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.

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.

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 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.

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.

Ulotaront, a Trace Amine-Associated Receptor 1/Serotonin 5-HT1A 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_1A 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. Mixed Model for Repeated Measures was used to assess change from baseline in the Scale for the Assessment of Positive Symptoms for Parkinson Disease (SAPS-PD) at 6 weeks (primary end point).

Results

The efficacy analysis sample comprised 38 patients (ulotaront, n = 24; placebo, n = 14). SAPS-PD total scores were numerically reduced in ulotaront-treated vs placebo-treated patients from week 1 to week 6: Least squares mean (95% confidence interval) difference in change from baseline at week 6 was -1.1 (-6.5, 4.3, p = 0.681). PDP symptom complete remission (≥100% improvement [reduction] from baseline in SAPS-PD total score) was observed in 25% of ulotaront-treated vs 0% of placebo-treated patients. SAPS-PD and Neuropsychiatric Inventory hallucinations subscales were numerically reduced vs placebo, and SAPS-PD total scores were reduced in patients with greater cognitive impairment (baseline Mini-Mental State Examination [MMSE] scores ≤24). Ulotaront improved Scales for Outcomes in Parkinson Disease Sleep Scale - Daytime Sleepiness scores (p = 0.022). There was no worsening of Unified Parkinson Disease Rating Scale Part III motor score, MMSE, or vital signs. Adverse events (≥10%) with ulotaront vs placebo included hallucinations (24% vs 14%), confusional state (20% vs 14%), dizziness (16% vs 7%), nausea (12% vs 7%), and falls (12% vs 21%).

Discussion

In this exploratory pilot study, ulotaront may decrease PDP symptoms without worsening motor function, particularly in patients with cognitive impairment.

Trial Registration Information

ClinicalTrials.gov identifier: NCT02969369; submitted: November 17, 2016; study start date: December 31, 2016.

Classification of Evidence

This Class II study was an exploratory pilot study that was underpowered to detect a statistically significant difference between ulotaront and placebo in the treatment of patients with Parkinson disease psychosis without worsening motor function.

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_1A 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.

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_1A 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. Subjects were randomly assigned (1:1) to dosing sequence AB or BA (A, 25 mg ulotaront tablet; B, 25 mg ulotaront capsule). The FE study also used an open-label randomized two-period crossover design in 20 healthy volunteers. Subjects were fasted overnight then randomly assigned (1:1) to dosing sequence AB or BA (A, fasted condition; B, fed condition). Dosing periods were separated by 1 week for both studies. Serial plasma samples from each period were collected and analyzed by LC-MS/MS. PK parameters were calculated using Phoenix WinNonlin_® software.

RESULTS

For the BE study, geometric mean ulotaront C_max values were 93.28 and 86.98 ng/mL for tablet and capsule, respectively. C_max ratio was 107.25% (90% CI 101.84-112.94%). Geometric mean ulotaront area under the plasma concentration-time curve from time 0 to infinity (AUC_0-∞) values were 868.8 and 829.3 ng·h/mL for tablet and capsule, respectively. AUC_0-∞ ratio was 104.76% (90% CI 100.68109.01%). For the FE study, geometric mean ulotaront C_max was 157.89 and 157.95 ng/mL under fed and fasted conditions, respectively. Geometric mean ratio of C_max was 99.96% (90% CI 94.48-105.77%). Geometric mean ulotaront AUC_0-∞ was 1584.2 ng·h/mL fed and 1589.2 ng·h/mL fasted. Geometric mean ratio for AUC_0-∞ was 99.69% (90% CI 95.02-104.58%). There was a delay in t_max (median difference 1.47 h) in the fed condition.

CONCLUSIONS

The results showed geometric mean ratios and 90% CIs for both C_max and AUC_0-∞ for ulotaront were well within typical bioequivalence criteria of 80-125% for both the BE and FE studies, thereby confirming the bioequivalence of the two dosage forms and no significant food effect.

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.

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_1A 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.

In Vitro ADME and Preclinical Pharmacokinetics of Ulotaront, a TAAR1/5-HT1A Receptor Agonist for the Treatment of Schizophrenia

Purpose

Ulotaront (SEP-363856) is a TAAR1 agonist with 5-HT_1A 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. Phenotyping studies were conducted using recombinant human CYPs and FMOs, human liver microsomes and human liver homogenates. Preclinical plasma and brain pharmacokinetics were determined after a single intraperitoneal, intravenous, and oral administration of ulotaront.

Results

Ulotaront is a compound of high solubility, high permeability, and low binding to plasma proteins. Ulotaront metabolism is mediated via both NADPH-dependent and NADPH-independent pathways, with CYP2D6 as the major metabolizing enzyme. Ulotaront is an inducer of CYP2B6, and an inhibitor of CYP2D6, OCT1 and OCT2, while SEP-383103 is neither a CYP inducer nor a potent inhibitor of CYPs and human transporters. Ulotaront exhibits rapid absorption, greater than 70% bioavailability, approximately 3.5 L/kg volume of distribution, 1.5-4 h half-life, 12-43 ml/min/kg clearance, and good penetration across the blood–brain barrier in preclinical species.

Conclusions

Ulotaront has been designated as a BCS1 compound by US FDA. The ability of ulotaront to penetrate the blood–brain barrier for CNS targeting has been demonstrated in mice and rats. The potential for ulotaront and SEP-383103 to act as perpetrators of CYP and transporter-mediated DDIs is predicted to be remote.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11095-022-03267-1.

