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. By mathematically solving for a drug distribution step into an effect compartment, and for binding to target receptors, the discovery of a novel PK/PD model (termed here as Distribution Model) accounted for hysteresis between plasma and brain, a lack of receptor saturation, and an absence of accumulation of drug occupancy with daily doses. The PK/PD disconnect solved by the Distribution Model provided model-informed drug development to continue in Phase III using the non-bioequivalent CR formulation with diminished QT prolongation as dose-equivalent to the immediate release (IR) formulation utilized in Phase II.

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 (H0) that a drug has equal benefit for all participants (HTE=0). We developed measure termed 'estimated heterogeneity of treatment effect' or eHTE, which estimates variability in drug response by comparing distributions between study arms. This approach was tested across numerous large placebo-controlled clinical trials. In contrast with variance-based methods which have not identified heterogeneity in psychiatric trials, reproducible instances of treatment heterogeneity were found. For example, heterogeneous response was found in a trial of venlafaxine for depression (peHTE=0.034), and two trials of dasotraline for binge eating disorder (Phase 2, peHTE=0.002; Phase 3, 4mg peHTE=0.011; Phase 3, 6mg peHTE=0.003). Significant response heterogeneity was detected in other datasets as well, often despite no difference in variance between placebo and drug arms. The implications of eHTE as a clinical trial outcomes independent from central tendency of the group is considered and the important of the eHTE method and results for drug developers, providers, and patients is discussed.

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. However, the translatability of these findings to humans has not been adequately assessed. Given that delayed gastric emptying (GE) was identified as a potential mechanism contributing to the metabolic benefits of TAAR1 agonists in rodents, the aim of this study was to evaluate the effect of ulotaront on GE in patients with schizophrenia and concurrent MetS with prediabetes. METHODS: Patients with schizophrenia were randomized to receive a single oral dose of ulotaront (150 mg) and their previous antipsychotic (PA) in an open-label, crossover, two-sequence design (NCT05402111). Eligible participants fulfilled at least three of five MetS criteria and had prediabetes defined by elevated glycated haemoglobin (5.7-6.4%) and/or fasting homeostatic model assessment of insulin resistance (i.e. ≥2.22). Following an overnight fast and 4 h post-dose, participants ingested a 99mTc-sulphur colloid radiolabelled egg meal (320 kcal, 30% fat). GE was measured by scintigraphy over 4 h. Endpoints included GE of solids half-time (T1/2) and percentage gastric retention at 1, 2 and 4 h. RESULTS: Thirty-one adults were randomized and 27 completed the study. Ulotaront significantly delayed GE of solids [median GE T1/2 ulotaront at 139 min (119, 182) vs. the participant's PA of 124 min (109, 132), p = .006]. A significant increase in gastric retention was seen in the ulotaront versus the PA group at 1 h (80% vs. 75%, p = .015), 2 h (61% vs. 50%, p = .023) and 4 h (17% vs. 7%, p = .002) post-meal. CONCLUSION: Ulotaront delayed the GE of solids in patients with schizophrenia and concurrent MetS with prediabetes. Additional studies are needed to assess whether treatment with TAAR1 agonists is associated with weight loss and glucoregulatory improvement.

Evaluation of OCT2-mediated drug-drug interactions between ulotaront and metformin in subjects with schizophrenia.

Ulotaront (SEP-363856) is a TAAR1 agonist, with 5-HT1A agonist activity, currently in clinical development for the treatment of schizophrenia. In vitro studies indicate ulotaront is an OCT2-specific inhibitor with IC50 of 1.27 µM. The primary objective of this study is to determine if a single dose of ulotaront affects the PK of metformin, an index substrate of OCT2, in subjects with schizophrenia. In a randomized, single-blind, 2-period crossover study, 25 adults with schizophrenia received a single dose of metformin-HCl 850 mg (approximately 663 mg metformin) with and without coadministration of 100 mg ulotaront. The plasma samples were analyzed by fully validated LC-MS/MS methods. The primary PK endpoints for metformin were AUCinf, AUClast, Cmax, and tmax. The highest-anticipated clinical dose of ulotaront (100 mg) had no statistically significant effect on the PK of a single dose of metformin based on Cmax and AUCinf. Geometric least squares mean ratios were 89.98% and 110.63%, respectively, with the 90% confidential interval (CI) for each parameter contained within 80%-125%. Median tmax was comparable across the treatments. Ulotaront does not act as a perpetrator of OCT2-mediated DDI against metformin. Co-administration of ulotaront is not expected to require dose adjustment of metformin or other drugs cleared by OCT2.

