A randomized, double-blind, cross-over, phase IV trial of oros-methylphenidate (CONCERTA(®)) and generic novo-methylphenidate ER-C (NOVO-generic)

Pharmacokinetics of Long-Acting Methylphenidate: Formulation Differences, Bioequivalence, Interchangeability

BACKGROUND AND OBJECTIVE: Attention deficit hyperactivity disorder is one of the most common neuropsychiatric conditions in children, and methylphenidate (MPH) is one of the first-line therapies. MPH is available in a variety of extended-release (ER) formulations worldwide, and most formulations are not considered bioequivalent due to differences in pharmacokinetics. It is hypothesized that the current bioequivalence guidelines from the different regulatory bodies may generate inconsistent findings or recommendations when assessing the bioequivalence of ER MPH formulations. This manuscript aims to conduct a comprehensive and narrative critical literature review to analyze pharmacokinetic data pertaining to ER formulations of MPH in order to assess bioequivalence, differences in regulatory guidelines, and additional pharmacokinetic-pharmacodynamic parameters that may help define interchangeability.

METHODS

A literature search was conducted in EMBASE, Medline, and Cochrane Library with no time limits. Study characteristics, non-compartmental pharmacokinetic parameters, and bioequivalence data were extracted for analysis.

RESULTS

Thirty-three studies were identified with primary pharmacokinetic data after the administration of ER MPH, of which 10 were direct comparative studies (i.e., at least 2 formulations tested within a single setting) and 23 were indirect comparisons (i.e., different experimental settings). Two formulations were consistently reported as bioequivalent across the regulatory bodies using criteria from their guidance documents, although inconsistencies have been observed. However, when additional kinetic criteria (discussed in this manuscript) were imposed, only one study met the more stringent definition of bioequivalence. Various clinical factors also had inconsistent effects on the pharmacokinetics and interchangeability of the different formulations, which were associated with a lack of standardization for assessing covariates across the regulatory agencies.

CONCLUSION

Additional pharmacokinetic parameters and consistency in guidelines across the regulatory bodies may improve bioequivalence assessments. Based on our findings, more research is also required to understand whether bioequivalence is an appropriate measure for determining MPH interchangeability. This critical review is suitable for formulation scientists, clinical pharmacologists, and clinicians.

Analysis of Daily Sleep Diary Measures From Multilayer Extended-Release Methylphenidate (PRC-063) Studies in Children and Adults With ADHD

OBJECTIVE

To compare the effect of a once-daily extended-release methylphenidate formulation (PRC-063) versus placebo on sleep, measured via daily electronic diary in two clinical trials in pediatric (6-12 years) and adult (≥18 years) patients with attention deficit hyperactivity disorder (ADHD).

METHOD

A diary was completed by adult patients or parents/caregivers of pediatric patients during two randomized, double-blind, placebo-controlled laboratory classroom studies. Following dose optimization of PRC-063, patients were randomized to 1 week of double-blind treatment with PRC-063 or placebo before attending a full-day laboratory classroom session.

RESULTS

In the studies, 148 pediatric patients and 239 adult patients were randomized to either PRC-063 or placebo. When compared with the diaries of placebo patients, the sleep diaries in both pediatric and adult patients showed no statistical difference in total sleep time, efficiency, or latency.

CONCLUSION

PRC-063 did not impact subjective measures of sleep versus placebo in pediatric and adult patients with ADHD.

Randomized, Double-Blind, Placebo-Controlled, Parallel-Group, Adult Laboratory Classroom Study of the Efficacy and Safety of PRC-063 (Extended-Release Methylphenidate) for the Treatment of ADHD

OBJECTIVE

To evaluate the efficacy, safety, and duration of action of the once-daily extended-release methylphenidate formulation PRC-063 for the treatment of ADHD in an adult laboratory classroom (ALC).

METHOD

After dose optimization with PRC-063 over 7 weeks, adults with ADHD were randomized to 1 week of double-blind treatment with PRC-063 or placebo that ended with an ALC evaluation. The primary outcome measure was Permanent Product Measure of Performance-Total (PERMP-T) score.

