What the label lists and what reports show
Luspatercept side effects
Luspatercept's FDA label: “The most common (>10%) adverse reactions were fatigue, headache, musculoskeletal pain, arthralgia, dizziness/vertigo, nausea, diarrhea, cough, abdominal pain, dyspnea, COVID-19, edema peripheral, hypertension, and hypersensitivity ( 6.1 ).” FAERS holds 2,464 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is haemoglobin decreased (142 reports).
- No generic listed
Check it at the source: the luspatercept FDA label on DailyMed (effective February 27, 2026); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of REBLOZYL?REBLOZYL may cause serious side effects, including: • Blood clots. Blood clots in the arteries, veins, brain, and lungs have happened in people with beta thalassemia during treatment with REBLOZYL. The risk of blood clots may be higher in people who have had their spleen removed or who take hormone replacement therapy or birth control (oral contraceptives). Call your healthcare provider or get medical help right away if you get any of these symptoms: o chest pain o trouble breathing or shortness of breath o pain in your leg, with or without swelling o a cold or pale arm or leg o sudden numbness or weakness that are both short-term or continue to happen over a long period of time, especially on one side of the body o severe headache or confusion o sudden problems with vision, speech, or balance (such as trouble speaking, difficulty walking, or dizziness) • High blood pressure. […]
Source: FDA drug label, Celgene Corporation, effective February 27, 2026 (SPL set 82f4d266-3f52-41eb-86ba-0abf3cf468e8), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (>10%) adverse reactions were fatigue, headache, musculoskeletal pain, arthralgia, dizziness/vertigo, nausea, diarrhea, cough, abdominal pain, dyspnea, COVID-19, edema peripheral, hypertension, and hypersensitivity ( 6.1 ).
Table 9: Adverse Reactions (≥5%) in Patients Receiving REBLOZYL in COMMANDS Trial
| Reaction | All Grades n (%) | Grade ≥3 n (%) | All Grades n (%) | Grade ≥3 n (%) |
|---|---|---|---|---|
| Fatigue a,b | 38 (22) | 0 (0) | 12 (7) | 0 (0) |
| Edema peripheral | 23 (13) | 0 (0) | 12 (7) | 0 (0) |
| Non-cardiac chest pain | 9 (5) | 1 (1) | 6 (3) | 0 (0) |
| Pyrexia | 9 (5) | 1 (1) | 12 (7) | 1 (1) |
| Diarrhea | 26 (15) | 0 (0) | 20 (11) | 0 (0) |
| Nausea | 21 (12) | 0 (0) | 13 (7) | 0 (0) |
| Hypertension a | 25 (14) | 17 (10) | 13 (7) | 9 (5) |
| Dyspnea | 21 (12) | 7 (4) | 13 (7) | 2 (1) |
| Dyspnea exertional | 9 (5) | 0 (0) | 1 (1) | 0 (0) |
| Dizziness | 16 (9) | 1 (1) | 15 (9) | 0 (0) |
| Headache | 15 (8) | 0 (0) | 12 (7) | 1 (1) |
| Back Pain | 16 (9) | 2 (1) | 13 (7) | 3 (2) |
| Arthralgia | 10 (6) | 0 (0) | 14 (8) | 0 (0) |
| Myalgia | 9 (5) | 0 (0) | 5 (3) | 0 (0) |
| Osteoarthritis | 9 (5) | 1 (1) | 4 (2) | 0 (0) |
| COVID-19 | 19 (11) | 6 (3) | 17 (10) | 2 (1) |
| Urinary tract infection | 13 (7) | 0 (0) | 7 (4) | 0 (0) |
| Pneumonia | 8 (5) | 7 (4) | 15 (9) | 11 (6) |
| Hyperuricemia | 12 (7) | 1 (1) | 10 (6) | 1 (1) |
| Decreased appetite | 8 (5) | 0 (0) | 11 (6) | 0 (0) |
| Thrombocytopenia | 11 (6) | 7 (4) | 3 (2) | 1 (1) |
| Neutropenia | 9 (5) | 7 (4) | 13 (7) | 10 (6) |
| Insomnia | 9 (5) | 0 (0) | 6 (3) | 0 (0) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in the labeling: • Thrombosis/Thromboembolism [see Warnings and Precautions ( 5.1 )] • Hypertension [see Warnings and Precautions ( 5.2 )] • Extramedullary Hematopoietic Masses [see Warnings and Precautions ( 5.3 )] The most common (>10%) adverse reactions were fatigue, headache, musculoskeletal pain, arthralgia, dizziness/vertigo, nausea, diarrhea, cough, abdominal pain, dyspnea, COVID-19, edema peripheral, hypertension, and hypersensitivity ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Bristol-Myers Squibb at 1-888-423-5436 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data in the WARNINGS AND PRECAUTIONS reflect exposure to REBLOZYL as a single agent administered across a range of doses (0.125 mg/kg to 1.75 mg/kg) in 571 patients in 4 trials. Beta Thalassemia The safety of REBLOZYL in patients with beta thalassemia was evaluated in the BELIEVE trial [see Clinical Studies ( 14.1 )]. …
Source: FDA drug label, Celgene Corporation, effective February 27, 2026 (SPL set 82f4d266-3f52-41eb-86ba-0abf3cf468e8), via openFDA; the full label on DailyMed
What do FAERS reports show?
2,464 reports list luspatercept among the medicines taken, each a report of something that happened, not proof the medicine caused it; 393 are coded as a death and 531 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Luspatercept: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions