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A Study to Determine the Efficacy and Safety of Luspatercept in Adults With Non Transfusion Dependent Beta (β)-Thalassemia

A Phase 2, Double-Blind, Randomized, Placebo-Controlled Multicenter Study to Determine the Efficacy and Safety of Luspatercept (ACE-536) Versus Placebo in Adults With Non-Transfusion Dependent Beta (β)-Thalassemia (The BEYOND™ Study)

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03342404
Acronym
BEYOND
Enrollment
145
Registered
2017-11-17
Start date
2018-02-05
Completion date
2022-11-28
Last updated
2023-12-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Thalassemia

Keywords

(β)-Thalassemia, Beta-Thalassemia, Phase 2, Luspatercept, ACE-536, Safety, Efficacy, Placebo, Red Blood Cell Transfusions, Erythrocyte transfusion, Hb increase, NTDT

Brief summary

This is a Phase 2, double-blind, randomized, placebo-controlled, multicenter study to determine the efficacy and safety of luspatercept (ACE-536) versus placebo in adults with non-transfusion dependent beta (β)-thalassemia. The study is divided into the Screening Period, Double-blind Treatment Period (DBTP), Open-label Phase (OLP), and Post-Treatment Follow-up Period (PTFP). It is planned to randomize approximately 150 subjects at a 2:1 ratio of luspatercept versus placebo.

Detailed description

The primary objective is: \- To evaluate the effect of luspatercept (BMS-986346) versus placebo on anemia, as measured by mean hemoglobin concentration in the absence of transfusions over a continuous 12-week interval, from Week 13 to Week 24, compared to baseline. The secondary objectives are: * To evaluate the effect of luspatercept versus placebo in anemia-related symptoms in participants with β-thalassemia, as measured by non-transfusion dependent β-thalassemia-patient reported outcome (NTDT-PRO) over continuous 12-week intervals (from Weeks 13 to 24 and from Weeks 37 to 48) compared to baseline. * To evaluate the effect of luspatercept versus placebo on functional and health-related quality of life (QoL) as measured by Medical Outcomes Study 36-Item Short Form (SF-36) and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) questionnaires * To evaluate the long-term effect of luspatercept versus placebo on anemia, as measured by mean hemoglobin concentration in the absence of transfusions over a continuous 12-week interval from Week 37 to Week 48, compared to baseline * To evaluate the effect of luspatercept versus placebo on iron overload, as measured by liver iron concentration (LIC) and iron chelation therapy (ICT) daily dose * To evaluate the effect of luspatercept versus placebo on iron overload, as measured by serum ferritin * To evaluate the duration of erythroid response * To evaluate the effect of luspatercept versus placebo on physical activity measured by 6-minute walk test (6MWT) Safety and Pharmacokinetics (PK) Objectives * To evaluate safety and tolerability of luspatercept, including immunogenicity * To evaluate population pharmacokinetics (PK) of luspatercept in subjects with β-thalassemia The exploratory objectives are: * To evaluate the effect of luspatercept versus placebo on measures of extra-medullary hematopoietic (EMH) masses, bone mineral density, splenomegaly, pulmonary hypertension, and leg ulcers, when present * To evaluate the effect of luspatercept versus placebo on the β-thalassemia severity as measured by the NTDT severity score system * To evaluate the effect of luspatercept versus placebo on the β-thalassemia severity as measured by the Morbidity-free Survival parameters * To examine the relationship of baseline and change in serum Growth Differentiation Factor 11 (GDF11) and other related biomarkers with response to treatment with luspatercept * To examine the effect of luspatercept on fetal hemoglobin (HbF) * To examine the effect of luspatercept on Health Resource Utilization (HRU)

Interventions

DRUGLuspatercept

Subjects will start with luspatercept at 1 mg/kg dose level every 3 weeks and can be dose escalated up to 1.25 mg/kg.

OTHERPlacebo

Placebo, Subcutaneous, every 21 days

OTHERBest Supportive Care (BSC)

Best Supportive Care (BSC)

Sponsors

Acceleron Pharma, Inc., a wholly-owned subsidiary of Merck & Co., Inc., Rahway, NJ USA
CollaboratorINDUSTRY
Celgene
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

Subjects must satisfy the following criteria to be enrolled in the study: 1. Subjects must be ≥ 18 years of age at the time of signing the informed consent document (ICF). 2. Subject must understand and voluntarily sign an ICF prior to any study-related assessments/procedures being conducted. 3. Subject is willing and able to adhere to the study visit schedule (eg, not scheduled to receive hematopoietic stem cell transplantation) and other protocol requirements. 4. Subject must have documented diagnosis of β-thalassemia or hemoglobin E/ β-thalassemia. Concomitant alpha globin mutation and/or duplication are allowed. 5. Subject must be non-transfusion dependent, defined as 0 to 5 units of RBCs received during the 24-week period prior to randomization. Note: 1 unit defined for this entry criterion as approximately 200 to 350 mL of transfused packed RBCs. 6. Subject must not be on a regular transfusion program and must be RBC transfusion-free for at least ≥ 8 weeks prior to randomization 7. Subject must have mean baseline hemoglobin ≤ 10 g/dL, based on a minimum of 2 measurements ≥ 1 week apart within 4 weeks prior to randomization; hemoglobin values within 21 days post-transfusion will be excluded. 8. Subject must have performance status: Eastern Cooperative Oncology Group (ECOG) performance score of 0 to 1. 9. A female of childbearing potential (FCBP) for this study is defined as a female who: 1\) has achieved menarche at some point, 2) has not undergone a hysterectomy or bilateral oophorectomy or 3) has not been naturally postmenopausal (amenorrhea following cancer therapy does not rule out childbearing potential) for at least 24 consecutive months (ie, has had menses at any time in the preceding 24 consecutive months). A FCBP participating in the study must: 1. Have 2 negative pregnancy tests as verified by the Investigator prior to starting study therapy. She must agree to ongoing pregnancy testing during the course of the study, and after end of study treatment. This applies even if the subject practices true abstinence\* from heterosexual contact. 2. Either commit to true abstinence\* from heterosexual contact (which must be reviewed on a monthly basis and source documented). If a FCBP engages in sexual activity that may result in a pregnancy, she must agree to use, and be able to comply during the study therapy (including dose interruptions), and for 12 weeks (approximately 5 times the mean terminal half-life of luspatercept based on multiple dose pharmacokinetics \[PK\] data) after discontinuation of study therapy. 10\. Male subjects must: a. Practice true abstinence (which must be reviewed on a monthly basis) or agree to use a condom during sexual contact with a pregnant female or a female of childbearing potential while participating in the study, during dose interruptions and for at least 12 weeks (approximately 5 times the mean terminal half-life of luspatercept based on multiple-dose PK data) following IP discontinuation, even if he has undergone a successful vasectomy

