Characterization of respiratory deposition of fluticasone-salmeterol hydrofluoroalkane-134a and hydrofluoroalkane-134a beclomethasone in asthmatic patients

The effects of airway disease on the deposition of inhaled drugs

INTRODUCTION

The deposition of inhaled medications is the first step in the pulmonary pharmacokinetic process to produce a therapeutic response. Not only lung dose but more importantly the distribution of deposited drug in the different regions of the lung determines local bioavailability, efficacy, and clinical safety. Assessing aerosol deposition patterns has been the focus of intense research that combines the fields of physics, radiology, physiology, and biology.

AREAS COVERED

The review covers the physics of aerosol transport in the lung, experimental, and in-silico modeling approaches to determine lung dose and aerosol deposition patterns, the effect of asthma, chronic obstructive pulmonary disease, and cystic fibrosis on aerosol deposition, and the clinical translation potential of determining aerosol deposition dose.

EXPERT OPINION

Recent advances in in-silico modeling and lung imaging have enabled the development of realistic subject-specific aerosol deposition models, albeit mainly in health. Accurate modeling of lung disease still requires additional refinements in existing imaging and modeling approaches to better characterize disease heterogeneity in peripheral airways. Nevertheless, recent patient-centric innovation in inhaler device engineering and the incorporation of digital technology have led to more consistent lung deposition and improved targeting of the distal airways, which better serve the clinical needs of patients.

A scintigraphy study of budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler in patients with moderate-to-very severe chronic obstructive pulmonary disease

BACKGROUND

Triple therapy with inhaled corticosteroids/long-acting muscarinic antagonists/long-acting β2-agonists (ICS/LAMA/LABA) is recommended for patients with chronic obstructive pulmonary disease (COPD) with continued symptoms or exacerbations, despite treatment with LAMA/LABA or ICS/LABA. The pulmonary, extrathoracic, and regional lung deposition patterns of a radiolabeled ICS/LAMA/LABA triple fixed-dose combination budesonide/glycopyrrolate/formoterol fumarate (BGF 320/18/9.6 μg), delivered via a single Aerosphere metered dose inhaler (MDI) were previously assessed in healthy volunteers and showed good deposition to the central and peripheral airways (whole lung deposition: 37.7%). Here, we report the findings assessing BGF in patients with moderate-to-very severe COPD.

METHODS

This phase I, single-dose, open-label gamma scintigraphy imaging study (NCT03906045) was conducted in patients with moderate-to-very severe COPD. Patients received two actuations of BGF MDI (160/9/4.8 μg per actuation) radiolabeled with technetium‑99‑pertechnetate, not exceeding 5 MBq per actuation. Immediately following each inhalation, patients performed a breath-hold of up to 10 s, then exhaled into an exhalation filter. Gamma scintigraphy imaging of the anterior and posterior views of the lungs and stomach, and a lateral head and neck view, were performed immediately after exhalation. The primary objective of the study was to assess the pulmonary deposition of BGF. Secondary objectives assessed the deposited dose of radiolabeled BGF in the oropharyngeal and stomach regions, on the actuator, and on the exhalation filter in addition to regional airway deposition patterns in the lungs.

RESULTS

The mean BGF emitted dose deposited in the lungs was 32.1% (standard deviation [SD] 15.6) in patients with moderate-to-very severe COPD, 35.2% (SD 12.8) in patients with moderate COPD, and 28.7% (SD 18.4) in patients with severe/very severe COPD. Overall, the mean normalized outer/inner ratio was 0.55 (SD 0.19), while the standardized central/peripheral ratio was 2.21 (SD 1.64).

CONCLUSIONS

Radiolabeled BGF 320/18/9.6 μg was efficiently delivered and deposited throughout the entire lung, including large and small airways, in patients with moderate-to-very severe COPD, with similar deposition in patients with moderate COPD and patients with severe/very severe COPD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03906045. Registered 8 April 2019, https://clinicaltrials.gov/ct2/show/NCT03906045.

In vitro-in vivo correlation of cascade impactor data for orally inhaled pharmaceutical aerosols

In vitro-in vivo correlation is the establishment of a predictive relationship between in vitro and in vivo data. In the context of cascade impactor results of orally inhaled pharmaceutical aerosols, this involves the linking of parameters such as the emitted dose, fine particle dose, fine particle fraction, and mass median aerodynamic diameter to in vivo lung deposition from scintigraphy data. If the dissolution and absorption processes after deposition are adequately understood, the correlation may be extended to the pharmacokinetics and pharmacodynamics of the delivered drugs. Correlation of impactor data to lung deposition is a relatively new research area that has been gaining recent interest. Although few in number, experiments and meta-analyses have been conducted to examine such correlations. An artificial neural network approach has also been employed to analyse the complex relationships between multiple factors and responses. However, much research is needed to generate more data to obtain robust correlations. These predictive models will be useful in improving the efficiency in product development by reducing the need of expensive and lengthy clinical trials.

Consistent Pulmonary Drug Delivery with Whole Lung Deposition Using the Aerosphere Inhaler: A Review of the Evidence

Metered dose inhalers (MDIs) are one of the most common device types for delivering inhaled therapies. However, there are several technical challenges in development and drug delivery of these medications. In particular, suspension-based MDIs are susceptible to suspension heterogeneity, in vitro drug–drug interactions, and patient handling errors, which may all affect drug delivery. To overcome these challenges, new formulation approaches are required. The Aerosphere^TM inhaler, formulated using co-suspension delivery technology, combines drug crystals with porous phospholipid particles to create stable, homogenous suspensions that dissolve once they reach the airways. Two combination therapies using this technology have been developed for the treatment of COPD: glycopyrrolate/formoterol fumarate (GFF MDI; dual combination) and budesonide/glycopyrrolate/formoterol fumarate (BGF MDI; triple combination). Here, we review the evidence with a focus on studies assessing dose delivery, lung deposition, and effects on airway geometry. In vitro assessments have demonstrated that the Aerosphere inhaler provides consistent dose delivery, even in the presence of simulated patient handling errors. Combination therapies delivered with this technology also show a consistent fine particle fraction (FPF) and an optimal particle size distribution for delivery to the central and peripheral airways even when multiple drugs are delivered via the same inhaler. Studies using gamma scintigraphy and functional respiratory imaging have demonstrated that GFF MDI is effectively deposited in the central and peripheral airways, and provides clinically meaningful benefits on airway volume and resistance throughout the lung. Overall, studies suggest that the Aerosphere inhaler, formulated using co-suspension delivery technology, may offer advantages over traditional formulations, including consistent delivery of multiple components across patient handling conditions, optimal particle size and FPF, and effective delivery to the central and peripheral airways. Future studies may provide additional evidence to further characterize the clinical benefits of these technical improvements in MDI drug delivery.

