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Keywords:

  • allergen bronchoprovocation test;
  • asthma;
  • VLA4 receptor antagonist

Summary

Background Very late antigen-4 (VLA4) plays a key role in the recruitment of eosinophils in allergic responses in animal studies.

Objective We investigated whether pretreatment with multiple doses of a VLA4 receptor antagonist, HMR 1031, protects against allergen-induced airway responses and airway inflammation in humans.

Methods Fourteen asthmatics (7F/7M), 18–49 years, PC20 forced expiratory volume in 1 s (FEV1) methacholine (M) (<8 mg/mL; FEV1 82.3–116.1% predicted) with dual responses to inhaled allergen participated in a double-blind, placebo-controlled, cross-over study. Each treatment period consisted of 9 days, separated by geqslant R: gt-or-equal, slanted2 weeks. Exhaled nitric oxide (eNO), PC20FEV1(M) and hypertonic saline-induced sputum was obtained on Days 1, 7 and 9. Subjects inhaled HMR 1031 (20 mg b.i.d.) or placebo (P) on Days 1–8. On Day 8, an allergen bronchoprovocation test was performed, the airway response was measured by FEV1, and expressed as %fall from baseline. Data from 12 evaluable subjects are presented here.

Results Both treatments were well tolerated. There was no significant difference between HMR 1031 and P in the early asthamatic response: mean AUC (0–3 h)±SEM (%fall h): 26.01±4.26 and 17.41±4.26, respectively (P=0.18), nor in the late response: mean AUC (3–9 h)±SEM (%fall h): 97.09±8.63 and 97.61±8.63, respectively, P=0.97. This corresponded to the absence of significant allergen-induced changes in PC20FEV1(M), eNO, sputum eosinophils and soluble inflammation markers between both treatment periods.

Conclusions Treatment with multiple inhaled doses of the VLA4 antagonist, HMR 1031, did not result in detectable protection against allergen-induced airway responses or airway inflammation in asthma.