A Neurofunctional Domains Approach to Evaluate D1/D5 Dopamine Receptor Partial Agonism on Cognition and Motivation in Healthy Volunteers With Low Working Memory Capacity.

BACKGROUND: Dopamine D1 receptor signaling plays key roles in core domains of neural function, including cognition and reward processing; however, many questions remain about the functions of circuits modulated by dopamine D1 receptor, largely because clinically viable, selective agonists have yet to be tested in humans. METHODS: Using a novel, exploratory neurofunctional domains study design, we assessed the safety, tolerability, pharmacodynamics, and pharmacokinetics of PF-06412562, a selective D1/D5R partial agonist, in healthy male volunteers who met prespecified criteria for low working memory capacity. Functional magnetic resonance imaging, electrophysiologic endpoints, and behavioral paradigms were used to assess working memory, executive function, and motivation/reward processing following multiple-dose administration of PF-06412562. A total of 77 patients were assigned PF-06412562 (3 mg twice daily and 15 mg twice daily) or placebo administered for 5 to 7 days. Due to the exploratory nature of the study, it was neither powered for any specific treatment effect nor corrected for multiple comparisons. RESULTS: Nominally significant improvements from baseline in cognitive endpoints were observed in all 3 groups; however, improvements in PF-06412562-treated patients were less than in placebo-treated participants. Motivation/reward processing endpoints were variable. PF-06412562 was safe and well tolerated, with no serious adverse events, severe adverse events, or adverse events leading to dose reduction or temporary discontinuation except for 1 permanent discontinuation due to increased orthostatic heart rate. CONCLUSIONS: PF-06412562, in the dose range and patient population explored in this study, did not improve cognitive function or motivation/reward processing more than placebo over the 5- to 7-day treatment period. CLINICALTRIALS.GOV IDENTIFIER: NCT02306876.

Phosphodiesterase 10A Inhibitor Monotherapy Is Not an Effective Treatment of Acute Schizophrenia.

BACKGROUND: Current treatments for psychotic symptoms associated with schizophrenia often provide inadequate efficacy with unacceptable adverse effects. Improved therapeutics have long been a goal of research. Preclinical testing suggests that phosphodiesterase 10A (PDE10A) inhibitors may provide a novel approach to treating psychosis associated with schizophrenia. METHODS: The efficacy and safety of a highly selective PDE10A inhibitor, PF-02545920, was evaluated in a phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Eligible patients (18-65 years) with an acute exacerbation of schizophrenia were randomized 2:2:1:2 to PF-02545920 (5 or 15 mg every 12 hours [Q12H] titrated), risperidone (3 mg Q12H), or placebo for 28 days (n = 74:74:37:74). The primary objectives were to evaluate the efficacy of PF-02545920 using the Positive and Negative Syndrome Scale (PANNS) and safety/tolerability. RESULTS: At day 28, PF-02545920 (either dose) was not significantly different from placebo for mean change from baseline in the PANNS total score (primary end point) or most other end points. Pharmacokinetics exposures seemed adequate for binding/inhibiting PDE10A enzyme. Risperidone was statistically different from placebo for the PANNS total score, demonstrating study sensitivity. Incidence rates for adverse events were similar among the groups. Both doses of PF-02545920 were generally well tolerated. Dystonia occurred in 1, 6, 0, and 3 patients in the PF-02545920 5 mg Q12H, PF-02545920 15 mg Q12H, risperidone, and placebo groups, respectively. CONCLUSIONS: Neither dose of PF-02545920 was superior to placebo for the primary and most secondary end points. This indicates that PDE10A inhibition does not produce an antipsychotic effect in patients with acute exacerbation of schizophrenia.

A Proof-of-Concept Study Evaluating the Phosphodiesterase 10A Inhibitor PF-02545920 in the Adjunctive Treatment of Suboptimally Controlled Symptoms of Schizophrenia.

