Effects of the Toll-like receptor 7 (TLR7) agonist, AZD8848, on allergen-induced responses in patients with mild asthma: a double-blind, randomised, parallel-group study

Leaker, Brian R.; Singh, Dave; Lindgren, Sam; Almqvist, Gun; Eriksson, Leif; Young, Barbara; O’Connor, Brian

The study enrolled male and female, non-and exsmokers aged 18-55 years with Global Initiative for Asthma (GINA)-defined mild-to-moderate asthma of ≥6 months' duration and a positive skin prick test to grass, house dust mite or cat dander within the previous 24 months (clinicaltrials.gov identifier NCT00999466). The study was conducted with an initial safety and tolerability pilot study (AZD8848 n = 6, placebo n = 3), before initiating the main study. For inclusion in the main part of the study, patients had to demonstrate forced expiratory volume in 1 s (FEV 1 ) > 70% of predicted normal; an early asthmatic response (EAR) corresponding to ≥20% decrease in FEV 1 within 2 h and a late asthmatic response (LAR) corresponding to ≥15% decrease in FEV 1 between 4 and 10 h post-allergen challenge on 2 consecutive occasions and a methacholine provocation concentration leading to a 20% reduction in FEV 1 (PC 20 ) < 16 mg/mL. The inhaled allergen to be used was one of those to which the patient had shown a positive response in the skin prick test.