Selective β2-AR Antagonism in Asthma

After a run-in period of 2 weeks, 12 eligible patients will be randomised to treatment with either TR4 or placebo. Nine patients will take incremental doses of 2.5, 5, 10 and 20 mg of TR4 capsules, each dose three times daily for 7 days, and then 40 mg three times daily for 21 days, over a total period of 7 weeks. Three patients will take matching placebo capsules in a similar manner. The number of visits and the types are as follows. There will be a maximum of 10 visits to Hammersmith Medicines Research (HMR) for those subjects who complete the whole study according to the protocol. Visit 1 is an out-patient visit for informed consent and screening. Visit 2 is a short out-patient visit at the start of a 2-week run-in period for those subjects who pass screening. After the run-in period, patients who are still eligible will be given a schedule for 8 further visits (Visits 3-10). Participants will stay on the ward for 2 nights during 5 of those visits (Visits 3-7), and for 1 night during Visit 10. Visits 8 and 9 are short out-patient visits. The study will take each subject \~10 weeks to complete. For purposes of data collection and management the study is divided into one session for screening, a run-in period and 5 treatment periods.