Successful management of mite-allergic asthma with modified extracts of Dermatophagoides pteronyssinus and Dermatophagoides farinae in a double-blind, placebo-controlled study.

Abstract

Mite sensitivity is highly prevalent in tropical and subtropical regions, such as the Canary Islands. To evaluate the clinical efficacy and safety of a depigmented polymerized allergen vaccine containing a 50% mixture of Dermatophagoides pteronyssinus and Dermatophagoides farinae. Sixty-four patients participated in the study. It was prospective, double-blind, and placebo-controlled, with random allocation of patients to receive active treatment or placebo. The active group received a mixture of modified allergen extracts containing 50% D pteronyssinus and 50% D farinae; the control group received placebo. All individuals were diagnosed with mild/moderate asthma and rhinoconjunctivitis caused by sensitization to D pteronyssinus and D farinae. Bronchial provocation test (BPT) was considered the main outcome to document clinical efficacy. Fifty-four patients completed the study. The active group experienced a significant improvement in BPT (P < .001), whereas the placebo group did not (P = .648). At the end of the study, 20 patients in the active versus 9 in the placebo group (P = .013; odds ratio, 5.71 [1.76, 18.51]) needed more than twice the amount of allergen to obtain a positive BPT. The median improvement in the active group over placebo was 53.76% in total symptom and 58.09% in medication scores. Immunotherapy with a mixture of modified allergen extracts of D pteronyssinus and D farinae is safe and efficacious to treat mite-allergic asthma. This immunotherapy modifies the natural course of the illness because it improves all clinical outcomes measured and prevents the worsening of specific bronchial hyperreactivity.