Brand and generic use of inhalation medication and frequency of switching in children and adults: A population-based cohort study

The impact of unsupervised and unconsented switch of inhalers in patients with controlled asthma - A targeted literature review

Inhaler combination formulations consisting of an inhaled corticosteroid (ICS) (fluticasone propionate) and a long-acting β2 agonist (salmeterol xinafoate) are indicated as maintenance treatments for patients with asthma and/or for selected patients with chronic obstructive pulmonary disease. The emergence of generic equivalents to branded inhalers is expected to offer economic edge/savings; however, some may argue that cost advantages offered by generic inhalers may be offset by worsening outcomes due to improper inhaler use, reduced adherence, and consequently worse disease control. To understand how unsupervised and unconsented switch of dry-powder inhalers and/or metered-dose inhalers affects clinical and humanistic outcomes in asthma, comprehensive searches of Embase and MEDLINE were conducted to identify research articles published in the English language since 2011. Patients with asthma of any age who underwent an unsupervised and unconsented switch from an ICS/long-acting β2 agonist to another (brand-to-generic or brand-to-brand) for non-medical reasons were the target of this research. Relevant outcomes included asthma control, medication adherence, and healthcare resource utilization. In total, 11 studies were identified for review (ten non-interventional and one post hoc); cohorts ranged from 19 to 42,553 patients. Six studies indicated that unsupervised and unconsented inhaler switch had a negative impact on asthma control; six studies indicated reduced medication adherence post-switching; and five studies reporting healthcare resource utilization showed it was unchanged or increased post-switching. Findings from this targeted review support concerns that unsupervised and unconsented inhaler switch has a largely negative impact on asthma-associated outcomes. Additional studies are warranted to further explore unsupervised and unconsented switch in asthma.

The Role of ICS/LABA Fixed-Dose Combinations in the Treatment of Asthma and COPD: Bioequivalence of a Generic Fluticasone Propionate-Salmeterol Device

Both asthma and chronic obstructive pulmonary disease (COPD) are inflammatory chronic respiratory conditions with high rates of morbidity and mortality worldwide. The objectives of this review are to briefly describe the pathophysiology and epidemiology of asthma and COPD, discuss guideline recommendations for uncontrolled disease, and review a new generic option for the treatment of asthma and COPD. Although mild forms of these diseases may be controlled with as-needed pharmacotherapy, uncontrolled or persistent asthma and moderate or severe COPD uncontrolled by bronchodilators with elevated eosinophilia or frequent exacerbations may require intervention with combination therapy with inhaled corticosteroids (ICS) and long-acting beta agonists (LABAs), according to international guidelines. Fixed-dose combinations of ICS/LABA are commonly prescribed for both conditions, with fluticasone propionate (FP) and salmeterol forming a cornerstone of many treatment plans. An oral inhalation powder containing the combination of FP and salmeterol has been available as Advair Diskus® in the United States for almost 20 years, and the first and only substitutable generic version of this product has recently been approved for use: Wixela™ Inhub™. Bioequivalence of Wixela Inhub and Advair Diskus has been established. Furthermore, the Inhub inhaler was shown to be robust and easy to use, suggesting that Wixela Inhub may provide an alternative option to Advair Diskus for patients with asthma or COPD requiring intervention with an ICS/LABA.

General Practitioner Use of Generically Substitutable Inhaler Devices and the Impact of Training on Device Mastery and Maintenance of Correct Inhaler Technique

INTRODUCTION

Generic substitution of inhaler devices is a relatively new phenomenon. The best patient outcomes associated with generic substitution occur when prescribers obtain consent from their patients to prescribe a generic inhaler and also teach their patient how to correctly use the new device. To date, no prospective observational study has assessed the level of training required for general practitioners (GPs) to demonstrate correct inhaler technique using two dry powder inhaler devices delivering fixed-dose combination budesonide/formoterol therapy. This study aims to (1) determine the level of training required for GPs to master and maintain correct IT when using two different dry powder inhalers that are able to be substituted in clinical practice and (2) determine the number and types of errors made by GPs on each device and inhaler device preference at each training visit.

METHOD

A randomized, parallel-group cross-over study design was used to compare the inhaler technique of participants with a Spiromax® placebo device and a Turbuhaler® placebo device. This study consisted of two visits with each participant over a period of 4 ± 1 weeks (visit 1 and visit 2). A total of six levels of assessment and five levels of training were implemented as required. Level 1, no instruction; level 2, following use of written instruction; level 3, following viewing of instructional video; level 4, expert tuition from the researcher; level 5/level 6, repeats of expert tuition from the researcher when required. Participants progressed through each level and stopped at the point at which they demonstrated device mastery. At each level, trained researchers assessed the inhaler technique of the participants. Participants were also surveyed about their previous inhaler use and training.