BACKGROUND: Effective treatments for managing suboptimal clinical responses to current therapy for schizophrenia remain a critical unmet need. Phosphodiesterase 10A (PDE10A) inhibition represents a mechanistically novel approach to the treatment of schizophrenia, with preclinical studies suggesting improvements in partially responsive symptoms could be achieved via adjunctive use of the PDE10A inhibitor PF-02545920. Therefore, the adjunctive safety, tolerability, pharmacokinetics, and efficacy of multiple repeat doses of PF-02545920 were investigated in a phase 1b study and subsequent phase 2 study. METHODS: The phase 1b study randomized 37 adult patients with stable symptomatology and stable antipsychotic regimens within 3 cohorts. Study participants received ascending doses of PF-02545920 or placebo for 10 to 18 days. The phase 2 study randomized 240 outpatients with stable symptomatology but suboptimal response to current antipsychotic regimens 1:1:1 to PF-02545920 5 mg, PF-02545920 15 mg, or placebo every 12 hours for 12 weeks. The primary efficacy end point of the phase 2 study was change in the Positive and Negative Syndrome Scale total score from baseline to week 12, with changes in other clinical assessments as secondary end points. RESULTS: Treatment was well tolerated, and observed PF-02545920 exposures were within the range predicted to be adequate for demonstrating efficacy. However, no significant differences in the prespecified efficacy end points between the 2 PF-02545920 treatment arms and placebo were observed. CONCLUSIONS: Current data and results of a prior monotherapy study in which PF-02545920 failed to differentiate from placebo refute the hypothesis that PDE10A inhibitors have use as antipsychotic agents for schizophrenia.

INTERACT: a randomized phase 2 study of the DAAO inhibitor luvadaxistat in adults with schizophrenia.

Deficits in N-methyl-d-aspartate receptor (NMDAR) signaling are implicated in the pathogenesis of schizophrenia. Luvadaxistat (TAK-831/NBI-1065844) is an investigational d-amino acid oxidase (DAAO) inhibitor that increases d-serine levels at NMDAR coagonist sites. INTERACT is a phase 2 randomized, placebo-controlled study that evaluated the efficacy and safety of three doses of luvadaxistat, covering a range of DAAO occupancy and d-serine levels, in patients with schizophrenia with persistent negative symptoms. The study included a 14-day, single-blinded placebo run-in period and a 12-week, double-blinded treatment period. The primary efficacy endpoint was the 12-week change from baseline in Positive and Negative Syndrome Scale-Negative Symptom Factor Score (PANSS NSFS). Secondary efficacy endpoints included the 12-week changes from baseline in Brief Assessment of Cognition in Schizophrenia (BACS) score and Schizophrenia Cognition Rating Scale (SCoRS) score. Safety endpoints included adverse event assessments. The full analysis set included all randomized patients (N = 256 [placebo, n = 87; luvadaxistat 50 mg, n = 58; 125 mg, n = 56; 500 mg, n = 55]); 228 patients completed the study. No significant improvements in PANSS NSFS were observed at any dose versus placebo at week 12. Improvements were observed with luvadaxistat 50 mg versus placebo in cognitive endpoints: BACS composite score (nominal one-sided p = 0.031) and SCoRS interviewer total score (nominal one-sided p = 0.011). Luvadaxistat did not significantly improve negative symptoms of schizophrenia. However, luvadaxistat 50 mg met the prespecified secondary endpoints for cognitive performance (BACS) and function (SCoRS), warranting further investigation in patients with cognitive impairment associated with schizophrenia. Luvadaxistat was well-tolerated in INTERACT, with no new safety signals observed. ClinicalTrials.gov: NCT03382639.

Results of a randomized double-blind study evaluating luvadaxistat in adults with Friedreich ataxia.