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.

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.

A sensitive LC-MS/MS method for simultaneous quantification of ulotaront and its N-desmethyl metabolite in human plasma and application to a clinical study

Ulotaront (SEP-363856) is a novel non-D2-receptor-binding agent under development for the treatment of patients with schizophrenia. A highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with lower limit of quantitation of 0.0200 ng/mL (i.e. 20.0 pg/mL) was successfully developed and validated for the simultaneous quantitation of ulotaront and its N-desmethyl metabolite (M11A) in human plasma. Plasma samples were extracted by solid phase extraction with Oasis MCX 96-well plate, followed by a reversed phase LC separation coupled with MS/MS detection in positive mode (m/z 184.1 → 135.0 for ulotaront and 170.1 → 135.0 for M11A). Stable isotope-labeled compounds SEP-363856-d₃ and M11A-d₄ were used as internal standards (IS) for corresponding analytes. The validated calibration curve range was 0.0200-20.0 ng/mL for both analytes using a 0.200 mL plasma. Extraction recoveries were found to be 75.7% and 75.1% for ulotaront and IS1, and 82.7% and 83.9% for M11A and IS2, respectively. Frozen plasma samples were confirmed to be stable for up to 730 days at both -20 °C and -70 °C. The validated method has been successfully used to evaluate the pharmacokinetics (PK) of ulotaront and M11A in clinical studies. The application to the first-in-human PK study (single ascending dose) presented in this work demonstrated that ulotaront exhibited near dose proportionality for both C_max (maximum concentration) and AUC (area under the curve) over the dose range from 5 to 125 mg. M11A was found as a minor metabolite with an exposure of about 2-3% of the parent compound.

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.

Population pharmacokinetic analysis of ulotaront in subjects with schizophrenia

Ulotaront (SEP-363856) is a trace amine-associated receptor 1 agonist with 5-HT1A agonist activity in phase III development for the treatment of schizophrenia. The efficacy of ulotaront is not mediated by blockade of D2 or 5-HT2A receptors. The aim of this study was to evaluate the population pharmacokinetics (PopPKs) of ulotaront in adult subjects using pooled data from seven phase I studies, one phase II acute study, and one 6-month extension study. Single and multiple (up to 7 days) oral doses (5-150 mg/day) were studied in both healthy adult subjects (with intensive serial plasma sampling) and adult patients with schizophrenia (some with intensive and some with sparse plasma sampling). Ulotaront was well-absorbed and exhibited dose-proportionality in doses ranging from 10 to 100 mg, in mean maximum concentration, area under the concentration-time curve, and minimum concentration. Moderate interindividual variability was observed in concentration-time profiles. The estimated median time to maximal concentration was 2.8 h and the median effective half-life was 7 h, corresponding to an exposure accumulation ratio of 1.10 at steady-state with daily dosing. There was no indication of time-dependent changes in PKs after up to 12 weeks of daily dose administration. No clinically meaningful effects on ulotaront PK parameters were observed based on race, age, sex, formulation (capsule or tablet), or clinical status (healthy volunteer vs. patient with schizophrenia); body weight was the only meaningful covariate.

Discovery of Nonracemic Amisulpride to Maximize Benefit/Risk of 5-HT7 and D2 Receptor Antagonism for the Treatment of Mood Disorders

In contrast to the dose‐occupancy relationship in the treatment of schizophrenia, the minimal effective level of dopamine receptor 2 (D2R) blockade for antipsychotics in the treatment of bipolar depression is unknown. Lower doses aimed at reducing extrapyramidal side effects must be balanced against the need to retain the therapeutic benefit of D2R blockade on emergent cycling, mixed, manic, anxiety, and/or psychotic symptoms. Dose‐reductions intended to lower D2R blockade, however, could also decrease concomitant serotonin receptor antagonism and its potential benefit on depressive symptoms. Here, we uncoupled the potential antidepressant activity in amisulpride, driven by 5‐HT7 receptor (5‐HT7R) antagonism, from the D2R‐mediated antipsychotic activity by discovering that each enantiomer favors a different receptor. Aramisulpride was more potent at 5‐HT7R relative to esamisulpride (Ki 47 vs. 1,900 nM, respectively), whereas esamisulpride was more potent at D2R (4.0 vs. 140 nM). We hypothesized that a nonracemic ratio might achieve greater 5‐HT7R‐mediated antidepressant effects at a lower level of D2R blockade. The dose‐occupancy relationship of esamisulpride at D2R was determined by positron emission tomography (PET) imaging in human volunteers. Separately the dose‐relationship of aramisulpride was established in humans using suppression of rapid eye movement (REM) sleep as a marker of 5‐HT7R antagonism. These results led to the discovery of an 85:15 ratio of aramisulpride to esamisulpride (SEP‐4199) that maximizes the potential for antidepressant benefit of aramisulpride via 5‐HT7R and reduces esamisulpride to minimize D2R‐related extrapyramidal side effects while still retaining D2R‐mediated effects predicted to provide benefit in bipolar depression. The antidepressant efficacy of SEP‐4199 was recently confirmed in a proof‐of‐concept trial for the treatment of bipolar depression (NCT03543410).

