Keros Therapeutics has dosed the first patient in the Phase 3 RENEW clinical trial evaluating elritercept for transfusion-dependent anemia in myelodysplastic syndromes.

• KER-065 demonstrated favorable safety profile with no serious adverse events in Phase 1 trial, showing evidence of activin inhibition across multiple tissues of interest. • The novel ligand trap therapy showed promising biomarker changes including increased bone formation, fat mobilization, bone mineral density, and muscle mass, supporting its potential in treating DMD. • Keros plans to engage with regulatory authorities in Q3 2025 and aims to advance KER-065 into Phase 2 clinical trials for Duchenne muscular dystrophy by Q1 2026.

• Keros Therapeutics stopped dosing in two arms of a Phase 2 trial of cibotercept for pulmonary arterial hypertension (PAH) due to safety concerns, specifically pericardial effusion. • The company's stock price plunged 73% following the announcement, wiping out over $2 billion in market value, as investors lost confidence in the drug's potential. • The Tropos trial will continue with the lowest dose of cibotercept, but the future of the drug's development is uncertain, especially in competition with Merck's Winrevair. • Takeda's recent agreement to pay $200 million for rights to Keros' elritercept, an experimental blood disease drug, outside of specific regions, remains unaffected.

• Keros Therapeutics halts dosing in the 3.0 mg/kg and 4.5 mg/kg arms of its Phase 2 TROPOS trial of cibotercept for pulmonary arterial hypertension (PAH) after detecting pericardial effusion. • The decision follows a safety review and consultation with an independent Data Monitoring Committee; dosing continues in the 1.5 mg/kg arm. • Keros is working with investigators and the FDA to understand the findings and expects to share topline data from all trial arms in Q2 2025. • Despite this setback, Keros will continue safety and efficacy data collection for all treatment arms in the TROPOS trial.

• Takeda Pharmaceuticals has secured an exclusive licensing agreement with Keros Therapeutics for elritercept, an activin inhibitor targeting anemia in hematologic cancers. • The deal includes a $200 million upfront payment to Keros, with potential milestone payments exceeding $1.1 billion, plus tiered royalties on net sales. • Elritercept is currently in Phase II trials for myelofibrosis and myelodysplastic syndromes (MDS) and has FDA Fast Track designation for certain MDS subtypes. • Takeda aims to advance elritercept into late-stage development, potentially competing with Bristol Myers Squibb’s Reblozyl in the treatment of anemia in blood cancers.