Role of the endocannabinoid system in fragile X syndrome: potential mechanisms for benefit from cannabidiol treatment.

Multiple lines of evidence suggest a central role for the endocannabinoid system (ECS) in the neuronal development and cognitive function and in the pathogenesis of fragile X syndrome (FXS). This review describes the ECS, its role in the central nervous system, how it is dysregulated in FXS, and the potential role of cannabidiol as a treatment for FXS. FXS is caused by deficiency or absence of the fragile X messenger ribonucleoprotein 1 (FMR1) protein, FMRP, typically due to the presence of >200 cytosine, guanine, guanine sequence repeats leading to methylation of the FMR1 gene promoter. The absence of FMRP, following FMR1 gene-silencing, disrupts ECS signaling, which has been implicated in FXS pathogenesis. The ECS facilitates synaptic homeostasis and plasticity through the cannabinoid receptor 1, CB1, on presynaptic terminals, resulting in feedback inhibition of neuronal signaling. ECS-mediated feedback inhibition and synaptic plasticity are thought to be disrupted in FXS, leading to overstimulation, desensitization, and internalization of presynaptic CB1 receptors. Cannabidiol may help restore synaptic homeostasis by acting as a negative allosteric modulator of CB1, thereby attenuating the receptor overstimulation, desensitization, and internalization. Moreover, cannabidiol affects DNA methylation, serotonin 5HT1A signal transduction, gamma-aminobutyric acid receptor signaling, and dopamine D2 and D3 receptor signaling, which may contribute to beneficial effects in patients with FXS. Consistent with these proposed mechanisms of action of cannabidiol in FXS, in the CONNECT-FX trial the transdermal cannabidiol gel, ZYN002, was associated with improvements in measures of social avoidance, irritability, and social interaction, particularly in patients who are most affected, showing ≥90% methylation of the FMR1 gene.

A randomized, controlled trial of ZYN002 cannabidiol transdermal gel in children and adolescents with fragile X syndrome (CONNECT-FX).

BACKGROUND: Fragile X syndrome (FXS) is associated with dysregulated endocannabinoid signaling and may therefore respond to cannabidiol therapy. DESIGN: CONNECT-FX was a double-blind, randomized phase 3 trial assessing efficacy and safety of ZYN002, transdermal cannabidiol gel, for the treatment of behavioral symptoms in children and adolescents with FXS. METHODS: Patients were randomized to 12 weeks of ZYN002 (250 mg or 500 mg daily [weight-based]) or placebo, as add-on to standard of care. The primary endpoint assessed change in social avoidance (SA) measured by the Aberrant Behavior Checklist-Community Edition FXS (ABC-CFXS) SA subscale in a full cohort of patients with a FXS full mutation, regardless of the FMR1 methylation status. Ad hoc analyses assessed efficacy in patients with ≥ 90% and 100% methylation of the promoter region of the FMR1 gene, in whom FMR1 gene silencing is most likely. RESULTS: A total of 212 patients, mean age 9.7 years, 75% males, were enrolled. A total of 169 (79.7%) patients presented with ≥ 90% methylation of the FMR1 promoter and full mutation of FMR1. Although statistical significance for the primary endpoint was not achieved in the full cohort, significant improvement was demonstrated in patients with ≥ 90% methylation of FMR1 (nominal P = 0.020). This group also achieved statistically significant improvements in Caregiver Global Impression-Change in SA and isolation, irritable and disruptive behaviors, and social interactions (nominal P-values: P = 0.038, P = 0.028, and P = 0.002). Similar results were seen in patients with 100% methylation of FMR1. ZYN002 was safe and well tolerated. All treatment-emergent adverse events (TEAEs) were mild or moderate. The most common treatment-related TEAE was application site pain (ZYN002: 6.4%; placebo: 1.0%). CONCLUSIONS: In CONNECT-FX, ZYN002 was well tolerated in patients with FXS and demonstrated evidence of efficacy with a favorable benefit risk relationship in patients with ≥ 90% methylation of the FMR1 gene, in whom gene silencing is most likely, and the impact of FXS is typically most severe. TRIAL REGISTRATION: The CONNECT-FX trial is registered on Clinicaltrials.gov (NCT03614663).

Post-hoc analyses of the edaravone clinical trials Study 16 and Study 19: a step toward more efficient clinical trial designs in amyotrophic lateral sclerosis.

Objectives: The edaravone development program established a study design in which a treatment effect slowing functional loss in amyotrophic lateral sclerosis (ALS) could be documented within a 24-week time frame. This report elucidates the strategic enrichment design utilized to create efficiency and precision in the development program. Methods: Post-hoc analyses describe learning, sequential iteration, and evolution in study design. Results: The first Phase 3 study of edaravone in ALS (Study MCI186-16) included a large proportion (35%) of placebo patients who were minimal progressors. These patients demonstrated high heterogeneity in change in ALSFRS-R score (-4 median with interquartile range [IQR] 7.5) and a modal distribution score of 0, suggesting evidence of minimal change in ALSFRS-R during the study. This level of variability and rate of progression may have made it difficult to detect a prospective treatment effect in the study. A strategic enrichment strategy provided the second Phase 3 study (Study MCI186-19) with the ability to detect a treatment effect. In Study MCI186-19, only 13% of the placebo patients were minimal progressors. Further, these placebo patients demonstrated less heterogeneity and greater functional progression of ALS, thereby providing greater likelihood of detecting a treatment effect. The enrichment strategy may have excluded some rapidly progressing patients, potentially supporting the detection of a treatment effect. As previously published, Study MCI186-19 prospectively documented a 33% reduction in rate of progression of ALS (p = 0.0013). Conclusions: Strategic choices in the design of Study MCI186-19 reduced the proportion of minimally progressing patients and supported detection of a treatment effect.

The Alcohol Clinical Trials Initiative (ACTIVE): purpose and goals for assessing important and salient issues for medications development in alcohol use disorders.

Although progress has been made in the treatment of alcohol use disorders, more effective treatments are needed. In the last 15 years, several medications have been approved for use in alcohol dependence but have only limited effectiveness and clinical acceptance. While academics have developed some 'standards' for the performance of clinical trials for alcohol dependence, they vary considerably, in the type of populations to be studied, the length of trials, salient outcome measures, and data analyses to be used (especially in the treatment of missing data). This variability impedes the commercial development of medications to treat alcohol dependence. Using a model similar to that used to develop an expert consensus for medications to improve cognitive aspects of schizophrenia (MATRICS) and in the treatment of pain (IMMPACT), a workgroup has been formed under the auspices of ACNP, known as the ACTIVE (Alcohol Clinical Trials Initiative) group, to evaluate data from completed clinical trials to develop a consensus on key issues in the conduct of clinical trials in alcohol dependence. ACTIVE consists of academic experts, industry representatives, and staff from the Food and Drug Administration, the National Institute on Alcohol Abuse and Alcoholism, and the National Institute on Drug Abuse. This paper describes the rationale behind the effort, its history and organization, and initial key questions that have been identified as the primary focus of the workgroup. Future papers will focus on knowledge gained from the re-analysis of completed trials and provide consensus opinions regarding the performance of clinical trials that might be undertaken in the future.

Dosing and switching strategies for paliperidone palmitate: based on population pharmacokinetic modelling and clinical trial data.

Paliperidone palmitate is a second-generation, long-acting injectable (LAI) antipsychotic recently approved by the US FDA and European Medicines Agency for use in patients with schizophrenia. This article reviews the recommended dosing regimens for initiation and maintenance treatment with paliperidone palmitate in adult patients with schizophrenia. We also address issues of switching to paliperidone palmitate from other antipsychotics, managing missed doses and dosing in special patient populations. The dosing recommendations that were approved by the FDA and other regulatory agencies around the world are based on the results of population pharmacokinetic (PK) simulations and data from clinical trials that are presented in this review. A one-compartment disposition model with zero/first-order absorption best described the PK of paliperidone palmitate. Population PK models for extended-release paliperidone and long-acting risperidone were also developed and we report the results from these models. The PK profiles for 5000 patients were simulated after paliperidone palmitate injections. The population median and 90% prediction intervals of the simulated plasma concentration versus time profiles after multiple doses are graphically displayed in this review. Based on the data from model-based PK simulations, the approved recommended initiation regimen for paliperidone palmitate is 150 mg equivalent (mg eq.) paliperidone (paliperidone palmitate 234 mg) on day 1 followed by 100 mg eq. paliperidone (paliperidone palmitate 156 mg) on day 8, each administered into the deltoid muscle, using a 1-inch 23-gauge needle in those weighing <90 kg and a 1.5-inch 22-gauge needle in those weighing ≥90 kg. No oral supplementation is required. Monthly maintenance dosing is in the range of 25-150 mg eq. paliperidone (paliperidone palmitate 39-234 mg; recommended dose of 75 mg eq. paliperidone [paliperidone palmitate 117 mg]) injected into the deltoid (needle size is weight adjusted) or gluteal (using a 1.5-inch 22-gauge needle) muscle. The day 8 dose may be administered ±2 days and monthly doses ±7 days, without a clinically significant impact on plasma concentrations. The re-initiation schedule in patients whose last maintenance dose was >6 weeks previously is dependent upon the duration of time since the last paliperidone palmitate injection. In patients with mild renal impairment (creatinine clearance [CL(CR)]: 50-80 mL/min), dosage should be adjusted. No dose adjustment is required in patients with mild or moderate hepatic impairment; no data currently exist regarding severe hepatic impairment. Elderly patients with normal renal function should receive the same dosage as younger adult patients with normal renal function. In the event of an age-related decline in CL(CR), dosage should be adjusted accordingly. Paliperidone palmitate can be initiated the day after discontinuing previous oral antipsychotic treatment. In patients switching from other LAIs (including long-acting risperidone), paliperidone palmitate dosing should be initiated at the time of what would have been the next scheduled injection of the previous LAI, and continued monthly thereafter. In summary, following initiation dosing, paliperidone palmitate is administered on a monthly basis. It is the first of the second-generation antipsychotics to be available and approved with this dosing regimen. Population PK modelling presented in this review has helped provide practical guidance for administering this novel LAI antipsychotic.

Deltoid injections of risperidone long-acting injectable in patients with schizophrenia.

BACKGROUND: Risperidone long-acting injectable was previously approved for treatment of schizophrenia as biweekly injections in the gluteal muscle only. We present data on local injection-site tolerability and safety of risperidone long-acting injectable and comparability of systemic exposure of deltoid versus gluteal injections. METHODS: Risperidone long-acting injectable was administered in an open-label, single-dose, two-way crossover study, with patients randomized to receive either 25mg gluteal/37.5mg deltoid crossover in two treatment periods or 50mg gluteal/50mg deltoid injections crossover; each treatment period was separated by an 85-day observation period (Study 1) and an open-label, multiple-dose study (4 sequential 37.5mg or 50mg deltoid injections every 2 weeks) (Study 2). The pharmacokinetic results from both the studies have already been published. RESULTS: In Study 1 (n=170), the majority of patients had no local injection-site findings, based on investigator and patient-rated evaluations. In Study 2 (n=53), seven of the 51 patients who received at least two deltoid injections discontinued (primary endpoint). However, none of the discontinuations were due to injection-site related reasons. The 90-percent upper confidence limit of the true proportion of injection-site issue withdrawals was 5.7 percent. No moderate or severe injection-site reactions were reported. CONCLUSION: Intramuscular injections via the deltoid and gluteal sites are equivalent routes of administration of risperidone long-acting injectable with respect to local injection-site tolerability. The overall safety and tolerability profile of risperidone long-acting injectable was comparable when administered as an intramuscular injection in the deltoid (37.5mg and 50mg) and gluteal (25mg and 50mg) sites.