Exclusion criteria

The presence of any of the following will exclude a subject from enrollment: 1. Any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from participating in the study. 2. Any condition including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study. 3. Any condition that confounds the ability to interpret data from the study. 4. Diagnosis of hemoglobin S/β-thalassemia or alpha (α)-thalassemia (eg,Hemoglobin H). 5. Active hepatitis C (HCV) infection 6. Deep vein thrombosis (DVT) or stroke requiring medical intervention ≤ 24 weeks prior to randomization. 7. Subjects on chronic anticoagulant therapy are excluded, unless they stopped the treatment at least 28 days prior to randomization. Anticoagulant therapies for prophylaxis and for surgery or high-risk procedures as well as low molecular weight (LMW) heparin for superficial vein thrombosis (SVT) and chronic aspirin are allowed before and during the study. 8. Treatment with another investigational drug or device ≤ 28 days prior to randomization. 9. Prior exposure to sotatercept (ACE-011) or luspatercept (ACE-536). 10. Platelet count \> 1000 x 109/L. 11. Subjects on iron chelation therapy (ICT) at the time of ICF signature must have initiated the treatment with ICT at least 24 weeks before the predicted randomization date. ICT can be initiated at any time during treatment and should be used according to the label. 12. Subject had Hydroxyurea and ESA treatment ≤ 24 weeks prior to randomization, and no prior gene therapy. 13. Subject is pregnant or a lactating female. 14. Uncontrolled hypertension. Controlled hypertension for this protocol is considered ≤ Grade 1 according to National Cancer Institute Common Terminology for Adverse Events (NCI CTCAE) version 4.0 (current active minor version). 15. Subject has major organ damage, including: 1. Liver disease with alanine aminotransferase (ALT) \> 3 x upper limit of normal (ULN) or history/evidence of cirrhosis, as well as presence of masses/tumor detected by ultrasound at screening. 2. Heart disease, heart failure as classified by the New York Heart Association (NYHA) classification 3 or higher, or significant arrhythmia requiring treatment, or recent myocardial infarction (MI) within 6 months of randomization. 3. Severe lung disease, including pulmonary fibrosis or pulmonary hypertension, ie, ≥G3 NCI CTCAE version 4.0 (current active minor version). 4. Estimated glomerular filtration rate (eGFR) \< 60 ml/min/1.73 m2 (per Modification of Diet in Renal Disease \[MDRD\] formula). 16. Subject has received chronic systemic glucocorticoids ≤ 12 weeks prior to randomization (physiologic replacement therapy for adrenal insufficiency is allowed). 17. Major surgery ≤ 12 weeks prior to randomization (subjects must have completely recovered from any previous surgery prior to randomization). 18. History of severe allergic or anaphylactic reactions or hypersensitivity to recombinant proteins or excipients in the investigational product (see Investigator Brochure). 19. Subject has received immunosuppressants ≤ 28 days prior to randomization. 20. History or current malignancies (solid tumors and hematological malignancies) unless the subject has been free of the disease (including completion of any active or adjuvant treatment for prior malignancy) for ≥ 5 years. However, subjects with the following history/concurrent conditions are allowed: * Basal or squamous cell carcinoma of the skin * Carcinoma in situ of the cervix * Carcinoma in situ of the breast * Incidental histologic finding of prostate cancer (T1a or T1b using the tumor, nodes, metastasis \[TNM\] clinical staging system)

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Participants Achieving Erythroid Response (Week 13 to Week 24)From Week 13 to Week 24 of study treatmentErythroid Response is defined as an increase from baseline ≥1.0 g/dL in mean of hemoglobin values over a continuous 12-week interval from Weeks 13 to 24 of treatment in the absence of transfusions. Baseline hemoglobin (Hb) is the average of 2 or more Hb measurements at least 1 week apart within 4 weeks prior to Dose 1.

