Differential pharmacology and clinical utility of long-acting bronchodilators in COPD - focus on olodaterol

Advances in soft mist inhalers

INTRODUCTION

Soft mist inhalers (SMIs) are propellant-free inhalers that utilize mechanical power to deliver single or multiple doses of inhalable drug aerosols in the form of a slow mist to patients. Compared to traditional inhalers, SMIs allow for a longer and slower release of aerosol with a smaller ballistic effect, leading to a limited loss in the oropharyngeal area, whilst requiring little coordination of actuation and inhalation by patients. Currently, the Respimat® is the only commercially available SMI, with several others in different stages of preclinical and clinical development.

AREAS COVERED

The primary purpose of this review is to critically assess recent advances in SMIs for the delivery of inhaled therapeutics.

EXPERT OPINION

Advanced particle formulations, such as nanoparticles which target specific areas of the lung, Biologics, such as vaccines, proteins, and antibodies (which are sensitive to aerosolization), are expected to be generally delivered by SMIs. Furthermore, repurposed drugs are expected to constitute a large share of future formulations to be delivered by SMIs. SMIs can also be employed for the delivery of formulations that target systemic diseases. Finally, digitalizing SMIs would improve patient adherence and provide clinicians with fundamental insights into patients' treatment progress.

A Post Hoc Holter ECG Analysis of Olodaterol and Formoterol in Moderate-to-Very-Severe COPD

Background

Patients with chronic obstructive pulmonary disease (COPD) are at risk of developing cardiac arrhythmias and elevated heart rate. A theoretical mechanistic association based on the interaction of long-acting β₂-agonists (LABAs) with adrenoreceptors in the heart and vasculature is assumed as a potential class-related risk. Therefore, we performed a pooled analysis of Holter electrocardiogram (ECG) data from four 48-week, randomized, double-blind, placebo-controlled, parallel-group, Phase III clinical trials evaluating olodaterol (5 μg or 10 μg) or formoterol (12 µg) versus placebo.

Methods

We analyzed Holter ECG data from a representative subset of 775 patients with Global Initiative for Chronic Obstructive Lung Disease stage 2–4 COPD from four studies (1222.11–14) assessing olodaterol (5 μg and 10 μg) and formoterol (12 µg) versus placebo.

Results

No statistically significant (P>0.3) or clinically relevant differences in the shift from baseline of premature supraventricular or ventricular beats were observed among the active treatment and the placebo groups. Minor and transient differences were observed in the adjusted mean heart rate from baseline during treatment in all groups. There was a numerically small but statistically significant increase for formoterol at Week 24, olodaterol 5 μg at Weeks 12 and 40, and olodaterol 10 μg at Week 40 (all less than 3.0 beats per minute). Mean heart rates returned to a statistically non-significant change at Week 48 for all treatment groups. No increase in major adverse cardiovascular events was observed.

Conclusion

Treatment with olodaterol or formoterol is not associated with arrhythmias or a persistent increase in heart rate as assessed by Holter ECG in patients with COPD.

Trial Registration

ClinicalTrials.gov identifiers: NCT00782210 (1222.11); NCT00782509 (1222.12); NCT00793624 (1222.13); NCT00796653 (1222.14).

Long-Acting β2-Agonists in Asthma: Enantioselective Safety Studies are Needed

Long-acting β2-agonists (LABAs) such as formoterol and salmeterol are used for prolonged bronchodilatation in asthma, usually in combination with inhaled corticosteroids (ICSs). Unexplained paradoxical asthma exacerbations and deaths have been associated with LABAs, particularly when used without ICS. LABAs clearly demonstrate effective bronchodilatation and steroid-sparing activity, but long-term treatment can lead to tolerance of their bronchodilator effects. There are also concerns with regard to the effects of LABAs on bronchial hyperresponsiveness (BHR), where long-term use is associated with increased BHR and loss of bronchoprotection. A complicating factor is that formoterol and salmeterol are both chiral compounds, usually administered as 50:50 racemic (rac-) mixtures of two enantiomers. The chiral nature of these compounds has been largely forgotten in the debate regarding LABA safety and effects on BHR, particularly that (S)-enantiomers of β2-agonists may be deleterious to asthma control. LABAs display enantioselective pharmacokinetics and pharmacodynamics. Biological plausibility of the deleterious effects of β2-agonists (S)-enantiomers is provided by in vitro and in vivo studies from the short-acting β2-agonist (SABA) salbutamol. Supportive clinical findings include the fact that patients in emergency departments who demonstrate a blunted response to salbutamol are more likely to benefit from (R)-salbutamol than rac-salbutamol, and resistance to salbutamol appears to be a contributory mechanism in rapid asthma deaths. More effort should therefore be applied to investigating potential enantiospecific effects of LABAs on safety, specifically bronchoprotection. Safety studies directly assessing the effects of LABA (S)-enantiomers on BHR are long overdue.