Inhaled Corticosteroids and Endocrine Effects in Childhood

Asthma is the most common chronic inflammatory disease of children, and inhaled corticosteroids (ICSs) are the most effective and commonly used treatment of persistent asthma. ICSs currently approved for and commonly used by children with asthma include beclomethasone dipropionate, budesonide, fluticasone propionate, mometasone furoate, ciclesonide, and triamcinolone acetonide. This article reviews 4 areas critical to understanding potential adverse endocrine outcomes of ICSs and placing them in proper perspective: (1) influence of drug/delivery device properties on systemic steroid burden; (2) adrenal insufficiency during ICS treatment; (3) growth effects of ICS and asthma itself; and (4) bone mineral accretion during ICS therapy.

Regional Lung Deposition: In Vivo Data

The method section of this chapter on in vivo regional lung deposition highlights a nonradioactive method to measure regional deposition, which uses a photometer to quantify inhaled and exhaled particles and in that way is able to estimate the lung region from which the particles are exhaled and to what amount. The radioactive methods cover the measurement of clearance of the deposited particles as well as different imaging techniques to determine regional deposition. The result section reviews in vivo trials in human subjects. It also addresses different parameters that influence the regional deposition in the lungs: particle size, inhalation maneuver, carrier gas, disease, and inhalation device. All of these factors can affect regional deposition significantly. By choosing specific values of these parameters, it should be feasible to target different regions of the lungs for the therapy of different diseases.

Pulmonary deposition of budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler formulated using co-suspension delivery technology in healthy male subjects

This gamma scintigraphy imaging study assessed pulmonary, extrathoracic and regional lung deposition patterns of a radiolabelled inhaled corticosteroid/long-acting muscarinic antagonist/long-acting β₂-agonist triple fixed-dose combination budesonide/glycopyrronium/formoterol fumarate dihydrate (BGF 320/14.4/10 μg), delivered by pressurised metered dose inhaler (pMDI) using innovative co-suspension delivery technology (Aerosphere™). In this Phase I, randomised, single-centre, single-dose, two-period, crossover study (NCT03740373), 10 healthy male adults received two actuations of BGF MDI (160/7.2/4.8 μg per actuation) radiolabelled with ^99mTc, not exceeding 5 MBq per actuation. Immediately following each inhalation, subjects performed a 10- or 3-second breath-hold, then exhaled into an exhalation filter. The primary objective was to assess the pulmonary deposition of BGF MDI following the 10-second breath-hold. The secondary objectives were to assess deposition after the 3-second breath-hold and lung regional and extrathoracic deposition after each breath-hold length. Imaging of the lungs, stomach, head and neck was recorded by gamma scintigraphy immediately after exhalation. The mean BGF MDI emitted dose deposited in the lungs was 37.7% for the 10-second breath-hold and 34.5% for the 3-second breath-hold. Emitted dose detected in the exhalation filter was ≤0.4% for both breath-hold lengths. The mean normalised peripheral/central ratio was 0.65 and 0.75 for the 10- and 3-second breath-holds, respectively, while the standardised central/peripheral ratios were 1.79 and 1.40, respectively. There were no new or unexpected safety findings. In conclusion, BGF MDI was efficiently deposited in the central and the peripheral regions of the lungs, with similar regional deposition patterns following a 10- and 3-second breath-hold.

Cascade Impactor Performance of Commercial pMDI Formulations Using Modified Induction Ports

The induction port (IP) for aerosol analysis with the Next Generation Pharmaceutical Impactor as monographed in the United States and European pharmacopoeia (USPIP) lacks physiological relevance, which, amongst other reasons, has been identified as critical for the predictability of in vitro aerosol data to lung deposition observed in vivo. In this publication, we report the impact of replacing the USPIP with two modified induction ports, which were designed based around geometries derived from a computer tomographic scan of a human trachea and the distal section of the USPIP. Test formulations were selected on the basis of availability of in vivo lung deposition data so that results obtained in vitro could be evaluated for their predictability. All formulations assessed showed increased deposition in the modified induction ports, and different mechanisms of particle deposition have been identified. In vitro predictions of the lung deposition were found to correlate well with the in vivo observations reported using the modified induction ports. Furthermore, the quality of the correlation was found superior to the one achieved with the USPIP with an average deviation of the predicted from observed values (n = 10) of 6 ± 4, 12 ± 6, and 16 ± 6% for the modified induction ports (mIP and mIPext) and the USPIP, respectively, when using a fine particle fraction (FPF) cutoff value of 5 μm. Using a FPF cutoff value of 3 μm yielded a more accurate in vitro-in vivo correlation with an average deviation of the predicted from observed values of 5 ± 4, 7 ± 5, and 8 ± 4% for the mIP, mIPext, and USPIP, respectively. For both FPF size cutoff values, the mIP yielded the most accurate in vitro-in vivo correlation.

An innovative corticosteroid/long-acting β2-agonist breath-triggered inhaler: facilitating lung delivery of fluticasone propionate/formoterol fumarate for the treatment of asthma

Introduction: Incorrect inhaler technique is one reason why the efficacies of inhaled asthma treatments in clinical trials and effectiveness in the real world differ. Inhaler technique is critical for drug delivery to the lungs; incorrect technique negatively impacts asthma control and long-term outcomes. Breath-triggered inhalers (BTIs) can simplify drug administration and are suitable for most patients, including those with reduced inspiratory flow. Until recently, no inhaled corticosteroid/long-acting β₂-agonist combination BTI was available in Europe. The flutiform® (fluticasone propionate/formoterol fumarate [FP/FORM]) k-haler® is the first combination BTI now approved in Europe for asthma maintenance treatment.Areas covered: We review studies examining the challenges posed to patients by different inhaler types and explore evidence demonstrating the clinical efficacy of FP/FORM administered via a pressurized metered-dose inhaler. We also review the pharmacokinetic/pharmacodynamic studies supporting FP/FORM k-haler use, and consider data showing high lung deposition with the device. Finally, we review patient experiences using the BTI, device characteristics, and health economic aspects.Expert opinion: Despite the availability of therapies, asthma control levels remain low, and there is a clear need for easy-to-use inhalers. Research to increase our understanding of critical errors with each inhaler and how to overcome them is important for improving care.Abbreviations: AUC_t: area under the plasma concentration-time curve from the time of dosing to the last measurable concentration; BDP: beclometasone dipropionate; BTI: breath-triggered inhaler; BUD: budesonide; CI: confidence interval; C_max: maximum observed plasma concentration; DPI: dry powder inhaler; FDC: fixed-dose combination; FEV₁: forced expiratory volume in 1 s; FORM: formoterol fumarate; FP: fluticasone propionate; HCP: health-care professional; ICS: inhaled corticosteroid; LABA: long-acting β₂-agonist; OR: odds ratio; PIL: patient information leaflet; pMDI: pressurized metered-dose inhaler; SAL: salmeterol xinafoate.