Secondary

MeasureTime frameDescription
Mean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 13 to Week 24)Baseline and over a continuous 12 week period (from week 13 through week 24)Mean change from baseline in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 13 to Week 24 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.
Percentage of Participants Achieving Erythroid Response (Week 37 to Week 48)Assessed over a continuous 12 week period (from week 37 through week 48)Erythroid Response is defined as an increase from baseline ≥1.0 g/dL in mean of hemoglobin values over a continuous 12-week interval from Weeks 37 to 48 of treatment in the absence of transfusions. Baseline hemoglobin (Hb) is the average of 2 or more Hb measurements at least 1 week apart within 4 weeks prior to Dose 1.
Mean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)Baseline and over a continuous 12 week period (from week 13 through week 24)The FACIT-F is a multidimensional, self-report quality of life instrument which includes the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire (27 items over 4 different domains), and the Fatigue subscale (FS) component (13 items). FACIT-F version 4 has been used for this study. For the Fatigue subscale, each of the 13 items is scored from 0 (not at all) to 4 (very much). The scores from individual items are summed to generated the final FS score, which ranges from 0 (best outcome) to 52 (worst outcome). The questionnaire is completed every other dose, and the mean of FS scores from Week 13 to Week 24 is compared to the FS score at baseline (last score available before start of study treatment). Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13.
Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 13 to Week 24)Baseline and over a continuous 12 week period (from week 13 through week 24)The NTDT-PRO V2.1 assess the severity of anemia-related symptoms associated with NTD β-thalassemia. It is a daily electronic diary with recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness (lack of energy) when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness (lack of strength) when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Shortness of Breath (SoB) domain score represents the average score of items 5 and 6 above. SoB domain score ranges from 0 (best outcome, no shortness of breath) to 10 (worst outcome, extreme shortness of breath). Weekly SoB Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12 week period (from Week 13 to Week 24) are compared to the SoB Domain Score at baseline.
Mean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 37 to Week 48)Baseline and over a continuous 12 week period (from week 37 through week 48)Mean change from baseline in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 37 to Week 48 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.
Percentage of Participants With an Increase From Baseline ≥1.5 g/dL in Mean Hemoglobin Values in the Absence of TransfusionFrom Week 13 to Week 24 of study treatmentPercentage of participants who have an increase from baseline ≥1.5 g/dL in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 13 to Week 24 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.
Mean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)Baseline and over a continuous 12 week period (from week 37 through week 48)The FACIT-F is a multidimensional, self-report quality of life instrument which includes the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire (27 items over 4 different domains), and the Fatigue subscale (FS) component (13 items). FACIT-F version 4 has been used for this study. For the Fatigue subscale, each of the 13 items is scored from 0 (not at all) to 4 (very much). The scores from individual items are summed to generated the final FS score, which ranges from 0 (best outcome) to 52 (worst outcome). The questionnaire is completed every other dose, and the mean of FS scores from Week 37 to Week 48 is compared to the FS score at baseline (last score available before start of study treatment). Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.
Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 37 to Week 48)Baseline and over a continuous 12 week period (from week 37 through week 48)NTDT-PRO V2.1 assess the severity of anemia-related symptoms. It's a daily recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Tiredness/Weakness (T/W) domain score represents the average score of items 1 through 4 above. T/W domain score ranges from 0 (best outcome, no tiredness/weakness) to 10 (worst outcome, extreme tiredness/weakness). Weekly T/W Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 37 to Week 48) are compared to the T/W Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.
Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 37 to Week 48)Baseline and over a continuous 12 week period (from week 37 through week 48)NTDT-PRO V2.1 assess the severity of anemia-related symptoms. It is a daily recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Shortness of Breath (SoB) domain score represents the average score of items 5 and 6 above. SoB domain score ranges from 0 (best outcome, no shortness of breath) to 10 (worst outcome, extreme shortness of breath). Weekly SoB Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 37 to Week 48) are compared to the SoB Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.
Percentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)Baseline and over a continuous 12 week period (from week 13 through week 24)The FACIT-Fatigue, is a multidimensional, self-report quality of life instrument. It consists of 27 core items, the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire, which assesses patient function in 4 domains: Physical, Social/Family, Emotional, and Functional well-being, which is further supplemented by a 13-item measure designed to capture cancer-related fatigue, the Fatigue subscale (FS). The items are measured on a response scale with five options (0 = not at all to 4 = very much). Participants completed the questionnaire at screening and every other dose. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13. Score is calculated by multiplying the sum of item scores by the n of items in the scale, then divided by n of items answered.
Percentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)Baseline and over a continuous 12 week period (from week 37 through week 48)The FACIT-Fatigue, is a multidimensional, self-report quality of life instrument. It consists of 27 core items, the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire, which assesses patient function in 4 domains: Physical, Social/Family, Emotional, and Functional well-being, which is further supplemented by a 13-item measure designed to capture cancer-related fatigue, the Fatigue subscale (FS). The items are measured on a response scale with five options (0 = not at all to 4 = very much). Participants completed the questionnaire at screening and every other dose. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37. Score is calculated by multiplying the sum of item scores by the n of items in the scale, then divided by n of items answered.
Mean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)From baseline to Week 24 and from baseline to Week 48 of study treatmentThe SF-36v2 is a 36-item generic PRO questionnaire used to assess patient-reported outcomes. The SF-36 yields scores for 8 domains of health: Physical Functioning (PF), Role-Physical (RP), Bodily Pain (BP), General Health (GH), Vitality (VT), Social Functioning (SF), Role Emotional (RE), and Mental Health (MH) as well as physical component summary (PCS) and mental component summary (MCS) scores. Scores from each of the 8 domains of health are first normalized based on US general population means, then aggregated and transformed so that the scores from each of the 8 domains of health will contribute differently to the determination of PCS and MCS summary scores. PCS and MCS scores range from 0 to 100, with higher scores indicating a better quality of life. Baseline is defined as the last value taken on or before the first dose of study drug administered.
Percentage of Participants With Improvement of Iron OverloadWeek 24 and Week 48 of study treatmentIron overload was measured by Liver Iron Concentration (LIC) and Iron Chelation Therapy (ICT) daily dose. Improvement is defined as: - For participants with baseline LIC ≥3 mg/g: ≥20% reduction in LIC or ≥ 33% decrease in ICT daily dose - For participants with baseline LIC \<3 mg/g: no increase in LIC \>1 mg/g and not starting treatment with ICT, or no increase in ICT daily dose ≥ 33% (if on ICT at baseline)
Mean Change From Baseline in Serum FerritinWeek 24 and Week 48 of study treatmentBaseline mean serum ferritin is calculated during the 24 weeks on or prior to dose 1 day 1. Post-baseline mean serum ferritin is calculated as mean of ferritin values during the last 24 weeks on or prior to the end date of the first 24 week or 48 week treatment
Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 13 to Week 24)Baseline and over a continuous 12 week period (from week 13 through week 24)The NTDT-PRO assesses the severity of anemia-related symptoms with a daily recall of symptoms composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Tiredness/Weakness (T/W) domain score is the average score of items 1 through 4 above. T/W domain score ranges from 0 (best outcome, no tiredness/weakness) to 10 (worst outcome, extreme tiredness/weakness). Weekly T/W Scores are the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 13 to Week 24) are compared to the T/W Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13.
Percentage of Participants Who Are Transfusion-Free Over 24 WeeksFrom first dose to Week 24Transfusion free is defined as the absence of any transfusion during Week 1-24 of study treatment. Participants who discontinued treatment prior to Week 24 were not considered as transfusion free during Week 1-24.
Percentage of Participants Who Are Transfusion-Free Over 48 WeeksFrom first dose to Week 48Transfusion free is defined as the absence of any transfusion during Week 1-48 of study treatment. Participants who discontinued treatment prior to Week 48 were not considered as transfusion free during Week 1-48.
Duration of the Mean Hemoglobin Increase From Baseline ≥1.0 g/dLFrom baseline up to approximately 56 monthsThis outcome measure is the cumulative mean of the duration of hemoglobin response for the ≥ 1.0 g/dL during any 12-week rolling period. Any hemoglobin values within 21 days after a transfusion were excluded from the analysis.
Mean Change From Baseline in the 6-Minute Walk Test (6MWT) DistanceFrom baseline to Week 24 and from baseline to Week 48 of study treatmentThe 6MWT is typically used to objectively assess functional exercise capacity and response to medical interventions in patients with various moderate to severe diseases. Particiapnts are asked to walk as quickly as possible without running along a 30-meter corridor for six minutes, and the total distance covered during that time is measured. Baseline is defined as the last value on or before the first dose of study drug is administered. Postbaseline is defined as the closest visit at Week 24 or Week 48.
Percentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain ScoreFrom Week 13 to Week 24 and from Week 37 to Week 48 of study treatmentThe responder definition (RD) threshold is the individual participant score change over a predetermined time period that will be interpreted as a treatment benefit. The RD for the NTDT-PRO T/W domain score was defined as ≥ 1-point decrease (ie, RD = -1) from baseline over the time from Week 13 to Week 24 or from Week 37 to Week 48. Participants with missing NTDT-PRO T/W scores at the indicated 12-week period are classified as non-responders in the analysis.
Number of Participants Experiencing Adverse EventsFrom first dose to 63 days after last dose (up to approximately 56 months)An Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Adverse events are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.
Number of Participants With Anti-drug Antibody (ADA) Positive Test for LuspaterceptFrom first dose and up to 2 years following last dose, up to approximately 56 monthsPresence of anti-drug (ACE-536/Luspatercept) antibodies was assessed every 24 weeks from serum samples. A participant is counted as 'positive' if there is any positive result captured during the study.
Apparent Clearance (CL/F) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsApparent Clearance (CL/F) of Luspatercept
Apparent Volume of Distribution of the Central Compartment (V1/F) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsApparent Volume of Distribution of the Central Compartment (V1/F) of Luspatercept
Time to Reach Maximum Concentration (Tmax) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsTime to Reach Maximum Concentration (Tmax) of Luspatercept
Maximum Concentration (Cmax) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsMaximum Concentration (Cmax) of Luspatercept
Maximum Concentration From Steady State (Cmax,ss) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsMaximum Concentration From Steady State (Cmax,ss) of Luspatercept
Area Under the Curve From Steady State (AUCss) of LuspaterceptDoses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 monthsArea Under the Curve From Steady State (AUCss) of Luspatercept
Mean Change From Baseline in Liver Iron Concentration (LIC)Week 24 and Week 48 of study treatmentLIC was measured by Magnetic Resonance Imaging (MRI). Baseline is defined as the last value on or before the first dose of study drug is administered; Postbaseline is defined as the closest visit at Week 24 or Week 48. Participants with LIC value \>43 are not included in the analysis.

