Efficacy of a short course of specific immunotherapy in patients with allergic rhinoconjunctivitis to ragweed pollen

Abstract

Specific immunotherapy acts to modify the underlying cause of allergic rhinoconjunctivitis. Addition of adjuvants, such as monophosphoryl lipid A (MPL), might allow for efficacious and safe treatment with only 4 injections administered preseasonally, which is in contrast to most available schedules requiring long injection courses. The primary objective was to assess the clinical efficacy of Ragweed MATA MPL (short ragweed pollen allergoid adsorbed to L-Tyrosine + MPL) versus placebo in reducing allergic rhinoconjunctivitis symptoms caused by ragweed pollen in an environmental exposure chamber (EEC) 3 weeks after treatment. This was a randomized, double-blind, placebo-controlled phase IIb study to evaluate the clinical efficacy and safety of Ragweed MATA MPL compared with placebo by using controlled ragweed pollen exposure in an EEC. Two hundred twenty-eight patients with a history of ragweed allergy and positive skin prick test responses to ragweed were randomized and received 4 weekly injections of active treatment or placebo. Total nasal and nonnasal symptom scores were obtained in the EEC before and after treatment. Mean improvement in total symptom scores in the Ragweed MATA MPL group was statistically significantly greater than in the placebo group (relative mean improvement of active vs placebo, 48%; P < .05; median improvement, 82%). The majority of adverse events (AEs) experienced by subjects were mild injection-site reactions. No severe systemic AEs or serious AEs occurred during the study. This study demonstrated that an ultrashort course of Ragweed MATA MPL is efficacious in reducing allergy symptoms in patients with seasonal allergic rhinitis and that it is well tolerated.