Evaluation of Bio-relevant Mouth-Throat Models for Characterization of Metered Dose Inhalers

For inhalation drug characterization, the traditionally used USP induction port provides limited in vivo predictive capability because it does not adequately mimic airway geometry. In this study, various bio-relevant mouth-throat (MT) models, including Alberta Idealized Throat (AIT), and 3D printed large/medium/small-sized VCU (Virginia Commonwealth University) models were evaluated using two metered dose inhaler (MDI) drug products: a solution MDI containing beclomethasone dipropionate (BDP-MDI) and a suspension MDI containing fluticasone propionate (FP-MDI). For BDP-MDI, use of VCU large and small MT models resulted in a significantly higher MT deposition and lower fine particle fraction (FPF) compared with the other MT models. In the case of FP-MDI, the three VCU models resulted in higher MT deposition and lower FPF compared with the USP induction port and AIT. Overall, the in vitro testing results for the suspension MDI were more sensitive to geometric differences of the MT models than those for the solution MDI. Our results suggest that in vitro characterization of MDI products can be influenced by many factors, including the type of formulation, the MT geometry, shape, internal space volume, and the material used to make the MT models.

Studies of Radioaerosol Deposition in the Respiratory Tract

Deposition of aerosols in the respiratory tract can be quantitatively and qualitatively studied by scintigraphy. The most commonly used radionuclide for this purpose is technetium-99m. The effects of various factors on particle deposition have been investigated by using radiolabeled aerosols in the past decade. Most of these studies were in vivo but some were in vitro or ex vivo. The factors examined include particle size, formulation, inhaler design, inhalation flowrate, body posture, and gravity. They have been shown to influence pulmonary deposition, nasal high flow nebulization, and intranasal delivery. A thorough understanding of the various factors is required for the advancement of respiratory-drug delivery. Scintigraphy is a powerful technique that can assist in this regard.

Use of functional respiratory imaging to characterize the effect of inhalation profile and particle size on lung deposition of inhaled corticosteroid/long-acting β2-agonists delivered via a pressurized metered-dose inhaler

Background:

Functional respiratory imaging (FRI) uses three-dimensional models of human lungs and computational fluid dynamics to simulate functional changes within airways and predict the deposition of inhaled drugs. This study used FRI to model the effects of different patient inhalation and drug formulation factors on lung deposition of an inhaled corticosteroid/long-acting β₂-agonist (ICS/LABA) combination, administered by a pressurized metered-dose inhaler.

Methods:

Three-dimensional models of the lungs of six patients with asthma (mean forced expiratory volume in 1 s, 83%), treated with an ICS/LABA, were included. FRI modelling was used to simulate (1) the effects on lung deposition of inhalation duration and particle size [fine particle fraction (FPF), proportion of particles <5 µm; and mass median aerodynamic diameter (MMAD), average size of inhalable particles]; (2) deposition of fluticasone propionate/formoterol (FP/FORM) 125/5 µg; and (3) how inhalation profiles and flow rates affected FP/FORM deposition.

Results:

Total lung depositions (TLDs) following 1-, 3- and 5-s inhalations were 22.8%, 36.1% and 41.6% (metered dose), respectively, and central-to-peripheral deposition (C:P) ratios were 1.81, 0.86 and 0.61, respectively. TLD increased with increasing FPF, from ~8% at 10% FPF to ~36% at 40% FPF (metered dose); by contrast, MMAD had little effect on TLD, which was similar across MMADs (1.5–4.5 µm) at each FPF. FP/FORM deposited throughout central and peripheral airways with gradual (sinusoidal) and sharp (rapid) inhalations. TLD ranged from 35.8 to 44.0% (metered dose) for gradual and sharp inhalations at 30 and 60 L/min mean flow rates.

Conclusions:

These data provide important insights into the potential effects of inhalation characteristics (inhalation profile and duration) and aerosol formulation (FPF) on lung deposition of inhaled therapies. FRI thus represents a useful alternative to scintigraphy techniques. Future FRI studies will further our understanding of the deposition of inhaled drugs and help improve the management of asthma.

Pulmonary deposition of fluticasone propionate/formoterol in healthy volunteers, asthmatics and COPD patients with a novel breath-triggered inhaler

INTRODUCTION

A combination of fluticasone propionate/formoterol fumarate (FP/FORM) has been incorporated within a novel, breath-triggered device, named K-haler^®. This low resistance device requires a gentle inspiratory effort to actuate it, triggering at an inspiratory flow rate of approximately 30 L/min; thus avoiding the need for coordination of inhalation with manual canister depression. The aim of the study was to evaluate total and regional pulmonary deposition of FP/FORM when administered via the K-haler device.

MATERIALS AND METHODS

Twelve healthy subjects, 12 asthmatics, and 12 COPD patients each received a single dose of 2 puffs ^99mtechnetium-labelled FP/FORM 125/5 μg. A gamma camera was used to obtain anterior and posterior two-dimensional images of drug deposition. Prior transmission scans (using a^99mtechnetium flood source) allowed the definition of regions of interest and calculation of attenuation correction factors. Image analysis was performed per standardised methods.

RESULTS

Of 36 subjects, 35 provided evaluable post-dose scintigraphic data. Mean subject ages were 35.7 (healthy), 44.5 (asthma) and 61.7 years (COPD); mean FEV₁% predicted values were 109.8%, 77.4% and 43.2%, respectively. Mean pulmonary deposition was 26.6% (healthy), 44.7% (asthma), 39.0% (COPD) of the delivered dose. The respective mean penetration indices (peripheral:central ratio normalised to a transmission lung scan) were 0.44, 0.31 and 0.30.

CONCLUSION

FP/FORM administration via the K-haler device resulted in high lung deposition in patients with obstructive lung disease but somewhat lesser deposition in healthy subjects. Regional deposition data demonstrated drug deposition in both the central and peripheral regions in all subject populations.

EUDRACT NUMBER

2015-000744-42.

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.

