Ulotaront, a trace amine-associated receptor 1 (TAAR1) and serotonin 5-HT1A receptors agonist, has demonstrated efficacy in the treatment of patients with an acute exacerbation of schizophrenia in a 4-week, double-blind, placebo-controlled study. The aim of this 26-week open-label extension study was to evaluate the safety and effectiveness of ulotaront (25/50/75 mg/d) in patients who completed the initial 4-week study. Of the 193 4-week completers, 157 patients (81.3%) continued into the open-label extension study; 66.9% were completers. Among all extension phase patients, treatment with ulotaront was associated with minimal changes in body weight (mean [SD] change from double-blind baseline: -0.3 [3.7] kg), cholesterol (median change, -2.0 mg/dL), triglycerides (median, -5.0 mg/dL), and prolactin (female, median, -3.4 ng/mL; male, median, -2.7 ng/mL). Movement disorder scales showed no extrapyramidal effects. Twenty-six weeks of extension phase treatment was associated with a mean (95% CI) observed change from open-label baseline in the PANSS total score of -22.6 (-25.6, -19.6; effect size, 1.46), and a mean (95% CI) change in the CGI-Severity score of -1.0 (-1.2, -0.8; effect size, 1.07). Long-term treatment with the TAAR1 agonist ulotaront, in the daily dose range of 25-75 mg, was characterized by a relatively high completion rate, an adverse event profile notable for the absence of extrapyramidal-related adverse effects, a low liability for adverse weight and metabolic effects, and no effect on prolactin levels. Additional studies are needed to further confirm the long-term efficacy and safety of ulotaront.
