5-HT receptor activation produces rapid antidepressant-like effects in rodents.

Ketamine is noted for its rapid onset antidepressant response and effectiveness in patients with treatment resistant depression. While most research has focused on glutamatergic mechanisms, recent studies show that antidepressant-like effects in rodents are dependent upon the serotonergic (5-HT) system and suggest a potential contribution of the 5-HT receptor. In this study we utilized CP-94253 to examine whether 5-HT receptor agonism produces rapid and sustained antidepressant-like effects, focusing on rodent models and treatment approaches commonly used to demonstrate the differentiated response to ketamine.

TAAR1 and 5-HT receptor agonists attenuate autism-like irritability and aggression in rats prenatally exposed to valproic acid.

Despite the rising prevalence of autism spectrum disorder (ASD), there remains a significant unmet need for pharmacotherapies addressing its core and associative symptoms. While some atypical antipsychotics have been approved for managing associated irritability and aggression, their use is constrained by substantial side effects. This study aimed firstly to develop behavioral measures to explore frustration, irritability and aggression phenotypes in the rat prenatal valproic acid (VPA) model of ASD.

Evaluating speech latencies during structured psychiatric interviews as an automated objective measure of psychomotor slowing.

We sought to derive an objective measure of psychomotor slowing from speech analytics during a psychiatric interview to avoid potential burden of dedicated neurophysiological testing. Speech latency, which reflects response time between speakers, shows promise from the literature. Speech data was obtained from 274 subjects with a diagnosis of bipolar I depression enrolled in a randomized, doubleblind, 6-week phase 2 clinical trial.

A clinical trial inclusion criteria to enrich for patients presenting with canonical symptom structure in bipolar depression.

Clinical drug development in psychiatry is challenging due to heterogeneous patient populations and the uncertainty of measuring neuropsychiatric constructs with symptom rating scales. Here we describe the development and implementation of an enrichment algorithm that identifies canonical versus anomalous symptom presentations, at the individual subject level, based on MADRS ratings obtained at screening and baseline. Data from 5 randomized, placebo-controlled, phase 3 trials in bipolar I disorder was used (N = 2026 subjects and 15,239 MADRS assessments).

Mesostriatal Dopaminergic Circuit Dysfunction in Schizophrenia: A Multimodal Neuromelanin-Sensitive Magnetic Resonance Imaging and [F]-DOPA Positron Emission Tomography Study.

Background: Striatal hyperdopaminergia is implicated in the pathoetiology of schizophrenia, but how this relates to dopaminergic midbrain activity is unclear. Neuromelanin (NM)-sensitive magnetic resonance imaging provides a marker of long-term dopamine function. We examined whether midbrain NM-sensitive magnetic resonance imaging contrast-to-noise ratio (NM-CNR) was higher in people with schizophrenia than in healthy control (HC) participants and whether this correlated with dopamine synthesis capacity.

Discovery and Model-Informed Drug Development of a Controlled-Release Formulation of Nonracemic Amisulpride that Reduces Plasma Exposure but Achieves Pharmacodynamic Bioequivalence in the Brain.

Nonracemic amisulpride (SEP-4199) is an investigational 85:15 ratio of aramisulpride to esamisulpride and currently in clinical trials for the treatment of bipolar depression. During testing of SEP-4199, a pharmacokinetic/pharmacodynamic (PK/PD) disconnect was discovered that prompted the development of a controlled-release (CR) formulation with improved therapeutic index for QT prolongation. Observations that supported the development of a CR formulation included (i) plasma concentrations of amisulpride enantiomers were cleared within 24-hours, but brain dopamine D2 receptor (D2R) occupancies, although achieving stable levels during this time, required 5 days to return to baseline; (ii) nonracemic amisulpride administered to non-human primates produced significantly greater D2R occupancies during a gradual 6-hour administration compared with a single bolus; (iii) concentration-occupancy curves were left-shifted in humans when nonracemic amisulpride was gradually administered over 3 and 6 hours compared with immediate delivery; (iv) CR solid oral dose formulations of nonracemic amisulpride were able to slow drug dissolution in vitro and reduce peak plasma exposures in vivo in human subjects.

