Xanomeline/Trospium (Cobenfy): A Novel Approach for the Treatment of Schizophrenia in Adults

BACKGROUND: Schizophrenia is characterized by 3 main groups of symptoms: positive, negative, and cognitive. Traditional antipsychotics primarily address positive symptoms via dopamine D2 receptor blockade but often cause side effects like movement disorders, sedation, and hormonal imbalances xanomeline/trospium, Food and Drug Administration (FDA) approved for the treatment of schizophrenia in adults, represents a novel, nondopaminergic approach to schizophrenia treatment, without being categorized as an antipsychotic. Xanomeline is a muscarinic receptor agonist (mainly M1 and M4) that reduces dopamine release in the associative striatum, a region linked to psychotic symptoms, while sparing sensorimotor regions involved in movement and endocrine regulation. M1 receptor stimulation also influences Gamma-aminobutyric acid (GABA)/glutamate pathways that modulate the ventral tegmental area, contributing to dopaminergic balance. PHARMACODYNAMICS AND PHARMACOKINETICS: Xanomeline binds to all 5 muscarinic receptor subtypes, exerting central effects. Trospium, a peripherally acting anticholinergic with limited blood-brain barrier penetration, mitigates xanomeline's peripheral cholinergic side effects, such as nausea, vomiting, and sweating. However, higher doses of trospium may introduce additional peripheral side effects. Xanomeline undergoes extensive liver metabolism, whereas trospium is primarily excreted unchanged in urine. The combination is contraindicated in patients with moderate to severe hepatic or renal impairment or urinary retention. CLINICAL TRIALS: EMERGENT-1 was a phase 2 trial, whereas the subsequent 2 EMERGENT trials were phase 3 studies evaluating the safety, tolerability, and efficacy of xanomeline/trospium compared with placebo in adult patients diagnosed with schizophrenia. The final 2 EMERGENT trials were 52-week, open-label studies designed to assess the long-term safety and efficacy of the drug. Xanomeline/trospium treatment significantly reduced Positive and Negative Syndrome Scale (PANSS) total score across the 2 phase 3 trials. THERAPEUTIC ADVANCE: Xanomeline/trospium represents an innovative drug approach, targeting the improvement in positive, cognitive, and negative symptoms in individuals with schizophrenia. This combination seeks to provide therapeutic benefits while displaying a different adverse effect profile than antipsychotic medications and potentially reducing the treatment discontinuation risk.