Keros Therapeutics is a clinical-stage biopharmaceutical company developing protein therapeutics that target the TGF-β signaling pathway. Keros has no approved products and no product revenue. Its two lead drug candidates are elritercept (KER-050) and rinvatercept (KER-065), both engineered ligand traps. Elritercept is designed to promote blood cell production by inhibiting TGF-β proteins that block blood cell maturation, targeting patients with myelodysplastic syndromes and myelofibrosis who suffer from anemia and low platelet counts. A Phase 3 trial in lower-risk MDS began in 2024, with the first patient dosed in July 2025. Keros licensed elritercept to Takeda for global rights outside of China, receiving a $200M upfront payment, and to Hansoh for China. Rinvatercept is designed to block proteins that suppress muscle and bone growth, targeting Duchenne muscular dystrophy and ALS. Keros retains full rights to rinvatercept, with a Phase 2 trial in DMD expected to start in Q2 2026. Keros funds itself through licensing partnerships and capital markets, with manufacturing fully outsourced to CMOs. The company operates with 78 employees and a lean cost structure. Its broader strategy is to build a pipeline of ActRII ligand traps across neuromuscular diseases, rare bone and fibrosis diseases, and other indications, leveraging its TGF-β biology platform.