Efficacy of 2 months of allergen-specific immunotherapy with Bet v 1-derived contiguous overlapping peptides in patients with allergic rhinoconjunctivitis: Results of a phase IIb study

Background: An immunotherapy formulation consisting of 3 contiguous overlapping peptides (COPs) derived from Bet v 1, the major birch pollen allergen, showed good clinical tolerability in a previous phase I/IIa clinical trial. Objectives: We sought to evaluate the efficacy and safety of allergen-specific immunotherapy using 2 dose regimens of Bet v 1 COPs versus placebo in subjects with birch pollen-induced allergic rhinoconjunctivitis. Methods: A randomized, double-blind, placebo-controlled phase IIb clinical trial was performed to assess the efficacy of Bet v 1 COP immunotherapy during the 2013 birch pollen season. Before the season, Bet v 1 COPs (50 and 100 mu g in aluminum hydroxide) or placebo (saline and aluminum hydroxide) were administered as 5 subcutaneous injections to 239 adults with allergic rhinoconjunctivitis to birch pollen. Bet v 1 COPs at 25 or 50 mu g were administered on day 1, and 50 or 100 mu g was administered on days 8, 15, 29, and 57, respectively. Patients were monitored for adverse events during the treatment period and assessed for combined rhinoconjunctivitis symptom and medication scores, as well as quality of life. Results: Rhinoconjunctivitis symptom and medication scores improved in both Bet v 1 COP-treated groups, reaching statistical significance over placebo in the 50-mu g group (least squares mean, -0.23; 26% improvement; P = .015). Both active groups showed significant improvement in quality of life and nighttime nasal symptom scores, supporting the primary end point findings. Bet v 1 COP injections were well tolerated, with a higher frequency of systemic adverse events in the 100-mu g group. Conclusion: Two months of preseasonal immunotherapy with 3 COPs derived from Bet v 1 at a 50-mu g dose showed promising efficacy, small risk for systemic reactions, and immunomodulatory changes in this single-season, dose-finding, phase IIb trial in patients allergic to birch pollen.