A Long-Term, Open-Label, Safety Study of Triple-Bead Mixed Amphetamine Salts (SHP465) in Adults With ADHD

The Therapeutic Potential of Amphetamine-like Psychostimulants

This review delves into the therapeutic applications of amphetamine-type stimulants such as lisdexamphetamine dimesylate, mixed amphetamine salts, 3,4-methylenedioxymethamphetamine (MDMA), dextroamphetamine, and phentermine. These compounds have been investigated for their potential in treating a range of psychiatric disorders, including attention deficit hyperactivity disorder (ADHD), drug dependence, post-traumatic stress disorder (PTSD), and obesity. Lisdexamphetamine dimesylate has shown promise in effectively treating ADHD symptoms in both children and adults. Additionally, it has been explored as a potential treatment for drug dependency and withdrawal, demonstrating encouraging results. Mixed amphetamine salts have also exhibited efficacy in reducing ADHD symptoms in adults. Future research should explore their potential use in treating bipolar disorder and cocaine dependence, considering the associated risks and benefits. MDMA-assisted psychotherapy has emerged as an innovative approach to treating PTSD, leading to sustained reductions in symptoms and even promoting post-traumatic growth. Furthermore, it has shown promise in managing anxiety related to life-threatening illnesses. Dextroamphetamine and phentermine have demonstrated efficacy in treating cocaine and opioid dependence, ADHD, and obesity. However, careful consideration and monitoring by medical professionals are essential due to the potential risks and benefits associated with them. In conclusion, amphetamine-type stimulants present a promising avenue for therapeutic interventions in various psychiatric conditions. Nevertheless, further research is necessary to comprehensively understand their mechanisms of action, dosage requirements, and long-term effects in different patient populations.

The effects of stimulant and non-stimulant medications on the autonomic nervous system (ANS) functioning in people with ADHD: A systematic review and meta-analysis

We carried out a systematic review and meta-analysis to investigate the effects of stimulant and non-stimulant medications on autonomic functioning in people with ADHD (PROSPERO: CRD42020212439). We searched (9th August 2021) PsycInfo, MEDLINE, EMBASE, Web of Science and The Cochrane Library, for randomised and non-randomised studies reporting indices of autonomic activity, (electrodermal, pupillometry and cardiac), pre- and post-medication exposure in people meeting DSM/ICD criteria for ADHD. In the narrative syntheses, we included 5 electrodermal studies, 1 pupillometry study and 57 studies investigating heart rate and blood pressure. In the meta-analyses, 29 studies were included on blood pressure and 32 on heart rate. Administration of stimulants, and to a lesser degree, non-stimulants increased heart rate and blood pressure in people with ADHD. Similarly, an upregulation of arousal, reflected in increased electrodermal activity and pupil diameter was observed following stimulant use. Yet, the methodological diversity of studies presented in this review reinforces the need for more standardised and rigorous research to fully understand the relationship between arousal, medication, and behaviour in ADHD.

New Formulations of Stimulants: An Update for Clinicians

In the last 15 years, there has been a marked increase in the number of available stimulant formulations with the emphasis on long-acting formulations, and the introduction of several novel delivery systems such as orally dissolving tablets, chewable tablets, extended-release liquid formulations, transdermal patches, and novel "beaded" technology. All of these formulations involve changes to the pharmaceutical delivery systems of the two existing compounds most commonly employed to treat attention-deficit/hyperactivity disorder (ADHD), amphetamine (AMP) and methylphenidate (MPH). In addition to these new formulations, our knowledge about the individual differences in response has advanced and contributes to a more nuanced approach to treatment. The clinician can now make increasingly informed choices about these formulations and more effectively individualize treatment in a way that had not been possible before. In the absence of reliable biomarkers that can predict individualized response to ADHD treatment, clinical knowledge about differences in MPH and AMP pharmacodynamics, pharmacokinetics, and metabolism can be utilized to personalize treatment and optimize response. Different properties of these new formulations (delivery modality, onset of action, duration of response, safety, and tolerability) will most likely weigh heavily into the clinician's choice of formulation. To manage the broad range of options that are now available, clinicians should familiarize themselves in each of these categories for both stimulant compounds. This review is meant to serve as an update and a guide to newer stimulant formulations and includes a brief review of ADHD and stimulant properties.

A randomized, double-blind study of SHP465 mixed amphetamine salts extended-release in adults with ADHD using a simulated adult workplace design

OBJECTIVES

The objective of this paper was to evaluate the efficacy, duration of effect, and tolerability of SHP465 mixed amphetamine salts (MAS) extended-release versus placebo and immediate-release MAS (MAS IR) in adults with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Adults with ADHD Rating Scale, Version IV (ADHD-RS-IV) scores ≥24 were randomized to SHP465 MAS (50 or 75 mg), placebo, or 25 mg MAS IR in a double-blind, three-period, crossover study using a simulated adult workplace environment. On the final day of each 7-day treatment period, efficacy was assessed for 16 h postdose. Primary efficacy analyses for Permanent Product Measure of Performance (PERMP) total score averaged across all postdose assessments and each postdose time point were conducted in the intent-to-treat population using a mixed linear model. Secondary end-points included PERMP problems attempted and answered correctly and ADHD-RS-IV scores based on clinician ratings of counselor observations using the Time Segment Rating System and participant self-report. Tolerability assessments included treatment-emergent adverse events (TEAEs) and vital signs.

