Luspatercept is a recombinant fusion protein and erythroid maturation agent used in the management of anemia associated with certain hematological disorders. It is designed to regulate late-stage erythroid maturation by modulating signaling within the transforming growth factor-beta (TGF-β) superfamily pathway.
Luspatercept consists of a modified extracellular domain of human activin receptor type IIB (ActRIIB) linked to the Fc portion of human immunoglobulin G1 (IgG1). It is produced using recombinant DNA technology in Chinese hamster ovary (CHO) cells. FDA describes the calculated molecular mass of luspatercept-aamt as approximately 76 kDa.
Unlike conventional chemically synthesized pharmaceutical compounds, luspatercept is a complex biologic protein. Consequently, it does not have a conventional small-molecule molecular formula or a single molecular weight expressed in g/mol.
The FDA identifies luspatercept as a receptor fusion protein composed of a modified human activin receptor type IIB extracellular domain linked to a human IgG1 Fc domain. The product is manufactured through recombinant DNA technology in CHO cells.
CAS Number: 1373715-00-4 is listed by the FDA Substance Registration System among the identifiers/synonyms associated with luspatercept.
Luspatercept binds several endogenous ligands belonging to the TGF-β superfamily, thereby reducing Smad2/3 signaling.
In patients with disorders such as beta thalassemia and myelodysplastic syndromes, abnormal Smad2/3 signaling can contribute to ineffective erythropoiesis. By reducing this signaling, luspatercept promotes differentiation and maturation of late-stage erythroid precursors, supporting increased production of mature red blood cells.
Luspatercept is used for the treatment of anemia associated with beta thalassemia and certain myelodysplastic syndromes (MDS).
The current U.S. labeling includes treatment of anemia in adults with beta thalassemia who require regular red blood cell transfusions, as well as specified adult MDS populations.
In the European Union, Reblozyl containing luspatercept is indicated in adults for transfusion-dependent anemia associated with very low-, low- and intermediate-risk MDS and for anemia associated with transfusion-dependent and non-transfusion-dependent beta thalassemia.
As a recombinant protein, luspatercept requires specialized biologic characterization and quality-control testing rather than only conventional small-molecule API testing.
Applicable analytical programs may include identity, purity, potency, protein concentration, aggregation, charge variants, glycosylation and other critical quality attributes. Appropriate microbiological and bioburden/endotoxin controls are also relevant to the manufacturing process.
The specific acceptance criteria should always be based on the manufacturer's approved specification, validated analytical methods, Certificate of Analysis and applicable regulatory requirements.
Luspatercept is supplied as a lyophilized powder for solution for injection. The EMA product information describes Reblozyl 25 mg and 75 mg presentations, with the active substance produced in CHO cells using recombinant DNA technology.
The U.S. product is also described as a sterile, preservative-free, white to off-white lyophilized powder for subcutaneous use after reconstitution.
Luspatercept should be stored according to the approved product specification and applicable cold-chain requirements. The product should be protected from unsuitable temperature conditions and handled according to validated biologic-product storage and transportation procedures.
Luspatercept may be supplied for qualified pharmaceutical development, biologic formulation development, analytical activities and manufacturing requirements, subject to applicable regulatory and quality requirements.
Luspatercept is a specialized recombinant biologic requiring controlled manufacturing, characterization and quality systems appropriate for therapeutic proteins. Qualified customers can request product specifications, analytical documentation, Certificate of Analysis, packaging information and commercial details according to their requirements.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 2.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 20 ppm |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |