergic reaction to it or any of its ingredients. (all confirmed markets) (1)
Tell your clinician about
- Any history of blood clots, stroke, or conditions that increase clotting risk.
- Whether you have had your spleen removed (splenectomy), since this increases blood clot risk, particularly in beta thalassaemia.
- Whether you take hormone replacement therapy, since this may add to blood clot risk.
- Any history of high blood pressure.
- Any unusual lumps, masses, or symptoms such as back pain, numbness, or weakness, since extramedullary blood-forming masses have been reported, particularly in beta thalassaemia.
- Pregnancy, plans for pregnancy, or breastfeeding -- and whether effective contraception is in place, since luspatercept may cause fetal harm.
How to take luspatercept
- Luspatercept is given as an injection under the skin (subcutaneous injection) by a healthcare professional, usually once every 3 weeks.
- Your blood pressure will be checked before every dose.
- Your dose may be adjusted by your clinician based on your response and any side effects.
- Do not change your dose or stop treatment without talking to your haematology or oncology team first.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5)
Missed dose
Luspatercept is given by a healthcare professional on a set schedule. If an appointment is missed, contact your care team to arrange the next dose as soon as possible -- do not attempt to adjust your own schedule.
Overdose
Because luspatercept is administered by a healthcare professional, an overdose in the usual sense is unlikely; if you experience severe or unusual symptoms after a dose, contact your care team or seek urgent medical attention. (1)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms.
Fatigue, headache, and dizziness/vertigo -- common (each reported in more than 10% of patients).
What to notice: Fatigue, headache, and dizziness/vertigo -- common (each reported in more than 10% of patients).
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Musculoskeletal pain and joint pain (arthralgia) -- common.
What to notice: Musculoskeletal pain and joint pain (arthralgia) -- common.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Nausea, diarrhoea, and abdominal pain -- common.
What to notice: Nausea, diarrhoea, and abdominal pain -- common.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Cough and shortness of breath (dyspnoea) -- common.
What to notice: Cough and shortness of breath (dyspnoea) -- common.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Swelling in the legs or feet (peripheral oedema) and high blood pressure -- common.
What to notice: Swelling in the legs or feet (peripheral oedema) and high blood pressure -- common.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Hypersensitivity (allergic-type) reactions -- common.
What to notice: Hypersensitivity (allergic-type) reactions -- common.
What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)
Serious warnings
Signs of a blood clot (thrombosis or thromboembolism) — high caution
Symptoms: Swelling, pain, or redness in a leg; sudden shortness of breath or chest pain; sudden weakness, numbness, or difficulty speaking (possible stroke).
Action: Seek prompt medical attention -- blood clots, including deep vein thrombosis, pulmonary embolism, portal vein thrombosis, and stroke, have been reported in patients treated with luspatercept, particularly in beta thalassaemia (reported in 3.6% of patients in clinical trials). The risk may be higher if you have had your spleen removed or take hormone replacement therapy; your clinician may consider preventive blood-thinning treatment if you are at higher risk. (1) (3)
New or worsening high blood pressure — moderate caution
Symptoms: Headache, dizziness, or a high blood pressure reading.
Action: Your blood pressure will be checked before every dose. New or worsening high blood pressure has been reported with luspatercept (in roughly 1 in 10 patients across studies) and may need treatment with blood-pressure-lowering medicine, or in some cases a change to your luspatercept dose or schedule as directed by your clinician. (1) (3)
Signs of an extramedullary haematopoietic mass — high caution
Symptoms: New lump, back pain, numbness, weakness, or other new neurological symptoms.
Action: Tell your care team promptly -- masses of blood-forming tissue outside the bone marrow can occur, particularly in beta thalassaemia, and can cause serious complications such as spinal cord compression if they press on nearby structures. (1)
Risk to an unborn baby — high caution
Symptoms: Not applicable -- this is a treatment-related risk, not a symptom to watch for.
Action: Luspatercept may cause fetal harm based on its mechanism of action. Discuss effective contraception with your care team before and during treatment. (1)
Signs of a severe allergic (hypersensitivity) reaction — emergency
Symptoms: Swelling of the face, lips, or throat; difficulty breathing; widespread rash or hives; dizziness or fainting.
Action: Seek emergency medical attention -- hypersensitivity reactions have been reported with luspatercept. (1)
Interactions
- No specific drug-drug interaction studies were detailed in the sources reviewed for this page -- tell your care team about all other medicines you take, particularly blood thinners or medicines for high blood pressure, since these may affect how your treatment is monitored. (1)
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Luspatercept may cause fetal harm based on its mechanism of action. Discuss effective contraception with your care team before and during treatment. (1) (2) (3) (4) (5)
Breastfeeding
Discuss with your care team; data on luspatercept in human milk were not detailed in the sources reviewed. (1) (2) (3) (4) (5)
Children
Safety and efficacy in children have not been established in the sources reviewed. (1) (2) (3) (4) (5)
Elderly
Used in older adults with beta thalassaemia or MDS; your clinician will weigh individual risks, including blood clot and blood pressure risks, which may be more significant in older or frailer patients. (1) (2) (3) (4) (5)
Hepatic_impairment
Discuss with your clinician; specific dose-adjustment data for hepatic impairment were not detailed in the sources reviewed. (1) (2) (3) (4) (5)
Renal_impairment
Discuss with your clinician; specific dose-adjustment data for renal impairment were not detailed in the sources reviewed. (1) (2) (3) (4) (5)
Fertility
Discuss fertility-related questions with your care team before starting treatment if relevant to you. (1) (2) (3) (4) (5)
Source_ids
Monitoring
Before starting
- Baseline blood pressure
- Review of blood clot risk factors, including prior splenectomy and hormone replacement therapy use
- Pregnancy test and contraception plan where relevant
- Baseline blood counts
During treatment
- Blood pressure check before every dose.
