Merck shares fall as FDA pauses new patients on MS drug trial

Shares in German pharmaceutical company Merck fell on Wednesday after the US Food and Drug Administration (FDA) placed a temporary hold on use of its multiple sclerosis evobrutinib drug on new patients.

The FDA was responding to two potential liver injury cases during phase III studies, Merck said in a statement, adding that both had been asymptomatic and the patients' liver enzymes had fully normalised after discontinuation of the study medication.

"Merck is working closely with the FDA to establish the best path forward for the benefit of patients in current and future trials with evobrutinib," Merck said. It is now investigating whether the patients had some characteristics that could predispose them to liver injury.

The pause will affect studies involving patients who have been taking the drug for less than 70 days, as well as new entrants to the trial.

Merck said recruitment for a phase III trial of the drug was already complete with 2,000 participants and an ongoing study is to continue as planned. It expects to present the first data from that study in the fourth quarter of 2023.

Reporting by Frank Prenesti for Sharecast.com