Characterization of specific and distinct patient types in clinical trials of acute schizophrenia using an uncorrelated PANSS score matrix transform (UPSM)

Understanding the specificity of symptom change in schizophrenia can facilitate the evaluation antipsychotic efficacy for different symptom domains. Previous work identified a transform of PANSS using an uncorrelated PANSS score matrix (UPSM) to reduce pseudospecificity among symptom domains during clinical trials of schizophrenia. Here we used UPSM-transformed factor scores to identify 5 distinct patient types, each having elevated and specific severity among each of 5 symptom domains. Subjects from placebo-controlled clinical trials of acute schizophrenia were clustered (baseline) and classified (post-baseline) by a machine-learning algorithm. At baseline, all 5 patient types were similar in PANSS total score. Post-baseline, subjects' memberships among the 5 UPSM patient types were relatively stable over treatment duration and were relatively insensitive to overall improvements in symptoms, in contrast to other methods based on untransformed PANSS items. Using UPSM-transformed PANSS, drug treatment effect sizes versus placebo were doubly-dissociated for specificity across symptom domains and within specific patient types. This approach illustrates how broader clinical trial populations can nevertheless be utilized to characterize the specificity of new mechanisms across the dimensions of schizophrenia psychopathology.

Efficacy and Safety of Dasotraline in Adults With Binge-Eating Disorder: A Randomized, Placebo-Controlled, Flexible-Dose Clinical Trial

OBJECTIVE

Binge-eating disorder (BED) is the most prevalent eating disorder; however, few evidence-based treatments are available. The aim of this study was to evaluate the efficacy and safety of dasotraline, a novel dopamine and norepinephrine reuptake inhibitor, in adults with BED.

METHODS

Patients with a DSM-5 diagnosis of BED (intent-to-treat sample, N = 315) were randomized to 12 weeks of double-blind treatment with once-daily, flexible doses (4, 6, or 8 mg/d) of dasotraline or placebo. Primary endpoint was change in diary-based assessment of number of binge-eating days per week at week 12. Key secondary endpoints included changes from baseline in Clinical Global Impressions-Severity of Illness scale (CGI-S) and Yale-Brown Obsessive Compulsive Scale Modified for Binge-Eating (YBOCS-BE) and percentage of subjects with cessation of binge eating in the final 4 weeks.

RESULTS

Treatment with dasotraline was associated with a significantly greater reduction in binge-eating days per week at study endpoint (vs placebo; least squares mean [SE] difference score, -0.99 [0.17]; P < .0001; effect size [ES], 0.74). Significant endpoint improvement was observed for the 3 key secondary measures, CGI-S (P < .0001; ES, 0.95), YBOCS-BE (P < .0001; ES, 0.96), and 4-week cessation of binge eating (46.5% vs 20.6%; P < .0001). The most common adverse events in the dasotraline vs placebo groups were insomnia (44.6% vs 8.1%), dry mouth (27.4% vs 5.0%), decreased appetite (19.7% vs 6.9%), and anxiety (17.8% vs 2.5%). Discontinuation due to adverse events occurred in 11.3% of patients on dasotraline vs 2.5% on placebo.

CONCLUSIONS

The results of this placebo-controlled, double-blind study found dasotraline to be an efficacious, safe, and generally well-tolerated treatment for BED.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02564588.

A Non-D2-Receptor-Binding Drug for the Treatment of Schizophrenia

BACKGROUND

An oral compound, SEP-363856, that does not act on dopamine D2 receptors but has agonist activity at trace amine-associated receptor 1 (TAAR1) and 5-hydroxytryptamine type 1A (5-HT_1A) receptors, may represent a new class of psychotropic agent for the treatment of psychosis in schizophrenia.

METHODS

We performed a randomized, controlled trial to evaluate the efficacy and safety of SEP-363856 in adults with an acute exacerbation of schizophrenia. The patients were randomly assigned in a 1:1 ratio to receive once-daily treatment with SEP-363856 (50 mg or 75 mg) or placebo for 4 weeks. The primary end point was the change from baseline in the total score on the Positive and Negative Symptom Scale (PANSS; range, 30 to 210; higher scores indicate more severe psychotic symptoms) at week 4. There were eight secondary end points, including the changes from baseline in the scores on the Clinical Global Impressions Severity (CGI-S) scale and the Brief Negative Symptom Scale (BNSS).

RESULTS

A total of 120 patients were assigned to the SEP-363856 group and 125 to the placebo group. The mean total score on the PANSS at baseline was 101.4 in the SEP-363856 group and 99.7 in the placebo group, and the mean change at week 4 was -17.2 points and -9.7 points, respectively (least-squares mean difference, -7.5 points; 95% confidence interval, -11.9 to -3.0; P = 0.001). The reductions in the CGI-S and BNSS scores at week 4 were generally in the same direction as those for the primary outcome, but the results were not adjusted for multiple comparisons. Adverse events with SEP-363856 included somnolence and gastrointestinal symptoms; one sudden cardiac death occurred in the SEP-363856 group. The incidence of extrapyramidal symptoms and changes in the levels of lipids, glycated hemoglobin, and prolactin were similar in the trial groups.

CONCLUSIONS

In this 4-week trial involving patients with an acute exacerbation of schizophrenia, SEP-363856, a non-D2-receptor-binding antipsychotic drug, resulted in a greater reduction from baseline in the PANSS total score than placebo. Longer and larger trials are necessary to confirm the effects and side effects of SEP-363856, as well as its efficacy relative to existing drug treatments for patients with schizophrenia. (Funded by Sunovion Pharmaceuticals; ClinicalTrials.gov number, NCT02969382.).

