Serotonergic Drugs for the Treatment of Attention-Deficit/Hyperactivity Disorder: A Review of Past Development, Pitfalls and Failures, and a Look to the Future.

Serotonin has been implicated in the neurobiology of attention-deficit/hyperactivity disorder (ADHD) due to its association with impulsivity, attention, and emotional regulation. Many compounds with serotonergic properties have been evaluated in ADHD, but few have been approved by regulatory authorities. Utilizing a search of public databases, we identified interventions studied in ADHD. Prescribing information and peer-reviewed and gray literature helped us to determine which compounds had an underlying mechanism of action associated with changing serotonin levels. Of the 24 compounds that met the search criteria, 16 had either failed clinical studies in an ADHD population or had been discontinued from future development. The available evidence was assessed to identify the developmental history of drugs with serotonergic activity and the outlook for new ADHD drug candidates targeting serotonin. Several treatment candidates floundered due to an inability to balance effectiveness with safety, underscoring the potential importance of potency, and selectivity. Ongoing drug development includes compounds with multimodal mechanisms of action targeting neurotransmission across serotonin, norepinephrine, and dopamine pathways; it appears likely that treatment which balances competing and complementary monoamine effects may provide improved outcomes for patients. It is hoped that continuing research into ADHD treatment will produce new therapeutic options targeting the serotonergic system, which can positively impact a wide range of symptoms, including mood, anxiety, and sleep as well as attention and hyperactivity.

Efficacy and Safety of Esmethadone (REL-1017) in Patients With Major Depressive Disorder and Inadequate Response to Standard Antidepressants: A Phase 3 Randomized Controlled Trial.

Objective: To test esmethadone (REL-1017) as adjunctive treatment in patients with major depressive disorder (MDD) and inadequate response to standard antidepressants.Methods: In this phase 3, double-blind, placebo-controlled trial, outpatients with MDD (DSM-5) were randomized to daily oral esmethadone (75 mg on day 1, followed by 25 mg daily on days 2 through 28) or placebo between December 2020 and December 2022. The primary efficacy measure was change from baseline (CFB) to day 28 in the Montgomery-Asberg Depression Rating Scale (MADRS) score. The intent-to-treat (ITT) population included all randomized participants. The per-protocol (PP) population included completers without major protocol deviations impacting assessment. Post hoc analyses included participants with severe depression (baseline MADRS score ≥35).Results: For the ITT analysis (n = 227), mean CFB was 15.1 (SD 11.3) for esmethadone (n = 113) and 12.9 (SD 10.4) for placebo (n = 114), with a mean difference (MD) of 2.3, which was not statistically significant (P = .154; Cohen effect size [ES] = 0.21). Remission rates were 22.1% and 13.2% (P = .076), and response rates were 39.8% and 27.2% (P = .044) with esmethadone and placebo, respectively. For the PP analysis (n = 198), mean CFB was 15.6 (SD 11.2) for esmethadone (n = 101) and 12.5 (SD 9.9) for placebo (n = 97), with an MD of 3.1 (P = .051; ES =0.29). In post hoc analyses of patients with baseline MADRS ≥35 in the ITT population (n = 112), MD was 6.9; P = .0059; ES = 0.57, and for the PP population (n = 98), MD was 7.9; P = .0015; ES = 0.69. Adverse events (AEs) were predominantly mild or moderate and transient, with no significant differences between groups.Conclusions: The primary end point was not met. Esmethadone showed stronger efficacy in PP than in ITT analyses, with the discrepancy not attributable to AEs impacting treatment adherence. Significant efficacy occurred in post hoc analyses of patients with severe depression. Esmethadone was well tolerated, consistent with prior studies.Trial Registration: ClinicalTrials.gov identifier: NCT04688164.

Serdexmethylphenidate/dexmethylphenidate for children with attention-deficit/hyperactivity disorder: dose optimization from a laboratory classroom study.