A randomized, placebo- and active-controlled study of paliperidone extended release for the treatment of acute manic and mixed episodes of bipolar I disorder.

OBJECTIVES: To evaluate the antimanic efficacy and safety of paliperidone extended-release (ER) tablets in patients with bipolar I disorder. METHODS: This study included a 3-week, double-blind, acute treatment phase (paliperidone ER versus placebo, with quetiapine as control), and a 9-week, double-blind, maintenance phase (paliperidone ER versus quetiapine). Patients [n = 493; Young Mania Rating Scale (YMRS) score >or= 20] were randomized (2:2:1) to flexibly dosed paliperidone ER (3-12 mg/day), quetiapine (400-800 mg/day), or placebo for the acute treatment phase. During the maintenance phase, patients assigned to placebo were switched to paliperidone ER but not included in analysis of efficacy. RESULTS: Paliperidone ER was superior to placebo at the 3-week endpoint {primary outcome; least-squares mean difference in change from baseline in YMRS scores [95% confidence interval (CI)]: -5.5 (-7.57; -3.35); p < 0.001} and noninferior to quetiapine at the 12-week endpoint [least-squares mean difference (95% CI): 1.7 (-0.47; 3.96)]. The median mode dose during the 12-week treatment period was 9 mg for paliperidone ER and 600 mg for quetiapine. The most common (>or= 10%) treatment-emergent adverse events during the 12-week period were: headache (16%), somnolence (10%), and akathisia (10%) for paliperidone ER; somnolence (21%), sedation and dry mouth (17% each), headache (14%), and dizziness (13%) for quetiapine. Body weight increase >or= 7% from baseline to 12-week endpoint was 8% with paliperidone ER and 17% with quetiapine. A higher percentage of paliperidone ER (13.9%) versus quetiapine patients (7.5%) 'switched to depression' at the12-week endpoint. CONCLUSIONS: Paliperidone ER (3-12 mg/day) was efficacious and tolerable in the treatment of acute mania.

Risperidone long-acting injectable monotherapy in the maintenance treatment of bipolar I disorder.

BACKGROUND: Treatment adherence is a significant problem in patients with bipolar disorder. This study was designed to determine the efficacy of risperidone long-acting injectable (LAI) in the maintenance treatment of bipolar I disorder. METHODS: Eligible patients with current or recent manic or mixed episodes (n = 559, aged 18-65 years) were treated with open-label oral risperidone for 3 weeks (period II) and open-label risperidone LAI for 26 weeks (n = 501; period III). Patients who maintained response (n = 303) were randomly allocated 1:1 to placebo injections (n = 149) or to continue risperidone LAI (n = 154) for up to 24 months (period IV). RESULTS: Most (77%) patients on risperidone LAI received a dose of 25 mg every 2 weeks during period IV. Time to recurrence for any mood episode (primary outcome variable) was significantly longer in the risperidone LAI group versus placebo (p < .001); the difference was significant for time to recurrence of elevated-mood episode (p < .001) but not time to recurrence of depressive episode (p = .805). Weight gains > or = 7% (compared with the period's baseline) occurred in 15% of patients in period III; in 12% of patients on risperidone LAI and 3% of patients on placebo in period IV. CONCLUSIONS: Risperidone LAI monotherapy significantly delayed the time to recurrence of mood episodes, versus placebo, in this controlled, randomized study in patients with bipolar I disorder. Risperidone LAI was tolerable and no new safety concerns emerged compared with previous studies of risperidone LAI.

A double-blind, placebo-controlled, randomized study evaluating the effect of paliperidone extended-release tablets on sleep architecture in patients with schizophrenia.

