Preliminary data from phase II studies with Respimat, a propellant-free soft mist inhaler

In Vitro Tests for Aerosol Deposition. VI: Realistic Testing with Different Mouth–Throat Models and In Vitro—In Vivo Correlations for a Dry Powder Inhaler, Metered Dose Inhaler, and Soft Mist Inhaler

Background:In vitro-in vivo correlations (IVIVC) for lung deposition may be established by testing inhalers in vitro with realistic mouth-throat (MT) models and inhalation profiles (IP). This study was designed to compare the currently available MT models and their ability to predict in vivo lung deposition. Methods: Budelin^® Novolizer^®, Ventolin^® Evohaler^®, and Respimat^® fenoterol were chosen to represent a dry powder inhaler (DPI), metered dose inhaler (MDI), and soft mist inhaler (SMI) in tests using eight MT models: small, medium, and large Virginia Commonwealth University (VCU) models; small, medium, and large oropharyngeal consortium (OPC) models, the medium adult Alberta Idealized Throat (AIT), and the United States Pharmacopeia (USP) Induction Port, with IPs that simulated those used by volunteers in lung scintigraphy studies. Drug deposition in MT was compared across the models, and IVIVCs evaluated by comparing values for total lung dose in vitro (TLD_{in vitro}) to those reported in the clinic. Results: MT deposition was dependent on both the flow condition and MT geometry for all the inhalers, while the deposition rank order was independent of both factors. The overall ranking was USP <OPC_L <AIT <VCU_L <VCU_M <OPC_M <VCU_S <OPC_S. All model groups (VCU, OPC, AIT, and USP) produced TLD_{in vitro} comparable with TLD_{in vivo} for the DPI, where flow conditions dominated aerosol deposition. Only the VCU and OPC models produced good IVIVCs for the MDI, where MT geometry dominated deposition. In vitro tests with the SMI at 15-45 L/min underestimated MT deposition and overestimated lung deposition with all MT models except OPCs, although testing at higher flow rates showed good agreement with in vivo results. Conclusions: While realistic in vitro tests may produce results that correspond to drug deposition in vivo, MT model selection was most important for the MDI and SMI, but much less important than inhalation strength for the DPI.

Lack of paradoxical bronchoconstriction after administration of tiotropium via Respimat® Soft Mist™ Inhaler in COPD

Bronchoconstriction has been reported in asthma and chronic obstructive pulmonary disease (COPD) patients after administration of some aqueous inhalation solutions. We investigated the incidence of this event during long-term clinical trials of tiotropium delivered via Respimat^® Soft Mist™ Inhaler (SMI). We retrospectively analyzed pooled data from two identical Phase III clinical trials, in which 1990 patients with COPD received 48 weeks’ treatment with once-daily tiotropium (5 or 10 μg) or placebo inhaled via Respimat^® SMI. We recorded the incidence of bronchospasm and of a range of respiratory events that could suggest bronchoconstriction during the first 30 minutes after inhalation of study treatment on each of the eight test days. No patients reported bronchospasm. Six patients (0.3%) reported a combination of at least two events suggestive of bronchoconstriction, and 21 (1.1%) reported either rescue medication use or a respiratory adverse event. Asymptomatic falls in forced expiratory volume in one second (FEV₁) of ≥15% were recorded on all test days, with no change in incidence over time, and affected 8.2% of those in the tiotropium groups and 14.5% of those on placebo. In COPD patients receiving long-term treatment with tiotropium 5 or 10 μg via Respimat^® SMI, no bronchospasm was recorded, and the number of events possibly indicative of paradoxical bronchoconstriction was very low.

Clinical effectiveness of the Respimat inhaler device in managing chronic obstructive pulmonary disease: evidence when compared with other handheld inhaler devices

Objectives:

Medication for the management of chronic obstructive pulmonary disease (COPD) may be delivered by a number of different inhaler devices. This study was undertaken to determine the clinical effectiveness of the Respimat^® handheld inhaler device compared with other handheld inhaler devices for the delivery of medication in stable COPD.