Estimating heterogeneity of treatment effect in psychiatric clinical trials.

Currently, placebo-controlled clinical trials report mean change and effect sizes, which masks information about heterogeneity of treatment effects (HTE). Here, we present a method to estimate HTE and evaluate the null hypothesis (H) that a drug has equal benefit for all participants (HTE=0). We developed measure termed 'estimated heterogeneity of treatment effect' or which estimates variability in drug response by comparing distributions between study arms.

TAAR1 agonist ulotaront delays gastric emptying of solids in patients with schizophrenia and concurrent metabolic syndrome with prediabetes.

Background: Metabolic syndrome (MetS), which can be induced or exacerbated by the current class of antipsychotic drugs, is highly prevalent in patients with schizophrenia and presents significant challenges to lifetime disease management. Supported by initial clinical results, trace amine-associated receptor 1 (TAAR1) agonists have emerged as potential novel treatments for schizophrenia. Notably, non-clinical studies have also shown weight-lowering and glucoregulatory effects of TAAR1 agonists, including the investigational agent ulotaront.

TAAR1 agonists improve glycemic control, reduce body weight and modulate neurocircuits governing energy balance and feeding.

Objective: Metabolic Syndrome, which can be induced or exacerbated by current antipsychotic drugs (APDs), is highly prevalent in schizophrenia patients. Recent preclinical and clinical evidence suggest that agonists at trace amine-associated receptor 1 (TAAR1) have potential as a new treatment option for schizophrenia. Intriguingly, preclinical tudies have also identified TAAR1 as a novel regulator of metabolic control.

TAAR1 agonist ulotaront modulates striatal and hippocampal glutamate function in a state-dependent manner.

Aberrant dopaminergic and glutamatergic function, particularly within the striatum and hippocampus, has repeatedly been associated with the pathophysiology of schizophrenia. Supported by preclinical and recent clinical data, trace amine-associated receptor 1 (TAAR1) agonism has emerged as a potential new treatment approach for schizophrenia. While current evidence implicates TAAR1-mediated regulation of dopaminergic tone as the primary circuit mechanism, little is known about the effects of TAAR1 agonists on the glutamatergic system and excitation-inhibition balance.

A Novel Method for Deriving Adverse Event Prevalence in Randomized Controlled Trials: Potential for Improved Understanding of Benefit-Risk Ratio and Application to Drug Labels.

Introduction: Adverse event (AE) data in randomized controlled trials (RCTs) allow quantification of a drug's safety risk relative to placebo and comparison across medications. The standard US label for Food and Drug Administration-approved drugs typically lists AEs by MedDRA Preferred Term that occur at ≥ 2% in drug and with greater incidence than in placebo. We suggest that the drug label can be more informative for both patients and physicians if it includes, in addition to AE incidence (percent of subjects who reported the AE out of the total subjects in treatment), the absolute prevalence (percent of subject-days spent with an AE out of the total subject-days spent in treatment) and expected duration (days required for AE incidence to be reduced by half).

Effects of ulotaront on brain circuits of reward, working memory, and emotion processing in healthy volunteers with high or low schizotypy.

Ulotaront, a trace amine-associated receptor 1 (TAAR1) and serotonin 5-HT1A receptor agonist without antagonist activity at dopamine D or the serotonin 5-HT2A receptors, has demonstrated efficacy in the treatment of schizophrenia. Here we report the phase 1 translational studies that profiled the effect of ulotaront on brain responses to reward, working memory, and resting state connectivity (RSC) in individuals with low or high schizotypy (LS or HS). Participants were randomized to placebo (n = 32), ulotaront (50 mg; n = 30), or the D receptor antagonist amisulpride (400 mg; n = 34) 2 h prior to functional magnetic resonance imaging (fMRI) of blood oxygen level-dependent (BOLD) responses to task performance.