Countries

Greece, Italy, Lebanon, Thailand, United Kingdom, United States

Participant flow

Participants by arm

ArmCount
Luspatercept
Luspatercept was administered as subcutaneous injection once every 3 weeks (administered on Study Day 1 of each 21-day treatment cycle). The starting dose level was 1.00 mg/kg and could be escalated to 1.25 mg/kg and/or reduced to 0.80, 0.60, and 0.45 mg/kg. Participants were treated for a minimum of 48 weeks.
96
Placebo
Placebo (0.9% sodium chloride for injection) was administered as subcutaneous injection once every 3 weeks (administered on Study Day 1 of each 21-day treatment cycle) for a minimum of 48 weeks. Eligible participants entered an open-label phase and started Luspatercept treatment for up to approximately 24 months.
49
Total145

Withdrawals & dropouts

PeriodReasonFG000FG001
Blinded Treatment PhaseAdverse Event54
Blinded Treatment PhaseDeath10
Blinded Treatment PhaseLack of Efficacy217
Blinded Treatment PhaseNoncompliance with study drug10
Blinded Treatment PhaseOther reasons10
Blinded Treatment PhasePhysician Decision10
Blinded Treatment PhaseWithdrawal by Subject1710
Open-Label PhaseAdverse Event03
Open-Label PhaseLost to Follow-up01
Open-Label PhaseOther reasons01
Open-Label PhaseWithdrawal by Subject06

Baseline characteristics

CharacteristicPlaceboTotalLuspatercept
Age, Continuous41.1 Years
STANDARD_DEVIATION 11.9
39.9 Years
STANDARD_DEVIATION 12.79
39.3 Years
STANDARD_DEVIATION 13.24
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants3 Participants2 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
48 Participants142 Participants94 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race/Ethnicity, Customized
Race
Asian
13 Participants44 Participants31 Participants
Race/Ethnicity, Customized
Race
Other
8 Participants14 Participants6 Participants
Race/Ethnicity, Customized
Race
White
28 Participants87 Participants59 Participants
Sex: Female, Male
Female
26 Participants82 Participants56 Participants
Sex: Female, Male
Male
23 Participants63 Participants40 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
1 / 960 / 490 / 38
other
Total, other adverse events
96 / 9648 / 4938 / 38
serious
Total, serious adverse events
23 / 9613 / 493 / 38

Outcome results

Primary

Percentage of Participants Achieving Erythroid Response (Week 13 to Week 24)

Erythroid Response is defined as an increase from baseline ≥1.0 g/dL in mean of hemoglobin values over a continuous 12-week interval from Weeks 13 to 24 of treatment in the absence of transfusions. Baseline hemoglobin (Hb) is the average of 2 or more Hb measurements at least 1 week apart within 4 weeks prior to Dose 1.

Time frame: From Week 13 to Week 24 of study treatment

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants Achieving Erythroid Response (Week 13 to Week 24)77.1 Percent of Participants
PlaceboPercentage of Participants Achieving Erythroid Response (Week 13 to Week 24)0.0 Percent of Participants
95% CI: [63.4, 87]
95% CI: [68.7, 85.5]
Secondary

Apparent Clearance (CL/F) of Luspatercept

Apparent Clearance (CL/F) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (GEOMETRIC_MEAN)Dispersion
LuspaterceptApparent Clearance (CL/F) of Luspatercept0.458 L/dayGeometric Coefficient of Variation 33.8
Secondary

Apparent Volume of Distribution of the Central Compartment (V1/F) of Luspatercept

Apparent Volume of Distribution of the Central Compartment (V1/F) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (GEOMETRIC_MEAN)Dispersion
LuspaterceptApparent Volume of Distribution of the Central Compartment (V1/F) of Luspatercept7.79 LitersGeometric Coefficient of Variation 19.6
Secondary

Area Under the Curve From Steady State (AUCss) of Luspatercept

Area Under the Curve From Steady State (AUCss) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (GEOMETRIC_MEAN)Dispersion
LuspaterceptArea Under the Curve From Steady State (AUCss) of Luspatercept130 day*μg/mLGeometric Coefficient of Variation 34.4
Secondary

Duration of the Mean Hemoglobin Increase From Baseline ≥1.0 g/dL

This outcome measure is the cumulative mean of the duration of hemoglobin response for the ≥ 1.0 g/dL during any 12-week rolling period. Any hemoglobin values within 21 days after a transfusion were excluded from the analysis.

