Sizing Up Future Trends in Asthma Therapy

No matter how good a product is, it can almost always be improved. In that spirit, researchers are continuing to develop more effective formulations and delivery devices for existing asthma medications.

Improving inhaled corticosteroids

The development of inhaled corticosteroids in the 1970s heralded a new age in asthma therapy. For the first time, anti-inflammatory drugs were available that could reduce swelling and mucus production in the airway, decrease airway hyperreactivity ("twitchiness") in response to asthma triggers, and in some cases even prevent airway remodeling (in which healthy, functioning tissue is replaced with non-functional scar tissue due to chronic airway inflammation).

In recent years, as pharmaceutical researchers have continued improving inhaled corticosteroids, most physicians have come to consider these products the therapy of choice for treating patients with moderate to severe asthma symptoms.

The newest generation of these drugs, which are currently in development or due for FDA approval, may provide even more effective therapy by directly targeting the lungs with greater accuracy while also reducing typical adverse side effects associated with inhaled corticosteroids. Ciclesonide (Alvesco) and mometasone (Asmanex) have shown great promise in clinical trials, especially in treating children with asthma.

Combining for complementary effect

Another promising trend in recent asthma pharmacology has been the development of products that combine an inhaled corticosteroid with a long-acting bronchodilator in order to achieve a complementary effect. Advair Diskus, which the FDA approved in 2000 and is now one of the most prescribed asthma drugs in the United States, combines fluticasone, an inhaled corticosteroid, and salmeterol, a long-acting bronchodilator.

This focus on complementary therapy is continuing and shows great promise with Symbicort, which the FDA should soon approve. This product combines budesonide, an inhaled corticosteroid, with formoterol, which is the only rapid-onset, long-acting bronchodilator available in the United States. In the near future, expect to see more products that combine formoterol, or other long-acting bronchodilators that are still in development, with some of the newer inhaled corticosteroids.

Special delivery: More effective devices

To really make a difference in effectively managing asthma, as well as other respiratory conditions, the inhaled medications that patients take — whether they're newly developed drugs or improved formulations of older products — need to reach as deep into the airways as possible. As a result, much of asthma medication development also focuses on improving delivery devices, especially inhalers.

Metered-dose inhalers (MDIs) have been standard delivery devices for asthma medications since the advent of beta₂-adrenergic bronchodilators and inhaled corticosteroids. However, many of these devices require a certain level of coordination for effective use (often requiring the patient to also use a holding chamber or spacer for optimal results) and at best only deliver 10 to 20 percent of the spray to the airways where it's really needed. Additionally, many MDI medications are formulated with ozone-depleting chlorofluorocarbons (CFCs) as propellants.

To overcome the shortcomings of older MDIs, newer inhaled asthma products, both recently approved ones and those still in clinical trials, offer the following improvements:

• Environmentally friendly propellants. The FDA approved Hydrofluoroalkane (HFA), a new non-CFC propellant for use in formulations of albuterol (Proventil HFA, Ventolin HFA) and beclomethasone (QVAR-HFA). Not only are these newer HFA-propelled products better for the ozone layer, but they also deliver medications to the lungs more effectively than the older CFC-based MDIs. You can soon expect to see more formulations of inhaled asthma drugs using HFA, or other soon-to-be approved non-CFC propellants.

• User-friendlier MDIs. The recently developed Maxair Autohaler is a prime example of this trend. The Autohaler, which is indicated for short-term relief of suddenly worsening respiratory symptoms, is a breath-activated MDI that delivers the short-acting beta₂-adrenergic bronchodilator pirbuterol without the need for a holding chamber and also requires less coordination to use compared to many other MDIs. Look for more delivery devices along these lines in the near future, especially for use with short-term or rescue medications.

• Dry-powder inhalers (DPIs). Rather than dispensing their product as an aerosolized spray, as do MDIs, these newer types of inhalers deliver asthma drugs in special dry-powder formulations. DPIs are also designed for easy use, and if operated properly, are very effective at delivering medication to the tiniest airways. The FDA has thus far approved DPI formulations of four inhaled products:

• Budesonide, an inhaled corticosteroid (Pulmicort Turbuhaler)

• Fluticasone, also an inhaled corticosteroid (Flovent Rotadisk, used with the Diskhaler device)

• Salmeterol, a long-acting bronchodilator (Serevent Diskus)

• Fluticasone and salmeterol in combination (Advair Diskus)

More DPI formulations are also in the pipeline, so breathe easy. Your doctor will continue to have a wider choice of simpler and more effective ways for delivering medications deeper into your airways than ever before.

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