Add-on LABA in a separate inhaler as asthma step-up therapy versus increased dose of ICS or ICS/LABA combination inhaler

Asthma management guidelines recommend adding a long-acting β2-agonist (LABA) or increasing the dose of inhaled corticosteroid (ICS) as step-up therapy for patients with uncontrolled asthma on ICS monotherapy. However, it is uncertain which option works best, which ICS particle size is most effective, and whether LABA should be administered by separate or combination inhalers. This historical, matched cohort study compared asthma-related outcomes for patients (aged 12-80 years) prescribed step-up therapy as a ≥50% extrafine ICS dose increase or add-on LABA, via either a separate inhaler or a fine-particle ICS/LABA fixed-dose combination (FDC) inhaler. Risk-domain asthma control was the primary end-point in comparisons of cohorts matched for asthma severity and control during the baseline year. After 1:2 cohort matching, the increased extrafine ICS versus separate ICS+LABA cohorts included 3232 and 6464 patients, respectively, and the fine-particle ICS/LABA FDC versus separate ICS+LABA cohorts included 7529 and 15 058 patients, respectively (overall mean age 42 years; 61-62% females). Over one outcome year, adjusted OR (95% CI) for achieving asthma control were 1.25 (1.13-1.38) for increased ICS versus separate ICS+LABA and 1.06 (1.05-1.09) for ICS/LABA FDC versus separate ICS+LABA. For patients with asthma, increased dose of extrafine-particle ICS, or add-on LABA via ICS/LABA combination inhaler, is associated with significantly better outcomes than ICS+LABA via separate inhalers.

Inhaled beclometasone dipropionate/formoterol fumarate extrafine fixed combination for the treatment of asthma

Inhaled therapy is often considered the cornerstone of asthma management and international guidelines recommend combination therapy of inhaled corticosteroids (ICS) and long-acting-beta2-agonists (LABA) in a large proportion of asthmatic patients. The effectiveness of ICS/LABA is dependent on the correct choice of device and proper inhalation technique, this influences drug delivery and distribution along the bronchial tree, including the most peripheral airways. The fixed combination of beclometasone dipropionate/formoterol fumarate (BDP/FF) is the only extrafine formulation available in pressurized metered dose inhaler (pMDI) and in dry powder inhaler (DPI). Here, we focus on the recent significant advances regarding BDP/FF fixed combination for the treatment of asthma.

Fixed-Dose combination of the inhaled corticosteroid and long-acting beta2-agonist therapy in adults with persistent asthma

INTRODUCTION

Asthma is a respiratory condition characterized by airway inflammation, airflow obstruction, and bronchial hyperresponsiveness. The standard treatment of asthma comprises inhaled corticosteroid and beta2-agonist. Inhaled short-acting-beta2-agonists have been used as rescue medication for exacerbation. However, long-acting-beta2-agonists (LABA) used as monotherapy for asthma had been reported for having a safety concern. Consequently, it had been recommended as an add-on treatment to inhaled corticosteroid (ICS) in moderate to severe persistent asthma. The fixed-dose combination (FDC) of ICS and LABA has been approved since the year 2000. Evidences revealed using the combination of these medications is more effective in asthma control.

AREAS COVERED

The rational and phase III onward randomized-controlled studies were reviewed. Sources of evidences were from studies published in Medline until November 2015.

EXPERT OPINION

There are six FDC inhaler regimens approved worldwide. The significant synergistic effects of ICS and LABA in one device are well evidenced. A FDC reduces the daily dosage of ICS and asthma exacerbation. It is safe to use regularly as controller. The efficacy of each individual combination on asthma treatment is generally similar. Clinical experience, ease of use, cost and side effects of medication would guide the clinician's preferences.

Symposium Summary: "Breathe In, Breathe Out, Its Easy: What You Need to Know About Developing Inhaled Drugs"

Developing inhaled drugs requires knowledge of lung anatomy, cell biology, respiratory physiology, particle physics, and some plumbing. Although dose makes the poison, in the context of an inhaled drug, the "dose" is not easily defined. This lack of clarity around dose poses issues and challenges in the design of inhalation toxicology programs. To better understand dose, the influence of ventilation is discussed as are the perturbations in pulmonary function observed with inhalation exposure that can affect dose. Methods for determining inhaled drug deposition to arrive at an estimate of lung dose are examined. Equally important to understanding dose are the techniques used to deliver aerosols to animals. With a better understanding of dose and inhalation exposure, species-specific histopathologic lesions, both common background and toxicologically significant lesions, are reviewed. Finally, insight into how regulators synthesize and evaluate these complex findings to assess clinical safety risks is presented.

Extra-fine particle inhaled corticosteroids, pharma-cokinetics and systemic activity in children with asthma

During recent years, extra-fine particle inhaled corticosteroids with a median aerodynamic diameter ≤2 μm have been introduced in the treatment of asthma. The aim of this paper was to review pharmacokinetics and systemic activity of extra-fine particle hydroalkane pressurized metered dose inhaled (pMDI) ciclesonide and beclomethasone dipropionate in children. A literature review was performed. Systemic bioavailability of oral and pulmonary deposition of extra-fine ciclesonide and beclomethasone dipropionate was 52% and 82%, the half-life in serum 3.2 and 1.5 h and first-pass hepatic metabolism >99% and 60%, respectively. Secondary analyses of urine cortisol/creatinine excretion found no effects of ciclesonide pMDI between 40 and 320 μg/day or of beclomethasone dipropionate pMDI between 80 and 400 μg/day. Ciclesonide pMDI 40, 80 and 160 μg/day caused no effects on short-term lower leg growth rate as assessed by knemometry. Ciclesonide 320 μg/day was associated with a numerically short-term growth suppression equivalent to 30% which was similar to 25% and 36% suppression caused by beclomethasone dipropionate HFA and CFC 200 μg/day, respectively. Consistent with the differences in key pharmacokinetic features, beclomethasone dipropionate is associated with a systemic activity detected by knemometry at a lower dose than ciclesonide. Whether that correlates with a clinically important difference remains to be explored. Assessments of systemic activity of beclomethasone dipropionate <200 μg/day and of ciclesonide >180 μg/day as well as head-to-head comparisons are warranted. Preferably, such studies should apply the sensitive method of knemometry.

Small-airway disease in asthma: pharmacological considerations

PURPOSE OF REVIEW

To review the pharmacological considerations and rationale for treating small-airway disease in asthma via the inhaled and systemic route, and to also directly address the comparison between small vs. large aerosol particles in the management of asthmatic patients.

RECENT FINDINGS

Airway inflammation in patients with asthma is predominantly present within the small airways and this region is the main contributor to airflow limitation. Assessing small-airway dysfunction has advanced in the last decade, allowing us to compare this region in disease to health and also in response to treatment. Recent pharmaceutical developments have led to inhaler devices with smaller aerosols and systemic biologic treatments, enabling therapeutic drug delivery to the distal lung regions. The question therefore is does targeting the small airways directly translate into health benefits for asthmatic patients with respect to an improvement in their disease control and quality of life?

