Model-based comparison of subcutaneous versus sublingual apomorphine administration in the treatment of motor fluctuations in Parkinson's disease.

The objective of this study was to compare the effectiveness of subcutaneous (SC) and sublingual (SL) formulations of apomorphine for the treatment of motor fluctuations in Parkinson's disease using a pharmacokinetics (PK)/pharmacodynamics (PD) modeling approach. The PK of SC and SL apomorphine are best described by a one-compartment model with first-order absorption and a two-compartment model with delayed absorption, respectively. The PK/PD model relating apomorphine plasma concentrations to the Unified Parkinson's Disease Rating Scale (UPDRS) motor scores was described by a sigmoidal Emax model assuming effective concentration = drug concentration in an effect compartment. Apomorphine concentrations and UPDRS motor scores were simulated from the PK/PD models using 500 hypothetical subjects. UPDRS motor score change from baseline was evaluated using time to clinically relevant response, response duration, area under the curve, maximal response, and time to maximal response. Higher doses of each apomorphine formulation were associated with shorter time to response, longer response duration, and greater maximal response. Although the mean maximal responses to SC and SL apomorphine were comparable, the time to response was four times shorter (7 vs. 31 min) and time to maximal response was two times shorter (27 vs. 61 min) for 4 mg SC vs. 50 mg SL. Thus, faster onset of action was observed for the SC formulation compared to SL. These data may be useful for physicians when selecting "on demand" therapy for patients with Parkinson's disease experiencing motor fluctuations.

A post hoc analysis of the effect of viloxazine extended-release capsules on learning and school problems in children and adolescents with attention-deficit/hyperactivity disorder.

Improvement in attention-deficit/hyperactivity disorder (ADHD) symptoms vs. placebo was reported in a series of pediatric clinical trials of viloxazine extended-release capsules (viloxazine ER; Qelbree™). This post hoc analysis of those studies evaluated the effect of viloxazine ER on learning and school problems (LSPs). We used data from four Phase 3 placebo-controlled trials of 100-600 mg/day viloxazine ER (N = 1354; 6-17 years of age). LSPs were evaluated using the School domain of the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P-S) and the Learning Problems content scale of the Conners 3rd Edition-Parent Short Form (C3PS-LP) at baseline and end of study (≥ Week 6). ADHD symptoms were assessed weekly using the ADHD Rating Scale 5th Edition. The analyses were performed using the general linear mixed model with participant as a random effect. The responder analyses were performed using the Chi-square test. Viloxazine ER demonstrated significantly greater improvements in WFIRS-P-S (p < 0.0001) and C3PS-LP (p = 0.0113) scores vs. placebo. The response rate for the WFIRS-P-S was significantly greater for viloxazine ER vs. placebo (p = 0.001), and the number needed to treat (NNT) was 10.3 (effect size 0.7). Conversely, response rates for C3PS-LP did not differ between groups (p = 0.9069). In addition to ADHD symptoms improvement demonstrated in previous studies, viloxazine ER significantly reduced LSPs in pediatric subjects with ADHD. The responder analyses and NNT estimates indicate that a substantial number of children and adolescents with ADHD treated with viloxazine ER improved in clinically assessed LSPs.

Predicting efficacy of viloxazine extended-release treatment in adults with ADHD using an early change in ADHD symptoms: Machine learning Post Hoc analysis of a phase 3 clinical trial.

Early response to viloxazine extended-release (viloxazine ER, Qelbree®) treatment predicted efficacy outcome in pediatric subjects with attention-deficit/hyperactivity disorder (ADHD). This study sought to determine whether the machine learning lasso model used in the pediatric study would predict response to viloxazine ER in an adult population based on early improvements in ADHD symptoms. We used data from a double-blind, placebo-controlled, flexible-dose (200-600 mg) study of viloxazine ER (N = 354; 18 to 60 years old). Area under the Receiver Operating Characteristic Curve (ROC AUC) statistics were computed using the lasso model from pediatric data to predict responder status in adults. Response was defined as ≥50% reduction from baseline in the Adult ADHD Investigator Symptoms Rating Scale (AISRS) Total score at Week 6. The adult study sample included 127 viloxazine ER-treated subjects with Week 6 data. Fifty-one subjects (40.2%) were categorized as responders. The ROC curves indicated that data collected up to Week 2 were sufficient to accurately predict treatment response at Week 6 with 68% positive predictive power, 80% sensitivity, and 74% specificity. This analysis demonstrated that the predictive model estimated from the child data generalizes to adults with ADHD, further supporting the consistency of viloxazine ER treatment across age groups.

