Karuna Pharmaceuticals, an affiliate of UK-listed biopharma PureTech Health, has kicked off a Phase II study of KarXT, which is being developed for the treatment of psychosis in schizophrenia.

KarXT consists of xanomeline, a novel muscarinic acetylcholine receptor agonist with shown efficacy in placebo-controlled human trials in schizophrenia and Alzheimer’s disease, and trospium chloride, an FDA-approved muscarinic receptor antagonist that has been shown not to enter the central nervous system.

In a Phase I study completed by Karuna, KarXT successfully demonstrated tolerability at a dose level exceeding those shown to be efficacious in previous studies of xanomeline alone.

Data from the study supported dose selection for the Phase II study, which is aimed at reproducing significant efficacy previously observed in a schizophrenia trial with xanomeline monotherapy.

The trial aims to enroll around 160 patients with schizophrenia, its primary endpoint being the total change from baseline Positive and Negative Syndrome Scale (PANSS) score compared to placebo.

“We are pleased with the progress Karuna has made to advance KarXT into a Phase II study, bringing us one step closer to potentially delivering the first new mechanism in more than 60 years for the treatment of psychosis in schizophrenia,” said Eric Elenko, chief of research and strategy at PureTech.

According to Karuna’s chief executive Steve Paul, the treatment “could be effective in treating not only positive symptoms but also the disabling negative and cognitive symptoms of the disease.”