RESULTS

Least squares mean (95% CI) treatment differences (combined 50/75 mg SHP465 MAS-placebo) significantly favored SHP465 MAS over placebo for PERMP total score averaged across all postdose assessments (18.38 [11.28, 25.47]; P < .0001) and at each postdose assessment (all P < .02). Nominal superiority of MAS IR over placebo for PERMP total score averaged across all postdose assessments was observed (nominal P = .0001); treatment differences between SHP465 MAS and MAS IR were not significant (nominal P = .2443). The two most frequently reported TEAEs associated with SHP465 MAS were insomnia (36.5%) and anorexia (21.2%). Mean increases in pulse and blood pressure with SHP465 MAS exceeded those of placebo.

CONCLUSIONS

SHP465 MAS (combined 50/75 mg) significantly improved PERMP total score versus placebo, with superiority observed from 2 to 16 h postdose. The tolerability profile of SHP465 MAS was similar to previous reports of SHP465 MAS in adults with ADHD.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT00928148 identifier is NCT00928148.

Efficacy and Safety of SHP465 Mixed Amphetamine Salts in the Treatment of Attention-Deficit/Hyperactivity Disorder in Adults: Results of a Randomized, Double-Blind, Placebo-Controlled, Forced-Dose Clinical Study

OBJECTIVE

The objective of this randomized, double-blind, placebo-controlled study was to evaluate the efficacy and safety of SHP465 mixed amphetamine salts (MAS) in adults with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Eligible adults [aged 18-55 years; meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ADHD criteria; baseline ADHD Rating Scale with Adult Prompts (ADHD-RS-AP) total scores ≥28] were randomized 1:1:1 to placebo or forced-dose SHP465 MAS (12.5 or 37.5 mg/day) for 4 weeks. The ADHD-RS-AP total score change from baseline to week 4 (primary endpoint) and Clinical Global Impressions-Improvement score at week 4 (key secondary endpoint) were assessed using linear mixed-effects models for repeated measures. Other efficacy endpoints were changes from baseline to week 4 on the ADHD-RS-AP hyperactivity/impulsivity and inattentiveness subscales and the percentage of participants categorized as improved on the dichotomized Clinical Global Impressions-Improvement. Safety and tolerability assessments were treatment-emergent adverse events, vital sign and weight changes, Columbia-Suicide Severity Rating Scale responses, and electrocardiogram results.

RESULTS

Of 369 screened participants, 275 were randomized (placebo, n = 91; 12.5 mg/day of SHP465 MAS, n = 92; 37.5 mg/day of SHP465 MAS, n = 92) and 236 completed the study (placebo, n = 80; 12.5 mg/day of SHP465 MAS, n = 80; 37.5 mg/day of SHP465 MAS, n = 76). Least-squares mean (95% confidence interval) treatment differences at week 4 significantly favored SHP465 MAS over placebo for the ADHD-RS-AP total score change from baseline [12.5 mg/day: -8.1 (-11.7, -4.4), effect size = 0.67; 37.5 mg/day: -13.4 (-17.1, -9.7), effect size = 1.11; both p < 0.001] and Clinical Global Impressions-Improvement score [12.5 mg/day: -0.8 (-1.1, -0.4), effect size = 0.68; 37.5 mg/day: -1.2 (-1.6, -0.9), effect size = 1.11; both p < 0.001]. Treatment differences for the change from baseline at week 4 favored 12.5 and 37.5 mg/day of SHP465 MAS, respectively, over placebo on the ADHD-RS-AP hyperactivity/impulsivity (both nominal p < 0.001; effect size = 0.56 and 0.91) and inattentiveness (both nominal p < 0.001; effect size = 0.70 and 1.19) subscales. At the final on-treatment assessment, the percentage of participants categorized as improved on Clinical Global Impressions-Improvement was higher with both SHP465 MAS doses than with placebo (both nominal p < 0.001). Treatment-emergent adverse events reported (>5%) with SHP465 MAS were decreased appetite, dry mouth, insomnia, headache, anxiety, initial insomnia, irritability, and bruxism. Severe treatment-emergent adverse events and treatment-emergent adverse events leading to discontinuation, respectively, were reported by 8 and 12 participants (placebo, n = 2 and 0; 12.5 mg/day SHP465 MAS, n = 1 and 7; 37.5 mg/day SHP465 MAS, n = 5 and 5). At the final on-treatment assessment, mean ± standard deviation increases from baseline were observed with 12.5 and 37.5 mg/day of SHP465 MAS for pulse (3.3 ± 10.52 and 7.1 ± 11.48 bpm) and blood pressure (systolic 0.2 ± 7.24 and 1.7 ± 9.99 mmHg; diastolic 1.0 ± 7.46 and 2.8 ± 7.90 mmHg) and decreases were observed for weight (-0.97 ± 1.523 and -1.65 ± 2.333 kg), body mass index (-0.33 ± 0.519 and -0.56 ± 0.777 kg/m²), and Fridericia corrected QT interval (-3.0 ± 10.72 and -1.6 ± 13.70 ms). No participant in any treatment group had a positive response for on-study Columbia-Suicide Severity Rating Scale assessments.

CONCLUSIONS

SHP465 MAS was superior to placebo in reducing ADHD symptoms, with a safety profile consistent with other long-acting stimulants. ClinicalTrials.gov Registry Number: NCT02604407.