Methodology:

A systematic review of high-quality randomized controlled clinical trials comparing Respimat with other inhaler devices using the same medication was performed. Studies were searched for in the Cochrane Central Register of Controlled Trials as well as other relevant electronic databases. Manufacturers of inhaled COPD medication were also contacted for potential trials.

Results:

Seven studies of high methodological quality with 3813 participants were included in the review. Three trials used Handihaler^® as the comparator inhaler, three used a chlorofluorocarbon metered-dose inhaler (CFC-MDI), and one trial used a hydroflouroalkane (HFA)-MDI. When Respimat was compared with Handihaler, the following reported outcomes were not significantly different: trough forced expiratory volume in 1 second (FEV₁) (weighted mean difference [WMD] 0.01 L; P = 0.14), trough forced vital capacity (FVC) (WMD 0.001 L: P = 0.88), peak FEV₁ (WMD 0.01 L: P = 0.08), peak FVC (WMD 0.01 L: P = 0.55), morning peak expiratory flow rate (PEFR) (WMD 5.06 L/min: P = 0.08), and evening PEFR (WMD 4.39 L/min: P = 0.15). Furthermore, there were no differences when Respimat was compared with Handihaler for risk of exacerbations (relative risk [RR] 0.94: P = 0.81), dry mouth (RR 1.57: P = 0.34), or nasopharyngitis (RR 1.42: P = 0.22). For Respimat compared with CFC-MDI, the only outcome for which data were available for meta-analysis was exacerbations, which were not significantly different (RR 1.20: P = 0.12). In addition, five trials with 2136 patients showed that there was no difference in risk of exacerbations or nasopharyngitis when Respimat was compared with all other handheld inhaler devices (RR 1.18: P = 0.13 and RR 1.33: P = 0.19, respectively). None of the clinical outcome measures reported was significantly different when the same, higher, or lower doses of medication were used in the inhaler devices being compared. Unfortunately, none of the included trials reported mortality as an outcome measure.

Conclusions:

Evidence from high-quality trials published to date suggests that the Respimat inhaler does not provide any additional clinical benefit to that provided by other inhaler devices in the management of COPD. Although in vitro studies have reported differences between the Respimat inhaler device and other handheld devices, we found no difference in any clinical outcome measures, including lung function and adverse events. Although recent reports have highlighted concerns of increased mortality with the Respimat inhaler device, none of the included trials reported mortality as an outcome. Only a small number of trials reported data that could be used in this systematic review, and a limited number of studies have been published that compare Respimat with other inhaler devices using the same drug and strength. Therefore, further trials comparing Respimat with other handheld inhaler devices using the same drug and dose are required before firm conclusions can be drawn. The concern with increased mortality with Respimat use should be investigated urgently.

An in vitro study to assess facial and ocular deposition from Respimat Soft Mist inhaler

Respimat Soft Mist() inhaler (SMI) is a novel multidose propellant-free inhaler device for delivery of inhaled drugs to patients with asthma and chronic obstructive pulmonary disease. In vitro studies have been undertaken to assess facial and ocular deposition from Respimat SMI in several potential misuse situations. A placebo aqueous drug formulation in Respimat SMI was radiolabeled by addition of (99m)Tc. Deposition was quantified by gamma camera on a removable facemask that was fitted over the head of a resuscitation mannequin. The eyes were simulated by adhesive plaster patches. When Respimat SMI was fired in three preselected positions away from the head, total face deposition (% ex-valve dose) averaged 7.3%, 7.8%, and 9.1%, and eye deposition averaged 0.6%, 0.1%, and 0.3%. When the inhaler was fired into a simulated exhalation, upper face deposition (mean 3.8%) and eye deposition (mean 0.1%) were also small. It is concluded that low deposition on the face, and especially in the eyes, is to be expected when Respimat SMI is fired accidentally outside the body, or is fired at the same time as the patient exhales. When Respimat SMI is misused in the ways described in this study, there is likely to be little potential for unwanted side effects resulting from ocular deposition.

