Oralair Birch, a recombinant major birch pollen allergen tablet for sublingual immunotherapy of allergic rhinitis caused by birch pollen.

Oralair Birch is a dissolving tablet being developed for sublingual immunotherapy (SLIT) of allergic rhinitis caused by birch pollen allergy. Oralair Birch is being developed by Stallergenes SA and Canadian licensee Paladin Labs Inc. Oralair Birch is a recombinant protein that is synthesized from the DNA coding region of Bet v 1a, the major birch pollen allergen. During preclinical characterization, Oralair Birch had comparable structural and biological properties to the natural Bet v 1 allergen. However, Oralair Birch was more homologous than the natural Bet v 1 allergen, making a greater level of quality control possible. The administration of SLIT in tablet formulation provides a more uniform dose compared with liquid drops and better local application, which might enhance local uptake into dendritic cells of the sublingual submucosa and efficacy. Using skin prick testing, the performance of recombinant Bet v 1 was comparable to the natural Bet v 1 allergen. The results of a dose-finding phase IIb/III clinical trial of Oralair Birch were positive, with the primary endpoint met by all three tested doses. A confirmatory phase III trial was planned for 2011. Oralair Birch is a very promising treatment option for patients with birch pollen allergic rhinitis.