Time frame: From baseline up to approximately 56 months

Population: All participants with a mean hemoglobin increase ≥1.0 g/dL. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (MEAN)Dispersion
LuspaterceptDuration of the Mean Hemoglobin Increase From Baseline ≥1.0 g/dL1136.0 DaysStandard Deviation 491.86
PlaceboDuration of the Mean Hemoglobin Increase From Baseline ≥1.0 g/dL203.3 DaysStandard Deviation 170.82
Secondary

Maximum Concentration (Cmax) of Luspatercept

Maximum Concentration (Cmax) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (GEOMETRIC_MEAN)Dispersion
LuspaterceptMaximum Concentration (Cmax) of Luspatercept5.55 μg/mLGeometric Coefficient of Variation 16.9
Secondary

Maximum Concentration From Steady State (Cmax,ss) of Luspatercept

Maximum Concentration From Steady State (Cmax,ss) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (GEOMETRIC_MEAN)Dispersion
LuspaterceptMaximum Concentration From Steady State (Cmax,ss) of Luspatercept8.36 μg/mLGeometric Coefficient of Variation 27.7
Secondary

Mean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 13 to Week 24)

Mean change from baseline in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 13 to Week 24 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.

Time frame: Baseline and over a continuous 12 week period (from week 13 through week 24)

Population: All treated participants with available measurements at Baseline and From Week 13 to Week 24. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 13 to Week 24)1.48 g/dLStandard Error 0.078
PlaceboMean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 13 to Week 24)0.07 g/dLStandard Error 0.108
p-value: <0.000195% CI: [1.16, 1.67]ANCOVA
Secondary

Mean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 37 to Week 48)

Mean change from baseline in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 37 to Week 48 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.

Time frame: Baseline and over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants with available measurements at Baseline and From Week 37 to Week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 37 to Week 48)1.50 g/dLStandard Error 0.083
PlaceboMean Change From Baseline in Hemoglobin Values in the Absence of Transfusion (Week 37 to Week 48)0.01 g/dLStandard Error 0.13
p-value: <0.000195% CI: [1.2, 1.79]ANCOVA
Secondary

Mean Change From Baseline in Liver Iron Concentration (LIC)

LIC was measured by Magnetic Resonance Imaging (MRI). Baseline is defined as the last value on or before the first dose of study drug is administered; Postbaseline is defined as the closest visit at Week 24 or Week 48. Participants with LIC value \>43 are not included in the analysis.

Time frame: Week 24 and Week 48 of study treatment

Population: All treated participants with available measurements at Baseline and at week 24 or week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Liver Iron Concentration (LIC)Week 24-0.30 mg/g dry weightStandard Error 0.125
LuspaterceptMean Change From Baseline in Liver Iron Concentration (LIC)Week 48-0.34 mg/g dry weightStandard Error 0.233
PlaceboMean Change From Baseline in Liver Iron Concentration (LIC)Week 24-0.21 mg/g dry weightStandard Error 0.169
PlaceboMean Change From Baseline in Liver Iron Concentration (LIC)Week 48-1.00 mg/g dry weightStandard Error 0.329
Comparison: Mean change from baseline in LIC at Week 24p-value: 0.662895% CI: [-0.47, 0.3]ANCOVA
Comparison: Mean change from baseline in LIC at Week 48p-value: 0.085995% CI: [-0.09, 1.42]ANCOVA
Secondary

Mean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)

The FACIT-F is a multidimensional, self-report quality of life instrument which includes the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire (27 items over 4 different domains), and the Fatigue subscale (FS) component (13 items). FACIT-F version 4 has been used for this study. For the Fatigue subscale, each of the 13 items is scored from 0 (not at all) to 4 (very much). The scores from individual items are summed to generated the final FS score, which ranges from 0 (best outcome) to 52 (worst outcome). The questionnaire is completed every other dose, and the mean of FS scores from Week 13 to Week 24 is compared to the FS score at baseline (last score available before start of study treatment). Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13.

Time frame: Baseline and over a continuous 12 week period (from week 13 through week 24)

Population: All treated participants with available measurements at Baseline and at least one post-baseline FACIT-F questionnaire completed. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)1.64 Score on a scaleStandard Error 0.774
PlaceboMean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)0.26 Score on a scaleStandard Error 1.066
p-value: 0.264195% CI: [-1.06, 3.83]ANCOVA
Secondary

Mean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)

The FACIT-F is a multidimensional, self-report quality of life instrument which includes the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire (27 items over 4 different domains), and the Fatigue subscale (FS) component (13 items). FACIT-F version 4 has been used for this study. For the Fatigue subscale, each of the 13 items is scored from 0 (not at all) to 4 (very much). The scores from individual items are summed to generated the final FS score, which ranges from 0 (best outcome) to 52 (worst outcome). The questionnaire is completed every other dose, and the mean of FS scores from Week 37 to Week 48 is compared to the FS score at baseline (last score available before start of study treatment). Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.

Time frame: Baseline and over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants with available measurements at Baseline and at least one post-baseline FACIT-F questionnaire completed. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)2.43 Score on a scaleStandard Error 0.763
PlaceboMean Change From Baseline in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)0.24 Score on a scaleStandard Error 1.15
p-value: 0.095995% CI: [-0.39, 4.78]ANCOVA
Secondary

Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 13 to Week 24)

The NTDT-PRO V2.1 assess the severity of anemia-related symptoms associated with NTD β-thalassemia. It is a daily electronic diary with recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness (lack of energy) when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness (lack of strength) when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Shortness of Breath (SoB) domain score represents the average score of items 5 and 6 above. SoB domain score ranges from 0 (best outcome, no shortness of breath) to 10 (worst outcome, extreme shortness of breath). Weekly SoB Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12 week period (from Week 13 to Week 24) are compared to the SoB Domain Score at baseline.