Objective: To evaluate treatment responder rate using the Attention-Deficit/Hyperactivity Disorder Rating Scale-5 (ADHD-RS-5) score based on optimized dose level of serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) and changes in ADHD severity in children (aged 6-12 years) with ADHD. Methods: During a 21-day dose-optimization phase, 155 patients initiated treatment with 39.2/7.8 mg SDX/d-MPH in the first week and then were titrated to an optimum dose; 5 patients were downtitrated to 26.1/5.2 mg, 76 were uptitrated to 52.3/10.4 mg, and 69 remained at 39.2/7.8 mg during the following 2 weeks. Responder threshold values were 30% and 50% based on the percent change from baseline (day 0) to days 7, 14, and 21 in the ADHD-RS-5 score. The Conners 3rd Edition-Parent score was used to assess weekly changes in ADHD severity during the dose-optimization and treatment phases. Results: Of the 5 subjects whose dose was optimized at 26.1/5.2 mg, ≥80% across all days had ≥50% responder rate. Of the 69 subjects whose dose was optimized at 39.2/7.8 mg, 81.2% had ≥50% responder rate by day 21. Of the 76 subjects whose dose was optimized to 52.3/10.4 mg, 72.4% had ≥50% responder rate by day 21. Changes in ADHD severity, based on mean Conners 3rd Edition-Parent scores, improved from baseline at each visit during dose optimization for each subscale. At the dose-optimization phase, Conners 3rd Edition-Parent scores improved from baseline for SDX/d-MPH in all subscales. Conclusion: A high percentage of subjects were responders upon reaching their final optimized dose. SDX/d-MPH demonstrated significant reductions in ADHD severity in children based on the Conners 3rd Edition-Parent scores. Determining the optimal dosage of SDX/d-MPH and its effect on ADHD severity could enable the development of a more clinically relevant treatment regimen in children with ADHD.

Estimating Changes in Weight and Metabolic Parameters Before and After Treatment With Cariprazine: A Retrospective Study of Electronic Health Records.

PURPOSE: Weight gain and associated negative cardiometabolic effects can occur as a result of mental illness or treatment with second-generation antipsychotics (SGAs), leading to increased rates of morbidity and mortality. In this analysis, we evaluated the effect of the SGA cariprazine on weight and metabolic parameters in a real-world, retrospective, observational dataset. METHODS: Electronic health records from the Optum Humedica database (October 1, 2014-December 31, 2020) were analyzed during the 12-month period before starting cariprazine (baseline) and for up to 12 months following cariprazine initiation; approved and off-label indications were included. Body weight trajectories were estimated in the overall patient cohort and at 3-, 6-, and 12-month timepoints (primary objective). Changes in hemoglobin A1c (HbA1c), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides were also evaluated (secondary objectives). Percentages of patients with clinically relevant shifts in body weight, total cholesterol, and fasting triglycerides were also determined. Discontinuation rates for metabolic regulating medications were calculated. Average predicted values were estimated by linear mixed-effects regression models. FINDINGS: A total of 2,301 patients were included; average duration of follow-up was 133.7 days. Average predicted weight change for patients during the cariprazine overall follow-up period was +2.4 kg, with predicted weight changes of +0.8 kg (n = 811), +1.1 kg (n = 350), and +1.4 kg (n = 107) at months 3, 6, and 12, respectively. Overall, the majority of patients did not experience clinically significant (≥7%) weight gain (82.8%) or loss (90.5%) after starting cariprazine. Average predicted HbA1c levels (n = 189) increased during baseline (0.15%/year) and decreased during cariprazine treatment (-0.2%/year). Average predicted triglyceride levels (n = 257) increased during baseline (15.0 mg/dL/year) and decreased during cariprazine treatment (-0.7 mg/dL/year). Predicted LDL (n = 247) and HDL (n = 255) values decreased during baseline (-7.3 and -1.1 mg/dL/year, respectively); during cariprazine treatment, LDL increased by 5.6 mg/dL/year and HDL decreased by -0.6 mg/dL/year. During follow-up, most patients did not shift from normal/borderline to high total cholesterol (<240 to ≥240 mg/dL; 522 [90.2%]) or fasting triglyceride (<200 to ≥200 mg/dL; 143 [88.8%] patients) levels; shifts from high to normal/borderline levels occurred in 44 (61.1%) patients for total cholesterol and 38 (57.6%) patients for fasting triglycerides. After starting cariprazine, the discontinuation rate per 100 patient-years was 60.4 for antihyperglycemic medication and 87.4 for hyperlipidemia medication. IMPLICATIONS: These real-world results support short-term clinical trial findings describing a neutral weight and metabolic profile associated with cariprazine treatment and they expand the dataset to include long-term follow-up.

Efficacy of cariprazine in patients with bipolar depression and higher or lower levels of baseline anxiety: a pooled post hoc analysis.

Post hoc analyses evaluated cariprazine, a dopamine D 3 -preferring D 3 /D 2 receptor partial agonist, in patients with bipolar I depression and high baseline anxiety. Data were pooled from two phase 3, randomized, double-blind, placebo-controlled studies in adults with bipolar I disorder and a major depressive episode (NCT02670538, NCT02670551). Cariprazine 1.5 and 3 mg/d were evaluated in patient subgroups with higher and lower baseline anxiety. In patients with higher baseline anxiety, significant differences for cariprazine 1.5 mg/d versus placebo were observed on change in Montgomery-Åsberg Rating Scale (MADRS) total score, Hamilton Anxiety Rating Scale (HAM-A) total score and subscale scores, and rates of MADRS remission ( P < 0.05 all); nonsignificant numerical improvements were observed for cariprazine 3 mg/d versus placebo. In patients with lower anxiety, differences versus placebo were significant for HAM-A (cariprazine 3 mg/d) and MADRS (cariprazine 1.5 and 3 mg/d) total score changes ( P < 0.05 all). Rates of treatment-emergent mania were low and similar for cariprazine and placebo. Cariprazine 1.5 mg/d had consistent effects on anxiety and depression symptoms in patients with bipolar I depression and higher baseline anxiety; tolerability was favorable. Given few proven treatments for this common comorbidity, these preliminary results are promising.

Long-Term Safety and Efficacy of Initial and Repeat Treatment Courses With Zuranolone in Adult Patients With Major Depressive Disorder: Interim Results From the Open-Label, Phase 3 SHORELINE Study.

Objective: Zuranolone is a positive allosteric modulator of both synaptic and extrasynaptic γ-aminobutyric acid (GABA) type A receptors and a neuroactive steroid approved in the United States as an oral, once-daily, 14-day treatment course for adults with postpartum depression and under investigation for adults with major depressive disorder (MDD). Interim results from the open-label, longitudinal, phase 3 SHORELINE Study (NCT03864614) that evaluated the long-term safety and efficacy of zuranolone in adults with MDD are reported.Methods: This interim report includes patients who were enrolled and had the opportunity to be on study for up to 1 year between February 2019 and September 2021. Adults aged 18-75 years with MDD diagnosed per DSM-5 criteria and a 17-item Hamilton Rating Scale for Depression (HAMD-17) total score ≥ 20 received an initial 30-mg or 50-mg 14-day zuranolone course. HAMD-17 responders (≥ 50% reduction from baseline) at Day (D)15 of the initial treatment period were allowed to continue in the study beyond D28 and were followed up for ≤ 1 year, during which repeat treatment courses were permitted. The primary endpoint was safety and tolerability of the initial and repeat treatment courses through 1 year. Secondary endpoints included change from baseline (CFB) in HAMD-17 total score and need for repeat treatment course(s).Results: As of September 2021, among patients in the 30-mg (n = 725) and 50-mg (n = 199) Cohorts who received a zuranolone dose, 493 (68.0%) and 137 (68.8%), respectively, reported a treatment-emergent adverse event (TEAE); most patients who experienced TEAEs reported mild/moderate events (30-mg Cohort, 90.9% [448/493]; 50-mg Cohort, 85.4% [117/137]). Mean (standard deviation) CFB HAMD-17 total score at D15 of the initial treatment period was -15.2 (7.1) and -16.0 (6.0) for the 30-mg and 50-mg Cohorts, respectively; similar improvements were observed after repeat treatment courses. The proportion of patients who received only 1 treatment course during their time on study was 42.9% (210/489) in the 30-mg Cohort and 54.8% (80/146) in the 50-mg Cohort; 57.1% (279/489) and 45.2% (66/146) patients, respectively, received 2-5 total treatment courses. The majority of patients who initially responded to zuranolone received ≤ 2 total treatment courses (30-mg Cohort, 68.5% [335/489]; 50-mg Cohort, 79.5% [116/146]).Conclusions: Of patients who experienced TEAEs, most reported mild or moderately severe events, and responders to zuranolone experienced improvements in depressive symptoms with initial and repeat treatment courses.Trial Registration: ClinicalTrials.gov identifier: NCT03864614.