Efficacy and Safety of Dasotraline in Children With ADHD: A Laboratory Classroom Study

Objective: To evaluate the efficacy and safety of dasotraline for treatment of ADHD in children. Method: Children (ages 6-12 years; N = 112) with ADHD were randomized, double-blind, to 14 days of once-daily evening doses of dasotraline 4 mg or placebo. ADHD symptom severity was measured at baseline and Day 15 in seven, 30-min classroom sessions using the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) and the Permanent Product Measure of Performance (PERMP) math test. Results: Significant improvement was observed for dasotraline versus placebo in the SKAMP-combined score (-3.2 vs. +2.0; p < .001; effect size = 0.85) and SKAMP and PERMP subscale scores. The three most common adverse events for dasotraline (vs. placebo) were insomnia (19.6% vs. 3.6%), headache (10.7% vs. 8.9%), and decreased appetite (10.7% vs. 3.6%). Conclusion: In this laboratory classroom study, dasotraline 4 mg was found to be an efficacious and generally well-tolerated treatment for ADHD in children aged 6 to 12 years.

Dasotraline in Children with Attention-Deficit/Hyperactivity Disorder: A Six-Week, Placebo-Controlled, Fixed-Dose Trial

OBJECTIVE

Dasotraline is a potent inhibitor of presynaptic dopamine and norepinephrine reuptake with a pharmacokinetic profile characterized by slow absorption and a long elimination half-life. The aim of this study was to evaluate the efficacy and safety of dasotraline in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Children aged 6-12 years with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of ADHD were randomized to 6 weeks of double-blind once-daily treatment with dasotraline (2 or 4 mg) or placebo. The primary efficacy endpoint was change from baseline in the ADHD Rating Scale Version IV-Home Version (ADHD RS-IV HV) total score at week 6.

RESULTS

A total of 342 patients were randomized to dasotraline or placebo (mean age 9.1 years, 66.7% male). Treatment with dasotraline was associated with significant improvement at study endpoint in the ADHD RS-IV HV total score for the 4 mg/day dose versus placebo (-17.5 vs. -11.4; p < 0.001; effect size [ES], 0.48), but not for the 2 mg/day dose (-11.8 vs. -11.4; ns; ES, 0.03). A regression analysis confirmed a significant linear dose-response relationship for dasotraline. Significant improvement for dasotraline 4 mg/day dose versus placebo was also observed across the majority of secondary efficacy endpoints, including the Clinical Global Impression (CGI)-Severity score, the Conners Parent Rating Scale-Revised scale (CPRS-R) ADHD index score, and subscale measures of hyperactivity and inattentiveness. Discontinuation rates due to adverse events (AEs) were higher in the dasotraline 4 mg/day group (12.2%) compared with the 2 mg/day group (6.3%) and placebo (1.7%). The most frequent AEs associated with dasotraline were insomnia, decreased appetite, decreased weight, and irritability. Psychosis-related symptoms were reported as AEs by 7/219 patients treated with dasotraline in this study. There were no serious AEs or clinically meaningful changes in blood pressure or heart rate on dasotraline.

CONCLUSION

In this placebo-controlled study, treatment with dasotraline 4 mg/day significantly improved ADHD symptoms and behaviors, including attention and hyperactivity, in children aged 6-12 years. The most frequently reported AEs observed on dasotraline included insomnia, decreased appetite, decreased weight, and irritability.

Transformed PANSS Factors Intended to Reduce Pseudospecificity Among Symptom Domains and Enhance Understanding of Symptom Change in Antipsychotic-Treated Patients With Schizophrenia

Positive and Negative Syndrome Scale (PANSS) total score is the standard primary efficacy measure in acute treatment studies of schizophrenia. However, PANSS factors that have been derived from factor analytic approaches over the past several decades have uncertain clinical and regulatory status as they are, to varying degrees, intercorrelated. As a consequence of cross-factor correlations, the apparent improvement in key clinical domains (eg, negative symptoms, disorganized thinking/behavior) may largely be attributable to improvement in a related clinical domain, such as positive symptoms, a problem often referred to as pseudospecificity. Here, we analyzed correlations among PANSS items, at baseline and change post-baseline, in a pooled sample of 5 placebo-controlled clinical trials (N = 1710 patients), using clustering and factor analysis to identify an uncorrelated PANSS score matrix (UPSM) that minimized the degree of correlation between each resulting transformed PANSS factor. The transformed PANSS factors corresponded well with discrete symptom domains described by prior factor analyses, but between-factor change-scores correlations were markedly lower. We then used the UPSM to transform PANSS in data from 4657 unique schizophrenia patients included in 12 additional lurasidone clinical trials. The results confirmed that transformed PANSS factors retained a high degree of specificity, thus validating that low between-factor correlations are a reliable property of the USPM when transforming PANSS data from a variety of clinical trial data sets. These results provide a more robust understanding of the structure of symptom change in schizophrenia and suggest a means to evaluate the specificity of antipsychotic treatment effects.