Time frame: Baseline and over a continuous 12 week period (from week 13 through week 24)

Population: All treated participants with available measurements at Baseline and From Week 13 to Week 24. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 13 to Week 24)-0.46 Score on a scaleStandard Error 0.168
PlaceboMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 13 to Week 24)0.02 Score on a scaleStandard Error 0.228
p-value: 0.072195% CI: [-1.02, 0.04]ANCOVA
Secondary

Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 37 to Week 48)

NTDT-PRO V2.1 assess the severity of anemia-related symptoms. It is a daily recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Shortness of Breath (SoB) domain score represents the average score of items 5 and 6 above. SoB domain score ranges from 0 (best outcome, no shortness of breath) to 10 (worst outcome, extreme shortness of breath). Weekly SoB Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 37 to Week 48) are compared to the SoB Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.

Time frame: Baseline and over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants with available measurements at Baseline and From Week 37 to Week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 37 to Week 48)-0.59 Score on a scaleStandard Error 0.212
PlaceboMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Shortness of Breath (SoB) Domain Score (Week 37 to Week 48)0.47 Score on a scaleStandard Error 0.32
p-value: 0.004795% CI: [-1.8, -0.33]ANCOVA
Secondary

Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 13 to Week 24)

The NTDT-PRO assesses the severity of anemia-related symptoms with a daily recall of symptoms composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Tiredness/Weakness (T/W) domain score is the average score of items 1 through 4 above. T/W domain score ranges from 0 (best outcome, no tiredness/weakness) to 10 (worst outcome, extreme tiredness/weakness). Weekly T/W Scores are the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 13 to Week 24) are compared to the T/W Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13.

Time frame: Baseline and over a continuous 12 week period (from week 13 through week 24)

Population: All treated participants with available measurements at Baseline and from Week 13 to Week 24. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 13 to Week 24)-0.68 Score on a scaleStandard Error 0.176
PlaceboMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 13 to Week 24)-0.20 Score on a scaleStandard Error 0.24
p-value: 0.092495% CI: [-1.03, 0.08]ANCOVA
Secondary

Mean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 37 to Week 48)

NTDT-PRO V2.1 assess the severity of anemia-related symptoms. It's a daily recall of symptoms during the past 24 hours, composed of 6 items: 1. Tiredness (lack of energy) when not doing physical activity 2. Tiredness when doing physical activity 3. Weakness (lack of strength) when not doing physical activity 4. Weakness when doing physical activity 5. Shortness of breath when not doing physical activity 6. Shortness of breath when doing physical activity. The Tiredness/Weakness (T/W) domain score represents the average score of items 1 through 4 above. T/W domain score ranges from 0 (best outcome, no tiredness/weakness) to 10 (worst outcome, extreme tiredness/weakness). Weekly T/W Scores represent the average of daily scores for that week. The mean of weekly scores over a continuous 12-week period (from Week 37 to Week 48) are compared to the T/W Domain Score at baseline. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37.

Time frame: Baseline and over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants with available measurements at Baseline and at Week 37 to Week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 37 to Week 48)-0.78 Score on a scaleStandard Error 0.229
PlaceboMean Change From Baseline in Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score (Week 37 to Week 48)0.01 Score on a scaleStandard Error 0.347
p-value: 0.05195% CI: [-1.58, 0]ANCOVA
Secondary

Mean Change From Baseline in Serum Ferritin

Baseline mean serum ferritin is calculated during the 24 weeks on or prior to dose 1 day 1. Post-baseline mean serum ferritin is calculated as mean of ferritin values during the last 24 weeks on or prior to the end date of the first 24 week or 48 week treatment

Time frame: Week 24 and Week 48 of study treatment

Population: All treated participants with available measurements at Baseline and at week 24 or week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in Serum FerritinWeek 2429.32 ug/LStandard Error 22.949
LuspaterceptMean Change From Baseline in Serum FerritinWeek 4884.94 ug/LStandard Error 23.12
PlaceboMean Change From Baseline in Serum FerritinWeek 242.18 ug/LStandard Error 32.217
PlaceboMean Change From Baseline in Serum FerritinWeek 4871.48 ug/LStandard Error 32.457
Comparison: Mean change from baseline in serum ferritin at Week 24p-value: 0.594995% CI: [-46.77, 101.06]ANCOVA
Comparison: Mean change from baseline in serum ferritin at Week 48p-value: 0.345495% CI: [-61.01, 87.93]ANCOVA
Secondary

Mean Change From Baseline in the 6-Minute Walk Test (6MWT) Distance

The 6MWT is typically used to objectively assess functional exercise capacity and response to medical interventions in patients with various moderate to severe diseases. Particiapnts are asked to walk as quickly as possible without running along a 30-meter corridor for six minutes, and the total distance covered during that time is measured. Baseline is defined as the last value on or before the first dose of study drug is administered. Postbaseline is defined as the closest visit at Week 24 or Week 48.

Time frame: From baseline to Week 24 and from baseline to Week 48 of study treatment

Population: All treated participants with available measurements at Baseline and at Week 24 or Week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in the 6-Minute Walk Test (6MWT) Distance24 Weeks7.20 MetersStandard Error 7.017
LuspaterceptMean Change From Baseline in the 6-Minute Walk Test (6MWT) Distance48 Weeks8.82 MetersStandard Error 5.907
PlaceboMean Change From Baseline in the 6-Minute Walk Test (6MWT) Distance24 Weeks-8.96 MetersStandard Error 9.297
PlaceboMean Change From Baseline in the 6-Minute Walk Test (6MWT) Distance48 Weeks-3.62 MetersStandard Error 8.141
Comparison: Mean change from baseline in 6MWT distance at Week 24p-value: 0.146695% CI: [-5.73, 38.04]ANCOVA
Comparison: Mean change from baseline in 6MWT distance at Week 48p-value: 0.201195% CI: [-6.72, 31.59]ANCOVA
Secondary

Mean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)

The SF-36v2 is a 36-item generic PRO questionnaire used to assess patient-reported outcomes. The SF-36 yields scores for 8 domains of health: Physical Functioning (PF), Role-Physical (RP), Bodily Pain (BP), General Health (GH), Vitality (VT), Social Functioning (SF), Role Emotional (RE), and Mental Health (MH) as well as physical component summary (PCS) and mental component summary (MCS) scores. Scores from each of the 8 domains of health are first normalized based on US general population means, then aggregated and transformed so that the scores from each of the 8 domains of health will contribute differently to the determination of PCS and MCS summary scores. PCS and MCS scores range from 0 to 100, with higher scores indicating a better quality of life. Baseline is defined as the last value taken on or before the first dose of study drug administered.