Serdexmethylphenidate/dexmethylphenidate effects on sleep in children with attention-deficit/hyperactivity disorder.

Introduction: Sleep-related problems are common in children with attention-deficit/hyperactivity disorder (ADHD). Sleep disorders are also side effects of all stimulant ADHD medications. Serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) is a once-daily treatment approved for patients age 6 years and older with ADHD. In this analysis, sleep behavior was assessed during SDX/d-MPH treatment in children with ADHD. Methods: In a 12-month, dose-optimized, open-label safety study in 6- to 12-year-old participants (NCT03460652), a secondary endpoint was assessment of sleep behavior based on the Children's Sleep Habits Questionnaire (CSHQ) consisting of 8 sleep domains (bedtime resistance, sleep onset delay, sleep duration, sleep anxiety, night wakings, parasomnias, sleep-disordered breathing, and daytime sleepiness). This post hoc analysis examined the individual sleep domains in the 12-month safety study. Results: Of 282 participants enrolled, 238 were included in the sleep analysis. At baseline, mean (SD) CSHQ total sleep disturbance score was 53.4 (5.9). After 1 month of treatment, the mean (SD) CSHQ total score significantly decreased to 50.5 (5.4); least-squares mean change from baseline was -2.9 (95% CI: -3.5 to -2.4; p < 0.0001) and remained decreased up to 12 months. Mean sleep-score improvements from baseline to 12 months were statistically significant (p < 0.0001) for 5 of 8 sleep domains, including bedtime resistance, sleep anxiety, night wakings, parasomnias, and daytime sleepiness. Parasomnias and daytime sleepiness sleep domains showed the greatest mean improvement from baseline to 12 months. Sleep onset delay and sleep duration scores increased from baseline to 12 months. No statistically significant worsening occurred from baseline in sleep duration and sleep-disordered breathing domains; however, worsening of sleep onset delay was statistically significant. Conclusion: In this analysis of children taking SDX/d-MPH for ADHD, sleep problems did not worsen based on the mean CSHQ total sleep disturbance score. Statistically significant improvements in most CSHQ sleep domains were observed after 1 month and lasted for up to 12 months of treatment.

Understanding the mechanism of action and clinical effects of neuroactive steroids and GABAergic compounds in major depressive disorder.

The pathophysiology of major depressive disorder (MDD) is thought to result from impaired connectivity between key brain networks. Gamma-aminobutyric acid (GABA) is the key inhibitory neurotransmitter in the brain, working primarily via GABAA receptors, with an important role in virtually all physiologic functions in the brain. Some neuroactive steroids (NASs) are positive allosteric modulators (PAMs) of GABAA receptors and potentiate phasic and tonic inhibitory responses via activation of synaptic and extrasynaptic GABAA receptors, respectively. This review first discusses preclinical and clinical data that support the association of depression with diverse defects in the GABAergic system of neurotransmission. Decreased levels of GABA and NASs have been observed in adults with depression compared with healthy controls, while treatment with antidepressants normalized the altered levels of GABA and NASs. Second, as there has been intense interest in treatment approaches for depression that target dysregulated GABAergic neurotransmission, we discuss NASs approved or currently in clinical development for the treatment of depression. Brexanolone, an intravenous NAS and a GABAA receptor PAM, is approved by the U.S. Food and Drug Administration for the treatment of postpartum depression (PPD) in patients 15 years and older. Other NASs include zuranolone, an investigational oral GABAA receptor PAM, and PH10, which acts on nasal chemosensory receptors; clinical data to date have shown improvement in depressive symptoms with these investigational NASs in adults with MDD or PPD. Finally, the review discusses how NAS GABAA receptor PAMs may potentially address the unmet need for novel and effective treatments with rapid and sustained antidepressant effects in patients with MDD.

d-Amphetamine Transdermal System in Treatment of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Secondary Endpoint Results and Post Hoc Effect Size Analyses from a Pivotal Trial.

