ALG-802

ALG-802 is a recombinant protein drug candidate that functions as an activin receptor type IIB (ActRIIB) ligand trap, acting as an antagonist of the type II activin receptor pathway. Its mechanism involves inhibiting signaling through ActRIIB, which includes blocking myostatin—a negative regulator of muscle growth and function—thereby potentially promoting muscle mass and strength. The drug is being developed primarily for neuromuscular diseases such as spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and other forms of muscular atrophy. Originally developed by AliveGen, it was licensed to Biogen for further development[1][2][3][4]. As of the latest updates in 2024–2025, ALG-802 remains in preclinical development[1][2][6].