SUMMARY

Studies now show that treating the peripheral airways with smaller drug particle aerosols certainly achieve comparable efficacy (and some studies show superiority) compared with large particles, a reduction in the daily inhaled corticosteroid dose, and greater asthma control and quality of life in real-life studies. Hence, the small airways should not be neglected when choosing the optimal asthma therapy.

Respiratory Tract Deposition of HFA-Beclomethasone and HFA-Fluticasone in Asthmatic Patients

BACKGROUND

The asthmatic patient's respiratory tract deposition of HFA fluticasone (Flovent HFA(™)) has not been established. There is a known large particle size difference with another commercial inhaled HFA steroid (QVAR(™)). This study compared the 2D and 3D respiratory tract deposition of each inhaled steroid.

METHODS

This study was an open label, crossover study in eight patients diagnosed with asthma. The regional respiratory and oropharyngeal deposition of the two steroids were compared and contrasted using planar and SPECT imaging following delivery of the (99m)Tc-radiolabeled drug in each product. The SPECT images were merged with computed tomography images to quantify regional deposition within the patients.

RESULTS

Two-dimensional (2D) planar images indicated that 24% of the Flovent HFA dose and 55% of the QVAR dose deposited in the lungs. 2D oropharyngeal deposition indicated that 75% of the Flovent HFA dose was deposited in the oropharynx, while 42% of the QVAR dose deposited in the oropharynx. Three-dimensional (3D) SPECT data indicated that 22% of the Flovent HFA dose and 53% of the QVAR dose deposited in the lungs. 3D oropharyngeal and gut deposition indicated 78% of the Flovent HFA dose was deposited in the oropharynx, while 47% of the QVAR dose deposited in the oropharynx. The increased lung deposition and decreased oropharynx deposition for both 2D and 3D image data of QVAR were statistically different from Flovent HFA.

CONCLUSIONS

QVAR exhibited a significant increase in lung delivery compared to Flovent HFA. Conversely, QVAR delivered a significantly lower dose to the oropharynx than Flovent HFA. The findings were presumed to be driven by the smaller particle size of QVAR (0.7 microns MMAD) compared with Flovent HFA (2.0 microns MMAD).

Which factors affect the choice of the inhaler in chronic obstructive respiratory diseases?

Inhalation is the preferred route of drug administration in chronic respiratory diseases because it optimises delivery of the active compounds to the targeted site and minimises side effects from systemic distribution. The choice of a device should be made after careful evaluation of the patient's clinical condition (degree of airway obstruction, comorbidities), as well as their ability to coordinate the inhalation manoeuvre and to generate sufficient inspiratory flow. These patient factors must be aligned with the specific advantages and limitations of each inhaler when making this important choice. Finally, adherence to treatment is not the responsibility of the patient alone, but should be shared also by clinicians. Clinicians have access to a wide selection of pressurised metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) that can be used effectively when matched to the needs of individual patients; this should be perceived as an opportunity rather than a limitation.

Unlocking the quiet zone: the small airway asthma phenotype

The small airways in the distal lung have been called the quiet zone because they are difficult to assess and treat in patients with asthma who have disproportionate impairment of small airway function. Evidence is accumulating to support a distinct clinical phenotype for patients with asthma who have impaired small airway function. The small airway asthma phenotype, which is prevalent in patients at all steps of management guidelines, seems to be associated with poor disease control. Alternatively, small airway dysfunction might be a sensitive indicator of early disease rather than a phenotype. Conventional coarse-particle inhalers, which emit particles larger than 2 μm, might not address persistent small airway dysfunction in patients with asthma. To target the entire lung with extra-fine particle formulations (smaller than 2 μm) of inhaled corticosteroids alone or in combination with long-acting β-agonists might result in improved long-term asthma control along with a commensurate improvement in small airway function. Prospective randomised controlled trials with extra-fine-particle inhaled drugs are now needed for patients with the small airway asthma phenotype.

Comparing the effectiveness of small-particle versus large-particle inhaled corticosteroid in COPD

Purpose

Small airway changes and dysfunction contribute importantly to airway obstruction in chronic obstructive pulmonary disease (COPD), which is currently treated with inhaled corticosteroids (ICS) and long-acting bronchodilators at Global initiative for Obstructive Lung Disease (GOLD) grades 2–4. This retrospective matched cohort analysis compared effectiveness of a representative small-particle ICS (extrafine beclomethasone) and larger-particle ICS (fluticasone) in primary care patients with COPD.

Patients and methods

Smokers and ex-smokers with COPD ≥40 years old initiating or stepping-up their dose of extrafine beclomethasone or fluticasone were matched 1:1 for demographic characteristics, index prescription year, concomitant therapies, and disease severity during 1 baseline year. During 2 subsequent years, we evaluated treatment change and COPD exacerbations, defined as emergency care/hospitalization for COPD, acute oral corticosteroids, or antibiotics for lower respiratory tract infection.

Results

Mean patient age was 67 years, 57%–60% being male. For both initiation (n=334:334) and step-up (n=189:189) patients, exacerbation rates were comparable between extrafine beclomethasone and fluticasone cohorts during the 2 year outcome period. Odds of treatment stability (no exacerbation or treatment change) were significantly greater for patients initiating extrafine beclomethasone compared with fluticasone (adjusted odds ratio 2.50; 95% confidence interval, 1.32–4.73). Median ICS dose exposure during 2 outcome years was significantly lower (P<0.001) for extrafine beclomethasone than fluticasone cohorts (315 μg/day versus 436 μg/day for initiation, 438 μg/day versus 534 μg/day for step-up patients).

Conclusion

We observed that small-particle ICS at significantly lower doses had comparable effects on exacerbation rates as larger-particle ICS at higher doses, whereas initiation of small-particle ICS was associated with better odds of treatment stability during 2-years’ follow-up.

Irreversible acinar airway abnormality in well controlled asthma

RATIONALE

Even in stable asthma patients, acinar ventilation distribution can be abnormal, and we aimed to specifically maximize its reversibility by switching patients from a standard inhaled corticosteroid (iCS) to a fine particle iCS formulation.

METHODS

For this prospective double-blind double-dummy randomized study, 66 stable asthma patients under maintenance iCS (equivalent budesonide ≤ 800 μg/day) were screened for abnormal baseline acinar ventilation heterogeneity (Sacin). After a 3-week run-in period, 35 eligible patients were randomized to fine particle beclomethasone (HFA-BDP; Qvar Autohaler) or to budesonide (DPI-BUD; Pulmicort Turbohaler). Asthma Control Test (ACT) score and various lung function indices reflecting the small airways were obtained at baseline, after 6 and 12 weeks.

