159 Therapeutic Effect and Safety of the Sublingual Immunotherapy With Tropical House Dust Mite Allergen Vaccines in Asthmatic Cuban Adult Patients

BACKGROUND: Subcutaneous injection route (SCIT) is burdened with the risk of severe adverse events; therefore, sublingual immunotherapy (SLIT) is being increasingly investigated. The efficacy of SLIT in asthma has been reviewed in a Cochrane meta-analysis. Allergic sensitization to Dermatophagoides pteronyssinus (Dp), Dermatophagoides siboney (Ds) and Blomia tropicalis (Bt) is strongly linked to respiratory allergy and asthma in Cuba (3). These last 2 species are relevant in tropical countries or even only in the Caribbean region (4). Nevertheless, well conducted clinical studies of immunotherapy with standardized allergen vaccines of these particular species are very scarce. OBJECTIVE: This study was conducted to assess the therapeutic effect and safety of allergen therapeutic vaccines of Dermatophagoides pteronyssinus, Dermatophagoides siboney and Blomia tropicalis House-Dust mites (VALERGEN, BIOCEN, Cuba) by sublingual route, in asthmatic patients. METHODS: Three Double-Blind Placebo-Controlled clinical trials were performed in 40 patients each, showing asthmatic symptoms and positive predominant Skin Prick Test (SPT) to each mite, respectively. Half of subjects were randomized to active group. Treatment consisted of sublingual drops with increasing daily doses for 3 weeks and maintenance doses (2000 BU) twice a week until 12 months. RESULTS: Therapeutic effect was assessed after 6 and 12 months using symptoms/medication diary cards, peak expiratory flow (PEF) measures and skin sensitivity to investigated mites. Adverse reactions were classified using the World Allergy Organization scale. The treatment reduced significantly (P < 0.01) clinical symptoms (38%, 95% CI, 33-44) and medication intake (26%, 95% CI, 21-32) with respect to placebo. The skin sensitivity to the allergens decreased also significantly (P < 0.01). The allergen amount needed to induce a positive SPT increased 52-fold. PEF variability decreased also significantly (P < 0.05). The treatment was considered effective in 77% of patients. A major advantage as compared to subcutaneous route was a remarked lower frequency of adverse effects. Local reactions were noted only in 0.43% of administrations. No systemic reactions were observed. CONCLUSIONS: The results indicate that sublingual immunotherapy using allergen vaccines of tropical mite species is effective and safe in mite-sensitive asthmatic patients.