The Impact of Xanomeline and Trospium Chloride on Cognitive Impairment in Acute Schizophrenia: Replication in Pooled Data From Two Phase 3 Trials.

Objective: Xanomeline and trospium chloride (formerly known as KarXT), a novel M₁/M₄ muscarinic receptor agonist, demonstrated efficacy across phase 2 and 3 trials as monotherapy for the treatment of inpatients with acute schizophrenia on the Positive and Negative Syndrome Scale total score primary endpoint. In the phase 2 trial, xanomeline/trospium improved performance on a cognitive outcome measure in the subgroup of participants with clinically significant baseline cognitive impairment. The authors sought to confirm this finding using data from two phase 3 trials.

Methods: Data were pooled from two 5-week inpatient trials of xanomeline/trospium monotherapy in patients with acute schizophrenia. The statistical analysis plan prespecified comparisons of cognitive composite score changes between xanomeline/trospium and placebo in the full sample and the cognitively impaired (≤1 SD below norms at baseline) subgroup.

Results: There was no significant xanomeline/trospium effect in the full sample (N=357); however, in the impaired subgroup, xanomeline/trospium (N=71) had a significantly greater benefit for cognition compared with placebo (N=66; least squares mean difference=0.31, SE=0.10; d=0.54). The xanomeline/trospium effect size increased significantly with a more stringent baseline impairment threshold (≤-1.5 SD; d=0.80). Improvements in cognition were minimally correlated with concurrent changes in total, positive, and negative symptoms in both treatment groups.

Conclusions: Participants with acute schizophrenia with prespecified impairments demonstrated significant cognitive improvement with xanomeline/trospium compared with placebo. This result directly confirms earlier findings. This benefit is not attributable to changes in symptoms, despite substantial evidence of efficacy for psychosis. Evaluation of xanomeline/trospium's potential for cognitive enhancement in a well-controlled trial of stable patients with cognitive impairment is warranted.