OBJECTIVES: Friedreich ataxia (FRDA) is a rare disorder with progressive neurodegeneration and cardiomyopathy. Luvadaxistat (also known as TAK-831; NBI-1065844), an inhibitor of the enzyme d-amino acid oxidase, has demonstrated beneficial effects in preclinical models relevant to FRDA. This phase 2, randomized, double-blind, placebo-controlled, parallel-arm study evaluated the efficacy and safety of oral luvadaxistat in adults with FRDA. METHODS: Adult patients with FRDA were randomized 2:1:2 to placebo, luvadaxistat 75 mg twice daily (BID), or luvadaxistat 300 mg BID for 12 weeks. The primary endpoint changed from baseline at week 12 on the inverse of the time to complete the nine-hole peg test (9-HPT-1 ), a performance-based measure of the function of the upper extremities and manual dexterity. Comparisons between luvadaxistat and placebo were made using a mixed model for repeated measures. RESULTS: Of 67 randomized patients, 63 (94%) completed the study. For the primary endpoint, there was no statistically significant difference in change from baseline on the 9-HPT-1 (seconds-1 ) at week 12 between placebo (0.00029) and luvadaxistat 75 mg BID (-0.00031) or luvadaxistat 300 mg BID (-0.00059); least squares mean differences versus placebo (standard error) were -0.00054 (0.000746) for the 75 mg dose and -0.00069 (0.000616) for the 300 mg dose. Luvadaxistat was safe and well tolerated; the majority of reported adverse events were mild in intensity. INTERPRETATION: Luvadaxistat was safe and well tolerated in this cohort of adults with FRDA; however, it did not demonstrate efficacy as a treatment for this condition.

A novel approach to evaluate the pharmacodynamics of a selective dopamine D1/D5 receptor partial agonist (PF-06412562) in patients with stable schizophrenia.

BACKGROUND: PF-06412562 is an orally bioavailable, selective dopamine D1/D5 receptor partial agonist with a non-catechol structure under evaluation for treatment of cognitive impairment in schizophrenia. AIMS: This randomized, double-blind, placebo-controlled, parallel-group, Phase 1b study examined the pharmacokinetics and pharmacodynamics of three doses of PF-06412562 (3 mg, 9 mg, and 45 mg twice daily) over 15 days in patients with schizophrenia receiving antipsychotics. METHODS: Primary endpoints included adjunctive safety/tolerability and effects on MATRICS Consensus Cognitive Battery Working Memory domain and reward processing (Monetary Incentive Delay) tasks. Exploratory endpoints included other behavioral/neurophysiological tasks, including the N-back task. RESULTS: Among 95 subjects (78% male; mean age 34.8 years), baseline characteristics were similar across groups. The MATRICS Consensus Cognitive Battery Working Memory composite change from baseline on Day 13 improved in all groups, the smallest improvement was observed in the 45 mg group and was significantly smaller than that in the placebo group (two-sided p=0.038). For the Monetary Incentive Delay task (change from baseline in blood-oxygen-level-dependent functional magnetic resonance imaging activation in anterior ventral striatum for the contrast of cue gain>cue no gain on Day 15), no PF-06412562 dose was significantly different from placebo. No doses of PF-06412562 showed a significant difference on two-back task accuracy versus placebo. CONCLUSIONS: Adjunctive treatment with PF-06412562 was safe and well tolerated in patients with schizophrenia. PF-06412562 failed to show clinical benefit relative to placebo on assessments of cognition or reward processing in symptomatically stable patients over a 15-day treatment period. Numerous limitations due to the safety study design warrant further efficacy evaluation for this drug mechanism.

Psychiatric use and utility of divalproex sodium in Connecticut prisons.

Divalproex sodium (DVX) is used in correctional settings to treat impulsive aggression and mood lability in patients without comorbid bipolar disorder. This review of DVX use in the Connecticut Department of Correction examined the psychiatric diagnostic impression of patients prescribed DVX, the doses used, and the symptomatic and functional change over time. Clinical charts of 168 offenders treated with DVX for one or more months were randomly selected for clinical outcome review and were divided into subgroups based on clinical impression for DVX prescription. In participants without bipolar disorder (44.6%), DVX was used to target impulsivity (14.3%) and mood lability (17.3%). Clinical improvement was noted in bipolar and nonbipolar groups (p < .001). The impulsive/aggressive subgroup was the only nonbipolar subgroup in which DVX yielded clinical benefit. This symptom-driven use of DVX is associated with clinical improvement when impulsive aggression is the target symptom.

