485 Therapeutic Effect and Safety of Tropical Mite Allergen Vaccines by Subcutaneous Route in Allergic Asthmatics Patients

BACKGROUND: Allergen-specific subcutaneous immunotherapy (SCIT) is presently recognized as a biological response modifier, as it is the only available treatment able to influence the natural course of allergic disease. Extensive clinical evidence supports its efficacy. Safety concerns are related to the risks of anaphylactic reactions during treatment. Standardization of allergen vaccines in terms of allergenic activity allows a more precise control over the administered doses and can be, therefore, very relevant for both efficacy and safety of SCIT. House Dust Mites (HDM), particularly Dermatophagoides pteronyssinus (Dp), Dermatophagoides siboney (Ds) and Blomia tropicalis (Bt) have been described as very relevant allergen sources in Cuba, with a strong association to respiratory allergy symptoms. OBJECTIVE: To asses the efficacy and safety of standardized allergen vaccines of these 3 mite species (Valergen, Biocen, Cuba) in Cuban 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 patients received the active treatment consisting of subcutaneous injections with increasing doses, up to 6000 BU. RESULTS: The total 1 year cumulative dose was 63035 BU, in an average of 20.5 injections. The treatment was effective in the reduction of clinical symptoms (up to 32%, 95%CI: 28-36%; P = 0.0006) and medication intake (23%, 95%CI:18-28%), as compared to control treatment. The skin sensitivity to the allergens decreased significantly (P = 0.0001), with regard to the beginning of the treatment. The allergen amount needed to induce a positive SPT increased 297-fold. An improvement of the lung function was observed, expressed in a modest Peak-Expiratory-Flow increase (P < 0.05) and reduction of PEF daily variability. SIT was considered effective in 71% of patients. The frequency of local adverse reactions was 2.4 % of injections. CONCLUSIONS: The results indicates that immunotherapy, using standardized House Dust Mite vaccines, including tropical species, is effective and safe for the control and amelioration of the asthma in our population.