Safety of a Depigmented, Polymerized Vaccine for the Treatment of Allergic Rhinoconjunctivitis and Allergic Asthma

Background: Clinical efficacy of specific immunotherapy (SIT) with depigmented, polymerized allergen extracts is well documented in placebo-controlled trials, and safety data are encouraging although further data are required.

Methods: We enrolled 768 patients (51% men; mean age, 31 years) in this prospective multicenter study on safety and clinical effects of Depigoid (Laboratorios LETI, S.L., Madrid, Spain). Immunotherapy consisted of four injections of increasing doses of Depigoid at weekly intervals followed by monthly maintenance injections. All adverse events were documented. Moreover, nose, eye, and lung symptoms were assessed at baseline after 3 and 6 months. Results were compared with the scores of the preceding season.

Results: Rates for local and systemic reactions that might possibly be related to the study medication were 2.36 and 4.56/1000 injections, respectively. With 5923 injections given, 14 local reactions were reported (5 patients), and 27 systemic reactions were reported, including 20 of grade 1 (6 patients) and 7 of grade 2 (4 patients). The best safety profile was seen for patients vaccinated against house-dust mites. Reductions in nose, eye, and lung symptoms as well as in concomitant medication compared with either the preceding season (pollen-sensitized patients) or the baseline (house-dust mite-sensitized patients) were observed at the end of study.

Conclusion: In this large multicenter study on 768 patients with allergic rhinoconjunctivitis and allergic asthma under daily practice conditions SIT with Depigoid was well tolerated with low rates of local and systemic reactions. Furthermore, SIT resulted in considerable reductions in symptoms and concomitant medication.