Effect of pretreatment with fexofenadine on the safety of immunotherapy in patients with allergic rhinitis

Allergen-specific immunotherapy, although not a cure, remains the only treatment available that can alter the natural course of an allergic disease. However, the risk of allergen specific immunotherapy-related systemic reactions (SRs), reported to occur in approximately 1% to 14% of patients and which can range from mild to fatal in seriousness, represents a barrier to implementing this unique and effective treatment option. To explore the possibility that pretreatment with the H 1-antihistamine fexofenadine could prevent the occurrence of severe SRs induced by immunotherapy in Japanese patients with allergic rhinitis. In this open-label, multicenter study, 134 patients receiving immunotherapy for allergic rhinitis were randomized 1:1 to a group receiving pretreatment with fexofenadine hydrochloride (60 mg) 2 hours before immunization injection (n = 67) or to a control group receiving no pretreatment (n = 67). Patients were further grouped into those who received cedar pollen immunotherapy and those who received dust mite immunotherapy. Pretreatment with fexofenadine 2 hours before immunotherapy significantly reduced the occurrence of severe SRs ( P = .03), significantly increased the proportion of patients receiving cedar pollen immunotherapy who achieved the target maintenance dose (TMD) ( P = .03), and significantly reduced the length of time to attain the TMD ( P = .047 and P = .003 for patients receiving cedar pollen and dust mite immunotherapy, respectively). This study suggests a novel role for fexofenadine in enhancing the safety of immunotherapy and increasing the proportion of patients achieving the TMD.