RESULTS

Of 288 subjects enrolled, 221 completed the ALC visit. PERMP-T score was significantly higher for PRC-063 versus placebo at every assessment from 1 to 16 hours post-dose at the ALC visit and when averaged over 16 hours post-dose (least-squares mean difference 16.3, 95% confidence interval 7.6-24.9). The most frequent adverse events during dose optimization were headache, decreased appetite, and insomnia.

CONCLUSION

PRC-063 provided rapid and sustained symptom relief in adults with ADHD and was well tolerated. NCT03618030.

Long-term effectiveness of behavioural intervention in preschool children with attention deficit hyperactivity disorder in Southeast China - a randomized controlled trial

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is the most common behavioral disorder. Behavioural intervention in preschool children with ADHD is considered effective. This study discussed the long-term effectiveness of behavioural intervention in the context of nondrug therapy.

METHODS

The study was a prospective, randomised controlled trial in which 201 preschoolers diagnosed with ADHD who were not receiving any treatment were assigned to two groups from January 2018 to May 2019, 101 were assigned to the conventional group and 100 to the behavioural intervention group. The behavioural intervention group included parental training, behavioural therapy, attention training, relief therapy and game therapy, in addition to the conventional group offerings. Children were evaluated at a baseline, at the end of the 12-month intervention and six months after the intervention. The primary and secondary outcome variables included attention time, the impulse-hyperactivity and hyperactivity index from Conners parent symptom questionnaire (PSQ), full-scale attention quotient (FAQ) and full-scale response control quotient (FRCQ) from integrated visual and auditory comprehensive continuous performance tests. The attention time was observed and recorded by parents, and others were performe(PSQ)d by physicians in the clinic. All statistical analyses were conducted using SPSS V26.0 (IBM), including the descriptive statistics and mixed-effects models and so on.

RESULTS

The participants' mean age was (66.17±9.00) months in the behavioural group and (67.54±6.22) months in the conventional group .A total of 190 participants completed a follow-up six months after the intervention. The attention time, Conners parent symptom questionnaire (PSQ), full-scale attention quotient (FAQ) and full-scale response control quotient (FRCQ) increased significantly over time, and the behavioural group improvements were higher than those of conventional group. There was a significant main effect of time (pretest/posttest/follow-up) and group on all outcome measures (t =-12.549-4.069, p<0.05), and a significant interaction of time and group on attention time, impulsivity/hyperactivity, FAQ and FRCQ (t =-3.600-3.313, p<0.05).

CONCLUSION

Behavioural intervention can effectively improve behaviour management and relieve symptoms in children with ADHD. These effects lasted at least six months. This study provides a promising approach for improving clinical efficacy with preschool children with ADHD.

Pharmacists' knowledge, experiences and perceptions of treatments for attention-deficit/hyperactivity disorder

Background

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that begins in childhood and often persists into adulthood. ADHD increases the risk of various negative impacts, and pharmacists are well positioned to address these issues in the community.

Objectives

This survey study aims to first identify pharmacists' ADHD knowledge gaps and experience with ADHD management and to second assess their preferences for continuing education and their experience with sleep-related issues in ADHD.

Methods

A survey was sent to Part A Ontario pharmacists with active licenses who opted in to receive research-related emails (n = 6022). Descriptive statistics were used to analyze survey data, while free-form answers were pooled and evaluated for common themes and trends.

Results

A total of 238 complete responses were received. The average self-reported ADHD knowledge was 5.8 ± 1.96 on a 10-point scale. There was no correlation between the number of years of practice as a pharmacist, the number of working hours per week or the location of practice on pharmacists' self-reported knowledge scores. There was a significant difference in self-reported knowledge of ADHD between pharmacists who were not aware of the Canadian ADHD Resource Alliance (CADDRA) guidelines (5.1 ± 2.1) and those who refer to it for standard of care (7.1 ± 1.5). Almost all pharmacists (95%) indicated they could benefit from additional ADHD education, with a strong preference for "online continuing education modules" (81%). The majority of responders considered psychostimulant ADHD medication as the major possible contributor to sleep disturbances (47%) in ADHD, highlighting a need for further education on the inconclusive link between ADHD medication effects on sleep.