The role of placebo response in the efficacy outcome assessment in viloxazine extended-release pivotal trials in paediatric subjects with attention-deficit/hyperactivity disorder.

AIMS: Four Phase 3 studies evaluated efficacy and safety of viloxazine extended-release in the treatment of attention-deficit/hyperactivity disorder (ADHD). The primary efficacy objective-change from baseline in ADHD Rating Scale-5 (ADHD-RS-5) Total score at end of study (EOS)-was not met in one of the studies (812P304). A band-pass analysis was performed to evaluate the impact of placebo response on the results. METHODS: The distribution of placebo response at EOS of each trial was evaluated. The 2.5th and 97.5th percentiles of the distribution of ADHD-RS-5 Total score were used as boundaries for the band-pass analysis. An independent mixed model for repeated measures analysis was conducted for each trial using all eligible data (active and placebo) from the total and band-pass filtered populations. RESULTS: The 2.5th and 97.5th percentiles at EOS were 3.5 and 53.5, respectively. Application of the band-pass filter (filtering out all subjects [active, n = 305 (32.1%) and placebo, n = 134 (33.5%)] of clinical sites with placebo scores <3.5 or >53.5) revealed statistically significant improvement at the primary endpoint (600-mg/d viloxazine ER vs. placebo) in Study 812P304 (mean [confidence interval] = 4.9537 [0.5405-9.3669]), previously masked by a high placebo response (mean [confidence interval] = 3.5756 [-0.3332-7.4844]). The outcome of the analysis indicated that the impact of the band-pass adjustment is greater when placebo response is higher. CONCLUSION: This analysis indicated that a higher placebo response in Study 812P304 confounded the assessment of treatment effect. Application of the band-pass methodology confirmed the positive results of the 3 prior studies and the signal detection confounder in the fourth study.

Executive Function Outcome of Treatment with Viloxazine Extended-Release Capsules in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: A Post-Hoc Analysis of Four Randomized Clinical Trials.

AIM: The aim of this study was to evaluate the effect of viloxazine extended-release capsules (viloxazine ER; Qelbree™) on executive function deficits (EFDs) in pediatric subjects (6-17 years of age) with attention-deficit/hyperactivity disorder (ADHD). METHODS: Data from four phase III placebo-controlled trials of 100-600 mg/day viloxazine ER (6-8 weeks of treatment) were used to evaluate the change from baseline (CFB) in the Conners 3rd Edition Parent Short Form-Executive Function (C3PS-EF) content scale T-score. Subjects were defined as EFD responders if they had C3PS-EF T-score > 70 at baseline and < 65 at end of study. ADHD symptoms were assessed with ADHD Rating Scale 5th Edition (ADHD-RS-5). Subjects were defined as ADHD symptom responders if they had a ≥ 50% reduction in CFB ADHD-RS-5 Total score at Week 6. The number needed to treat (NNT) and Cohen's d effect sizes were estimated for EFD and ADHD symptoms. RESULTS: A total of 1154 subjects were included in the analysis. Statistically significant improvements in EFDs were observed with viloxazine ER versus placebo (p = 0.0002). There were 52.5% of EFD or ADHD symptom responders in the viloxazine ER treatment group and 35.4% in the placebo group (p < 0.0001). The NNT was 5.8. The Cohen's d effect size for EFD and ADHD symptoms was 0.31. CONCLUSION: Consistent with the efficacy of viloxazine ER demonstrated in pivotal trials, viloxazine ER significantly reduced EFDs in subjects with ADHD. Moreover, a substantial proportion of subjects treated with viloxazine ER had large improvements in EFDs, ADHD symptoms, or both. CLINICAL TRIAL REGISTRATION NUMBERS: NCT03247530, NCT03247517, NCT03247543, NCT03247556.

A Phase 3 Placebo-Controlled Trial of Once-Daily 400-mg and 600-mg SPN-812 (Viloxazine Extended-Release) in Adolescents with ADHD.