Low incidence of paradoxical bronchoconstriction in asthma and COPD patients during chronic use of Respimat soft mist inhaler

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler that offers improved lung deposition compared with chlorofluorocarbon metered dose inhalers (CFC-MDIs). Bronchodilators administered via Respimat SMI are preserved and stabilised with low concentrations of benzalkonium chloride and ethylene diamine tetra-acetic acid, both of which have been reported to cause dose-related paradoxical bronchoconstriction. The aim of this analysis was to compare the incidence of paradoxical bronchoconstriction after chronic use of bronchodilators via Respimat SMI and CFC-MDI. Data from three clinical trials, in which patients with asthma or chronic obstructive pulmonary disease (COPD) received ipratropium bromide alone or in combination with fenoterol hydrobromide, or placebo via Respimat SMI or CFC-MDI for 12 weeks, were included in the analysis. In order to evaluate the risk of paradoxical bronchoconstriction, we identified four respiratory events that might have occurred within 30 min of inhalation on four test days; these were: 'bronchospasm', 'other respiratory adverse events', 'rescue medication use' and 'asymptomatic drop in FEV(1) 15% from baseline'. In total, 631 asthma and 1538 COPD patients participated in the three studies. No occurrences of bronchospasm were reported with Respimat SMI on any test day. Overall, the incidence of respiratory events possibly indicative of paradoxical bronchoconstriction was low and similar for both devices. There was no increase in the incidence of events during 12 weeks' treatment. Delivery of bronchodilators by Respimat SMI is safe with regard to paradoxical bronchoconstriction during chronic use in patients with asthma or COPD.

Deposition of corticosteroid aerosol in the human lung by Respimat Soft Mist inhaler compared to deposition by metered dose inhaler or by Turbuhaler dry powder inhaler

Fourteen mild-to-moderate asthmatic patients completed a randomized four-way crossover scintigraphic study to determine the lung deposition of 200 microg budesonide inhaled from a Respimat Soft Mist Inhaler (Respimat SMI), 200 microg budesonide inhaled from a Turbuhaler dry powder inhaler (Turbuhaler DPI, used with fast and slow peak inhaled flow rates), and 250 microg beclomethasone dipropionate inhaled from a pressurized metered dose inhaler (Becloforte pMDI). Mean (range) whole lung deposition of drug from the Respimat SMI (51.6 [46-57]% of the metered dose) was significantly (p < 0.001) greater than that from the Turbuhaler DPI used with both fast and slow inhaled flow rates (28.5 [24-33]% and 17.8 [14-22]%, respectively) or from the Becloforte pMDI (8.9 [6-12]%). The deposition pattern within the lungs was more peripheral for Respimat SMI than for Turbuhaler DPI. The results of this study showed that Respimat SMI deposited corticosteroid more efficiently in the lungs than either of two widely used inhaler devices, Turbuhaler DPI or Becloforte pMDI.

Delivery options and devices for aerosolized therapeutics

Although inhalation is one of the oldest modes of drug delivery, it is currently receiving renewed attention. Prior to 1987, aerosolized therapeutics were delivered via systems that relied on chlorofluorocarbon propellant systems. The subsequent ban on all nonmedical uses of these inert gases stimulated pharmaceutical companies to investigate other propellant systems. Two hydrofluoroalkanes were effective. However, in some instances, the change in propellant required reformulation of the drugs to be delivered. In some cases, bioequivalence could be achieved at lower doses with reduced toxicity. Pressurized metered-dose inhalers (pMDIs) have been used to deliver many types of inhaled therapeutics since the 1960s. Their major limitation is that drug delivery and effectiveness are affected by patient factors, including coordination difficulties and problems related to breathing and breath holding in patients with airway disease. Dry-powder inhalers are being developed to deliver powdered formulations of drugs such as bronchodilators and anti-inflammatory drugs for the treatment of asthma and COPD, and, eventually, proteins, peptides, recombinant products, and gene therapeutics. These devices have been proven to be as efficient as pMDIs in clinical trials. In some cases, they deliver a greater amount of the drug to the lungs. Percentages of the emitted dose deposited in the lungs range from 15 to 40% with the current generation of these devices. Finally, metered-dose liquid inhalers also are under development. Drug deposition in the lung with devices that are currently being tested ranges from 30 to 80% of the emitted dose. The choice of delivery system depends on the effective dose, drug deposition, patient ability, patient acceptance, and cost. Patient education in the correct use of each device is essential to maximize the therapeutic benefit.