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. Here we evaluated the effects of three TAAR1 agonists, including the clinical development candidate ulotaront, on body weight, metabolic parameters and modulation of neurocircuits implicated in homeostatic and hedonic feeding. METHODS: Effects of TAAR1 agonists (ulotaront, RO5166017 and/or RO5263397) on body weight, food intake and/or metabolic parameters were investigated in rats fed a high-fat diet (HFD) and in a mouse model of diet-induced obesity (DIO). Body weight effects were also determined in a rat and mouse model of olanzapine-, and corticosterone-induced body weight gain, respectively. Glucose tolerance was assessed in lean and diabetic db/db mice and fasting plasma glucose and insulin examined in DIO mice. Effects on gastric emptying were evaluated in lean mice and rats. Drug-induced neurocircuit modulation was evaluated in mice using whole-brain imaging of c-fos protein expression. RESULTS: TAAR1 agonists improved oral glucose tolerance by inhibiting gastric emptying. Sub-chronic administration of ulotaront in rats fed a HFD produced a dose-dependent reduction in body weight, food intake and liver triglycerides compared to vehicle controls. In addition, a more rapid reversal of olanzapine-induced weight gain and food intake was observed in HFD rats switched to ulotaront or RO5263397 treatment compared to those switched to vehicle. Chronic ulotaront administration also reduced body weight and improved glycemic control in DIO mice, and normalized corticosterone-induced body weight gain in mice. TAAR1 activation increased neuronal activity in discrete homeostatic and hedonic feeding centers located in the dorsal vagal complex and hypothalamus with concurrent activation of several limbic structures. CONCLUSION: The current data demonstrate that TAAR1 agonists, as a class, not only lack APD-induced metabolic liabilities but can reduce body weight and improve glycemic control in rodent models. The underlying mechanisms likely include TAAR1-mediated peripheral effects on glucose homeostasis and gastric emptying as well as central regulation of energy balance and food intake.

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). We also propose a new method to analyze AEs in RCTs using drug-placebo difference in AE prevalence to improve safety signal detection. METHODS: AE data from six RCTs in schizophrenia were analyzed (five RCTs of the dopamine D2 receptor-based antipsychotic lurasidone and one RCT of the novel trace amine-associated receptor 1 [TAAR1] agonist ulotaront). We determined incidence, absolute prevalence, and expected duration of AEs for lurasidone and ulotaront vs respective placebo. We also calculated areas under the curve of drug-placebo difference in AE prevalence and mean percent contribution of each AE to this difference. RESULTS: A number of AEs with the same incidence had different absolute prevalence and expected duration. When accounting for these two parameters, AEs that did not appear in the 2% incidence tables of the drug label turned out to contribute substantially to drug tolerability. The percent contribution of a drug-related AE to the overall side effect burden increased the drug-placebo difference in AE prevalence, whereas the percent contribution of a placebo-related AE decreased such difference, revealing a continuum of risk between drug and placebo. AE prevalence curves for drug were generally greater than those for placebo. Ulotaront exhibited a small drug-placebo difference in AE prevalence curves due to a relatively low incidence and short duration of AEs in the ulotaront treatment arm as well as the emergence of disease-related AEs in the placebo arm. CONCLUSION: Reporting AE absolute prevalence and expected duration for each RCT and incorporating them in the drug label is possible, is clinically relevant, and allows standardized comparison of medications. Our new metric, the drug-placebo difference in AE prevalence, facilitates signal detection in RCTs. We piloted this metric in RCTs of several neuropsychiatric indications and drugs, offering a new way to compare AE burden and tolerability among treatments using existing clinical trial information.