Time frame: From baseline to Week 24 and from baseline to Week 48 of study treatment

Population: All treated participants with available measurements at Baseline, at Week 24 and at Week 48. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
LuspaterceptMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Physical Component Summary (PCS) up to Week 241.00 Score on a scaleStandard Error 0.499
LuspaterceptMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Physical Component Summary (PCS) up to Week 481.23 Score on a scaleStandard Error 0.571
LuspaterceptMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Mental Component Summary (MCS) up to Week 240.83 Score on a scaleStandard Error 0.674
LuspaterceptMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Mental Component Summary (MCS) up to Week 480.81 Score on a scaleStandard Error 0.784
PlaceboMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Mental Component Summary (MCS) up to Week 48-1.89 Score on a scaleStandard Error 1.152
PlaceboMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Physical Component Summary (PCS) up to Week 24-0.38 Score on a scaleStandard Error 0.684
PlaceboMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Mental Component Summary (MCS) up to Week 24-0.71 Score on a scaleStandard Error 0.947
PlaceboMean Change From Baseline in the Physical Component Summary (PCS) and Mental Component Summary (MCS) Scores of the Medical Outcomes Study 36-Item Short Form (SF-36)Physical Component Summary (PCS) up to Week 48-0.52 Score on a scaleStandard Error 0.822
Comparison: Mean change from baseline in SF-36 PCS to Week 24p-value: 0.084795% CI: [-0.19, 2.96]Mixed Models Analysis
Comparison: Mean change from baseline in SF-36 PCS to Week 48p-value: 0.071295% CI: [-0.15, 3.65]Mixed Models Analysis
Comparison: Mean change from baseline in SF-36 MCS to Week 24p-value: 0.163395% CI: [-0.63, 3.72]Mixed Models Analysis
Comparison: Mean change from baseline in SF-36 MCS to Week 48p-value: 0.046995% CI: [0.04, 5.36]Mixed Models Analysis
Secondary

Number of Participants Experiencing Adverse Events

An Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Adverse events are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.

Time frame: From first dose to 63 days after last dose (up to approximately 56 months)

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-emergent adverse-event (TEAE)96 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsSerious TEAE23 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related TEAE79 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related Serious TEAE4 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTEAE Leading to Death1 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTEAE Leading to Dose Reduction11 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTEAE Leading to Dose Delay47 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTEAE Leading to Study Drug Discontinuation5 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Death0 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Dose Reduction11 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Dose Delay10 Participants
LuspaterceptNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Study Drug Discontinuation4 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Dose Delay0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-emergent adverse-event (TEAE)48 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTEAE Leading to Dose Delay11 Participants
PlaceboNumber of Participants Experiencing Adverse EventsSerious TEAE13 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Dose Reduction0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related TEAE18 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTEAE Leading to Study Drug Discontinuation4 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related Serious TEAE0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Study Drug Discontinuation0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTEAE Leading to Death0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTreatment-related TEAE Leading to Death0 Participants
PlaceboNumber of Participants Experiencing Adverse EventsTEAE Leading to Dose Reduction0 Participants
Secondary

Number of Participants With Anti-drug Antibody (ADA) Positive Test for Luspatercept

Presence of anti-drug (ACE-536/Luspatercept) antibodies was assessed every 24 weeks from serum samples. A participant is counted as 'positive' if there is any positive result captured during the study.

Time frame: From first dose and up to 2 years following last dose, up to approximately 56 months

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo who crossed over to luspatercept.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
LuspaterceptNumber of Participants With Anti-drug Antibody (ADA) Positive Test for Luspatercept5 Participants
PlaceboNumber of Participants With Anti-drug Antibody (ADA) Positive Test for Luspatercept3 Participants
Secondary

Percentage of Participants Achieving Erythroid Response (Week 37 to Week 48)

Erythroid Response is defined as an increase from baseline ≥1.0 g/dL in mean of hemoglobin values over a continuous 12-week interval from Weeks 37 to 48 of treatment in the absence of transfusions. Baseline hemoglobin (Hb) is the average of 2 or more Hb measurements at least 1 week apart within 4 weeks prior to Dose 1.

Time frame: Assessed over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants Achieving Erythroid Response (Week 37 to Week 48)70.8 Percentage of Participants
PlaceboPercentage of Participants Achieving Erythroid Response (Week 37 to Week 48)2.0 Percentage of Participants
p-value: <0.000195% CI: [54.3, 80.4]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants Who Are Transfusion-Free Over 24 Weeks

Transfusion free is defined as the absence of any transfusion during Week 1-24 of study treatment. Participants who discontinued treatment prior to Week 24 were not considered as transfusion free during Week 1-24.

Time frame: From first dose to Week 24

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants Who Are Transfusion-Free Over 24 Weeks89.6 Percent of Participants
PlaceboPercentage of Participants Who Are Transfusion-Free Over 24 Weeks67.3 Percent of Participants
Comparison: Percentage of participants who were transfusion free over 24 weeksp-value: 0.001395% CI: [5, 38.6]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants Who Are Transfusion-Free Over 48 Weeks

Transfusion free is defined as the absence of any transfusion during Week 1-48 of study treatment. Participants who discontinued treatment prior to Week 48 were not considered as transfusion free during Week 1-48.

Time frame: From first dose to Week 48

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants Who Are Transfusion-Free Over 48 Weeks82.3 Percent of Participants
PlaceboPercentage of Participants Who Are Transfusion-Free Over 48 Weeks44.9 Percent of Participants
Comparison: Percentage of Participants Who are Transfusion-Free Over 48 Weeksp-value: <0.000195% CI: [20.9, 53]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score

The responder definition (RD) threshold is the individual participant score change over a predetermined time period that will be interpreted as a treatment benefit. The RD for the NTDT-PRO T/W domain score was defined as ≥ 1-point decrease (ie, RD = -1) from baseline over the time from Week 13 to Week 24 or from Week 37 to Week 48. Participants with missing NTDT-PRO T/W scores at the indicated 12-week period are classified as non-responders in the analysis.

