Reblozyl Luspatercept for Injection

1. Indications and Usage
β-Thalassemia: Treatment of adult patients with transfusion-dependent β-thalassemia who require regular red blood cell (RBC) transfusions.
Myelodysplastic Syndromes (MDS): Treatment of anemia in adult patients with intermediate- or low-risk MDS who have ring sideroblasts (RS) and require regular RBC transfusions.
MDS/MPN with Thrombocytosis: Treatment of anemia in adult patients with MDS/MPN-RS-T who have ring sideroblasts and thrombocytosis and require regular RBC transfusions.
2. Dosage and Administration
Route of Administration: For Subcutaneous (SC) Injection ONLY.
Recommended Dosage:
β-Thalassemia: Initial dose 1 mg/kg every 3 weeks. If RBC transfusion burden is not reduced after 2 doses (6 weeks), increase to 1.25 mg/kg.
MDS: Initial dose 1 mg/kg every 3 weeks. If RBC transfusion burden is not reduced after 2 doses (6 weeks), increase to 1.33 mg/kg; if still not reduced after 2 more doses, increase to 1.75 mg/kg (maximum).
MDS/MPN-RS-T: Initial dose 1 mg/kg every 3 weeks. If RBC transfusion burden is not reduced after 2 doses (6 weeks), increase to 1.33 mg/kg; if still not reduced after 2 more doses, increase to 1.75 mg/kg (maximum).
Critical Administration Instructions:
Hemoglobin Monitoring: If pre-administration hemoglobin (without recent transfusion) is ≥11.5 g/dL, delay administration until Hb is ≤11 g/dL.
Reconstitution: Reconstitute with Sterile Water for Injection. Gently swirl; do not shake.
Storage: Refrigerate reconstituted solution if not used immediately (up to 24 hours at 2°C to 8°C). Do not freeze.
3. Mechanism of Action
ActRIIB-Fc Fusion Protein: Luspatercept is a modified human activin receptor type IIB (ActRIIB) fused to an IgG1 Fc domain.
Modulation of Erythropoiesis: It acts as a “decoy” ligand, binding to specific members of the TGF-β superfamily (e.g., activins).
Erythrocyte Maturation: By neutralizing these inhibitors, luspatercept promotes the late-stage differentiation and maturation of erythroid progenitor cells, thereby improving red blood cell production and reducing anemia.
4. Safety and Warnings
Thromboembolic Events (TEE): TEEs have been reported in MDS patients. Monitor for signs and symptoms of thrombosis.
Embryo-Fetal Toxicity: Can cause fetal harm. Effective contraception is required during treatment and for at least 3 months after the final dose.
Hypersensitivity: Serious hypersensitivity reactions have been reported; discontinue immediately if severe reactions occur.
Ocular Disorders: Ocular disorders have been reported; monitor patients for visual changes.
5. Adverse Reactions and Clinical Research
Most Common Adverse Reactions: Bone pain, arthralgia, dizziness, hypertension, hyperuricemia, fatigue, and injection site reactions.
Clinical Research Highlights: Phase 3 trials (e.g., MEDALIST, COMMANDS) demonstrated significant reductions in RBC transfusion burden and improvements in hemoglobin levels compared to placebo.
6. Drug Interactions
Iron Chelators: No clinically significant pharmacokinetic interactions have been observed.
Vaccines: Live or attenuated vaccines should be avoided.
7. Pharmaceutical Information
Chemical Composition: Active Ingredient: Luspatercept (recombinant fusion protein).
Appearance: White to off-white lyophilized powder or cake.
Packaging: Single-dose vial (25 mg or 75 mg).
Storage: Store in the original carton at 2°C to 8°C. Do not freeze.