Methodological aspects on clinical trials with inhaled corticosteroids: results of two comparisons between two steroid aerosols in patients with asthma.

The efficacy of beclomethasone dipropionate aerosol (BDA) 100 micrograms q.i.d. was compared with that of budesonide aerosol 10 micrograms q.i.d. in 17 patients. The efficacy of inhaled BDA 100 micrograms q.i.d. was also compared with that of budesonide 50 micrograms q.i.d. with and without an extension tube (Inhalet) attached to the actuator in 23 patients. Both studies included placebo periods. The trials were performed with the cross-over technique in patients with stable asthma. Each treatment was randomized and given in periods of two weeks starting with a run-in period. The patients recorded peak expiratory flow rates (PEF) twice daily and filled in diary cards for cough, wheeze, breathing difficulties and use of beta 2-receptor stimulant aerosol. In the first study the patients came to the hospital twice weekly throughout the trial for spirometry and interview. In the second study they came every second week. Budesonide and BDA were superior to placebo. Budesonide in doses of 100 micrograms and 50 micrograms were as efficacious as BDA 100 micrograms q.i.d., while budesonide 50 micrograms q.i.d. with Inhalet was slightly more effective. Treatment for two weeks was found to be sufficient. For each parameter the average of the last four days of each period was found to be relevant in the comparison. The placebo period should preferably not be placed at random in the trial, but as the last treatment period.