A Phase I Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of the Novel Dopamine D1 Receptor Partial Agonist, PF-06669571, in Subjects with Idiopathic Parkinson's Disease.

BACKGROUND AND OBJECTIVES: There is an unmet medical need for additional treatment options for Parkinson's disease. This was a Phase I, double-blind clinical trial assessing safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple doses of the novel dopamine D1 receptor partial agonist, PF-06669571, in subjects with idiopathic Parkinson's disease on a stable dose of L-DOPA. METHODS: Subjects received PF-06669571 (or matching placebo) titrated from 1 mg to 3 mg over 7 days. The primary pharmacodynamic endpoint was the change from baseline in Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III total motor score at the pharmacodynamic time of maximum change from baseline on day 7. RESULTS: Twenty subjects were randomized and 19 completed the study. Maximum plasma concentrations (Cmax) of PF-06669571 were reached 3.35 and 3.19 h post-dose on day 1 and day 7. Geometric mean Cmax and area under the plasma concentration-time profile from time 0 to 24 h post-dose on day 7 were 92.51 ng/mL and 1626 ng·h/mL, respectively. The primary pharmacodynamic endpoint did not meet the pre-specified criteria for significant improvement; however, the criteria were met in a sensitivity analysis excluding data from a L-DOPA outlier (L-DOPA dose of 2550 mg/d). The most common adverse events (AEs) were nausea (experienced by 2 subjects each in the PF-06669571 and placebo groups). There were no permanent discontinuations or dose reductions due to AEs. DISCUSSION: Multiple daily doses of PF-06669571 were safe and well tolerated with no notable safety concerns. The pharmacodynamic endpoint did not meet the pre-specified criteria for significant improvement. CLINICALTRIALS. GOV IDENTIFIER: NCT02565628.

Systematic identification and classification of adverse events in human research.

Widely accepted standards and safeguards for research participants now include systematic surveillance and recording of adverse events. In the absence of a uniform regulation or structure for such reporting, each institution must now establish suitable yet efficient procedures to accomplish this task. We report herein our single center experience with a customized data collection, storage and review system specifically designed to identify and react appropriately to adverse events. Adverse events are classified by each investigator using three criteria in specific order: seriousness, expectedness and relatedness to the investigational intervention. Once classified, events are entered into an online database that includes collation, retrieval and search capabilities. Events meeting specified criteria are reviewed and adjudicated on a weekly basis by The University of Connecticut Research Adverse Events Committee, which makes advisory recommendations to the hospital's two Institutional Research Boards ranging from modification of informed consent to study suspension. Three hundred and seventy-one serious adverse events from > 900 studies were reviewed in the previous academic year. Our system, which combines timely on-line reporting with regular surveillance, provides a potential model that meets the need for comprehensive yet practical adverse events assessment and reporting.

First-in-Human Assessment of the Novel PDE2A PET Radiotracer 18F-PF-05270430.

