Keros Therapeutics discontinues development of cibotercept in PAH

Keros Therapeutics (KROS) announced topline data from the TROPOS trial, a Phase 2 clinical trial of cibotercept in combination with background therapy in patients with pulmonary arterial hypertension, or PAH. TROPOS is a global Phase 2 clinical trial to evaluate cibotercept in combination with background therapy in patients with PAH. On December 12, 2024, the company voluntarily halted the 3.0 mg/kg and 4.5 mg/kg treatment arms based on the observation of pericardial effusions at those dose levels. Furthermore, on January 15, 2025, the company voluntarily halted all dosing in the trial, including the 1.5 mg/kg and placebo treatment arms, based on the ongoing safety review due to new observations of pericardial effusion adverse events. Following the early termination of the trial, patients continued to be monitored through their end-of-trial visits. Following the analysis of all available safety and efficacy data from the TROPOS trial, the Company has decided to discontinue all development of cibotercept in PAH. The company plans to further evaluate the appropriate development strategy for cibotercept, if any, in other indications following the completion of the strategic alternative review process.