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. Here we assessed the impact of ulotaront (SEP-363856), a TAAR1 agonist in Phase III clinical development for schizophrenia, on glutamate function in the mouse striatum and hippocampus. Ulotaront reduced spontaneous glutamatergic synaptic transmission and neuronal firing in striatal and hippocampal brain slices, respectively. Interestingly, ulotaront potentiated electrically-evoked excitatory synaptic transmission in both brain regions, suggesting the ability to modulate glutamatergic signaling in a state-dependent manner. Similar striatal effects were also observed with the TAAR1 agonist, RO5166017. Furthermore, we show that ulotaront regulates excitation-inhibition balance in the striatum by specifically modulating glutamatergic, but not GABAergic, spontaneous synaptic events. These findings expand the mechanistic circuit hypothesis of ulotaront and TAAR1 agonists, which may be uniquely positioned to normalize both the excessive dopaminergic tone and regulate abnormal glutamatergic function associated with schizophrenia.

A Phase I, Open-Label, Fixed Sequence Study to Investigate the Effect of Cytochrome P450 2D6 Inhibition on the Pharmacokinetics of Ulotaront in Healthy Subjects.

BACKGROUND: Ulotaront is a novel psychotropic agent with agonist activity at trace amine-associated receptor 1 (TAAR1) and 5-hydroxytryptamine type 1A (5-HT1A) receptors in phase III clinical development for the treatment of schizophrenia. OBJECTIVE: This study aimed to investigate the effect of paroxetine, a strong cytochrome P450 (CYP) 2D6 inhibitor, on ulotaront pharmacokinetics (PK) in healthy volunteers. METHODS: Subjects received a single oral dose of 25 mg ulotaront on Day 1 and an oral dose of 20 mg paroxetine once daily from Days 5 to 10 to achieve steady-state plasma paroxetine levels. On Day 11, subjects received another single oral dose of 25 mg ulotaront, with continued daily oral dosing of 20 mg paroxetine from Days 11 to 14. All 24 subjects were CYP2D6 normal metabolizers. RESULTS: Coadministration of paroxetine increased ulotaront maximum observed plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to infinity (AUC∞) by 31% and 72%, respectively, and decreased ulotaront apparent clearance (CL/F) by approximately 42%. While coadministration of paroxetine increased AUC∞ of active but minor metabolite SEP-363854 by 32%, it had no effect on SEP-363854 Cmax, or on SEP-363854 to the ulotaront AUC from time zero to the last quantifiable concentration (AUClast) ratio. Based on the acceptable adverse event profile of ulotaront across previous phase II studies, the increase in ulotaront exposure is unlikely to be clinically meaningful. CONCLUSIONS: Weak drug-drug interactions were observed between ulotaront and the strong CYP2D6 inhibitor paroxetine; however, dose adjustment as a precondition when ulotaront is coadministered with strong CYP2D6 inhibitors or administered to CYP2D6 poor metabolizers should not be necessary.

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 D2 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 D2 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 increased subjective drowsiness, but reaction times were impaired by less than 10% and did not correlate with BOLD responses. In the Monetary Incentive Delay task (reward processing), ulotaront significantly modulated striatal responses to incentive cues, induced medial orbitofrontal responses, and prevented insula activation seen in HS subjects. In the N-Back working memory task, ulotaront modulated BOLD signals in brain regions associated with cognitive impairment in schizophrenia. Ulotaront did not show antidepressant-like biases in an emotion processing task. HS had significantly reduced connectivity in default, salience, and executive networks compared to LS participants and both drugs reduced this difference. Although performance impairment may have weakened or contributed to the fMRI findings, the profile of ulotaront on BOLD activations elicited by reward, memory, and resting state is compatible with an indirect modulation of dopaminergic function as indicated by preclinical studies. This phase 1 study supported the subsequent clinical proof of concept trial in people with schizophrenia.Clinical trial registration: Registry# and URL: ClinicalTrials.gov NCT01972711, https://clinicaltrials.gov/ct2/show/NCT01972711.

