Immunologic Effect and Tolerability of Intra-Seasonal Subcutaneous Immunotherapy With an 8-Day Up-Dosing Schedule to 10,000 Standardized Quality-Units: A Double-Blind, Randomized, Placebo-Controlled Trial

Abstract Background International guidelines recommend that allergen-specific immunotherapy for pollen-induced rhinoconjunctivitis is initiated preseasonally. However, because subjects often present to physicians with allergy symptoms during the pollen season, “within-season” initiation of specific immunotherapy is of special interest. Objective We evaluated the immunomodulatory effects and tolerability of subcutaneous immunotherapy (SCIT) with Standardized Quality (SQ) 6-grass mix and rye allergen extract, using an 8-day intra-seasonal up-dosing schedule to 10,000 SQ-units (SQ-U). Methods In a 9-week, multicenter, randomized, double-blind, placebo-controlled trial, adults (mean age, 34.6 years; 99.3% whites) with grass pollen–induced rhinoconjunctivitis (mean disease duration, 15.1 years) were randomized 3:1 to receive SCIT or placebo. Treatment was initiated during the 2008 pollen season, with an 8-day up-dosing from 100 to 10,000 SQ-U (6 daily injections) followed by 2 maintenance injections of 10,000 SQ-U at intervals of 2 and 4 weeks, respectively. The primary end point examined immunologic effects, assessing the difference in IgE-blocking factor (serum components competing with IgE for allergen binding) between SCIT and placebo at week 9. Secondary/explorative end points included the difference in IgE-blocking factor, specific IgG4 , and specific IgE at various times. Tolerability (adverse events, local and systemic allergic reactions) of the up-dosing schedule was also evaluated. Results Of the 148 treated subjects 144 (SCIT n = 109; placebo n = 35) were analyzed for the primary parameter. Immunologic response (significantly higher increase in IgE-blocking factor and IgG4 levels) occurred with SCIT versus placebo at week 9 (IgE-blocking factor, P = 0.0017; IgG4, P = 0.0215). Significant differences were observed as early as week 3. AEs were reported in 60.7% of SCIT- and 30.6% of placebo-treated subjects, with no treatment-related serious AEs. Local allergic reactions occurred in 46.4% of SCIT and 8.3% of placebo subjects (χ2 test, P < 0.0001). No significant difference was observed between groups in the incidence of systemic reactions (7.1% SCIT vs 5.6% placebo; χ2 test, P = 0.7413). Conclusions This trial provides the first description of short (8-day) intra-seasonal up-dosing with SCIT, which induced immunologic effects after only 3 weeks, and was generally well tolerated, although it induced a marked increase in the rate of local reactions compa