Objectives: Amphetamines are a preferred treatment for attention-deficit/hyperactivity disorder (ADHD), with the dextroamphetamine transdermal system (d-ATS) providing an alternative to oral formulations. A pivotal trial of d-ATS in children and adolescents with ADHD met primary and key secondary endpoints. This analysis reports additional endpoints and safety findings from the pivotal trial and evaluates effect size and number needed to treat (NNT) for d-ATS. Methods: In this study, a 5-week, open-label dose-optimization period (DOP) preceded a 2-week, randomized, crossover double-blind treatment period (DBP). Eligible patients received d-ATS 5 mg during the DOP, with weekly evaluations for increase to 10, 15, and 20 mg (equivalent to labeled doses of 4.5, 9, 13.5, and 18 mg/9 hours, respectively) until reaching and maintaining the optimal dose, which was utilized for the DBP. Secondary endpoints included assessment of Attention-Deficit/Hyperactivity Disorder Rating Scale IV (ADHD-RS-IV), Conners' Parent Rating Scale Revised Short Form (CPRS-R:S), and Clinical Global Impression (CGI) scores. NNT was calculated for ADHD-RS-IV and CGI-Improvement (CGI-I). Safety assessments included treatment-emergent adverse events (TEAEs) and dermal safety. Results: In total, 110 patients entered the DOP, with 106 patients randomized (DBP). During the DBP, the least-squares mean (95% confidence interval) difference for d-ATS versus placebo in ADHD-RS-IV total score was -13.1 (-16.2 to -10.0; p < 0.001), with effect size of 1.1 and NNT of 3 for ADHD-RS-IV remission, ≥30% improvement, and ≥50% improvement. Significant differences between placebo and d-ATS were also observed for CPRS-R:S and CGI-I scales (p < 0.001), with NNT of 2 for CGI-I response. Most TEAEs were mild or moderate, with three leading to study discontinuation in the DOP and none in the DBP. No patients discontinued due to dermal reactions. Conclusions: d-ATS was effective in treating ADHD in children and adolescents, meeting all secondary endpoints, with a large effect size and NNT of 2-3 to achieve a clinically meaningful response. d-ATS was safe and well tolerated, with minimal dermal reactions. Clinical Trial Registration: NCT01711021.

Analysis of Growth Velocity in Children with Attention-Deficit/Hyperactivity Disorder Treated for up to 12 Months with Serdexmethylphenidate/Dexmethylphenidate.

Objective: Serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) is approved for the treatment of patients aged ≥6 years with attention-deficit/hyperactivity disorder (ADHD). A 12-month, open-label safety study with SDX/d-MPH in children with ADHD showed that SDX/d-MPH was well tolerated and comparable with other methylphenidate products. In this post hoc analysis of the 12-month study, the objective was to characterize the effect of SDX/d-MPH on growth in children with ADHD over 12 months. Methods: This was a post hoc analysis of a dose-optimized, open-label, phase 3 safety study of SDX/d-MPH in children aged 6-12 years with ADHD (NCT03460652). Weight and height Z-score analyses were conducted. Z-score change from baseline was calculated based on the baseline values for the subjects remaining in the study at the observation time point. Results: Subjects (N = 238) from the treatment-phase safety population included all enrolled subjects who received ≥1 dose of study drug and had ≥1 postdose safety assessment. During treatment, the mean weight and height Z-scores decreased over time from their respective baselines. At the 12-month time point, mean (standard deviation [SD]) Z-score changes from baseline for weight and height for the subjects remaining in the study were -0.20 (0.50) and -0.21 (0.39), respectively; however, these mean changes in Z-scores were not clinically significant (change <0.5 SD). Long-term treatment with SDX/d-MPH was associated with modest reductions in expected weight and lower-than-expected increases in height: effects that plateaued or diminished later in treatment. Conclusion: The overall effects of SDX/d-MPH on growth velocity (the change in weight and height from one time point to the next) were minimal, and the range of changes was not considered clinically significant. ClinicalTrials.gov identifier: NCT03460652.