Merck ends PhII trials of Alzheimer’s and depression small molecule after liver toxicity observations

Merck has ended work on two separate Phase II studies of its small molecule for treatment-resistant depression and mild-to-moderate Alzheimer’s disease, the pharma confirmed to Endpoints News. An unblinded review of data from the two trials “suggested MK-1942 was potentially associated with observations of liver toxicity,” a Merck spokesperson told Endpoints in an email Wednesday morning. “This review was triggered by the identification of abnormalities in liver function tests for several study participants. No related Serious Adverse Events (SAE) were reported.” In updates to ClinicalTrials.gov, the pharma giant cited “benefit/risk assessment” as the reasoning for scrapping the studies of the oral capsule. The Alzheimer’s withdrawal was disclosed this week, and the depression decision was uploaded to the site in September. The moves serve as a precursor to Merck’s third-quarter earnings, which are scheduled for Thursday. The asset is still displayed on Merck’s pipeline page for treatment-resistant depression. At the JP Morgan Healthcare Conference in January, the drugmaker also presented MK-1942 as an Alzheimer’s disease treatment prospect. There’s been speculation that MK-1942 is part of the growing wave of psychedelic-based therapies in development for neuroscience conditions, as the pharma partnered with a clinical research site known for its testing of psychedelic medicines. The site, Novamind’s Cedar Clinical Research, has said it’s contributed to studies of investigational medicines like Janssen’s esketamine spray Spravato. The Merck spokesperson declined to comment on MK-1942’s profile. HammondCare, an Australian clinical trial site involved in the study, describes the molecule’s role in helping release glutamate, noting release of that chemical “has been linked to improved cognition.” With the culls, Merck’s neuroscience pipeline now relies heavily on the performance of two clinical-stage drugs. The New Jersey-based pharma is not well-known for its work in central nervous system disorders but rather for its megablockbuster immunotherapy Keytruda and its Gardasil vaccine. One of the key remaining neuroscience programs is a 500-person Phase IIb of MK-8189. The PDE10A small molecule is slated to collect final data for patients with acute episodes of schizophrenia in June. Merck also has a Phase I study testing an anti-tau monoclonal antibody in Alzheimer’s. That 48-patient trial of MK-2214 is expected to conclude in May 2025. “We remain committed to developing novel therapies for the treatment of Alzheimer’s and other neurodegenerative diseases,” the spokesperson said. Neuroscience has traditionally been one of the hardest drug development fields, but biopharma has made recent strides in Alzheimer’s, depression and schizophrenia with recent or expected near-term treatment approvals. Newer companies are also making big bets in the space, with investors supporting startups like Neumora and Rapport Therapeutics. Meanwhile, other Big Pharmas are ending work on mid-stage depression studies. psychedelic investors novamind research

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