A non-interventional study of extended-release methylphenidate in the routine treatment of adolescents with ADHD: effectiveness, safety and adherence to treatment

Safety Profile of Methylphenidate Under Long-Term Treatment in Adult ADHD Patients - Results of the COMPAS Study

INTRODUCTION

The Comparison of Methylphenidate and Psychotherapy in adult ADHD Study (COMPAS) was a prospective, randomized multicenter clinical trial, comparing methylphenidate (MPH) with placebo (PLAC) in combination with cognitive behavioral group psychotherapy (GPT) or individual clinical management (CM) over the period of 1 year. Here, we report results on treatment safety.

METHODS

MPH and PLAC were flexibly dosed. Among 433 randomized patients, adverse events (AEs) were documented and analyzed on an "as received" basis during week 0-52. Electrocardiogram data were recorded at baseline and week 24.

RESULTS

Comparing 205 patients who received ≥1 dose of MPH with 209 patients who received PLAC, AEs occurring significantly more frequently in the MPH group were decreased appetite (22 vs. 3.8%), dry mouth (15 vs. 4.8%), palpitations (13 vs. 3.3%), gastrointestinal infection (11 vs. 4.8%), agitation (11 vs. 3.3%), restlessness (10 vs. 2.9%), hyperhidrosis, tachycardia, weight decrease (all 6.3 vs. 1.9%), depressive symptom, influenza (both 4.9 vs. 1.0%), and acute tonsillitis (4.4 vs. 0.5%). Syncope occurred significantly more often in the PLAC group (2.4 vs. 0%). Clinically relevant ECG changes occurred very rarely in both groups. Serious AEs were rare and without a significant group difference. The comparison of 206 patients treated with GPT versus 209 patients who received CM revealed no major differences. Serious AE classified as psychiatric occurred in 5 cases in the CM group and in 1 case in the GPT group.

CONCLUSION

In this so far longest-running clinical trial, methylphenidate treatment was safe and well-tolerated.

Methylphenidate for attention deficit hyperactivity disorder (ADHD) in children and adolescents - assessment of adverse events in non-randomised studies

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood. The psychostimulant methylphenidate is the most frequently used medication to treat it. Several studies have investigated the benefits of methylphenidate, showing possible favourable effects on ADHD symptoms, but the true magnitude of the effect is unknown. Concerning adverse events associated with the treatment, our systematic review of randomised clinical trials (RCTs) demonstrated no increase in serious adverse events, but a high proportion of participants suffered a range of non-serious adverse events.

OBJECTIVES

To assess the adverse events associated with methylphenidate treatment for children and adolescents with ADHD in non-randomised studies.

SEARCH METHODS

In January 2016, we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 12 other databases and two trials registers. We also checked reference lists and contacted authors and pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included non-randomised study designs. These comprised comparative and non-comparative cohort studies, patient-control studies, patient reports/series and cross-sectional studies of methylphenidate administered at any dosage or formulation. We also included methylphenidate groups from RCTs assessing methylphenidate versus other interventions for ADHD as well as data from follow-up periods in RCTs. Participants had to have an ADHD diagnosis (from the 3rd to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders or the 9th or 10th edition of theInternational Classification of Diseases, with or without comorbid diagnoses. We required that at least 75% of participants had a normal intellectual capacity (intelligence quotient of more than 70 points) and were aged below 20 years. We excluded studies that used another ADHD drug as a co-intervention.

DATA COLLECTION AND ANALYSIS

Fourteen review authors selected studies independently. Two review authors assessed risk of bias independently using the ROBINS-I tool for assessing risk of bias in non-randomised studies of interventions. All review authors extracted data. We defined serious adverse events according to the International Committee of Harmonization as any lethal, life-threatening or life-changing event. We considered all other adverse events to be non-serious adverse events and conducted meta-analyses of data from comparative studies. We calculated meta-analytic estimates of prevalence from non-comparative cohorts studies and synthesised data from patient reports/series qualitatively. We investigated heterogeneity by conducting subgroup analyses, and we also conducted sensitivity analyses.