RESULTS

Thirty one patients [age:52 ± 17(SD) years; FEV1:76 ± 19(SD)%pred] completed the study (DPI-BUD:n = 16; HFA-BDP:n = 15). After 6 and 12 weeks, there were no significant changes in acinar or conductive ventilation heterogeneity, nor in mid-expiratory flow, RV/TLC, closing capacity, impulse oscillometry indices (resistance, reactance), bronchial NO production or alveolar NO, in either treatment arm. Asthma control was maintained in both arms.

CONCLUSION

In stable asthma patients with small airways dysfunction under maintenance therapy, there is a residual functional abnormality in the lung periphery which is probably not eosinophilic in origin and cannot be normalized with the iCS formulations under study. ISRCTN17195095.

The effect of beclometasone dipropionate/formoterol extra-fine fixed combination on the peripheral airway inflammation in controlled asthma

BACKGROUND

Suppression of small airway inflammation may contribute to achieving asthma control. We aimed to evaluate the additional effect of beclometasone dipropionate/formoterol (BDP/F) hydrofluoroalkane (HFA) pressurized metered dose inhaler (pMDI) (BDP/F-HFA 100/6 μg pMDI) on airway inflammation and functional parameters in asthma cases, who were optimally controlled by maintenance therapy.

METHODS

Ninety-five controlled asthmatic patients were included. They were grouped as Group 1 [budesonide/formoterol 320/9 μg dry powder inhaler (DPI)] and Group 2 (fluticasone/salmeterol 500/50 μg DPI) according to the combination they used. Then Group 3 was established by random selection from these two groups, and BDP/F-HFA 100/6 μg pMDI treatment was prescribed. All patients were evaluated in the beginning of the study and were re-evaluated at the end of a 3-week treatment period by spirometry, exhaled nitric oxide (eNO) levels, and small airway functional indices, namely, Sacin and Scond values.

RESULTS

There was no significant statistical difference in terms of age, height, weight, disease duration, symptoms, and spirometric parameters between the groups. There was a significant decrease in eNO levels in asthma cases who were on BDP/F-HFA therapy (p=0.001). A significant improvement in Sacin values at the end of the treatment period was observed in cases treated with BDP/F-HFA (p=0.001), indicating that inflammation was suppressed in peripheral airways.

CONCLUSIONS

These results emphasize that asthma treatment has mainly focused on the strategy to keep the disease under control; maintaining optimal functional level might be underestimated. BDP/F-HFA may have an additional favorable effect on the peripheral airway inflammation in the controlled asthma.

Small airways dysfunction in asthma: evaluation and management to improve asthma control

The small airways have been neglected for many years, but interest in the topic has been rekindled with recent advances in measurement techniques to assess this region and also the ability to deliver therapeutics to the distal airways. Current levels of disease control in asthmatic patients remain poor and there are several contributory factors including; poor treatment compliance, heterogeneity of asthma phenotypes and associated comorbidities. However, the proposition that we may not be targeting all the inflammation that is present throughout the whole respiratory tree may also be an important factor. Indeed decades ago, pathologists and physiologists clearly identified the importance of small airways dysfunction in asthmatic patients. With improved inhaler technology to deliver drug to target the whole respiratory tree and more sensitive measures to assess the distal airways, we should certainly give greater consideration to treating the small airway region when seeing our asthmatic patients in clinic. The aim of this review is to address the relevance of small airways dysfunction in the daily clinical management of patients with asthma. In particular the role of small particle aerosols in the management of patients with asthma will be explored.

NEXThaler, an innovative dry powder inhaler delivering an extrafine fixed combination of beclometasone and formoterol to treat large and small airways in asthma

INTRODUCTION

Airway inflammation and remodelling in asthma occur in the large airways and also in the small airways. The small airways are those < 2 mm in diameter and are significant sites of chronic asthmatic inflammation. It is important, therefore, to target the small as well as the large airways in any strategy for effective treatment of this disease.

AREAS COVERED

The present review deals with the recently developed fixed dose drug combination of beclometasone dipropionate/formoterol fumarate that emits extrafine particles when delivered from an innovative dry powder inhaler (DPI), NEXThaler®. The aim is to present the technical and clinical aspects of aerosolized drug delivery to the lungs.

EXPERT OPINION

The data show that the NEXThaler DPI is an efficient device for the management of persistent asthma. The evaluation of the inhalation profiles through the NEXThaler DPI demonstrates that device activation and consistent dose delivery occurs at patient achievable inhalation flow rates, and supports the broad utility of the NEXThaler DPI in patients with asthma. Overall, all the effectiveness, efficiency and satisfaction outcomes demonstrate the NEXThaler DPI is easy to use.

Fluticasone propionate/formoterol fumarate in fixed-dose combination for the treatment of asthma

A new combination inhaler containing fluticasone, a potent inhaled corticosteroid (ICS), and formoterol, a long-acting β-agonist (LABA) with rapid onset and sustained bronchodilator effect, has been approved for treatment of persistent asthma in patients ≥12 years of age requiring combination ICS-LABA therapy. The fluticasone/formoterol combination, delivered via pressurized metered-dose inhaler and available in three dose strengths, has demonstrated a good safety and tolerability profile in trials of up to 1 year. The efficacy of fluticasone/formoterol is greater than that of fluticasone or formoterol alone and noninferior to that of fluticasone/salmeterol and budesonide/formoterol in tightly controlled 8-12-week clinical trials. Advantages of the fluticasone/formoterol combination aerosol include rapid onset of bronchodilation, an attribute preferred by patients, and emission of a high fine-particle fraction that is consistent at different flow rates, which may aid consistency of delivery (given patient variability in inhalation maneuvers) and provide real-life benefits.

Advances in metered dose inhaler technology: formulation development

Pressurized metered dose inhalers (MDIs) are a long-standing method to treat diseases of the lung, such as asthma and chronic obstructive pulmonary disease. MDIs rely on the driving force of the propellant, which comprises the bulk of the MDI formulation, to atomize droplets containing drug and excipients, which ideally should deposit in the lungs. During the phase out of chlorofluorocarbon propellants and the introduction of more environmentally friendly hydrofluoroalkane propellants, many improvements were made to the methods of formulating for MDI drug delivery along with a greater understanding of formulation variables on product performance. This review presents a survey of challenges associated with formulating MDIs as solution or suspension products with one or more drugs, while considering the physicochemical properties of various excipients and how the addition of these excipients may impact overall product performance of the MDI. Propellants, volatile and nonvolatile cosolvents, surfactants, polymers, suspension stabilizers, and bulking agents are among the variety of excipients discussed in this review article. Furthermore, other formulation approaches, such as engineered excipient and drug-excipient particles, to deliver multiple drugs from a single MDI are also evaluated.