- Monitoring for signs and symptoms of blood clots.
- Monitoring for new masses, back pain, or neurological symptoms (possible extramedullary haematopoietic masses).
- Periodic blood counts to assess response.
Storage
Store the vial in a refrigerator, protected from light, as directed by your care team; this medicine is prepared and administered by a healthcare professional.
Professional information
Clinician-facing context only, sourced from the current US label and Canadian/UK regulatory context; verify against the current full label before prescribing. Should only be prescribed and administered by a clinician experienced in treating haematological conditions.
United States / United Kingdom / European Union / Canada / Australia
Indication: Anaemia in beta thalassaemia requiring regular RBC transfusions (and, in the EU, non-transfusion-dependent beta thalassaemia); anaemia in very low- to intermediate-risk MDS (ESA-naive), or MDS-RS/MDS-MPN-RS-T with unsatisfactory ESA response.
Dose summary: Starting dose 1 mg/kg subcutaneously once every 3 weeks, titrated up to 1.75 mg/kg based on response.
Renal context: No clinically significant differences in luspatercept pharmacokinetics were observed with mild to moderate renal impairment (eGFR 30 to 89 mL/min), and no dose adjustment is recommended for them. The effect of severe renal impairment (eGFR below 30 mL/min) on pharmacokinetics is unknown. (1) (5)
Hepatic guidance
Specific hepatic dose-adjustment data were not detailed in the sources reviewed.
Overdose note
Administered by a healthcare professional; manage supportively and monitor for hypertension and thromboembolic signs if excess dosing is suspected. (1)
Frequently asked questions
Does luspatercept carry a boxed warning?
No -- the current US label carries no boxed/black-box warning. Thrombosis/thromboembolism, hypertension, extramedullary haematopoietic masses, and embryo-fetal toxicity are presented as detailed Warnings and Precautions instead. (1)
Is luspatercept available in the UK?
It depends on what you mean by 'available.' Luspatercept (Reblozyl) does hold a real UK marketing authorisation from the MHRA for Great Britain (covering beta-thalassaemia). However, NICE has NOT recommended it for NHS funding in England and Wales for either reviewed use (beta-thalassaemia or myelodysplastic syndromes) -- both technology appraisals were terminated because the manufacturer did not submit supporting evidence. In practice, this means the medicine is licensed but may not be routinely funded on the NHS; ask your specialist about current local access. (2)
Why do I need blood clot monitoring on luspatercept?
Blood clots (including deep vein thrombosis, pulmonary embolism, and stroke) have been reported in patients treated with luspatercept, most notably in beta thalassaemia (around 3.6% of patients in clinical trials). The risk may be higher if you have had your spleen removed or take hormone replacement therapy. Tell your care team immediately about any leg swelling or pain, sudden shortness of breath, chest pain, or sudden weakness or numbness. (1)
Why is my blood pressure checked before every dose?
Luspatercept can cause new or worsening high blood pressure, reported in roughly 1 in 10 patients across clinical studies. Checking your blood pressure before each dose helps your care team catch and manage this early, including starting blood-pressure-lowering medicine if needed. (1)
What is the mechanism of action of luspatercept?
Luspatercept is a recombinant fusion protein consisting of a modified extracellular domain of the human activin receptor type IIB linked to the Fc portion of human immunoglobulin G1 (IgG1). It acts as a ligand trap, binding select members of the TGF-beta superfamily to reduce Smad2/3 signalling, which promotes late-stage maturation of red blood cell precursors (erythroid maturation), improving anaemia in beta thalassaemia and certain MDS subtypes. (1)
References
- REBLOZYL (luspatercept-aamt) for injection, for subcutaneous use -- full prescribing information, revised 27 February 2026 (initial US approval 2019)U.S. Food and Drug Administration / National Library of Medicine DailyMed, full prescribing information · United States · accessed 2026-07-31 · source 1
- Reblozyl (luspatercept) -- MHRA marketing authorisation (PLGB 15105/0154, beta-thalassaemia) and NICE technology appraisal statusUK Medicines and Healthcare products Regulatory Agency (MHRA); National Institute for Health and Care Excellence (NICE) · United Kingdom · accessed 2026-07-31 · source 2
- REBLOZYL (luspatercept) -- Product Monograph (revision dated 21 November 2022)Health Canada -- Celgene Inc./Bristol Myers Squibb, product monograph · Canada · accessed 2026-07-31 · source 3
- Reblozyl (luspatercept) -- Australian Public Assessment Report (AusPAR), published 27 April 2022Australian Therapeutic Goods Administration (TGA) · Australia · accessed 2026-07-31 · source 4
- Reblozyl (luspatercept) -- European Public Assessment Report (EPAR), EU centralised marketing authorisationEuropean Medicines Agency (EMA) · European Union · accessed 2026-07-31 · source 5
Brand names by country
Single-ingredient luspatercept names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Reblozyl25 mg, 75 mg · celgene corporation
United Kingdom
- Reblozyl (2)MHRA licensed PLGB 15105 0154 not NICE recommended · 25 mg, 75 mg vial · Bristol Myers Squibb Pharma Ltd
Canada
- Reblozyl (Celgene Inc.) (3)Health Canada authorised · not fully itemized in fetched sources · Celgene Inc.
Australia
- Reblozyl (4)TGA AusPAR assessed authorised · not fully itemized in fetched sources · See AusPAR (published 27 April 2022)
View brands in additional countries.
European Union
Reblozyl (5)