Merck KGaA stock falls after FDA pauses new patients on MS drug evobrutinib in trial

Merck KGaA (OTCPK:MKGAF) (OTCPK:MKKGY) said the U.S. Food and Drug Administration (FDA) placed a partial clinical hold on starting new patients on its multiple sclerosis therapy evobrutinib in the U.S.

The German company's shares trading on the Frankfurt Stock Exchange fell ~7% on Wednesday following the news.

The partial hold also applies to patients with less than 70 days exposure to the drug.

The FDA's decision was based on reported cases of laboratory values suggestive of drug-induced liver injury which were identified during the phase 3 trials.

Merck KGaA noted that both patients were asymptomatic, did not require any medical intervention or hospitalization for this condition and their liver enzymes fully normalized after discontinuing the study drug.

The company added that in partnership with external experts and an Independent Data Monitoring Committee for the trials, it is evaluating the potential contributory role of predisposing factors to the liver injury.

Merck KGaA noted that it is working with the FDA to decide the best path forward for the benefit of patients in current and future trials with evobrutinib.

Meanwhile, an ongoing, fully-enrolled phase 3 trial called EVOLUTION of evobrutinib in relapsing multiple sclerosis (RMS) will continue as planned with all participants remaining on treatment, as all have gone beyond 70 days of exposure to the study drug, according to the company.

Merck KGaA said the phase 3 trial program of evobrutinib is on track to read out in Q4 2023.

In October 2022, the company reported data from an open-label extension (OLE) part of a phase 2 trial noting that evobrutinib showed sustained clinical benefit in people with relapsing multiple sclerosis through more than three and half years.