Safety of Sublingual House Dust Mite (HDM) Immunotherapy: A Randomized, Double-blind, Placebo-controlled U.S. Trial

RATIONALE: In this first placebo-controlled, double-blind trial of HDM sublingual immunotherapy (SLIT) conducted in the U.S., we evaluated the safety of high and low dose SLIT in adults with allergic rhinitis +/− mild persistent asthma sensitized to HDM. METHODS: Of 74 eligible participants, thirty-one subjects were randomized to receive daily SLIT maintenance; high dose (4200 AU, N = 10) or low dose (60 AU, N = 10) of a standardized D. farinae vaccine (Greer Labs) or placebo (0.038 mg histamine, N = 11) over the course of 12-18 months. RESULTS: Ten subjects withdrew from the study, 6 of 10 for non-treatment related events. Four of 10 withdrawals were associated with possible treatment effects, one each in the high and lose dose groups (GI symptoms) and two in the control group (headache, increased allergic symptoms). Twenty-one subjects completed the study (high dose N = 9, low dose N = 7, placebo N = 5). Fifteen of the 21 subjects who completed the study experienced possible/probable treatment-related events (GI symptoms, oral/throat irritation) of mild to moderate severity (high dose N = 6, low dose N = 4, placebo N = 5). These adverse events all resolved spontaneously and the participants subsequently completed the study. No systemic reactions (urticaria, anaphylaxis) were observed in any group. CONCLUSIONS: In this trial of high and low dose HDM SLIT, we conclude that HDM SLIT was generally safe and tolerable.