MAIN RESULTS

We included a total of 260 studies: 7 comparative cohort studies, 6 of which compared 968 patients who were exposed to methylphenidate to 166 controls, and 1 which assessed 1224 patients that were exposed or not exposed to methylphenidate during different time periods; 4 patient-control studies (53,192 exposed to methylphenidate and 19,906 controls); 177 non-comparative cohort studies (2,207,751 participants); 2 cross-sectional studies (96 participants) and 70 patient reports/series (206 participants). Participants' ages ranged from 3 years to 20 years. Risk of bias in the included comparative studies ranged from moderate to critical, with most studies showing critical risk of bias. We evaluated all non-comparative studies at critical risk of bias. The GRADE quality rating of the evidence was very low.Primary outcomesIn the comparative studies, methylphenidate increased the risk ratio (RR) of serious adverse events (RR 1.36, 95% confidence interval (CI) 1.17 to 1.57; 2 studies, 72,005 participants); any psychotic disorder (RR 1.36, 95% CI 1.17 to 1.57; 1 study, 71,771 participants); and arrhythmia (RR 1.61, 95% CI 1.48 to 1.74; 1 study, 1224 participants) compared to no intervention.In the non-comparative cohort studies, the proportion of participants on methylphenidate experiencing any serious adverse event was 1.20% (95% CI 0.70% to 2.00%; 50 studies, 162,422 participants). Withdrawal from methylphenidate due to any serious adverse events occurred in 1.20% (95% CI 0.60% to 2.30%; 7 studies, 1173 participants) and adverse events of unknown severity led to withdrawal in 7.30% of participants (95% CI 5.30% to 10.0%; 22 studies, 3708 participants).Secondary outcomesIn the comparative studies, methylphenidate, compared to no intervention, increased the RR of insomnia and sleep problems (RR 2.58, 95% CI 1.24 to 5.34; 3 studies, 425 participants) and decreased appetite (RR 15.06, 95% CI 2.12 to 106.83; 1 study, 335 participants).With non-comparative cohort studies, the proportion of participants on methylphenidate with any non-serious adverse events was 51.2% (95% CI 41.2% to 61.1%; 49 studies, 13,978 participants). These included difficulty falling asleep, 17.9% (95% CI 14.7% to 21.6%; 82 studies, 11,507 participants); headache, 14.4% (95% CI 11.3% to 18.3%; 90 studies, 13,469 participants); abdominal pain, 10.7% (95% CI 8.60% to 13.3%; 79 studies, 11,750 participants); and decreased appetite, 31.1% (95% CI 26.5% to 36.2%; 84 studies, 11,594 participants). Withdrawal of methylphenidate due to non-serious adverse events occurred in 6.20% (95% CI 4.80% to 7.90%; 37 studies, 7142 participants), and 16.2% were withdrawn for unknown reasons (95% CI 13.0% to 19.9%; 57 studies, 8340 participants).

AUTHORS' CONCLUSIONS

Our findings suggest that methylphenidate may be associated with a number of serious adverse events as well as a large number of non-serious adverse events in children and adolescents, which often lead to withdrawal of methylphenidate. Our certainty in the evidence is very low, and accordingly, it is not possible to accurately estimate the actual risk of adverse events. It might be higher than reported here.Given the possible association between methylphenidate and the adverse events identified, it may be important to identify people who are most susceptible to adverse events. To do this we must undertake large-scale, high-quality RCTs, along with studies aimed at identifying responders and non-responders.

Relative Bioavailability of Methylphenidate Extended-release Chewable Tablets Chewed Versus Swallowed Whole

PURPOSE

Methylphenidate hydrochloride extended-release chewable tablet (MPH ERCT) is approved for treatment of attention deficit hyperactivity disorder in patients aged 6 years and older. This article evaluates the pharmacokinetic parameters and relative bioavailability of MPH ERCT when chewed versus swallowed whole.

METHODS

In this open-label, single-dose, 3-period, 3-treatment crossover study, 12 healthy adult volunteers were randomly assigned to treatment sequence. In each period, subjects received a single 40-mg dose of the assigned treatment (MPH ERCT chewed, MPH ERCT swallowed whole, or methylphenidate extended-release oral suspension [MEROS]). Blood samples for pharmacokinetic analysis were collected for 24 hours postdose. Key pharmacokinetic parameters included C_max, AUC_0-t, and AUC_0-∞.

FINDINGS

The geometric mean values for AUC_0-t, AUC_0-∞, and C_max were similar for MPH ERCT chewed, MPH ERCT swallowed whole, and MEROS. In all pairwise between-treatment comparisons, the 90% CIs of the geometric mean ratios for AUC_0-t, AUC_0-∞, and C_max were fully contained within the bioequivalence range of 80% to 125%. Early exposure over the first 4 hours after dosing (AUC_0-4) was similar for MPH ERCT chewed versus swallowed whole; AUC_0-4 was approximately 15% lower for MPH ERCT, either chewed or swallowed, compared with MEROS. Each treatment was generally well tolerated.