UNLABELLED: This was a first-in-human study of the novel phosphodiesterase-2A (PDE2A) PET ligand (18)F-PF-05270430. The primary goals were to determine the appropriate tracer kinetic model to quantify brain uptake and to examine the within-subject test-retest variability. METHODS: In advance of human studies, radiation dosimetry was determined in nonhuman primates. Six healthy male subjects participated in a test-retest protocol with dynamic scans and metabolite-corrected input functions. Nine brain regions of interest were studied, including the striatum, white matter, neocortical regions, and cerebellum. Multiple modeling methods were applied to calculate volume of distribution (VT) and binding potentials relative to the nondisplaceable tracer in tissue (BPND), concentration of tracer in plasma (BPP), and free tracer in tissue (BPF). The cerebellum was selected as a reference region to calculate binding potentials. RESULTS: The dosimetry study provided an effective dose of less than 0.30 mSv/MBq, with the gallbladder as the critical organ; the human target dose was 185 MBq. There were no adverse events or clinically detectable pharmacologic effects reported. Tracer uptake was highest in the striatum, followed by neocortical regions and white matter, and lowest in the cerebellum. Regional time-activity curves were well fit by multilinear analysis-1, and a 70-min scan duration was sufficient to quantify VT and the binding potentials. BPND, with mean values ranging from 0.3 to 0.8, showed the best intrasubject and intersubject variability and reliability. Test-retest variability in the whole brain (excluding the cerebellum) of VT, BPND, and BPP were 8%, 16%, and 17%, respectively. CONCLUSION: (18)F-PF-05270430 shows promise as a PDE2A PET ligand, albeit with low binding potential values.

Efficacy of sertraline in severe generalized social anxiety disorder: results of a double-blind, placebo-controlled study.

BACKGROUND: Generalized social anxiety disorder is an early onset, highly chronic, frequently disabling disorder with a lifetime prevalence of approximately 13%. The goal of the current study was to evaluate the efficacy and tolerability of sertraline for the treatment of severe generalized social anxiety disorder in adults. METHOD: After a 1-week single-blind placebo lead-in period, patients with DSM-IV generalized social phobia were randomly assigned to 12 weeks of double-blind treatment with flexible doses of sertraline (50-200 mg/day) or placebo. Primary efficacy outcomes were the mean change in the Liebowitz Social Anxiety Scale (LSAS) total score and the responder rate for the Clinical Global Impressions-Improvement scale (CGI-I), defined as a CGI-I score

Comparative effects of mirtazapine and fluoxetine on sleep physiology measures in patients with major depression and insomnia.

BACKGROUND: Sleep complaints are common in patients with major depressive disorder (MDD). Both MDD and antidepressant drugs characteristically alter objective sleep measures. This study compares the effects of mirtazapine and fluoxetine on sleep continuity measures in DSM-IV MDD patients with insomnia. METHOD: Patients (N = 19) received initial baseline polysomnography evaluations over 2 consecutive nights. Subjects were randomly assigned to either fluoxetine (20-40 mg/day) or mirtazapine (15-45 mg/day) treatment for an 8-week, double-blind, double-dummy treatment trial. Single-night polysomnograms were conducted at weeks 1, 2, and 8, with depression ratings assessed at baseline and weeks 1, 2, 3, 4, 6, and 8. Statistical analysis was performed by repeated-measures analysis of variance followed by Dunnet's post hoc analyses. RESULTS: Patients receiving mirtazapine (N = 8) had significant improvement in objective sleep physiology measures at 8 weeks. Improvements in sleep latency, sleep efficiency, and wake after sleep onset were significant after only 2 weeks of mirtazapine treatment. No significant changes in sleep continuity measures were observed in the fluoxetine group (N = 11). Both groups improved clinically in mood and subjective sleep measures from baseline, with no differences between groups. CONCLUSION: These data demonstrate the differential effects of mirtazapine and fluoxetine, with significant improvement in favor of mirtazapine, on objective sleep parameters in MDD patients with insomnia.

New approaches for the treatment of sleep disorders.

Epidemiological studies have established that sleep disorders are common and often untreated. Besides having a negative impact on overall health, these conditions can significantly disrupt normal daily functions. While a number of drugs are employed in the treatment of sleep disorders, safety, tolerability, and variable efficacy limit their utility. Clinical developments in the area have been facilitated especially by advances in neurobiology and neuropharmacology. In this regard, a wide array of neuroactive substances has been found to be responsible for regulating sleep and wakefulness. Advances in the understanding of neurotransmitter and hormone receptor mechanisms and classifications have led to new opportunities for developing novel therapeutics for treating sleep disorders. Provided in this report is an overview of some of the more prevalent sleep disorders, including narcolepsy, insomnia, obstructive sleep apnea syndrome, and restless legs syndrome, with a summary and critique of medications used to treat these conditions. For each disorder, information is provided on recent approaches taken to develop novel therapeutics based on laboratory findings relating to the underlying biological abnormalities associated with the condition, in addition to approaches that leverage existing therapeutics to develop new treatment options for patients. Significant advances in the future await a better understanding of the underlying pathophysiology of these conditions and of the neurobiological alterations associated with these disorders. It is hoped that some of the research directions described herein will stimulate additional research in this area and thereby help foster the discovery of novel agents for treating major sleep disorders.