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-HT1A 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. METHODS: In a multicenter, double-blind, placebo-controlled, randomized, 3-way crossover study, ulotaront was evaluated in 16 adults with narcolepsy-cataplexy. Two oral doses of ulotaront (25 mg and 50 mg) were administered daily for 2 weeks and compared with matching placebo (6-treatment sequence, 3-period, 3-treatment). RESULTS: Acute treatment with both 25 mg and 50 mg of ulotaront reduced minutes spent in nighttime REM compared to placebo. A sustained 2-week administration of both doses of ulotaront reduced the mean number of short-onset REM periods (SOREMPs) during daytime multiple sleep latency test (MSLT) compared to placebo. Although cataplexy events decreased from the overall mean baseline during the 2-week treatment period, neither dose of ulotaront statistically separated from placebo (p = 0.76, 25 mg; p = 0.82, 50 mg), and no significant improvement in patient and clinician measures of sleepiness from baseline to end of the 2-week treatment period occurred in any treatment group. CONCLUSIONS: Acute and sustained treatment with ulotaront reduced nighttime REM duration and daytime SOREMPs, respectively. The effect of ulotaront on suppression of REM did not demonstrate a statistical or clinically meaningful effect in narcolepsy-cataplexy. REGISTRATION: ClinicalTrials.gov identifier: NCT05015673.

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. Ulotaront has completed two Phase 2 trials (4-week acute study and 26-week open-label extension) which led to Breakthrough Therapy Designation from the US Food and Drug Administration for the treatment of schizophrenia. In the double-blind, placebo-controlled, acute study, ulotaront was associated with significant (p < 0.001) improvement in Positive and Negative Syndrome Scale (PANSS) total score (effect size [ES]: 0.45), with improvements vs. placebo also observed across secondary endpoints. Post-hoc analyses of the acute trial revealed additional evidence to support the effect of ulotaront on negative symptoms. In the 4-week study, ulotaront was well-tolerated, with an incidence of adverse events (AEs) numerically lower compared to placebo (45.8% vs. 50.4%; with a number needed to harm [NNH] for individual ulotaront AEs all > 40). The open-label extension demonstrated further improvement across schizophrenia symptoms and confirmed the tolerability of ulotaront, with a 6-month completion rate of 67%. Based on current data, ulotaront shows potential to be a first-in-class TAAR1 agonist for the treatment of schizophrenia with a safety and efficacy profile distinct from current antipsychotics.

A randomized, single-dose, crossover study of the effects of ulotaront on electrocardiogram intervals in subjects with schizophrenia.

This study (NCT04369391) evaluated the effects of ulotaront (SEP-363856), a novel trace amine-associated receptor 1 (TAAR1) agonist in development for schizophrenia, on electrocardiogram parameters. Study design was a randomized, single-dose, three-period crossover (ulotaront 150 mg, placebo, moxifloxacin 400 mg). Sixty subjects with schizophrenia completed all periods. Ulotaront had no clinically relevant effect on heart rate, PR interval, or QRS duration. In by-time-point analysis (secondary analysis), the upper bound of the two-sided 90% confidence interval for ΔΔQTcF (QT interval corrected for heart rate using Fridericia's formula) was below 10 ms at all time points for ulotaront. In concentration-QTc analysis (primary analysis), a linear mixed-effects model with ulotaront and its major metabolite SEP-383103 was selected as the primary model based on prespecified criteria. Effect on ∆∆QTcF exceeding 10 ms can be excluded within observed ranges of ulotaront and SEP-383103 plasma concentrations up to ~574 and ~272 ng/mL, respectively. The upper bound of 90% CI for ΔΔQTcF can be predicted to be below 10 ms at the highest anticipated clinical exposure, currently defined as steady-state mean Cmax at ulotaront 100 mg/day in CYP2D6 poor metabolizers, ~416 and ~211 ng/mL for ulotaront and SEP-383103, respectively. Assay sensitivity was demonstrated by the QTc effect caused by moxifloxacin. In conclusion, ulotaront is unlikely to cause clinically relevant QTc prolongation in patients with schizophrenia at the anticipated maximum therapeutic dose.