Understanding Antipsychotic Drug Treatment Effects: A Novel Method to Reduce Pseudospecificity of the Positive and Negative Syndrome Scale (PANSS) Factors

The Positive and Negative Syndrome Scale (PANSS) is the most widely used efficacy measure in acute treatment studies of schizophrenia. However, interpretation of the efficacy of antipsychotics in improving specific symptom domains is confounded by moderate-to-high correlations among standard (Marder) PANSS factors. The authors review the results of an uncorrelated PANSS score matrix (UPSM) transform designed to reduce pseudospecificity in assessment of symptom change in patients with schizophrenia. Based on a factor analysis of five pooled, placebo-controlled lurasidone clinical trials (N=1,710 patients), a UPSM transform was identified that generated PANSS factors with high face validity (good correlation with standard Marder PANSS factors), and high specificity/orthogonality (low levels of between-factor correlation measuring change during treatment). Between-factor correlations were low at baseline for both standard (Marder) PANSS factors and transformed PANSS factors. However, when measured change in symptom severity was measured during treatment (in a pooled 5-study analysis), there was a notable difference for standard PANSS factors, where changes across factors were found to be highly correlated (factors exhibited pseudospecificity), compared to transformed PANSS factors, where factor change scores exhibited the same low levels of between-factor correlation observed at baseline. At Week 6-endpoint, correlations among PANSS factor severity scores were moderate-to-high for standard factors (0.34-0.68), but continued to be low for the transformed factors (-0.22-0.20). As an additional validity check, we analyzed data from one of the original five pooled clinical trials that included other well-validated assessment scales (MADRS, Negative Symptom Assessment scale [NSA]). In this baseline analysis, UPSM-transformed PANSS factor severity scores (negative and depression factors) were found to correlate well with the MADRS and NSA. The availability of transformed PANSS factors with a high degree of orthogonality/specificity, but which retain a high degree of concurrent and face validity, can reduce pseudospecificity as a measurement confound, and should facilitate the drug development process, permitting a more accurate characterization of the efficacy of putative new agents in targeting specific symptom domains in patients with psychotic illness.

Absorption, distribution, metabolism, and excretion of [14C]-dasotraline in humans

Dasotraline is a dopamine and norepinephrine reuptake inhibitor, and the early clinical trials show a slow absorption and long elimination half‐life. To investigate the absorption, distribution, metabolism, and excretion of dasotraline in humans, a single dose of [¹⁴C]‐dasotraline was administered to eight healthy male adult volunteers. At 35 days, 90.7% of the dosed radioactivity was recovered in the urine (68.3%) and feces (22.4%). The major metabolic pathways involved were: (1) amine oxidation to form oxime M41 and sequential sulfation to form M42 or glucuronidation to form M43; (2) N‐hydroxylation and sequential glucuronidation to form M35; (3) oxidative deamination to form (S)‐tetralone; (4) mono‐oxidation of (S)‐tetralone and sequential glucuronidation to form M31A and M32; and (5) N‐acetylation to form (1R,4S)‐acetamide M102. A total of 8 metabolites were detected and structurally elucidated with 4 in plasma (M41, M42, M43, and M35), 7 in urine (M41, M42, M43, M31A, M32, M35, and (S)‐tetralone), and 3 in feces (M41, (S)‐tetralone, and (1R,4S)‐acetamide). The 2 most abundant circulating metabolites were sulfate (M42) and glucuronide (M43) conjugates of the oxime of dasotraline, accounting for 60.1% and 15.0% of the total plasma radioactivity, respectively; unchanged dasotraline accounted for 8.59%. The oxime M41 accounted for only 0.62% of the total plasma radioactivity and was detected only at early time points. M35 was a minor glucuronide metabolite, undetectable by radioactivity but identified by mass spectrometry. The results demonstrate that dasotraline was slowly absorbed, and extensively metabolized by oxidation and subsequent phase II conjugations. The findings from this study also demonstrated that metabolism of dasotraline by humans did not produce metabolites that may cause a safety concern.

Automation of In Vitro Dose-Inhibition Assays Utilizing the Tecan Genesis and an Integrated Software Package to Support the Drug Discovery Process

We have automated in vitro dose-inhibition assays to evaluate newly synthesized chemical entities and to rapidly produce and disseminate the results with minimal personnel. A variety of assay methods were automated using the Tecan Genesis Workstation to produce ten-point titration curves and generate reproducible KI values. Our integrated software package provides the unique ability to simultaneously inventory and schedule compounds into various in vitro assays. A worklist generator, in combination with a Gemini script automatically makes variable pre-dilutions of compounds, retrieves incubation plates from the Carousel using the RoMa Arm, performs serial dilutions of compounds within the final 96 well incubation plate using disposable tips, and adds essential assay reagents. Our “Expert System for Data Analysis” automatically retrieves data from a reader (e.g. TopCount, FLIPR or VIPR), analyzes the data based on a set of rules, and provides value added reports. An overview of the basic workflow and the integrated software for support of the drug discovery process is described. The ability of the Tecan Robot to produce dose-inhibition profiles is illustrated and validated by using a radioligand binding assay and a DMSO solubilized fluorescein dye method.

Pharmacokinetics and Exposure-Response Relationships of Dasotraline in the Treatment of Attention-Deficit/Hyperactivity Disorder in Adults

Background and Objectives

Dasotraline is a novel inhibitor of dopamine and norepinephrine reuptake currently being investigated in clinical studies for the treatment of attention-deficit/hyperactivity disorder (ADHD). Uniquely, relative to current ADHD medications, dasotraline has a slow absorption and long elimination half-life. Here we relate the pharmacokinetics and pharmacodynamics of dasotraline to reduction in ADHD symptoms based on simulated clinical trial outcomes.