Ulotaront, a Trace Amine-Associated Receptor 1/Serotonin 5-HT Agonist, in Patients With Parkinson Disease Psychosis: A Pilot Study.

Background And Objectives: Ulotaront (SEP-363856) is a trace amine-associated receptor 1 agonist with 5-HT receptor agonist activity currently in phase 3 clinical development for the treatment of schizophrenia. In this exploratory, flexibly dosed study, ulotaront was evaluated for the treatment of Parkinson disease psychosis (PDP).

Methods: Patients with PDP requiring antipsychotic therapy were randomized, double-blind to ulotaront (25, 50, or 75 mg/d) or placebo.

A multicenter, double-blind, placebo-controlled, randomized, Phase 1b crossover trial comparing two doses of ulotaront with placebo in the treatment of narcolepsy-cataplexy.

Background: Ulotaront (SEP-363856) is a novel agonist at trace amine-associated receptor 1 and serotonin 5-HT receptors in clinical development for the treatment of schizophrenia. Previous studies demonstrated ulotaront suppresses rapid eye movement (REM) sleep in both rodents and healthy volunteers. We assessed acute and sustained treatments of ulotaront on REM sleep and symptoms of cataplexy and alertness in subjects with narcolepsy-cataplexy.

Ulotaront: review of preliminary evidence for the efficacy and safety of a TAAR1 agonist in schizophrenia.

Ulotaront is a trace amine-associated receptor 1 (TAAR1) agonist in Phase 3 clinical development for the treatment of schizophrenia. Ulotaront was discovered through a unique, target-agnostic approach optimized to identify drug candidates lacking D2 and 5-HT2A receptor antagonism, while demonstrating an antipsychotic-like phenotypic profile in vivo. The mechanism of action (MOA) of ulotaront is thought to be mediated by agonism at TAAR1 and serotonin 5-HT1A receptors.

Comparative Bioequivalence of Tablet and Capsule Formulations of Ulotaront and the Effect of Food on the Pharmacokinetics of the Tablet Form in Humans.

Introduction: Ulotaront (SEP-363856), a dual trace animeassociated receptor 1 (TAAR1) and 5-HT receptor agonist, is in phase 3 clinical development for the treatment of schizophrenia. This study evaluated the comparative bioequivalence (BE) between tablet and capsule formulations of ulotaront and the food effect (FE) on pharmacokinetics (PK) of tablet form in healthy adult human subjects.

Methods: The BE study applied an open-label two-period crossover design in 24 healthy volunteers.

Treatment with the novel TAAR1 agonist ulotaront is associated with reductions in quantitative polysomnographic REM sleep without atonia in healthy human subjects: Results of a post-hoc analysis.

Background: Isolated REM sleep behavior disorder (RBD) is a potentially injurious parasomnia lacking an established treatment. Ulotaront is a trace amine-associated receptor 1 (TAAR1) agonist with 5-HT receptor agonist activity that has demonstrated efficacy in patients with schizophrenia. In a single dose challenge study in humans, ulotaront 50 mg demonstrated significant REM suppressant effects.

Challenges in the clinical development of non-D2 compounds for schizophrenia.

Schizophrenia is a chronic, heterogeneous, severe psychiatric disorder characterized by a spectrum of symptomology and is associated with substantial morbidity and mortality. For the last 70 years, available treatments have shared blockade of dopamine D2 receptors as their primary mechanism of action (MOA), the efficacy of which has been limited by incomplete resolution of all symptoms as well as treatment non-response in a select subset of patients. In addition, antipsychotics are associated with class-related side effects attributed to this primary MOA, including extrapyramidal symptoms (EPS).