Effects of psychiatric medications on sleep and sleep disorders.

Insomnia is a significant public health concern that has prompted substantial efforts to develop treatment and management strategies. A significant proportion of complaints of insomnia are related to psychiatric conditions such as anxiety disorders and depression, and treatments for these disorders are known to exert both direct and indirect benefits on sleep as well as some negative effects on sleep and sleep physiology. Insomnia is also a prominent symptom of a number of other psychiatric disorders, including schizophrenia and bipolar disorder. The observed impact of a variety of psychiatric medications on insomnia has prompted an empirically derived practice of treating non-psychiatric disorder-related insomnia with psychiatric medications by clinicians searching for alternatives to established medication treatments for primary insomnia. This article aims to review the evidence of the impact of psychiatric medications on sleep physiology, sleep disorders in psychiatric conditions, and on primary sleep disorders. The potential for exploiting the relevant pharmacological mechanisms of action in drug development for primary insomnia will be addressed as well.

A double-blind, placebo-controlled study of the efficacy and safety of desvenlafaxine succinate in the treatment of major depressive disorder.

OBJECTIVE: This study evaluated the efficacy and safety of desvenlafaxine succinate extended-release in major depressive disorder (MDD). METHOD: Adult outpatients with DSM-IV-defined MDD were randomly assigned to desvenlafaxine 100 mg/day (N = 114), 200 mg/day (N = 116), or 400 mg/day (N = 113) or placebo (N = 118) for 8 weeks. Efficacy variables included change from baseline in the 17-item Hamilton Rating Scale for Depression (HAM-D(17), the primary efficacy measure), Clinical Global Impressions-Improvement scale (CGI-I), Montgomery-Asberg Depression Rating Scale, Clinical Global Impressions-Severity of Illness scale (CGI-S), rates of response (> or = 50% decrease from baseline HAM-D(17) score) and remission (HAM-D(17) score < or =7), and Visual Analog Scale-Pain Intensity overall score. The study was conducted from November 2003 to November 2004. RESULTS: At the final on-therapy evaluation, the mean HAM-D(17) scores for desvenlafaxine 100 mg/day (12.75) and 400 mg/day (12.50) were significantly lower than for placebo (15.31; p = .0038 and p = .0023, respectively); for desvenlafaxine 200 mg/day, the mean score was 13.31 (p = .0764). CGI-I and Montgomery-Asberg Depression Rating Scale results were significant for all groups; CGI-S results were significant with 100 mg/day and 400 mg/day. Response rates were significantly greater for desven-lafaxine 100 mg/day (51%) and 400 mg/day (48%) versus placebo (35%; p = .017 and p = .046, respectively); the response rate for desvenlafaxine 200 mg/day was 45% (p = .142). Remission rates were significantly greater for desvenlafaxine 400 mg/day (32%) versus placebo (19%; p = .035); remission rates were 30% for desvenlafaxine 100 mg/day (p = .093) and 28% for desvenlafaxine 200 mg/day (p = .126). Visual Analog Scale-Pain Intensity results were significant for desvenlafaxine 100 mg/day versus placebo (p = .002), but not for the higher doses. The most commonly reported adverse events were nausea, insomnia, somnolence, dry mouth, dizziness, sweating, nervousness, anorexia, constipation, asthenia, and abnormal ejaculation/orgasm. CONCLUSIONS: Desvenlafaxine is effective and well tolerated in the short-term treatment of MDD.