IMPLICATIONS

There was no difference in overall rate or extent of exposure of methylphenidate when MPH ERCT was chewed versus swallowed whole by healthy volunteers.

Single-dose Pharmacokinetic Properties and Relative Bioavailability of a Novel Methylphenidate Extended-release Chewable Tablet Compared With Immediate-release Methylphenidate Chewable Tablet

PURPOSE

A novel methylphenidate hydrochloride extended-release chewable tablet (MPH ERCT) was developed to potentially address an unmet need for patients with attention-deficit/hyperactivity disorder, especially children, who cannot or will not swallow tablets or would prefer the convenience of a chewable tablet. This randomized, open-label, crossover trial compared the pharmacokinetic properties and relative bioavailability of MPH ERCT with an MPH chewable immediate-release tablet (IR MPH) formulation in healthy adults.

METHODS

Healthy men and women 18 to 55 years of age were randomly assigned to MPH ERCT 40 mg or 40 mg IR MPH administered in 2 equal doses of 20 mg 6 hours apart with a 7-day washout period. Plasma concentrations of MPH at selected time points up to 24 hours were measured, and pharmacokinetic parameters were determined using a noncompartmental approach in the SAS (Version 9.2) PROC general linear model procedure.

FINDINGS

A total of 33 participants were enrolled in the study; 31 participants were included in the pharmacokinetic analysis. The exposure ratios for MPH ERCT and IR MPH (MPH ERCT/IR MPH) for area under the analyte concentration versus time curves (AUC) from time zero to the last measurable analyte concentration (AUC0-last) (87.64%; 95% CI, 84.96-90.41) and AUC0-∞ (89.11%; 95% CI, 86.57-91.73) were within the standard 80% to 125% bioequivalence acceptance criteria. Mean Cmax for MPH ERCT and IR MPH was 12.51 ng/mL and 15.57 ng/mL, respectively; mean time to Cmax was 4.16 hours and 6.43 hours, respectively. The mean Cmax of MPH ERCT was 80% of the Cmax of IR MPH due to a higher peak concentration that occurs after the second dose of IR MPH. All adverse events were mild in severity.

IMPLICATIONS

The relative bioavailability of MPH ERCT 40 mg, based on the exposure (AUC), was comparable to that of IR MPH 40 mg administered in 2 equal doses of 20 mg 6 hours apart. Both formulations were generally well tolerated.

Probabilistic Markov Model Estimating Cost Effectiveness of Methylphenidate Osmotic-Release Oral System Versus Immediate-Release Methylphenidate in Children and Adolescents: Which Information is Needed?

BACKGROUND

Incidence of attention deficit hyperactivity disorder (ADHD) in children and adolescents has been increasing. The disorder results in high societal costs. Policymakers increasingly use health economic evaluations to inform decisions on competing treatments of ADHD. Yet, health economic evaluations of first-choice medication of ADHD in children and adolescents are scarce and generally do not include broader societal effects.

OBJECTIVES

This study presents a probabilistic model and analysis of methylphenidate osmotic-release oral system (OROS) versus methylphenidate immediate-release (IR). We investigate and include relevant societal aspects in the analysis so as to provide cost-effectiveness estimates based on a broad societal perspective.

METHODS

We enhanced an existing Markov model and determined the cost effectiveness of OROS versus IR for children and adolescents responding suboptimally to treatment with IR. Enhancements included screening of a broad literature base, updated utility values, inclusion of costs and effects on caregivers and a change of the model type from deterministic to probabilistic.

RESULTS

The base case scenario resulted in lower incremental costs (€-5815) of OROS compared with IR and higher incremental quality-adjusted life-year (QALY) gains (0.22). Scenario analyses were performed to determine sensitivity to changes in transition rates, utility of caregivers, medical costs of caregivers and daily medication dose.

CONCLUSIONS

The results indicate that, for children responding suboptimally to treatment with IR, the beneficial effect of OROS on compliance may be worth the additional costs of medication. The presented model adds to the health economic information available for policymakers and to considerations on a broader perspective in cost-effectiveness analyses.