Methods

Dasotraline pharmacokinetics were analyzed by population pharmacokinetic methodologies using data collected from 395 subjects after single or multiple oral dose administrations ranging from 0.2 to 36 mg (three phase I studies and one phase II ADHD study). Population pharmacokinetic and pharmacodynamic models related individual dasotraline exposures to norepinephrine metabolite 3,4-dihydroxyphenylglycol (DHPG) concentrations, ADHD symptoms, and study discontinuation (probability of dropout).

Results

Dasotraline pharmacokinetics were described by a one-compartment model with dual (linear plus nonlinear) elimination. In an ADHD population treated with dasotraline 4 or 8 mg/day, dasotraline was characterized by a mean apparent half-life of 47 h and plasma concentrations reached steady-state by 10 days of dosing. A population pharmacokinetic and pharmacodynamic model of DHPG indicated clinically significant norepinephrine transporter inhibition was achieved as a function of time-matched dasotraline concentrations. Dasotraline exposure reduced ADHD symptoms in a sigmoid E_max time-course model. Clinical trial simulations described the effects of dose, duration, and sample size on clinical outcomes.

Conclusion

These results related dasotraline pharmacokinetics to pharmacological activity in ADHD, and support the novel concept that maintaining constant, steady-state dopamine and norepinephrine reuptake inhibition throughout a 24-h dosing interval is a novel pharmacological approach to the management of ADHD symptoms.

Clinicaltrials.gov identifier: NCT01692782.

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-015-0358-7) contains supplementary material, which is available to authorized users.

Assessment of human abuse potential of dasotraline compared to methylphenidate and placebo in recreational stimulant users

AIMS

The aim of this study was to evaluate the abuse potential of dasotraline, a novel dopamine and norepinephrine reuptake inhibitor with slow absorption (tmax, 10-12h) and elimination (t1/2=47-77 h) that is in development for the treatment of attention deficit hyperactivity disorder (ADHD).

METHODS

Recreational stimulant users (N=48) who had specific experience with cocaine, and who were able to distinguish methylphenidate (60 mg) versus placebo in a qualification session, were randomized, in a 6-period, double-blind, crossover design, to receive single doses of dasotraline 8 mg, 16 mg, and 36 mg, methylphenidate (MPH) 40 mg and 80 mg, and placebo. The primary endpoint was the Drug Liking Visual Analog Scale (VAS) score at the time of peak effect (Emax).

RESULTS

There were no significant differences between the 3 doses of dasotraline and placebo on the drug liking VAS at Emax, and on most secondary endpoints. Both doses of MPH had significantly higher VAS-drug liking scores at Emax relative to both placebo (P<0.001 for all comparisons) and dasotraline 8 mg (P<0.001), 16 mg (P<0.001) and 36 mg (P<0.01). The increase in heart rate for MPH and dasotraline 36 mg showed a time-course that closely matched subject-rated measures such as Any Effects VAS.

CONCLUSIONS

In this study, dasotraline was found to have low potential for abuse, which may be, in part, related to its established pharmacokinetics (PK) profile, which is characterized by slow absorption and gradual elimination.

Dasotraline for the Treatment of Attention-Deficit/Hyperactivity Disorder: A Randomized, Double-Blind, Placebo-Controlled, Proof-of-Concept Trial in Adults

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity associated with clinically significant impairment in functioning. ADHD has an early onset, but frequently persists, with a prevalence estimate of 4% in adults. Dasotraline is a novel compound that is a potent inhibitor of dopamine and norepinephrine transporters that achieves stable plasma concentrations with once-daily dosing. In this study, adult outpatients meeting DSM-IV-TR criteria for ADHD were randomized to 4 weeks of double-blind, once-daily treatment with dasotraline 4 and 8 mg/day or placebo. The primary efficacy end point was change from baseline at week 4 in the ADHD Rating Scale, Version IV (ADHD RS-IV) total score. Secondary efficacy end points included the Clinical Global Impression, Severity (CGI-S) scale, modified for ADHD symptoms. Least squares (LS) mean improvements at week 4 in ADHD RS-IV total score were significantly greater for dasotraline 8 mg/day vs placebo (-13.9 vs -9.7; P=0.019), and nonsignificantly greater for 4 mg/day (-12.4; P=0.076). The LS mean improvements in modified CGI-S were significantly greater at week 4 for dasotraline 8 mg/day vs placebo (-1.1 vs -0.7; P=0.013), and for 4 mg/day vs placebo (-1.1 vs -0.7; P=0.021). The most frequent adverse events reported were insomnia, decreased appetite, nausea, and dry mouth. Discontinuations due to treatment-emergent adverse events were 10.3% and 27.8% of patients in 4 and 8 mg/day treatment groups, respectively. This study provides preliminary evidence that once-daily dosing with dasotraline, a long-acting, dual monoamine reuptake inhibitor, may be a safe and efficacious treatment for adult ADHD.

