A multicenter trial of immunotherapy with alginate--conjugated grass pollen extract

Conjuvac, a new generation of allergen extracts, has been developed to meet the need for improved characterization, purification, and standardization. Conjuvac consists of a dialyzed, standardized aqueous allergen extract chemically conjugated to a sodium alginate carrier and lyophilized in single-dose vials, thus ensuring stability until reconstituted with sterile water just before each injection. A preliminary study of Conjuvac 2 Grass by Pegelow (1984) involving a small number of patients showed this extract to have potential advantages. Accordingly, a study involving more patients was undertaken: two different maintenance dose levels of Conjuvac 2 Grass were investigated and compared to a pyridine-extracted, alum-precipitated two-grass extract called Allpyral, which in previous double-blind trials has been shown to be effective. The trial, which included 125 patients with hay fever and which extended over 2 years, involved ten allergists from seven European countries. Overall, the Conjuvac high-dose regimen proved slightly superior to Allpyral without any increased incidence of side effects, and all treatments stimulated marked increases in specific IgG levels without raising IgE levels.