Protective effect of nedocromil sodium on the dual asthmatic response to bronchial antigen challenge

The effects of nedocromil sodium and placebo on the asthmatic response to antigen bronchial provocation were studied in a double-blind, randomized, crossover trial. Twelve subjects sensitized to Dermatophagoides pteronyssinus were challenged with successive doubling doses of this allergen (1.25-80 x 10(-3) mg) on two separate occasions, at least 15 days apart. A single dose of either nedocromil sodium 4 mg, or, a matching placebo was given 30 min before challenge. Forced expiratory volume in 1 s (FEV1) was measured 5, 10 and 15 min after challenge. Early asthmatic response was analyzed using three indices: dose producing a 20% decrease in FEV1 (PD20), the slope of and area under the dose-response curve. Nedocromil sodium was significantly superior to placebo with respect to all three indices, providing significant inhibition of the early asthmatic responses. Seven of the 12 patients showed a late asthmatic response. There was no significant difference between the effects of nedocromil sodium and placebo treatments on the decline in peak expiratory flow rate (PEFR) during the late asthmatic response but it should be noted that when patients had been treated with nedocromil sodium they were receiving two to eight times the dose of allergen given after placebo treatment.