Time frame: From Week 13 to Week 24 and from Week 37 to Week 48 of study treatment

Population: All treated participants with available measurements at Baseline and at the indicated 12-week periods. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (NUMBER)
LuspaterceptPercentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain ScoreWeek 13 to week 2437.5 Percent of participants
LuspaterceptPercentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain ScoreWeek 37 to week 4831.3 Percent of participants
PlaceboPercentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain ScoreWeek 13 to week 2428.6 Percent of participants
PlaceboPercentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain ScoreWeek 37 to week 4818.4 Percent of participants
Comparison: Percentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score Week 13 to Week 24p-value: 0.198995% CI: [0.8, 3.7]Cochran-Mantel-Haenszel
Comparison: Percentage of Participants With a Decrease From Baseline ≥ RD (= 1) in the Non-Transfusion Dependent β-thalassemia-Patient Reported Outcome (NTDT-PRO) Tiredness and Weakness (T/W) Domain Score Week 37 to Week 48p-value: 0.073395% CI: [0.9, 5]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants With an Increase From Baseline ≥1.5 g/dL in Mean Hemoglobin Values in the Absence of Transfusion

Percentage of participants who have an increase from baseline ≥1.5 g/dL in mean of hemoglobin (Hb) values over a continuous 12-week interval from Week 13 to Week 24 in the absence of transfusions. Baseline was defined as the average of 2 or more Hb measurements at least 1 week apart within 4 weeks before Dose 1 Day 1.

Time frame: From Week 13 to Week 24 of study treatment

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants With an Increase From Baseline ≥1.5 g/dL in Mean Hemoglobin Values in the Absence of Transfusion52.1 Percentage of Participants
PlaceboPercentage of Participants With an Increase From Baseline ≥1.5 g/dL in Mean Hemoglobin Values in the Absence of Transfusion0.0 Percentage of Participants
Comparison: Percentage of Participants with an Increase From Baseline ≥1.5 g/dL in Mean Hemoglobin Values in the Absence of Transfusionp-value: <0.000195% CI: [36.2, 66.2]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)

The FACIT-Fatigue, is a multidimensional, self-report quality of life instrument. It consists of 27 core items, the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire, which assesses patient function in 4 domains: Physical, Social/Family, Emotional, and Functional well-being, which is further supplemented by a 13-item measure designed to capture cancer-related fatigue, the Fatigue subscale (FS). The items are measured on a response scale with five options (0 = not at all to 4 = very much). Participants completed the questionnaire at screening and every other dose. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 13. Score is calculated by multiplying the sum of item scores by the n of items in the scale, then divided by n of items answered.

Time frame: Baseline and over a continuous 12 week period (from week 13 through week 24)

Population: All treated participants with available measurements at Baseline and at least one post-baseline FACIT-F questionnaire completed. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)40.4 Percent of Participants
PlaceboPercentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 13 to Week 24)27.7 Percent of Participants
p-value: 0.135995% CI: [0.8, 4]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)

The FACIT-Fatigue, is a multidimensional, self-report quality of life instrument. It consists of 27 core items, the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire, which assesses patient function in 4 domains: Physical, Social/Family, Emotional, and Functional well-being, which is further supplemented by a 13-item measure designed to capture cancer-related fatigue, the Fatigue subscale (FS). The items are measured on a response scale with five options (0 = not at all to 4 = very much). Participants completed the questionnaire at screening and every other dose. Baseline is defined as the last value taken on or before the first dose of study drug administered in Week 37. Score is calculated by multiplying the sum of item scores by the n of items in the scale, then divided by n of items answered.

Time frame: Baseline and over a continuous 12 week period (from week 37 through week 48)

Population: All treated participants with available measurements at Baseline and at least one post-baseline FACIT-F questionnaire completed. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureValue (NUMBER)
LuspaterceptPercentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)36.2 Percent of Participants
PlaceboPercentage of Participants With an Increase From Baseline ≥ 3 in Mean Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Fatigue Subscale Score (Week 37 to Week 48)21.3 Percent of Participants
p-value: 0.065795% CI: [0.9, 5.4]Cochran-Mantel-Haenszel
Secondary

Percentage of Participants With Improvement of Iron Overload

Iron overload was measured by Liver Iron Concentration (LIC) and Iron Chelation Therapy (ICT) daily dose. Improvement is defined as: - For participants with baseline LIC ≥3 mg/g: ≥20% reduction in LIC or ≥ 33% decrease in ICT daily dose - For participants with baseline LIC \<3 mg/g: no increase in LIC \>1 mg/g and not starting treatment with ICT, or no increase in ICT daily dose ≥ 33% (if on ICT at baseline)

Time frame: Week 24 and Week 48 of study treatment

Population: All treated participants. Placebo participants are assessed up to crossing over to luspatercept. The luspatercept group does not include placebo participants who crossed over to luspatercept.

ArmMeasureGroupValue (NUMBER)
LuspaterceptPercentage of Participants With Improvement of Iron OverloadWeek 2444.8 Percent of participants
LuspaterceptPercentage of Participants With Improvement of Iron OverloadWeek 4834.4 Percent of participants
PlaceboPercentage of Participants With Improvement of Iron OverloadWeek 4849.0 Percent of participants
PlaceboPercentage of Participants With Improvement of Iron OverloadWeek 2449.0 Percent of participants
Comparison: Percentage of participants with improvement of iron overload (LIC/ICT responders) at Week 24p-value: 0.478795% CI: [-21.4, 13]Cochran-Mantel-Haenszel
Comparison: Percentage of participants with improvement of iron overload (LIC/ICT responders) at Week 48p-value: 0.082795% CI: [-31.5, 2.4]Cochran-Mantel-Haenszel
Secondary

Time to Reach Maximum Concentration (Tmax) of Luspatercept

Time to Reach Maximum Concentration (Tmax) of Luspatercept

Time frame: Doses 1 to 16: at predose (must be collected before first dose), Dose 2 Day 1, Dose 4 Day 1, Dose 6 Day 1, Dose 8 Day 1, Dose 12 Day 1, Dose 16 Day 1, Dose 6 Day 8, Dose 6 Day 15, and every 6 doses (at Dose 22, 28, etc.), up to approx. 48 months

Population: All treated participants who received the study drug.

ArmMeasureValue (MEDIAN)
LuspaterceptTime to Reach Maximum Concentration (Tmax) of Luspatercept5.50 Days

Source: ClinicalTrials.gov · Data processed: Mar 21, 2026