The long-acting beta(2)-agonist salmeterol xinafoate: effects on airway inflammation in asthma

Salmeterol xinafoate is an inhaled long-acting beta(2)-adrenoceptor agonist recently introduced for the treatment of asthma. Both in vitro and animal studies suggest that it may have anti-inflammatory activities of benefit in this disease. To assess this directly, the effects of 6 weeks' treatment w ith salmeterol on indices of clinical activity, airway dysfunction and infl ammation in subjects with stable atopic asthma were investigated. In a double blind study, asthmatic patients were randomized to 6 weeks' tre atment with either salmeterol 50 mu g twice daily (n=14) or placebo (n=12). They underwent bronchoscopy with bronchoalveolar lavage (BAL) and bronchia l biopsy immediately before starting treatment and again after 6 weeks. Treatment with salmeterol improved clinical indices of asthma activity, but there were no changes in BAL differential cell counts or mediator levels, and no change in T-cell numbers or activation status; In the biopsy specime ns there were no changes in numbers of inflammatory cells, sub-basement mem brane collagen deposition or mast cell degranulation. Regular treatment with salmeterol improves clinical indices of asthma but h as no effect on the underlying inflammatory process. These findings strengt hen guideline recommendations that long-acting beta(2)-agonists should not be prescribed as sole antiasthma medication.