Emerging Treatments for COPD: Evidence to Date on Revefenacin

Recalibrating Perceptions and Attitudes Toward Nebulizers versus Inhalers for Maintenance Therapy in COPD: Past as Prologue

Aerosol therapy administered via handheld inhaler or nebulizer device has long been standard for the treatment of chronic obstructive pulmonary disease (COPD), both for maintenance therapy and for management of acute exacerbations. Of the 2 options for drug delivery, inhaler devices are the most widely used for ambulatory patients with COPD as they are small, portable, and convenient and offer an array of medication options. They are, however, prone to suboptimal inhalation technique and use errors, which decrease the amount of medication delivered, compromise efficacy, and adversely affect clinical outcomes. Nebulizers are less often employed for aerosol delivery than inhalers, particularly in the home environment. Considered bulky and expensive, nebulizers have historically had limited medication options compared with inhalers. Nonetheless, nebulizers may be preferred over inhalers in specific patient populations, such as in patients with poor lung function, lack of hand-breath coordination, or cognitive impairment. Furthermore, technological advances and development of new nebulizer-compatible medications are shifting the benefit equation for nebulizers versus inhalers in a way that merits reconsideration of the role of nebulizers in the maintenance treatment of COPD. Using the available literature, this state-of-the-art review critically evaluates the benefits and limitations of aerosol therapy delivery via inhaler or nebulizer for patients with COPD; describes the factors that may influence the benefit equation, including current advances in nebulizer technology and future developments; and provides insights on implementation of nebulizer therapy in clinical practice.

Proof of lung muscarinic receptor occupancy by tiotropium: Translational Positron Emission Tomography studies in non-human primates and humans

Introduction

Molecular imaging has not been used to support the development of drugs for the treatment of pulmonary disorders. The aim of the present translational study was to advance quantitative pulmonary PET imaging by demonstrating occupancy of the reference asthma drug tiotropium at muscarinic acetylcholine receptors (mAChR).

Methods

PET imaging was performed using the muscarinic radioligand [11C]VC-002. The key methodological step involved estimating muscarinic receptor binding while disentangling it from the background of non-specific binding. The relationship between tiotropium exposure and receptor occupancy (RO) was assessed in non-human primates (NHPs) after intravenous injection of tiotropium doses at a broad dose interval (0.03-1 µg/kg). The feasibility of measuring RO in the human lung was then confirmed in seven healthy human subjects after inhalation of a single therapeutic dose of tiotropium (18 µg).

Results

There was an evident effect of tiotropium on [11C]VC-002 binding to mAChRs in lungs in both NHPs and humans. In NHPs, RO was 11 to 78% and increased in a dose dependent manner. Non-displaceable binding in NHPs was about 10% of total binding. In humans, RO was 6%-65%, and non-displaceable binding was about 20% of total binding at baseline.

Discussion

The results demonstrate that [11C]VC-002 binds specifically to mAChRs in the lungs enabling the assessment of RO following administration of muscarinic antagonist drugs. Furthermore, the methodology has potential not only for dose finding and comparison of drug formulations in future applied studies, but also for evaluating changes in lung receptor distribution during disease or in response to therapy.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT03097380.

Safety evaluation of revefenacin at the approved dose in patients with chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

Revefenacin is the first once-daily long-acting muscarinic antagonist (LAMA) for nebulization use in maintenance therapy for patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To investigate the safety and tolerability profile of revefenacin at the approved dose (175 μg), compared with placebo and a lower dose (88 μg), for the treatment of COPD.

METHODS

Available randomized controlled trials (RCTs), both published and unpublished, were identified via databases. Risk differences (RDs) and risk ratios (RRs), with their corresponding 95% confidence intervals (CIs) were calculated as effect sizes.

RESULTS

One unpublished RCT and four articles containing 5 RCTs were included. Combined results showed that there were no significant differences between COPD patients receiving 175 μg revefenacin and those receiving a placebo, concerning the risk of discontinuation due to adverse events (AEs), any all-grade AE, or any serious AE. 175 μg revefenacin also did not significantly increase the risk of antimuscarinic-related AEs, cardiovascular AEs, or 12 commonly reported AEs. Plus, a lower dose of 88 μg was shown to share a comparable safety profile with the 175 μg revefenacin. A non-significant trend towards a decrease in risks of AEs for 175 μg revefenacin was observed. The most frequently reported AE for each group was COPD worsening/exacerbation.

CONCLUSION

Revefenacin at the approved dose is generally well-tolerated and safe with minimal AEs, which supports its use as a once-daily nebulized LAMA for the treatment of moderate to severe stable COPD. Additional studies are needed to complete the safety and tolerability profile.

Emerging muscarinic receptor antagonists for the treatment of asthma

INTRODUCTION

The increased acetylcholine signaling in asthma pathophysiology offers the rationale for the use of LAMAs in the treatment of asthmatic patients. Tiotropium is still the only LAMA approved for use in asthma but there is a real interest in developing novel LAMAs for the treatment of asthma, or at least to extend this indication to other LAMAs already on the market.

AREAS COVERED

We examined and discussed trials and research that have studied or are evaluating the role of LAMAs already on the market in asthma and possible novel muscarinic acetylcholine receptor antagonists.

EXPERT OPINION

Glycopyrronium and umeclidinium will soon be included in the GINA strategy with the same current indications of tiotropium. It is likely that the choice of the LAMA will be influenced not so much by its pharmacological profile as by the type of triple therapy chosen. It is extremely difficult to identify a new LAMA that is more effective than tiotropium, but is it plausible that new technologies that will allow delivering the drug in a more targeted way and with a lower risk of adverse effects may represent the real progress in the use of LAMAs in asthma in the coming years.