Advances in metered dose inhaler technology: formulation development

Pressurized metered dose inhalers (MDIs) are a long-standing method to treat diseases of the lung, such as asthma and chronic obstructive pulmonary disease. MDIs rely on the driving force of the propellant, which comprises the bulk of the MDI formulation, to atomize droplets containing drug and excipients, which ideally should deposit in the lungs. During the phase out of chlorofluorocarbon propellants and the introduction of more environmentally friendly hydrofluoroalkane propellants, many improvements were made to the methods of formulating for MDI drug delivery along with a greater understanding of formulation variables on product performance. This review presents a survey of challenges associated with formulating MDIs as solution or suspension products with one or more drugs, while considering the physicochemical properties of various excipients and how the addition of these excipients may impact overall product performance of the MDI. Propellants, volatile and nonvolatile cosolvents, surfactants, polymers, suspension stabilizers, and bulking agents are among the variety of excipients discussed in this review article. Furthermore, other formulation approaches, such as engineered excipient and drug-excipient particles, to deliver multiple drugs from a single MDI are also evaluated.

Inhaled corticosteroids for asthma: on-demand or continuous use

Continuous inhaled corticosteroid treatment is highly effective in children and adults with mild persistent asthma, although some therapeutic benefits are not lost if treatment is delayed. Many patients do not adhere to continuous treatment with inhaled corticosteroids, but rather take them intermittently, usually at the time of increased symptoms. Based on these observations it has been proposed that for patients with mild persistent asthma inhaled corticosteroids should be used on-demand when symptoms are troublesome, rather than on a continuous basis. The article reviews the pharmacological properties of inhaled corticosteroids used in clinical trials of on-demand treatment, as well as the evidence for the efficacy and safety of on-demand compared with continuous inhaled corticosteroid treatment of mild persistent asthma in adults and children. The place of on-demand treatment with inhaled corticosteroids in the management of asthma is discussed, as well as future directions for different management strategies for this group.

Asthma pharmacotherapy

Asthma is a chronic inflammatory disease of the airway that leads to airway obstruction via bronchoconstriction, edema, and mucus hypersecretion. The National Asthma Education and Prevention Program has outlined evidence-based guidelines to standardize asthma therapy and improve outcomes. The initial recommendation of choice for persistent asthmatic patients is an inhaled corticosteroid (ICS). Long-acting beta-2 agonists in combination with ICS, oral corticosteroids, leukotriene modifiers, and anti-IgE therapeutic options can be considered for patients with persistent or worsening symptoms. Many novel therapies are being developed, with an emphasis on anti-inflammatory mechanisms, gene expression, and cytokine modification.

Oxidatively damaged DNA in animals exposed to particles

Exposure to combustion-derived particles, quartz and asbestos is associated with increased levels of oxidized and mutagenic DNA lesions. The aim of this survey was to critically assess the measurements of oxidatively damaged DNA as marker of particle-induced genotoxicity in animal tissues. Publications based on non-optimal assays of 8-oxo-7,8-dihydroguanine by antibodies and/or unrealistically high levels of 8-oxo-7,8-dihydroguanine (suggesting experimental problems due to spurious oxidation of DNA) reported more induction of DNA damage after exposure to particles than did the publications based on optimal methods. The majority of studies have used single intracavitary administration or inhalation with dose rates exceeding the pulmonary overload threshold, resulting in cytotoxicity and inflammation. It is unclear whether this is relevant for the much lower human exposure levels. Still, there was linear dose-response relationship for 8-oxo-7,8-dihydroguanine in lung tissue without obvious signs of a threshold. The dose-response function was also dependent on chemical composition and other characteristics of the administered particles, whereas dependence on species and strain could not be equivocally determined. Roles of cytotoxicity or inflammation for oxidatively induced DNA damage could not be documented or refuted. Studies on exposure to particles in the gastrointestinal tract showed consistently increased levels of 8-oxo-7,8-dihydroguanine in the liver. Collectively, there is evidence from animal experimental models that both pulmonary and gastrointestinal tract exposure to particles are associated with elevated levels of oxidatively damaged DNA in the lung and internal organs. However, there is a paucity of studies on pulmonary exposure to low doses of particles that are relevant for hazard/risk assessment.

Comparison of dry powder versus nebulized beta-agonist in patients with COPD who have suboptimal peak inspiratory flow rate

BACKGROUND

A peak inspiratory flow rate (PIFR) of <60 L/min against the internal resistance (resist) of a dry powder inhaler (DPI) may limit the ability of a patient with chronic obstructive pulmonary disease (COPD) to achieve bronchodilation. The hypothesis was that lung function would be higher with a beta-agonist inhaled via nebulization compared with dry powder in patients with COPD who exhibit a PIFRresist of <60 L/min against the Diskus(®).

METHODS

This study was randomized, single-blind, and crossover with spirometry and inspiratory capacity (IC) measured at 15, 30, and 120 min post treatment. The efficacy of arformoterol aerosol solution (15 μg/2 mL) via nebulizer was compared with salmeterol dry powder (50 μg) via Diskus. The primary outcome was the change in lung function from baseline at 2 hr as these two inhaled beta-agonists have the similar peak bronchodilator effect as measured by forced expiratory volume in 1 sec (FEV1).

RESULTS

Twenty patients (15 females/5 males) with postalbuterol FEV1 of 0.83±0.31 L (38±12% predicted) and PIFRresist of 53±5 L/min completed the study. At 15 min, improvements in FEV1, forced vital capacity (FVC), and IC were significantly higher with arformoterol than with salmeterol. At 2 hr, changes in FVC and IC, but not FEV1, were significantly higher with arformoterol. At visit 3, patient preference was similar for salmeterol Diskus (n=8) and arformoterol solution (n=7), whereas five patients reported no preference.

CONCLUSIONS

At peak effect (2 hr), volume responses were greater with arfomoterol via nebulizer compared with dry powder salmeterol in patients with COPD who had a PIFRresist of <60 L/min. Bronchodilator therapy via nebulization should be considered in patients with COPD who have a suboptimal PIFRresist against a particular DPI.

Targeting the small airways asthma phenotype: if we can reach it, should we treat it?