The effects of paliperidone extended-release on sleep architecture in patients with schizophrenia-related insomnia were evaluated in this multicenter, double-blind, randomized, placebo-controlled study. Patients received paliperidone extended-release 9 mg/day or matching placebo during the 14-day double-blind phase. Sleep architecture and sleep continuity were evaluated using polysomnograms. Subjective sleep measures were evaluated daily using the Leeds Sleep Evaluation Questionnaire. Efficacy and safety were also assessed. Thirty-six patients (17 on paliperidone extended-release, 19 on placebo; mean age 32.2 years) completed the study. Paliperidone extended-release treatment vs. placebo resulted in clinically and statistically significant differences in sleep measurements from baseline to endpoint including a reduction in: persistent sleep latency (41 min), sleep onset latency (35 min), number of awakenings after sleep onset (7), time awake in bed (50 min), and stage 1 sleep duration (12 min); prolongation in: total sleep time (53 min), sleep period time (42 min), stage 2 sleep duration (51 min), and rapid eye movement sleep duration (18 min); and an increase in sleep efficiency index (11%). Paliperidone extended-release, compared with placebo, did not exacerbate daytime somnolence and improved symptoms of schizophrenia. Paliperidone extended-release was well tolerated and improved sleep architecture and sleep continuity in patients diagnosed with schizophrenia and concomitant insomnia.

An open-label extension trial of risperidone monotherapy in the treatment of bipolar I disorder.

The primary objective of this 9-week open-label extension trial was to assess the effects of risperidone monotherapy in patients with acute bipolar I disorder who completed treatment in two preceding 3-week double-blind trials. Patients with DSM-IV bipolar I disorder, experiencing an acute manic episode, received a flexible dose of risperidone (1-6 mg/day) or placebo in two independent double-blind, randomized, 3-week monotherapy trials. Completers who required ongoing treatment were eligible to enter this open-label 9-week extension trial during which all patients received risperidone. The primary efficacy measure was the mean change in the Young Mania Rating Scale (YMRS) total score. Secondary efficacy measures included the Clinical Global Impressions-Severity Scale, Montgomery-Asberg Depression Rating Scale, Positive and Negative Syndrome Scale and Global Assessment Scale. Safety assessments included adverse event reports, laboratory tests, and the Extrapyramidal Symptom Rating Scale (ESRS). Of the 283 patients who entered the extension study, 160 had previously received risperidone (RIS/RIS) in the acute treatment trial and 123 had received placebo (PLA/RIS). This study was completed by 71% of these patients. The mean+/-SE modal dose of risperidone was 4.6+/-1.5 mg/day. Patients in both the RIS/RIS and PLA/RIS groups improved significantly at the endpoint of the 9-week open-label study compared to their open-label baseline scores (-5.2+/-0.69, P<0.001 and -9.12+/-1.44, P<0.001, respectively) on the YMRS. Furthermore, changes from double-blind baseline to open-label endpoint were -29.4+/-1.0 in the RIS/RIS group and -23.9+/-1.4 in the PLA/RIS group. Significant improvements from both double-blind and open-label baseline were seen at week 1 of the open-label trial (P<0.001) and at each subsequent timepoint. A similar pattern was observed on the secondary measures of efficacy. Most frequent adverse events were extrapyramidal disorder (18%) and somnolence (12%). Most adverse events were mild or moderate in severity. The mean score for the Parkinsonism subscale of the ESRS was 1.1 at open-label baseline, and decreased by 0.1 at endpoint. Mean increase in body weight from open-label baseline was 0.6 kg in patients treated with placebo in the preceding double-blind trial and 1.2 kg in patients previously treated with risperidone. Risperidone treatment was well tolerated and resulted in further improvement during the 9-week extension, beyond the 3 weeks of acute treatment. Patients switched from placebo to risperidone improved markedly. Risperidone treatment did not induce depression.