Depicting Risperidone Safety Profiles in Clinical Trials Across Different Diagnoses Using a Dopamine D-Based Pharmacological Class Effect Query Defined by FAERS.

Background And Objective: Current methods are not designed to relate the incidence of individual adverse events reported in clinical trials to the plurality of adverse events accumulated in spontaneous reporting databases during real-world use. We have previously reported on a pharmacological class-effect query of clinical trial data defined by a disproportionality analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) post-marketing data. The aim of the current analysis was to apply a dopamine D-based pharmacological class-effect query to clinical trial safety data of an atypical antipsychotic tested across different patient populations.

In Vitro ADME and Preclinical Pharmacokinetics of Ulotaront, a TAAR1/5-HT Receptor Agonist for the Treatment of Schizophrenia.

Purpose: Ulotaront (SEP-363856) is a TAAR1 agonist with 5-HT agonist activity currently in clinical development for the treatment of schizophrenia. The objectives of the current study were to characterize the in vitro ADME properties, preclinical PK, and to evaluate the DDI potential of ulotaront and its major metabolite SEP-383103.

Methods: Solubility, permeability, plasma protein binding, CYP inhibition and induction, transporter inhibition and uptake studies were conducted in vitro.

Assessment of Negative Symptoms in Clinical Trials of Acute Schizophrenia: Test of a Novel Enrichment Strategy.

Drug trials for negative symptoms in schizophrenia select patients based on the severity and stability of negative symptoms, using criteria that are not suitable for trials of acute exacerbation of schizophrenia. Here we present a method to prognostically enrich subjects having a predefined factor structure in PANSS and apply it to the measurement of negative symptoms specifically in trials of acute schizophrenia. A vector of 1335 elements based on between- and within-item variances, covariances, and differences of PANSS items was created to calculate an index of heterogeneity and to enrich for a predetermined symptom construct in PANSS.

Ulotaront: A TAAR1 Agonist for the Treatment of Schizophrenia.

Ulotaront (SEP-363856) is a trace-amine associated receptor 1 (TAAR1) agonist with 5-HT1A receptor agonist activity in Phase 3 clinical development, with FDA Breakthrough Therapy Designation, for the treatment of schizophrenia. TAAR1 is a G-protein-coupled receptor (GPCR) that is expressed in cortical, limbic, and midbrain monoaminergic regions. It is activated by endogenous trace amines, and is believed to play an important role in modulating dopaminergic, serotonergic, and glutamatergic circuitry.

Ulotaront, a novel TAAR1 agonist with 5-HT1A agonist activity, lacks abuse liability and attenuates cocaine cue-induced relapse in rats.

Background: Ulotaront (SEP-363856) is a trace amine-associated receptor 1 (TAAR1) agonist with 5-hydroxytryptamine type 1A (5-HT1A) agonist activity that is currently in Phase 3 clinical development for the treatment of schizophrenia. Unlike available antipsychotics, the efficacy of ulotaront is not mediated by blockade of dopamine D2 or serotonin 5-HT2A receptors. In a short-term randomized clinical trial, ulotaront has demonstrated significant efficacy in the treatment of adults with an acute exacerbation of schizophrenia.

Safety and effectiveness of ulotaront (SEP-363856) in schizophrenia: results of a 6-month, open-label extension study.

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.

Depicting Safety Profile of TAAR1 Agonist Ulotaront Relative to Reactions Anticipated for a Dopamine D2-Based Pharmacological Class in FAERS.

Background And Objectives: In clinical trials, the safety of drugs is summarized by the incidence of adverse events, while post-marketing reporting systems use disproportionate reporting of adverse drug reactions. Here, we propose a method to evaluate the novelty of a safety profile of a drug in a new class (in clinical trials), against that of those already on the market (using pharmacovigilance data).

Methods: Through Bayesian disproportionality analyses of the US Food and Drug Administration Adverse Event Reporting System (FAERS) data, we identified and ranked Preferred Terms for a pool of 30 antipsychotics.