PURPOSE:Although smoking cessation is critical for reducing chronic obstructive pulmonary disease (COPD) progression, some patients have difficulty quitting. Smoking is known to impair responses to inhaled corticosteroids, whereas its impact on the action of bronchodilators, an important component of current COPD treatments, is less known. A subgroup analysis was performed to investigate whether current smoking affected the efficacy of formoterol (FOR) and tiotropium (TIO) combination treatment in COPD patients.
METHODS:A randomized, double-blind, multicenter study originally designed to compare the efficacy of 12 weeks of treatment with coadministered FOR+TIO vs TIO alone (FOR 12 μg BID + TIO 18 μg QD vs TIO 18 μg QD) in COPD patients regardless of smoking status (primary data presented elsewhere) was analyzed for efficacy in current smokers and nonsmokers. Efficacy was assessed by the forced expiratory volume in 1 second (FEV1) area under the curve from 0–4 hours (FEV1 [AUC0–4h]) after the AM bronchodilator dose.
RESULTS:Out of 255 subjects, 47% were current smokers. From weeks 4–12, nonsmokers and smokers treated with FOR+TIO experienced an increase in FEV1 (AUC0–4h) ranging from 34.4–38.4% and 28.9–34.1% respectively, compared to baseline. Treatment with TIO alone for weeks 4–12 improved FEV1 (AUC0–4h) by a maximum of 18.1% in nonsmokers and 20.9% in smokers. At endpoint, nonsmokers and smokers treated with FOR+TIO experienced a 35.1% and 31.2% increase in FEV1 (AUC0–4h) respectively, from baseline (mean difference, 0.036 L). At endpoint TIO treatment alone only improved FEV1 (AUC0–4h) by 16.1% in nonsmokers (P<0.0001 vs FOR+TIO) and 17.3% in smokers (P=0.0005 vs FOR+TIO) (mean difference, –0.027 L for nonsmokers vs smokers).
CONCLUSION:Treatment with coadministered FOR+TIO yielded greater mean improvements in lung function compared with TIO treatment alone regardless of smoking status. Bronchodilator response did not appear to be affected by smoking status.
CLINICAL IMPLICATIONS:Coadministration of FOR and TIO can be used successfully to induce bronchodilation in both smokers and nonsmokers with COPD.
DISCLOSURE:Donald Tashkin, Grant monies (from industry related sources) I have received industry-sponsored grants from Schering-Plough and Boehringer-Ingelheim.; Consultant fee, speaker bureau, advisory committee, etc. I have received honoraria for advisory boards from Schering-Plough and Boehringer-Ingelheim.; No Product/Research Disclosure Information