Keros Thera slumps after halting parts of cibotercept trial

US clinical-stage drug developer Keros Therapeutics’ (Nasdaq: KROS) shares plummeted more than 73% to $18.20 in pre-market activity on revealing a setback for a lead investigational candidate.

Keros today announced that it has voluntarily halted dosing in the 3.0 mg/kg and 4.5 mg/kg treatment arms in the ongoing TROPOS trial, a Phase II clinical trial of cibotercept (KER-012) in combination with background therapy in patients with pulmonary arterial hypertension (PAH). It said that the decision was made based on a safety review due to the unanticipated observation of pericardial effusion adverse events in the trial.

“We are working diligently to gain a better understanding of these unanticipated findings,” said Jasbir Seehra, chairman and chief executive of Keros. “Above all, patient safety is our top priority when conducting any clinical trial. We will work with the investigators, the US Food and Drug Administration (FDA) and other relevant regulatory authorities to address this as quickly as possible,” he added.