Objectives: Three Phase 3 trials have demonstrated the efficacy and safety of SPN-812 in pediatric subjects with ADHD. Here, we report the results of a fourth trial. Methods: Eligible adolescent subjects (N = 297) were randomized to SPN-812 (400- or 600-mg/day) or placebo. The primary efficacy endpoint was change from baseline (CFB) at end of study (EOS) in the ADHD Rating Scale-5 (ADHD-RS-5) Total score. Statistical analyses included sequential testing for multiple treatment comparisons. Key secondary endpoints included: Clinical Global Impression-Improvement (CGI-I) score at EOS and CFB at EOS in the Conners 3-Parent Short Form (Conners 3-PS) Composite T-score and Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) Total average score. Results: The CFB at EOS ADHD-RS-5 Total score (least square [LS] means ± SE) for 400-mg/day, 600-mg/day SPN-812, and placebo was -18.3 ± 1.36, -16.7 ± 1.39, and -13.2 ± 1.38, respectively. The difference vs. placebo was statistically significant only for the 400-mg/day SPN-812 treatment group (600 mg/day: p = 0.0712; 400 mg/day: p = 0.0082). Neither dose could be considered superior to placebo due to the use of statistical method of sequential testing. Significant improvements were observed on a number of secondary endpoints. SPN-812 was well tolerated at both doses, with <5% discontinuation rate due to adverse events. Conclusions: Treatment with 400- but not 600-mg/day SPN-812 resulted in statistically significant improvement in the primary endpoint. The negative result seen in the 600-mg/day SPN-812 group was likely due to an unusually high placebo response. Safety data were consistent across all doses in the SPN-812 trials.

The Effect of Viloxazine Extended-Release Capsules on Functional Impairments Associated with Attention-Deficit/Hyperactivity Disorder (ADHD) in Children and Adolescents in Four Phase 3 Placebo-Controlled Trials.

PURPOSE: The ADHD Rating Scale (ADHD-RS) assesses 18 symptoms of inattention and hyperactivity/impulsivity and has been used in many clinical trials to evaluate the treatment effect of drugs on ADHD. The fifth edition of this scale (ADHD-RS-5) also assesses the impact of inattention and hyperactivity/impulsivity symptoms on six domains of functional impairment (FI): family relationships, peer relationships, completing/returning homework, academic performance at school, controlling behavior at school, and self-esteem. Here, we report the effect of viloxazine extended-release capsules (viloxazine ER), a novel nonstimulant treatment for ADHD in children and adolescents (ages 6-17 years), on FI from a post hoc analysis of four randomized, double-blind, placebo-controlled Phase 3 clinical trials (N=1354). PATIENTS AND METHODS: ADHD-RS-5 investigator ratings of ADHD symptoms and FIs were conducted at baseline and weekly post-baseline for 6-8 weeks in the four trials. Change from baseline (CFB) in ADHD-RS-5 FI scores (Total score [sum of 12 FI items] and Inattention and Hyperactivity/Impulsivity subscale scores [sum of 6 corresponding FI items]) and the 30% and 50% Responder Rates (ADHD-RS-5 FI Total score) were compared between viloxazine ER and placebo. RESULTS: The reduction (improvement) in ADHD-RS-5 FI scores (Total and subscale scores) and the percentage of responders (30% and 50%) at Week 6 were significantly greater in each viloxazine ER dose group vs placebo. In the 100-400 mg/day viloxazine ER groups, improvements were found as early as Week 1 (100-mg/day) or Week 2 (200-, 400-mg/day) of treatment. Analysis of individual items of ADHD-related FIs demonstrated that the effect of viloxazine ER was observed across all domains of impairment. CONCLUSION: Significant improvements observed in ADHD-related FIs are consistent with the reduction in inattention and hyperactivity/impulsivity symptoms demonstrated in the viloxazine ER Phase 3 pediatric trials. Therefore, viloxazine ER provides clinically meaningful improvement of ADHD symptoms and functioning in children and adolescents with ADHD, starting as early as Week 1-2 of treatment.

Once-Daily SPN-812 200 and 400 mg in the treatment of ADHD in School-aged Children: A Phase III Randomized, Controlled Trial.

PURPOSE: SPN-812 (viloxazine extended-release) is under investigation for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. This Phase III study evaluated the efficacy and tolerability of SPN-812 200 and 400 mg once daily in children 6-11 years of age with ADHD. METHODS: Patients were randomly assigned to receive SPN-812 200 mg, SPN-812 400 mg, or placebo, once daily for 8 weeks (including ≤3 weeks titration period). The primary efficacy endpoint was the change from baseline (CFB) in ADHD Rating Scale (RS)-5 Total score at end of study (EOS). Key secondary endpoints included Clinical Global Impression-Improvement (CGI-I) score at EOS, CFB in Conners 3-Parent Short Form (PS) composite T-score at EOS, and CFB in Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) Total average score at EOS. FINDINGS: A total of 313 patients were enrolled, with 301 in the intent-to-treat population (194 boys, 107 girls; mean age [SD], 8.4 [1.7] years). At EOS, the CFBs in ADHD-RS-5 Total score and CGI-I score were significantly improved with both 200- and 400-mg/d SPN-812 versus placebo (ADHD-RS-5, P = 0.0038 and 0.0063, respectively; CGI-I, P = 0.0028 and 0.0099). At EOS, the CFB in Conners 3-PS composite T-score was significantly improved with 200- (P = 0.0064), but not 400-mg/d (P = 0.0917), SPN-812 compared to placebo. No significant difference between the groups was found in WFIRS-P Total average score. The rate of discontinuations due to adverse events in both SPN-812 treatment groups combined was <5%. IMPLICATIONS: SPN-812 200 and 400 mg once daily was associated with improvements in ADHD symptoms in school-aged children and was generally well tolerated. ClinicalTrials.gov identifier: NCT03247543.

