Inhibition of the late asthmatic response by nedocromil sodium administered more than two hours after allergen challenge

Fourteen adult patients with bronchial asthma who were known late responders to bronchial allergen challenge were entered into a double-blind crossover study to compare the protective effects of nedocromil sodium (3 × 4 mg) and placebo aerosols on the late asthmatic response (LAR). After screening for development of an LAR (fall in forced expiratory volume in 1 second [FEV 1]≥20% at at least 3 consecutive time points, 4 to 10 hours after challenge), patients were randomized to test treatment on 2 study days, with an interval of at least 3 days. Nine of the patients had a dual late response, which is a combination of an immediate and a late response, and five other patients had an isolated late response only. On each study day the concentration of allergen that previously elicited a response was inhaled for 10 minutes. FEV 1 was recorded every 10 or 15 minutes for up to 1 hour after challenge, and then at hourly intervals for 12 hours and every second hour on the next 2 days. Test treatments were administered in three doses at 30-minute intervals, with the first dose given 90 minutes before the expected onset of the LAR for each patient. Compared with placebo, nedocromil sodium significantly inhibited the LAR ( p < 0.05) at each time point measured from 6 to 10 hours after challenge and reduced the maximum fall in FEV 1 by 21.0% overall ( p = 0.003).