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-HT1A 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. We now report post-hoc exploratory analyses designed to evaluate the effect of ulotaront on quantitative REM sleep without atonia (RSWA). METHODS: Young healthy adult men (ages 19-35) were randomized to double-blind, cross-over treatment (after 7-day wash-out) with single doses of ulotaront (50 mg or 10 mg) versus placebo followed by polysomnography (PSG) on each of the nights following treatment. Quantitative RSWA was analyzed in a blinded fashion using established visual and automated methods. RESULTS: Subjects received 50 mg (n = 11) or 10 mg (n = 9) of ulotaront. Treatment with ulotaront 50 mg was associated with lower RSWA (p < 0.05), with greatest RSWA reduction (vs. placebo) observed in subjects with RSWA levels above the mean on the baseline night. RSWA levels were similar between treatment with ulotaront 10 mg and placebo. CONCLUSION: Treatment with ulotaront 50 mg (but not 10 mg) was associated with reductions in RSWA levels in healthy subjects, especially in subjects with higher baseline RSWA levels, providing proof-of-concept for ulotaront efficacy in reducing RSWA levels. However, whether ulotaront might have efficacy as a treatment for human RBD awaits double-blind trials with ulotaront in clinical RBD populations.

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). The need for non-D2 treatment options for patients which offer a novel risk/benefit profile is therefore apparent. There has been substantial investment in the research and development of non-D2 drug candidates. However, none of these programs have received successful regulatory approval by the FDA (as of Oct 2022). In this article, the scale of industry-sponsored clinical trials for D2-based investigational pharmacological treatments in schizophrenia was quantified and compared with investigational compounds with non-D2 MOAs. In a dataset of 545 clinical trials identified in ClinicalTrials.gov from January 2002 to July 2022, total enrollments in trials of non-D2-based compounds for the treatment of schizophrenia summed to approximately 34,000 patients, compared with 27,144 patients for D2-based compounds. These data indicate that there remains substantial and ongoing investment in the development of novel non-D2 options for schizophrenia, with a success rate measured by regulatory approval that is well-below recent benchmarks for the broader category of CNS drugs. Improved trial design, conduct, endpoints, and analyses/methods may influence signal detection and reliability to support development and registration of non-D2 compounds.

Depicting Risperidone Safety Profiles in Clinical Trials Across Different Diagnoses Using a Dopamine D2-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 D2-based pharmacological class-effect query to clinical trial safety data of an atypical antipsychotic tested across different patient populations. METHODS: Patient-level adverse event data (n = 4400) from controlled clinical trials of the antipsychotic risperidone in schizophrenia, bipolar disorder, Alzheimer's disease psychosis, and autism were obtained through the Yale University Open Data Access (YODA) project. An Empirical Bayes Geometric Mean analysis was performed, and a three-fold threshold incidence level was applied to determine if a preferred term met criteria for being an antipsychotic class-related adverse event. RESULTS: In pooled data from seven trials of adult schizophrenia, class-specific adverse events were identified in 49% of patients treated with risperidone; in 49% of risperidone-treated patients in two trials in adolescent schizophrenia; in 65% of risperidone-treated patients in four trials in adult bipolar disorder; in 50% of risperidone-treated patients in two trials in adolescent schizophrenia; in 36% of risperidone-treated patients in one trial in Alzheimer's disease; and in 94% of risperidone-treated patients in one trial in autism. CONCLUSIONS: The cumulative curves of class-specific adverse events in risperidone clinical trials of schizophrenia were similar to those first reported for other atypical antipsychotic drugs. However, the class-specific adverse event curves were notably lower for Alzheimer's disease and higher for autism, suggesting that the diagnostic indication may have an important effect on the cumulative class-specific side-effect burden.

ECG Evaluation as Part of the Clinical Pharmacology Strategy in the Development of New Drugs: A Review of Current Practices and Opportunities Based on Five Case Studies.