The effects of a novel histamine-3 receptor inverse agonist on essential tremor in comparison to stable levels of alcohol

Essential tremor (ET) is a common movement disorder. Animal studies show that histaminergic modulation may affect the pathological processes involved in the generation of ET. Histamine-3 receptor inverse agonists (H3RIA) have demonstrated attenuating effects on ET in the harmaline rat model. In this double-blind, three-way cross-over, single-dose, double-dummy study the effects of 25 mg of a novel H3RIA (MK-0249) and a stable alcohol level (0.6 g L(-1)) were compared with placebo, in 18 patients with ET. Tremor was evaluated using laboratory tremorography, portable tremorography and a clinical rating scale. The Leeds Sleep Evaluation Questionnaire (LSEQ) and a choice reaction time (CRT) test were performed to evaluate potential effects on sleep and attention, respectively. A steady state of alcohol significantly diminished tremor as assessed by laboratory tremorography, portable tremorography and clinical ratings compared with placebo. A high single MK-0249 dose was not effective in reducing tremor, but caused significant effects on the LSEQ and the CRT test. These results suggest that treatment with a single dose of MK-0249 does not improve tremor in alcohol-responsive patients with ET, whereas stable levels of alcohol as a positive control reproduced the commonly reported tremor-diminishing effects of alcohol.

Discovery of 3-substituted aminocyclopentanes as potent and orally bioavailable NR2B subtype-selective NMDA antagonists

A series of 3-substituted aminocyclopentanes has been identified as highly potent and selective NR2B receptor antagonists. Incorporation of a 1,2,4-oxadiazole linker and substitution of the pendant phenyl ring led to the discovery of orally bioavailable analogues that showed efficient NR2B receptor occupancy in rats. Unlike nonselective NMDA antagonists, the NR2B-selective antagonist 22 showed no adverse affects on motor coordination in the rotarod assay at high dose. Compound 22 was efficacious following oral administration in a spinal nerve ligation model of neuropathic pain and in an acute model of Parkinson's disease in a dose dependent manner.

In vitro characterization of T-type calcium channel antagonist TTA-A2 and in vivo effects on arousal in mice

T-type calcium channels have been implicated in many behaviorally important neurophysiological processes, and altered channel activity has been linked to the pathophysiology of neurological disorders such as insomnia, epilepsy, Parkinson's disease, depression, schizophrenia, and pain. We have previously identified a number of potent and selective T-type channel antagonists (Barrow et al., 2007; Shipe et al., 2008; Yang et al., 2008). Here we describe the properties of the antagonist TTA-A2 [2-(4-cyclopropylphenyl)-N-((1R)-1-{5-[(2,2,2-trifluoroethyl)oxo]-pyridin-2-yl}ethyl)acetamide], assessed in patch-clamp experiments. TTA-A2 blocks T-type channels (Ca(v)3.1, 3.2, 3.3) voltage dependently and with high potency (IC(50) ∼100 nM). Stimulation at 3 Hz revealed additional use dependence of inhibition. A hyperpolarized shift of the channel availability curve and delayed channel recovery from inactivation suggest that the compound preferentially interacts with and stabilizes inactivated channels. The compound showed a ∼300-fold selectivity for Ca(v)3 channels over high-voltage activated calcium channels. Inhibitory effects on native T-type currents were confirmed in brain slice recordings from the dorsal lateral geniculate nucleus and the subthalamic nucleus. Furthermore, we demonstrate that in vivo T-type channel inhibition by TTA-A2 suppresses active wake and promotes slow-wave sleep in wild-type mice but not in mice lacking both Ca(v)3.1 and Ca(v)3.3, suggesting the selective effect of TTA-A2 on recurrent thalamocortical network activity. The discovery of the potent and selective T-type channel antagonist TTA-A2 has enabled us to study the in vivo effects of pharmacological T-channel inhibition on arousal in mice, and it will help to explore the validity of these channels as potential drug targets for sleep-related and other neurological diseases.

Discovery of a potent, CNS-penetrant orexin receptor antagonist based on an n,n-disubstituted-1,4-diazepane scaffold that promotes sleep in rats

Silent Night: Antagonism of the orexin (or hypocretin) system has recently been identified as a novel mechanism for the treatment of insomnia. Herein, we describe discovery of a dual (OX(1)R/OX(2)R) orexin receptor antagonist featuring a 1,4-diazepane central constraint that blocks orexin signaling in vivo. In telemetry-implanted rats, oral administration of this antagonist produced a decrease in wakefulness, while increasing REM and non-REM sleep.

Antagonism of T-type calcium channels inhibits high-fat diet-induced weight gain in mice

The epidemics of obesity and metabolic disorders have well-recognized health and economic burdens. Pharmacologic treatments for these diseases remain unsatisfactory with respect to both efficacy and side-effect profiles. Here, we have identified a potential central role for T-type calcium channels in regulating body weight maintenance and sleep. Previously, it was shown that mice lacking CaV3.1 T-type calcium channels have altered sleep/wake activity. We found that these mice were also resistant to high-fat diet-induced weight gain, without changes in food intake or sensitivity to high-fat diet-induced disruptions of diurnal rhythm. Administration of a potent and selective antagonist of T-type calcium channels, TTA-A2, to normal-weight animals prior to the inactive phase acutely increased sleep, decreased body core temperature, and prevented high-fat diet-induced weight gain. Administration of TTA-A2 to obese rodents reduced body weight and fat mass while concurrently increasing lean muscle mass. These effects likely result from better alignment of diurnal feeding patterns with daily changes in circadian physiology and potentially an increased metabolic rate during the active phase. Together, these studies reveal what we believe to be a previously unknown role for T-type calcium channels in the regulation of sleep and weight maintenance and suggest the potential for a novel therapeutic approach to treating obesity.