RESULTS

In total, 228 GPs participated in this study by demonstrating their ability to use a Turbuhaler® and a Spiromax® device. There was no significant difference between the proportion of participants who demonstrated device mastery with the Turbuhaler® compared with the Spiromax® at level 1, (no instruction), (119/228 (52%) versus 131/228 (57%), respectively, n = 228, p = 0.323 (McNemar's test of paired data). All but one participant had demonstrated correct inhaler technique for both devices by level 3(instructional video). There was a significant difference between the proportion of participants who demonstrated maintenance of device mastery with the Turbuhaler® compared with the Spiromax® at visit 2, level 1 (127/177 (72%) versus 151/177 (85%) respectively, p = 0.003; McNemar's test of paired data). All but two participants achieved device mastery by level 3, visit 2. More participants reported previous training with the Turbuhaler® than with Spiromax®.

DISCUSSION

This study demonstrates that GPs are able to equally demonstrate correct use of the Turbuhaler® and Spiromax® devices, even though most had not received training on a Spiromax® device prior to this study. The significance of being able to demonstrate correct technique on these two devices equally has ramifications on practice and supported generic substitution of inhaler devices at the point of prescribing, as the most impactful measure a GP can take to ensure effective use of inhaled medicine is the correct demonstration of inhaler technique.

Quantification of Adverse Drug Reactions Related to Drug Switches in The Netherlands

We performed a retrospective cohort study in the Dutch patient population to identify active substances with a relatively high number of adverse drug reactions (ADRs) potentially related to drug switching. For this, we analyzed drug switches and reported ADRs related to switching between June 1, 2009, and December 31, 2016, for a selection of 20 active substances. We also compared pharmacovigilance analyses based on the absolute, switch-corrected, and user-corrected numbers of ADRs. In total, 1,348 reported ADRs and over 23.8 million drug switches were obtained from the National Health Care Institute in The Netherlands and from Lareb, which is The Netherlands Pharmacovigilance Centre. There was no correlation between the number of ADRs and the number of switches, but, on average, we found 5.7 reported ADRs per 100,000 switches. The number was relatively high for rivastigmine, levothyroxine, methylphenidate, and salbutamol, with 74.9, 50.9, 47.6, and 26.1 ADRs per 100,000 switches, respectively. When comparing analyses using the absolute number and the switch-corrected number of ADRs, we demonstrate that different active substances would be identified as having a relatively high number of ADRs, and different time periods of increased numbers of ADRs would be observed. We also demonstrate similar results when using the user-corrected number of ADRs instead of the switch-corrected number of ADRs, allowing for a more feasible approach in pharmacovigilance practice. This study demonstrates that pharmacovigilance analyses of switch-related ADRs leads to different results when the number of reported ADRs is corrected for the actual number of drug switches.

Cost saving of switching to equivalent inhalers and its effect on health outcomes

BACKGROUND

Switching inhalers to cheaper equivalent products is often advocated as a necessary cost saving measure, yet the impact on patient's health and healthcare utilisation has not been measured.

METHODS

We identified asthma and chronic obstructive pulmonary disease (COPD) patients from UK primary care electronic healthcare records between 2000 and 2016. A self-controlled case series was used to estimate incidence rate ratios (IRR); comparing outcome rates during the risk period, 3 months after the exposure (financially motivated switch), and control periods (preswitch and postrisk period). Four outcomes were assessed: disease exacerbation, general practitioner consultation, non-specific respiratory events and adverse-medication events. Medication possession ratio (MPR) was calculated to assess adherence. 2017 National Health Service indicative prices were used to estimate cost differences per equivalent dose.

RESULTS

We identified a cohort of 569 901 asthma and 171 231 COPD regular inhaler users, 2% and 6% had been switched, respectively. Inhaler switches between a brand-to-generic inhaler, and all other switches (brand-to-brand, generic-to-generic, generic-to-brand), were associated with reduced exacerbations (brand-to-generic: IRR=0.75, 95% CI 0.64 to 0.88; all other: IRR=0.79, 95% CI 0.71 to 0.88). Gender, age, therapeutic class, inhaler device and inhaler-technique checks did not significantly modify this association (p<0.05). The rate of consultations, respiratory-events and adverse-medication events did not change significantly (consultations: IRR=1.00, 95% CI 0.99 to 1.01; respiratory-events: IRR=0.96, 95% CI 0.95 to 0.97; adverse-medication-events: IRR=1.05, 95% CI 0.96 to 1.15). Adherence significantly increased post-switch (median MPR: pre-switch=54%, post-switch=62%; p<0.001). Switching patients, in the cohort of regular inhaler users, to the cheapest equivalent inhaler, could have saved around £6 million annually.

CONCLUSION

Switching to an equivalent inhaler in patients with asthma or COPD appeared safe and did not negatively affect patient's health or healthcare utilisation.