Pharmacokinetics and pharmacodynamics of an extrafine fixed pMDI combination of beclometasone dipropionate/formoterol fumarate in adolescent asthma

Pharmacokinetics of extrafine beclometasone dipropionate/formoterol fumarate/glycopyrronium bromide in adolescent and adult patients with asthma

The single-inhaler extrafine formulation triple combination beclometasone dipropionate (BDP), formoterol fumarate (FF) plus glycopyrronium bromide (GB) is available for asthma management in adults. Its use in adolescents has not yet been evaluated. This study investigated the pharmacokinetic profile of BDP/FF/GB in adults and adolescents, with the aim of ruling out higher plasma exposure in adolescents compared to adults. In this open-label, non-randomized study, patients with asthma aged 12-17 (adolescents) and 18-64 years (adults) self-administered a single dose of BDP/FF/GB 400/24/50 μg via pressurized metered-dose inhaler (pMDI). The primary objective was to rule out higher systemic exposure to beclometasone 17-monopropionate (B17MP; active metabolite of BDP), formoterol, and GB in terms of the area under the plasma concentration-time curve from 0 to the last quantifiable concentration (AUC0-t ) in adolescents versus adults. A total of 40 adolescents and 40 adults entered the study (mean age of 14.8 and 43.6 years, respectively). The primary objective (AUC0-t ) was met, with the upper 90% confidence interval of the geometric mean ratio between adolescents and adults <125% for B17MP (point estimate 79.28 [90% CI 71.19; 88.29]), formoterol (88.68 [77.71; 101.20]) and GB (85.49 [72.96; 100.16]). All secondary pharmacokinetic endpoints supported the primary, with pharmacodynamic (safety) and tolerability results similar in the two populations. In conclusion, systemic exposure to extrafine BDP/FF/GB pMDI in adolescents was not higher than that in adults. Furthermore, there were no safety or tolerability signals to warrant a reduction in the dose of BDP/FF/GB for adolescents with asthma.

Considerations in establishing bioequivalence of inhaled compounds

INTRODUCTION

Generic inhalers are often perceived as inferior to their branded counterparts; however, they are safe and effective if they can meet the regulatory requirements. The approach to assess bioequivalence (BE) in oral dosage form products is not sufficient to address the complexities of inhalational products (e.g., patient-device interface); hence, more considerations are needed and caution should be applied in determining BE of inhaled compounds.

AREAS COVERED

This review outlines the evaluation process for generic inhalers, explores the regulatory approaches in BE assessment, and highlights the considerations and challenges in the current in vitro and in vivo approaches (lung deposition, pharmacokinetic, pharmacodynamic/clinical studies, and patient-device interface) for establishing BE of inhaled compounds.

EXPERT OPINION

The ultimate goals in this field are to establish uniformity in the regulatory approaches to speed the drug submission process in different regions, clear physicians' misconception of generic inhalers, and have meaningful clinical endpoints such as improvement in patient quality of life when compared to placebo and brand name drugs. As inhalational drugs become more common for other indications such as antibiotics, the technologies developed for inhaled compounds in the treatment of chronic pulmonary diseases may be extrapolated to these other agents.

Regulatory Approaches and Considerations in Establishing Bioequivalence of Inhaled Compounds

To be considered bioequivalent to their branded counterparts, generic drugs must meet the standards for bioequivalence (BE) described by the regulatory agencies. While BE of generic inhalational drugs can be evaluated using a similar approach as that for oral dosage from products or drugs that are delivered systemically, the approach is insufficient to address the complexities of inhalational products (e.g., localized site of action, device-patient interface). Therefore, more considerations are needed and caution should be applied when evaluating BE of inhaled compounds. The purpose of this review is to highlight the considerations and challenges in establishing BE of inhaled compounds by (1) outlining the current regulatory approaches (from Health Canada, the U.S. Food and Drug Administration, and the European Medicines Agency) to assess BE for subsequent entry inhaled products (SEIPs) and (2) reviewing the literature pertaining to testing considerations of SEIPs to establish BE.

Assessing the viability of long-acting β2-agonists in paediatric asthma patients: a pharmacokinetic/pharmacodynamic perspective

INTRODUCTION

Long-acting β₂-agonists (LABAs) combined with inhaled corticosteroids (ICSs) are still commonly prescribed to asthmatic children. Unfortunately, pediatric LABA use is based primarily on data from adults, despite the fact that children are not simply small adults and the magnitude of changes in dose exposure and/or exposure response may not be solely reflected by differences in body weight. Areas covered: The differences in pharmacokinetics (PK) and pharmacodynamics (PD) of LABAs are described and discussed with reference children and adults. Expert opinion: Data on the PK behavior of LABAs is very limited and there is almost no data on once-daily LABAs available in the pediatric population. We do not believe that this is due to a fundamental lack of information because therapeutic response and adverse effects are more useful for the optimization of β₂-agonist treatment than measurement of plasma drug concentrations per se. Nevertheless, population PK-PD studies in children are needed according to the European rules in order to define rational, patient-tailored dosing schemes. Population PK-PD modeling and simulation using non-linear mixed effect modeling should be considered as the preferred tool to develop effective and safe dosing regimens for children because they present an opportunity to analyze sparse and unbalanced datasets, thereby minimizing the burden for each child.

Dilemmas, Confusion, and Misconceptions Related to Small Airways Directed Therapy

During the past decade, there has been increasing evidence that the small airways (ie, airways < 2 mm in internal diameter) contribute substantially to the pathophysiologic and clinical expression of asthma and COPD. The increased interest in small airways is, at least in part, a result of innovation in small-particle aerosol formulations that better target the distal lung and also advanced physiologic methods of assessing small airway responses. Increasing the precision of drug deposition may improve targeting of specific diseases or receptor locations, decrease airway drug exposure and adverse effects, and thereby increase the efficiency and effectiveness of inhaled drug delivery. The availability of small-particle aerosols of corticosteroids, bronchodilators, or their combination enables a higher total lung deposition and better peripheral lung penetration and provides added clinical benefit, compared with large-particle aerosol treatment. However, a number of questions remain unanswered about the pragmatic approach relevant for clinicians to consider the role of small airways directed therapy in the day-to-day management of asthma and COPD. We thus have tried to clarify the dilemmas, confusion, and misconceptions related to small airways directed therapy. To this end, we have reviewed all studies on small-particle aerosol therapy systematically to address the dilemmas, confusion, and misconceptions related to small airways directed therapy.