A double-blind, placebo-controlled study of house dust mite immunotherapy in asthmatic patients in China

Abstract

Rationale The purpose of this study was to determine if house dust mite immunotherapy is effective in improving symptom control and reducing rescue medication use in Chinese patients with mild to moderate allergic asthma. Methods This is a double-blind, placebo-controlled study involving 132 asthmatic subjects aged 6 to 45 years recruited from 3 different regions of Mainland China. Subjects were given a 52-week course of Alutard Der P (ALK-Abello, Horsholm, Denmark) treatment or placebo while the dose of inhaled corticosteroids (ICS) was maintained. Results 129 subjects (64 active) completed the study. The symptom scores began to diverge at week 25 with the active group showing a significantly lower score until week 48 (p=0.018). Active treatment resulted in significantly lower scores during the second half only in subjects already taking ICS (p=0.013). Active treatment also resulted in a significantly greater reduction in rescue medication use (p=0.016). Both groups showed significant improvement in daily PEF, PEF variability, and histamine PD 20, with no difference between groups. Skin test response declined in active subjects only, but plasma ECP significantly decreased in both groups. Der P-specific IgE decreased in placebo but not active subjects. Active treatment resulted in a significantly greater improvement in self-evaluation scores (p<0.01). Conclusion One year treatment with Alutard Der P significantly reduced symptoms and medication use in asthmatic subjects, particularly in those who were already using ICS. This was associated with a greater subjective improvement in asthma control.