Although the inhaled delivery of drugs has major advantages over other methods of administration, inhaler devices are often difficult to use and can indirectly have a negative impact on symptom control. Unfortunately, in a classic catch-22 situation, those devices that are developed to overcome the disadvantages of the majority of inhalers often lack broad availability across different therapeutic molecules and drug classes. Offering physicians and patients a range of therapies in the same type of device will therefore improve proper use of inhalers, which can indirectly have a positive impact on the control of diseases like asthma and chronic obstructive pulmonary disease (COPD), according to a new report* by independent market analyst Datamonitor.
Respiratory diseases like asthma and COPD are mostly treated with inhaled drugs in order to relieve bronchoconstriction and target inflammation in the lungs. There are several advantages to administering these drugs via the inhaled route compared to oral therapy: a faster onset of action, lower drug doses and a better efficacy-to-safety ratio. Drug delivery by inhalation is also painless and is more convenient than injectable drugs.
Despite this impressive list of benefits, several drawbacks remain for inhaled medicines, explains Datamonitor respiratory analyst Lisette Oversteegen. “One of the biggest problems relates to the inhaler device through which the drug is delivered. Every type of device is different and requires a specific inhalation technique in order to get a sufficient amount of drug to the lungs.
“Since there are so many different types of inhalers available, it can be difficult for the patient to learn and remember the correct use for each one of them. An incorrect inhalation technique is likely to have a big impact on a patient's daily life, since their asthma or COPD symptoms could be less well controlled than optimally possible,” she says.
There are two main types of portable inhaler devices used in the treatment of asthma and COPD: metered dose inhalers (MDIs), including pressurised MDIs (pMDIs) and breath-activated MDIs (BAIs), and dry powder inhalers (DPIs) (including single-unit dose DPIs, multi-dose reservoir DPIs and multi-unit dose DPIs).
Amongst the BAIs and DPIs especially, there is a wide variation in design, making it impossible to learn only one technique to use them correctly.
The standard pMDI is the oldest and most often-used inhaler since it is cheap and available containing many different molecules. Nonetheless, a large proportion of patients cannot use them correctly. One of the most common problems is a failure to co-ordinate inhalation with actuation of the device (pressing the canister to release the drug). Patients often actuate the inhaler before or at the end of inhalation, and some may even hold their breath while activating the inhaler. Other errors include failure to exhale fully before inhalation and failure to continuously inhale slowly after actuation.
Because of the problems associated with pMDIs, attention has focused on the improvement of inhaler devices to optimise the delivery of medication. Breath-activated MDIs (BAIs) help to overcome the problem of co-ordinating actuation with inhalation, thus providing the opportunity to improve drug delivery and overall disease control. However, the major drawback of BAIs is that there are only a few drugs available in these devices due to the high cost involved in developing them, Oversteegen says. “Since physicians cannot offer all of the medicines a patient needs in a BAI, they are forced to switch back to a pMDI or combine different devices in one treatment regimen.”
Dry powder inhalers offer an alternative response to the difficulties associated with pMDIs. These devices release the drug by passing air from the patient's inhalation effort through medication formulated as a dry powder. Although this partially resolves the co-ordination problem since the drug is only released when the patient inhales, there are other disadvantages to DPIs, Oversteegen says. “While the inhalation technique for pMDIs is generally the same, the wide variety of DPIs available means that inhalation instructions can be very different.
“Furthermore, to ensure that most of the drug emitted from a dry powder inhaler reaches the lungs, it is necessary for the patient to inhale deep and fast enough. A number of asthma and COPD patients are unable to do so, especially the elderly, children and people with severe airflow limitation,” she says.
Both physicians and patients agree that there are certain characteristics to an ideal inhaler. It should be small, easy-to-use and suitable for patients with low inspiratory volume. It should be breath-actuated and only release the drug when all prerequisites for successful inhalation are met. “And most importantly”, Oversteegen says, “the drug delivery should be flow-independent and multiple automatic feedback mechanisms should exist to reassure the patient that the drug was successfully deposited in the lungs.”
However, since there is no inhaler device combining all of the above characteristics (although some characteristics are met in different individual inhalers), physicians have to make a choice from the range of available inhaler devices, Oversteegen says. “Clearly, physicians should recognise that patients differ and a device that is most appropriate for their needs and circumstances should be matched individually.
“Additionally, cost plays an increasingly important role and many governments will ask physicians to start their patients on a cheap pMDI, and only use a more expensive inhaler when necessary,” she says.
Nevertheless, the concept of matching an inhaler to a patient becomes redundant if inhaler availability is a problem. There can be quite a difference in the availability of inhaler devices across treatments. Although most molecules are available in both DPIs and pMDIs in the six major markets**, availability within one country can be very different.
Obviously, when patients are on a pMDI and all the treatments they require are available in pMDIs, there is no problem as there is no difference between the inhalation techniques of these devices. However, DPIs differ significantly and the availability of certain molecules in certain DPIs may limit a physicians' choice. If, for example, a physician recommends Symbicort (AstraZeneca's budesonide/formoterol combination) for a patient, all the other choices of drugs are limited to their availability in the Turbuhaler, of which there are few.
Having a range of molecules available in the same device will allow physicians to prescribe a complete treatment regimen in the same type of device, minimising errors in inhalation technique, Oversteegen says. “This would also lead to increased convenience for the patient, as only one technique needs to be learnt and remembered.
“Indeed, some companies market one type of inhaler device with different molecules across drug classes, covering all the needs of a standard asthma patient. However, these are all generic molecules and the newer treatments are not available in the same range, leaving many asthma and COPD patients struggling with their daily medication,” she says.
* Stakeholder Insight: Portable Inhaler Devices - Key tools to differentiate brands and survive generic pressure
** Six major markets: US, France, Germany, Italy, Spain and the UK.
Datamonitor's report Stakeholder Insight: Portable Inhaler Devices - Key tools to differentiate brands and survive generic pressure provides a comparative overview of portable inhaler devices used in the respiratory market. Gives insight into the current market situation based on IMS Sales Data. Assesses case studies to provide insight into potential market strategies.
Lisette Oversteegen is Respiratory Analyst and report author at Datamonitor, a UK-based research company and one of the world's leading provider of online data, analytic and forecasting platforms for key vertical sectors. Through their proprietary databases and wealth of expertise, they seek to provide clients with unbiased expert analysis and in-depth forecasts for seven industry sectors: Automotive & Logistics, Consumer Markets, Energy, Financial Services, Healthcare, Retail and Technology. Datamonitor maintains its headquarters in London and has regional offices in New York, San Francisco, Hyderabad and Sydney. See http://www.datamonitor.com for further details.