Early response to SPN-812 (viloxazine extended-release) can predict efficacy outcome in pediatric subjects with ADHD: a machine learning post-hoc analysis of four randomized clinical trials.

Machine learning (ML) was used to determine whether early response can predict efficacy outcome in pediatric subjects with ADHD treated with SPN-812. We used data from four Phase 3 placebo-controlled trials of 100- to 600-mg/day SPN-812 (N=1397; 6-17 years of age). The treatment response was defined as having a ≥50% reduction in change from baseline (CFB) in ADHD Rating Scale-5 (ADHD-RS-5) Total score at Week 6. The variables used were: ADHD-RS-5 Total score, age, body weight, and body mass index at baseline; CFB ADHD-RS-5 Total score at Week 1, cumulative change in ADHD-RS-5 Total score at Week 2, and cumulative change in ADHD-RS-5 Total score at Week 3; Clinical Global Impressions-Improvement (CGI-I) score at Week 1, 2, and 3; and target dose. Using the best selected model, lasso regression, to generate importance scores, we found that change in ADHD-RS-5 Total score and CGI-I score were the best predictors of efficacy outcome. Change in ADHD-RS-5 Total score at Week 2 could predict treatment response at Week 6 (75% positive predictive power, 75% sensitivity, 74% specificity). Therefore, early response after two weeks of treatment with once-daily SPN-812 in pediatric patients with ADHD can predict efficacy outcome at Week 6.

Hippocampal long-term potentiation is disrupted during expression and extinction but is restored after reinstatement of morphine place preference.

Learned associations between environmental cues and morphine use play an important role in the maintenance and/or relapse of opioid addiction. Although previous studies suggest that context-dependent morphine treatment alters glutamatergic transmission and synaptic plasticity in the hippocampus, their role in morphine conditioned place preference (CPP) and reinstatement remains unknown. We investigated changes in synaptic plasticity and NMDAR expression in the hippocampus after the expression, extinction, and reinstatement of morphine CPP. Here we report that morphine CPP is associated with increased basal synaptic transmission, impaired hippocampal long-term potentiation (LTP), and increased synaptic expression of the NR1 and NR2b NMDAR subunits. Changes in synaptic plasticity, synaptic NR1 and NR2b expression, and morphine CPP were absent when morphine was not paired with a specific context. Furthermore, hippocampal LTP was impaired and synaptic NR2b expression was increased after extinction of morphine CPP, indicating that these alterations in plasticity may be involved in the mechanisms underlying the learning of drug-environment associations. After extinction of morphine CPP, a priming dose of morphine was sufficient to reinstate morphine CPP and was associated with LTP that was indistinguishable from saline control groups. In contrast, morphine CPP extinguished mice that received a saline priming dose did not show CPP and had disrupted hippocampal LTP. Finally, we found that reinstatement of morphine CPP was prevented by the selective blockade of the NR2b subunit in the hippocampus. Together, these data suggest that alterations in synaptic plasticity and glutamatergic transmission play an important role in the reinstatement of morphine CPP.

Increased small conductance calcium-activated potassium type 2 channel-mediated negative feedback on N-methyl-D-aspartate receptors impairs synaptic plasticity following context-dependent sensitization to morphine.