Conclusion

The study results raise the concern that pharmacists may require additional ADHD education but also show the lack of awareness of available resources, such as the CADDRA guidelines. Can Pharm J (Ott) 2021;154:xx-xx.

Switching medication products during the treatment of psychiatric illness

BACKGROUND

The common practice of switching between branded (reference) medications and their corresponding generic products, between generic products, or even from a generic product to a branded medication during the treatment of central nervous system (CNS) disorders may compromise efficacy and/or tolerability.

METHODS

We assessed the published literature from March 1, 2010 through June 30, 2017 via PubMed using the MeSH term 'generics, drugs' alone and in combination with class-specific terms (e.g., 'anticonvulsants', 'mood stabilisers'), for studies detailing outcomes following product switches.

RESULTS

Although some studies comparing the initiation of reference versus generic drugs suggest equivalence between products, several studies detailing a switch between reference and generic products describe reductions in efficacy, reduced medication adherence and persistence, and increased overall health care resource utilization and costs associated with generic substitution.

CONCLUSION

When product switches are considered, they should only proceed with the full knowledge of both patient and provider.

Differences in Adverse Event Reporting Rates of Therapeutic Failure Between Two Once-daily Extended-release Methylphenidate Medications in Canada: Analysis of Spontaneous Adverse Event Reporting Databases

PURPOSE

Our study evaluated adverse events of therapeutic failure (and specifically reduced duration of action) with the use of a branded product, Osmotic Release Oral System (OROS) methylphenidate, which is approved for the treatment of attention deficit/hyperactivity disorder, and a generic product (methylphenidate, methylphenidate ER-C), which was approved for marketing in Canada based on bioequivalence to OROS methylphenidate. This study was initiated following reports that some US-marketed generic methylphenidate ER products had substantially higher reporting rates of therapeutic failure than did the referenced brands.

METHODS

Through methodology similar to that used by the US Food and Drug Administration to investigate the issue with the US-marketed generic, reporting rates were calculated from cases of therapeutic failure identified in the Canadian Vigilance Adverse Reaction Online database for a 1-year period beginning 8 months after each product launch. Corresponding population exposure was estimated from the number of tablets dispensed. An in-depth analysis of narratives of individual case safety reports (ICSRs) with the use of the generic product was conducted in duplicate by 2 physicians to assess causality and to characterize the potential safety risk and clinical pattern of therapeutic failure. Similar secondary analyses were conducted on the US-marketed products.

FINDINGS

Reporting rates of therapeutic failure with the use of methylphenidate ER-C (generic) and OROS methylphenidate (brand name) were 411.5 and 37.5 cases per 100,000 patient-years, respectively (reporting rate ratio, 10.99; 95% CI, 5.93-22.21). In-depth analysis of narratives of 230 ICSRs of therapeutic failure with the Canadian-marketed generic determined that all ICSRs were either probably (60 [26%]) or possibly (170 [74%]) causally related to methylphenidate ER-C. Clinical symptoms suggestive of overdose were present in 31 reports of loss of efficacy (13.5%) and occurred primarily in the morning, and premature loss of efficacy (shorter duration of action) was described in 98 cases (42.6%) and occurred primarily in the afternoon. Impacts on social functioning, such as disruption in work or school performance or adverse social behaviors, were found in 51 cases (22.2%).

IMPLICATIONS

The ~10-fold higher reporting rate of therapeutic failure with the generic product relative to its reference product in the present Canadian study resembles findings with US-marketed generic products. While these results should be interpreted with caution due to the limitations of spontaneous adverse event reporting, which may confound comparisons across products, similar findings nonetheless led the US Food and Drug Administration to declare in 2014 that 2 methylphenidate ER generic products in the United States were neither bioequivalent nor interchangeable with OROS methylphenidate-their reference product. Our results indicate a potential safety issue with the Canadian-marketed generic and suggest a need for further investigation by Health Canada.