Luspatercept improves hemoglobin levels and blood transfusion requirements in a study of patients with β-thalassemia

Blood. 2019 Mar 21;133(12):1279-1289. doi: 10.1182/blood-2018-10-879247. Epub 2019 Jan 7.


β-thalassemia is a hereditary disorder with limited approved treatment options; patients experience anemia and its complications, including iron overload. The study aim was to determine whether luspatercept could improve anemia and disease complications in patients with β-thalassemia. This open-label, nonrandomized, uncontrolled study consisted of a 24-week dose-finding and expansion stage (initial stage) and a 5-year extension stage, currently ongoing. Sixty-four patients were enrolled; 33 were non-transfusion dependent (mean hemoglobin, <10.0 g/dL; <4 red blood cell [RBC] units transfused per 8 weeks), and 31 were transfusion dependent (≥4 RBC units per 8 weeks). Patients received 0.2 to 1.25 mg/kg luspatercept subcutaneously every 21 days for ≥5 cycles (dose-finding stage) and 0.8 to 1.25 mg/kg (expansion cohort and 5-year extension). The primary end point was erythroid response, defined as hemoglobin increase of ≥1.5 g/dL from baseline for ≥14 consecutive days (without RBC transfusions) for non-transfusion-dependent patients or RBC transfusion burden reduction ≥20% over a 12-week period vs the 12 weeks before treatment for transfusion-dependent patients. Eighteen non-transfusion-dependent patients (58%) receiving higher dose levels of luspatercept (0.6-1.25 mg/kg) achieved mean hemoglobin increase ≥1.5 g/dL over ≥14 days vs baseline. Twenty-six (81%) transfusion-dependent patients achieved ≥20% reduction in RBC transfusion burden. The most common grade 1 to 2 adverse events were bone pain, headache, and myalgia. As of the cutoff, 33 patients remain on study. In this study, a high percentage of β-thalassemia patients receiving luspatercept had hemoglobin or transfusion burden improvements. These findings support a randomized clinical trial to assess efficacy and safety. This study was registered at as #NCT01749540 and #NCT02268409.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activin Receptors, Type II
  • Activins / therapeutic use*
  • Adult
  • Erythrocyte Transfusion / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Hemoglobins / analysis*
  • Humans
  • Immunoglobulin Fc Fragments / therapeutic use*
  • Male
  • Middle Aged
  • Prognosis
  • Recombinant Fusion Proteins / therapeutic use*
  • Young Adult
  • beta-Thalassemia / drug therapy*


  • Hemoglobins
  • Immunoglobulin Fc Fragments
  • Recombinant Fusion Proteins
  • Activins
  • luspatercept
  • Activin Receptors, Type II

Associated data