Effects of Macrolides on Asthma Control

Asthma is a common disease in Westernised societies, affecting up to 10% of the population. Corticosteroids are the most effective treatment for asthma but the therapeutic response varies considerably between individuals. A major cause of corticosteroid insensitivity in asthma is cigarette smoking. Active cigarette smoking occurs in over 25% of adults with asthma and a further 25% are ex-smokers. In a series of proof of concept clinical studies the investigators demonstrated for the first time that the efficacy of inhaled and oral corticosteroids is markedly impaired in smokers with asthma and to a lesser extent in ex-smokers with asthma. Active cigarette smoking has other detrimental effects on asthma morbidity including more severe symptoms, increased rates of hospitalisation, and accelerated decline in lung function. Smoking cessation advice is often ineffective because many adult smokers with asthma do not believe that they are personally at risk from their smoking, take many years until stopping smoking and frequently restart smoking after quitting. Alternative or additional drugs to corticosteroids are needed for smokers with asthma who are unable to obtain the clinical benefits associated with stopping smoking. In a proof of concept clinical trial the investigators will test the hypothesis that macrolides improve asthma control and reduce sputum neutrophil counts of smokers with chronic asthma.