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

Background: The purpose of this study was to determine if house dust mite immunotherapy with Alutard SQ 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 6–45 years recruited from three different regions of Mainland China. Subjects were given a 52‐week course of immunotherapy with Dermatophagoides pteronyssinus extract (Alutard Der p, ALK‐Abelló, Hørsholm, Denmark) or placebo while their dose of inhaled corticosteroids (ICS) was maintained. Results: 129 subjects (64 in active group) completed the study. The symptom scores began to diverge at week 29 with the immunotherapy group showing a significantly lower score until week 48 (P = 0.018). Immunotherapy resulted in a significant decline in symptom (P = 0.002) and medication (P = 0.007) scores during the second half of the treatment period. Both groups showed significant improvement in peak flow rate and bronchial hyperresponsiveness. Serum eosinophil cationic protein (ECP) also decreased in both groups of subjects, but peripheral blood eosinophil count remained unchanged. Skin test response decreased in actively treated subjects only, but Der p‐specific immunoglobulin E (IgE) remained unchanged. Immunotherapy resulted in a significantly greater improvement in self‐evaluation scores (P < 0.01). Conclusions: One year treatment with Alutard SQ house dust mite immunotherapy significantly reduced symptoms and medication use in asthmatic subjects. This was associated with a greater subjective improvement in asthma control.