Investigators conducted a prospective trial to determine whether the ketolide antibiotic telithromycin could improve treatment of acute exacerbations of asthma. They enrolled 278 persons, between 18 and 55 years of age, who visited a medical facility for treatment of such an exacerbation. During the 10-day study period, each subject received oral telithromycin (two 400-mg capsules daily) or placebo in addition to customary care, which could include use of bronchodilators, inhaled corticosteroids, antileukotrienes, and theophylline.
Every day, subjects rated the severity and frequency of their asthma symptoms on a seven-point scale and, every morning, measured their peak expiratory flow rate. In addition, investigators evaluated subjects' pulmonary function at the end of the study period. They also tested for infection with Chlamydophila pneumoniae and Mycoplasma pneumoniae. (Ketolides have antibacterial activity against these pathogens, which may have a role in the pathogenesis of asthma exacerbations.)
Asthma symptoms in the telithromycin group were reduced by 40.4%, compared with 26.5% in the placebo group. The percentage of symptom-free days was larger in the telithromycin group (16%) than in the placebo group (8%). Peak expiratory flow rate, recorded by patients at home, did not differ between the two groups, but four in-clinic pulmonary function tests demonstrated a significant treatment benefit-although none of those effects was apparent after six weeks. The two groups had a similar number of mostly mild and moderate adverse events, but nausea was significantly more common in the telithromycin group than in the placebo group.
Commentary These findings are enticing but, at this point should stimulate more study, not prompt immediate antibiotic treatment of asthmatic patients. Telithromycin is a semisynthetic derivative of a macrolide. Because its effect was not measurably different in patients with evidence of Chlamydophila or Mycoplasma infection and patients without infection, the drug may have some nonantibiotic mechanism of action on asthma. Watch for more information on this topic!