BACKGROUND: Hippocampal long-term potentiation (LTP) is impaired following repeated morphine administration paired with a novel context. This procedure produces locomotor sensitization that can be abolished by blocking calcium (Ca(2+))-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) in the hippocampus. However, the mechanisms underlying LTP impairment remain unclear. Here, we investigate the role of N-methyl-D-aspartate receptors (NMDARs), AMPARs, and small conductance Ca(2+)-activated potassium type 2 (SK2) channels in LTP induction after context-dependent sensitization to morphine. METHODS: Mice were treated with saline or escalating doses of morphine (5, 8, 10, and 15 mg/kg) every 12 hours in a locomotor activity chamber and a challenge dose of 5 mg/kg morphine was given 1 week later. After the challenge, the hippocampi were removed to assay phosphatase 2A (PP2A) activity, NMDAR, and SK2 channel synaptic expression or to perform electrophysiological recordings. RESULTS: Impaired hippocampal LTP, which accompanied morphine-induced context-dependent sensitization, could not be restored by blocking Ca(2+)-permeable AMPARs. Context-dependent sensitization to morphine altered hippocampal NMDAR subunit composition and enhanced the SK2 channel-mediated negative feedback on NMDAR. Increased PP2A activity observed following context-dependent sensitization suggests that the potentiated SK2 channel effect on NMDAR was mediated by increased SK2 sensitivity to Ca(2+). Finally, inhibition of SK2 channel or PP2A activity restored LTP. CONCLUSIONS: Our studies demonstrate that the SK2 channel-NMDAR feedback loop plays a role in opiate-induced impairment of hippocampal plasticity and that the positive modulation of SK2 channels occurs via increases in PP2A activity. This provides further evidence that small conductance Ca(2+)-activated potassium channels play a role in drug-induced plasticity.

Differential expression of two distinct functional isoforms of melanopsin (Opn4) in the mammalian retina.

Melanopsin is the photopigment that confers photosensitivity to a subset of retinal ganglion cells (pRGCs) that regulate many non-image-forming tasks such as the detection of light for circadian entrainment. Recent studies have begun to subdivide the pRGCs on the basis of morphology and function, but the origin of these differences is not yet fully understood. Here we report the identification of two isoforms of melanopsin from the mouse Opn4 locus, a previously described long isoform (Opn4L) and a novel short isoform (Opn4S) that more closely resembles the sequence and structure of rat and human melanopsins. Both isoforms, Opn4L and Opn4S, are expressed in the ganglion cell layer of the retina, traffic to the plasma membrane and form a functional photopigment in vitro. Quantitative PCR revealed that Opn4S is 40 times more abundant than Opn4L. The two variants encode predicted proteins of 521 and 466 aa and only differ in the length of their C-terminal tails. Antibodies raised to isoform-specific epitopes identified two discrete populations of melanopsin-expressing RGCs, those that coexpress Opn4L and Opn4S and those that express Opn4L only. Recent evidence suggests that pRGCs show a range of anatomical subtypes, which may reflect the functional diversity reported for mouse Opn4-mediated light responses. The distinct isoforms of Opn4 described in this study provide a potential molecular basis for generating this diversity, and it seems likely that their differential expression plays a role in generating the variety of pRGC light responses found in the mammalian retina.

Metabotropic regulation of intrinsic excitability by synaptic activation of kainate receptors.

Prolonged modification of intrinsic neuronal excitability is gaining prominence as an activity-dependent form of plasticity. Here we describe a potential synaptic initiation mechanism for these changes in which release of the transmitter glutamate acts on kainate receptors to regulate the postspike slow afterhyperpolarization (sAHP). This action of synaptically released glutamate was occluded by previous kainate application. Furthermore, inhibition of glutamate uptake enhanced the effects of synaptic activation. Glutamate-mediated kainate receptor inhibition of sAHP current (I(sAHP)) was blocked by the PKC inhibitor calphostin C, confirming the requirement for a metabotropic signaling cascade. These data describe a new physiological function for glutamate release: activation of metabotropic kainate receptors, which control directly the excitability of pyramidal cells and probably contribute to prolonged excitability changes.

Metabotropic-mediated kainate receptor regulation of IsAHP and excitability in pyramidal cells.

Kainate receptors (KARs) on CA1 pyramidal cells make no detectable contribution to EPSCs. We report that these receptors have a metabotropic function, as shown previously for CA1 interneurons. Brief kainate exposure caused long-lasting inhibition of a postspike potassium current (I(sAHP)) in CA1 pyramidal cells. The pharmacological profile was independent of AMPA receptors or the GluR5 subunit, indicating a possible role for the GluR6 subunit. KAR inhibition of I(sAHP) did not require ionotropic action or network activity, but was blocked by the inhibitor of pertussis toxin-sensitive G proteins, N-ethylmaleimide (NEM), or the PKC inhibitor calphostin C. These data suggest how KARs, putatively containing GluR6, directly increase excitability of CA1 pyramidal cells and help explain the propensity for seizure activity following KAR activation.