Treatment effects of low-dose theophylline combined with an inhaled corticosteroid in COPD.
BACKGROUND
Inhaled corticosteroids (ICS) have proved disappointing at reducing airway inflammation in COPD. However, previous studies indicate that low doses of theophylline enhance the activity of a key corticosteroid-associated corepressor protein, histone deacetylase (HDAC)2, which is reduced in COPD. This may account, at least in part, for the relative corticosteroid resistance. Thus, combination therapy with an ICS and low-dose theophylline may be of benefit in the treatment of COPD.


METHODS
To test the hypothesis that ICS and theophylline have a greater therapeutic effect than theophylline alone, 30 patients with COPD were treated with placebo theophylline capsules and either inhaled fluticasone propionate (FP) (500 microg bid) or inhaled placebo for 4 weeks in a double-dummy, randomized, double-blind, parallel study. After a 2-week washout, patients were given active theophylline capsules (plasma level of 8.8-12.4 mg/L).


RESULTS
In an across-arm comparison, combination treatment with FP and theophylline did not reduce total sputum neutrophils but significantly reduced total sputum eosinophils (P < .05). Additional across-arm comparisons suggest a further reduction in percentage sputum neutrophils and sputum chemokine (C-X-C motif) ligand 8/IL-8 (P < .05). Furthermore, within-arm observational data also demonstrated increases in forced midexpiratory flow rate and FEV(1)% predicted (P < .05) following combination treatment only. In an open-label study, low-dose theophylline when added to inhaled FP increased total HDAC activity in peripheral blood monocytes ninefold (P < .01) compared with FP alone from the same patients with COPD.


CONCLUSIONS
Combination therapy with an inhaled corticosteroid and low-dose theophylline may attenuate airway inflammation in patients with COPD.


TRIAL REGISTRATION
clinicaltrials.gov; Identifier NCT00241631.