[Treatments targeting distal airways in asthma: update on clinical studies]

Two strategies are possible for targeting distal airways in asthma. The first one is systemic, with the delivery of medications either orally or intravenously. Montelukast is the only oral drug that has demonstrated its efficacy on distal airways by reducing lung hyperinflation. The second possible strategy is to deliver inhaled medications using ultrafine particles. Studies performed with formoterol-HFA solution (Formoair Modulite), the only available long-acting beta2 agonist with ultrafine particles have shown a non-inferior bronchodilator effect and a good tolerance as compared to inhaled long acting beta2 agonists with non-ultrafine particles. Studies performed with BDP-HFA alone (QVAR) or combined BDP-HFA/formoterol (Fostair) with ultrafine particles have mostly demonstrated their clinical non- inferiority on bronchodilation, quality of life, and symptoms in asthmatic subjects as compared to non-ultrafine inhaled medications. With the exception of a few studies, most publications have been performed in a limited number of patients and for only short durations. The available studies have not yet demonstrated a long-term benefit in terms of additional clinical efficacy of these ultrafine inhaled medications on symptoms, control and exacerbations of asthma.