OBJECTIVE

To review the available methods of evaluating the small airways disease in asthma and the therapeutic strategies to achieve better control using emerging extrafine particle inhaler technologies.

DATA SOURCES

The PubMed, MEDLINE (Ebsco), Scirus, Scopus, and Google Scholar databases were all scanned with Cross-search using the following keywords: asthma, small airways, hydrofluoroalkane 134a, extrafine particle, inhaled corticosteroid, long-acting β-agonist, spirometry, impulse oscillometry, nitrogen washout, exhaled nitric oxide, airway hyperresponsiveness, and adrenal suppression.

STUDY SELECTION

Key clinical studies considered to being relevant to the topic under review were evaluated.

RESULTS

There is an unmet need in current asthma guidelines for those individuals who exhibit the small airways asthma phenotype with a preserved forced expiratory volume in 1 second but abnormal forced midexpiratory flow and peripheral airway resistance, which tends to be associated with poorer control. Extrafine hydrofluoroalkane solution formulations of inhaled corticosteroid either alone or in combination with long-acting β-agonist may improve small airways outcomes and associated control.

CONCLUSION

From a pragmatic perspective, it makes sense to try to deliver asthma treatment to more of the lung to improve clinical outcomes, especially in patients who exhibit the small airways asthma phenotype.

Asthma outcomes and costs of therapy with extrafine beclomethasone and fluticasone

BACKGROUND

Characteristics of inhaled corticosteroids (ICSs) differ, but data comparing the real-life effectiveness of various ICSs for asthma are lacking.

OBJECTIVE

We sought to compare real-life asthma outcomes and costs of extrafine hydrofluoroalkane (HFA)-beclomethasone and fluticasone administered through a pressurized metered-dose inhaler.

METHODS

This retrospective matched cohort study examined database markers of asthma control from a large US longitudinal health care claims database over 1 baseline and 1 outcome year for 10,312 patients with asthma aged 12 to 80 years receiving their first ICS as HFA-beclomethasone or fluticasone and matched on baseline demographic characteristics and asthma severity.

RESULTS

Patients started on HFA-beclomethasone had significantly higher odds (adjusted odds ratio, 1.19; 95% CI; 1.08-1.31) of achieving overall control (risk and impairment), which was defined as no hospital attendance for asthma, oral corticosteroids, or antibiotics for lower respiratory tract infection and less than 2 puffs per day of short-acting β-agonist; they also experienced a lower rate of respiratory-related hospitalizations or referrals (adjusted rate ratio, 0.82; 95% CI, 0.73-0.93) than patients started on fluticasone. Other database outcome measures were similar in the 2 cohorts. Prescribed HFA-beclomethasone doses were lower (P < .001) than fluticasone doses (median, 320 μg/d [interquartile range, 160-320 μg/d] vs 440 μg/d [interquartile range, 176-440 μg/d]). Adjusted respiratory-related health care costs were significantly lower for HFA-beclomethasone than fluticasone (mean, $1869 [95% CI, $1727-$2032] vs $2259 [95% CI, $2111-$2404]), representing a mean annual savings of $390 (95% CI, $165-$620) per patient prescribed HFA-beclomethasone rather than fluticasone.

CONCLUSIONS

Asthma treatment outcomes were similar or better with HFA-beclomethasone prescribed at significantly lower doses and with lower costs than fluticasone.

Lung penetration and patient adherence considerations in the management of asthma: role of extra-fine formulations

The mainstay of management in asthma is inhalation therapy at the target site, with direct delivery of the aerosolized drug into the airways to treat inflammation and relieve obstruction. Abundant evidence is available to support the concept that inflammatory and functional changes at the level of the most peripheral airways strongly contribute to the complexity and heterogeneous manifestations of asthma. It is now largely accepted that there is a wide range of clinical phenotypes of the disease, characterized primarily by small airways involvement. Thus, an appropriate diagnostic algorithm cannot exclude biological and functional assessment of the peripheral airways. Similarly, achievement of optimal control of the disease and appropriate management of specific phenotypes of asthma should be based on drugs (and delivery options) able to distribute uniformly along the bronchial tree and to reach the most peripheral airways. Products developed with the Modulite^® technology platform have been demonstrated to meet these aims. Recent real-life studies have shown clearly that extra-fine fixed-combination inhaled therapy provides better asthma control than non-extra-fine formulations, thus translating the activity of the drugs into greater effectiveness in clinical practice. We suggest that in patients with incomplete asthma control despite good lung function, involvement of the peripheral airways should always be suspected. When this is the case, treatments targeting both the large and small airways should be used to improve asthma control. Above all, it is emphasized that patient adherence with prescribed medications can contribute to clinical success, and clinicians should always be aware of the role played by patients themselves in determining the success or failure of treatment.

Treating the small airways

The final article in this series evaluates the approaches undertaken to treating the small-airway region of the lungs and the clinical implications of inhaled therapy targeting the periphery in patients with asthma and chronic obstructive pulmonary disease.

The importance of imaging and physiology measurements in assessing the delivery of peripherally targeted aerosolized drugs

Considerable recent effort has been directed towards developing new aerosol formulations and delivery devices that can target drugs to the lung periphery. In order to determine the efficacy of targeted drug therapy, it is essential that the peripheral lung region be adequately assessed. Imaging of the airways structure and pathology has greatly advanced in the last decade and this rate of growth is accelerating as new technologies become available. Lung imaging continues to play an important role in the study of the peripheral airways and, when combined with state-of-the-art lung function measurements and computational modeling, can be a powerful tool for investigating the effects of inhaled medication. This article focuses on recent strategies in imaging and physiological measurements of the lungs that allow the assessment of inhaled medication delivered to the periphery and discusses how these methods may help to further optimize and refine future aerosol delivery technology.

Assessing and accessing the small airways; implications for asthma management

Despite the wealth of experience in the management of asthma, the disease remains inadequately controlled in some patients, who face long-term respiratory impairment and disability. The disease has been characterised as an inflammatory condition affecting first the larger airways and eventually the smaller airways, but there is evidence that peripheral airway involvement defines a particular and more severe phenotype of asthma. For this reason, assessing functional and biological parameters reflective of small airways involvement is important prognostically. No assessment method is universally and directly representative of peripheral airway function, but the traditional spirometric tests, including vital capacity, residual volume and forced vital capacity, are somewhat correlated with this function; useful methods for further assessment include the single-breath nitrogen wash-out test, impulse oscillometry, nitrous oxide and exhaled breath concentrate measurements, as well as computed tomography to reflect air trapping and response to treatment. Formulation advancements have made for easier treatment access to the smaller airways, with the new extrafine formulations resulting in better asthma control compared with non-extrafine formulations.