Uncovering the genetic landscape for multiple sleep-wake traits

Despite decades of research in defining sleep-wake properties in mammals, little is known about the nature or identity of genes that regulate sleep, a fundamental behaviour that in humans occupies about one-third of the entire lifespan. While genome-wide association studies in humans and quantitative trait loci (QTL) analyses in mice have identified candidate genes for an increasing number of complex traits and genetic diseases, the resources and time-consuming process necessary for obtaining detailed quantitative data have made sleep seemingly intractable to similar large-scale genomic approaches. Here we describe analysis of 20 sleep-wake traits from 269 mice from a genetically segregating population that reveals 52 significant QTL representing a minimum of 20 genomic loci. While many (28) QTL affected a particular sleep-wake trait (e.g., amount of wake) across the full 24-hr day, other loci only affected a trait in the light or dark period while some loci had opposite effects on the trait during the light vs. dark. Analysis of a dataset for multiple sleep-wake traits led to previously undetected interactions (including the differential genetic control of number and duration of REM bouts), as well as possible shared genetic regulatory mechanisms for seemingly different unrelated sleep-wake traits (e.g., number of arousals and REM latency). Construction of a Bayesian network for sleep-wake traits and loci led to the identification of sub-networks of linkage not detectable in smaller data sets or limited single-trait analyses. For example, the network analyses revealed a novel chain of causal relationships between the chromosome 17@29cM QTL, total amount of wake, and duration of wake bouts in both light and dark periods that implies a mechanism whereby overall sleep need, mediated by this locus, in turn determines the length of each wake bout. Taken together, the present results reveal a complex genetic landscape underlying multiple sleep-wake traits and emphasize the need for a systems biology approach for elucidating the full extent of the genetic regulatory mechanisms of this complex and universal behavior.

Refined anatomical isolation of functional sleep circuits exhibits distinctive regional and circadian gene transcriptional profiles

Powerful new approaches to study molecular variation in distinct neuronal populations have recently been developed enabling a more precise investigation of the control of neural circuits involved in complex behaviors such as wake and sleep. We applied laser capture microdissection (LCM) to isolate precise brain nuclei from rat CNS at opposing circadian time points associated with wake and sleep. Discrete anatomical and temporal analysis was performed to examine the extent of variation in the transcriptional control associated with both identifiable anatomical nuclei and with light/dark cycle. Precise isolation of specific brain nuclei regulating sleep and arousal, including the LC, SCN, TMN, VTA, and VLPO, demonstrated robust changes in gene expression. Many of these differences were not observed in previous studies where whole brain lysates or gross dissections were used to probe for changes in gene expression. The robust and differential profiles of genomic data obtained from the approaches used herein underscore the requirement for careful anatomical refinement in CNS gene expression studies designed to understand genomic control within behaviorally-linked, but functionally isolated brain nuclei.

High-throughput analysis of drug binding interactions for the human cardiac channel, Kv1.5

The voltage-gated potassium channel Kv1.5 is one of the key regulators of membrane potential repolarization in human atrial myocytes and is considered a potential drug target to treat atrial fibrillation. In this study we sought to determine molecular mechanism of action of DPO-1, a diphenylphosphine oxide derivative recently shown to terminate experimental atrial arrhythmia without affecting ventricular refractory period. In addition, we provided similar analysis for additional two small molecule blockers, representing different structural classes: cyclohexanones (PAC) and nor-triterpenoids (correolide). To rapidly identify the residues within the Kv1.5 channel critical for blocking activity of these molecules, two functional high-throughput ion channel assays were employed together with site-directed mutagenesis. Our study revealed that the residues critical for blocking activity of for DPO-1 include T480, localized at the outer mouth of the pore, and two residues along S6 helix: V505 and I508. The overlapping site was identified for PAC and included residues T480 and V505. In contrast to DPO-1, the I508A mutation resulted in only a modest reduction in the block of Kv1.5 by PAC (9-fold). Correolide, the largest molecule examined, made widespread interactions along the entire length of the pore (from T480 to V516). In summary, we have identified multiple residues involved in forming high affinity binding site for Kv1.5 blockers. Similar approaches of high-throughput ion channel technologies, combined with site-directed mutagenesis, may allow for parallel, rapid and accurate analysis of ion channel interactions with multiple compounds and could facilitate the design of more potent and selective ion channel blockers.

Discovery of 1,4-substituted piperidines as potent and selective inhibitors of T-type calcium channels

The discovery of a novel series of potent and selective T-type calcium channel antagonists is reported. Initial optimization of high-throughput screening leads afforded a 1,4-substituted piperidine amide 6 with good potency and limited selectivity over hERG and L-type channels and other off-target activities. Further SAR on reducing the basicity of the piperidine and introducing polarity led to the discovery of 3-axial fluoropiperidine 30 with a significantly improved selectivity profile. Compound 30 showed good oral bioavailability and brain penetration across species. In a rat genetic model of absence epilepsy, compound 30 demonstrated a robust reduction in the number and duration of seizures at 33 nM plasma concentration, with no cardiovascular effects at up to 5.6 microM. Compound 30 also showed good efficacy in rodent models of essential tremor and Parkinson's disease. Compound 30 thus demonstrates a wide margin between CNS and peripheral effects and is a useful tool for probing the effects of T-type calcium channel inhibition.