A New Treatment Strategy for Asthma —
Single Inhaler Maintenance and Reliever Therapy (SMART)
Dr. Robert R. Schellenberg, Professor, Dept. of Medicine, UBC, Head of the Division of Allergy & Immunology at UBC and St. Paul's Hospital, Vancouver, BC
The main goal of asthma therapy is to control symptoms and avoid episodes of worsening symptoms that interfere with school, work and normal activities. Although some asthmatics may be able to do this by avoiding triggers such as allergies and infections, most people require drug treatment. The mainstay of this treatment is regular daily doses of an inhaled corticosteroid (ICS) combined with a separate inhaler for relief when required (short-acting beta-agonist such as salbutamol or terbutaline). For asthmatics with persistent symptoms, a combination of an ICS with a long-acting beta agonist (LABA) in one inhaler provides better control in the majority of patients. Although the two LABA's available in Canada (salmeterol and formoterol) are available as single inhalers, there are dangers associated with using these alone without an ICS and therefore the combination products are recommended when an ICS alone is insufficient. Single inhaler combinations are salmeterol / fluticasone (Advair®) and formoterol / budesonide (Symbicort®).
Many clinical asthma studies have shown that use of either of these combination products produce better asthma symptom control, fewer acute worsenings of asthma (exacerbations) and better lung function than using the inhaled steroid alone.
Recently, studies have evaluated a new treatment strategy whereby patients use just one inhaler for their asthma. The combination of formoterol / budesonide in a single inhaler was used twice a day as maintenance therapy (control of inflammation) as well as for additional doses when extra or acute relief was required. This was possible because formoterol has a very fast onset of action in dilating the airways in addition to causing long-lasting (12 hour) symptom relief or bronchodilation and because it can be safely used at dosages up to 72 µg /day (which is 12 inhalations since each inhaler has 6 µg / dose). Unfortunately, this treatment strategy is not possible or safe with the salmeterol / fluticasone combination product.
In two recent studies (references 1 and 2) that lasted 1 year in duration, with more than 2700 patients trying three different ways to treat their asthma (some patients as young as 4 years in one study although most patients were adults), using the combination formoterol / budesonide inhaler as the rescue (acute reliever) medication in addition to twice a day regular dosing led to fewer exacerbations, less symptoms and fewer inhalations of rescue medication.
Separate analysis of the 341 children aged 4-11 years that were a part of the second study showed the same benefit of using the SMART strategy as seen for adults (reference 3).
This new strategy does not aim for total control of symptoms but rather to treat any symptoms immediately to avoid worsening of asthma control. It means that when you experience asthma symptoms requiring a reliever medication, you need more inhaled steroid to reduce ongoing inflammation in your lungs and an inhalation of formoterol / budesonide provides this as well as provide the need for rapid symptom relief. All of this can be achieved using one inhaler. Using formoterol alone as the reliever instead of the combination of formoterol / budesonide failed to show these benefits.
By using this strategy, the asthmatic subject must take the combination formoterol / budesonide regularly twice a day and not simply use this drug on an “as needed” basis for symptom relief. If many extra doses are being used, it makes sense to increase the regular twice-a-day dose until symptoms are controlled.
- O'Byrne, PM et al. Budesonide / formoterol combination therapy as both maintenance and reliever medication in asthma. Am. J. Respir. Crit. Care Med. 2005; 171: 129-136.
- Rabe, KF et al. Effect of budesonide in combination with formoterol for reliever therapy in asthma exacerbations: a randomized controlled, double-blind study. Lancet 2006; 368: 744-753.
- Bisgaard, H et al. Budesonide / formoterol maintenance plus reliever therapy. A new strategy for pediatric asthma. Chest 2006; 130: 1733-1743.