The International Conference on Harmonization (ICH) E14 document was revised in 2015 to allow concentration-corrected QT interval (C-QTc) analysis to be applied to data from early clinical pharmacology studies to exclude a small drug-induced effect on QTc. Provided sufficiently high concentrations of the drug are obtained in the first-in-human (FIH) study, this approach can be used to obviate the need for a designated thorough QT (TQT) study. The E14 revision has resulted in a steady reduction in the number of TQT studies and an increased use of FIH studies to evaluate electrocardiogram (ECG) effects of drugs in development. In this review, five examples from different sponsors are shared in which C-QTc analysis was performed on data from FIH studies. Case 1 illustrates a clearly negative C-QTc evaluation, despite observations of QTc prolongation at high concentrations in nonclinical studies. In case 2 C-QTc analysis of FIH data was performed prior to full pharmacokinetic characterization in patients, and the role of nonclinical assays in an integrated risk assessment is discussed. Case 3 illustrates a positive clinical C-QTc relationship, despite negative nonclinical assays. Case 4 demonstrates a strategy for characterizing the C-QTc relationship for a nonracemic therapy and formulation optimization, and case 5 highlights an approach to perform a preliminary C-QTc analysis early in development and postpone the definitive analysis until proof of efficacy is demonstrated. The strategy of collecting and storing ECG data from FIH studies to enable an informed decision on whether and when to apply C-QTc analysis to obviate the need for a TQT study is described.

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. TAAR1 agonism data are reported herein for ulotaront and its analogues in comparison to endogenous TAAR1 agonists. In addition, a human TAAR1 homology model was built around ulotaront to identify key interactions and attempt to better understand the scaffold-specific TAAR1 agonism structure-activity relationships.

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. Given ulotaront's novel mechanism of action a series of preclinical studies were performed to evaluate its potential abuse liability. METHODS: A battery of studies were conducted in male and female rats to evaluate whether ulotaront produces behavioral changes suggestive of human abuse potential. In addition, studies were undertaken to probe the potential for ulotaront to block reinstatement of cocaine-seeking behavior in male rats. RESULTS: Ulotaront was not self-administered by rats trained to self-administer amphetamine, cocaine, or heroin. The subjective qualities of ulotaront were distinct from those produced by amphetamine in a drug discrimination procedure. Ulotaront, and buspirone, a non-scheduled anxiolytic with 5-HT1A agonism, partially generalized to the interoceptive cue elicited by 3, 4-methylenedioxymethamphetamine (MDMA). In addition, ulotaront demonstrated a trend to reduce cocaine-primed induced reinstatement, and dose-dependently reduced cue-reinstated responding. CONCLUSION: The current results suggest that the TAAR1/5-HT1A agonist ulotaront is not likely to pose a risk for recreational abuse in humans and may have potential therapeutic utility as a treatment of substance use disorders.

A Randomized, Double-blind, Placebo-controlled Proof-of-Concept Trial to Evaluate the Efficacy and Safety of Non-racemic Amisulpride (SEP-4199) for the Treatment of Bipolar I Depression.

BACKGROUND: Non-racemic amisulpride (SEP-4199) is an 85:15 ratio of aramisulpride:esamisulpride with a 5-HT7 and D2 receptor binding profile optimized for the treatment of bipolar depression. The aim of this study was to evaluate the efficacy and safety of SEP-4199 for the treatment of bipolar depression. METHODS: Patients meeting DSM-5 criteria for bipolar I depression were randomized to 6 weeks of double-blind, placebo-controlled treatment with SEP-4199 200 mg/d or 400 mg/d. The primary endpoint was change in the Montgomery-Asberg Depression Rating Scale (MADRS) at Week 6. The primary efficacy analysis population consisted of patients in Europe and US (n = 289); the secondary efficacy analysis population (ITT; n = 337) included patients in Japan. RESULTS: Endpoint improvement in MADRS total score was observed on both the primary analysis for SEP-4199 200 mg/d (P = 0.054; effect size [ES], 0.31) and 400 mg/d (P = 0.054; ES, 0.29), and on the secondary (full ITT) analysis for SEP-4199 200 mg/d (P = 0.016; ES, 0.34) and 400 mg/d (P = 0.024; ES, 0.31). Study completion rates were 81% on SEP-4199 200 mg/d, 88% on 400 mg/d, and 86% on placebo. SEP-4199 had low rates of individual adverse events (<8%) and minimal effects on weight and lipids; median increases in prolactin were +83.6 µg/L on 200 mg/d, +95.2 µg/L on 400 mg/d compared with 0.0 µg/L on placebo. LIMITATIONS: The study excluded patients with bipolar II depression and serious psychiatric or medical comorbidity. CONCLUSION: Study results provide preliminary proof of concept, needing confirmation in subsequent randomized trials, for the efficacy of non-racemic amisulpride in bipolar depression.

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 (81.3%) 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.