Expert: Modified activin receptor type IIB Fc-fusion protein that acts as a ligand trap for TGF-beta superfamily members (GDF8, GDF11, activins). Inhibits SMAD2/3 signaling to promote late-stage erythroid differentiation and maturation. Addresses ineffective erythropoiesis in MDS by enhancing red blood cell production from existing progenitors.

Everyday: In MDS, the bone marrow makes defective red blood cells that die before maturing. Luspatercept acts like a trap that catches signals (activins) that are blocking red blood cell maturation. By removing these blockers, more red blood cells survive and mature properly, reducing the need for blood transfusions.

Targets: []

First-line ESA alternative for LR-MDS anemia (COMMANDS Phase 3 superiority vs EPO). Also approved for beta-thalassemia. MEDALIST Phase 3: 38% TI at 8 weeks vs 13% placebo in ESA-refractory LR-MDS. Main comparator for Rytelo (imetelstat). Key difference: Reblozyl promotes erythroid maturation (symptomatic), Rytelo depletes malignant clones (potentially disease-modifying).