glutaraldehyde-modified, tyrosine-adsorbed short ragweed extract: a double-blind, placebo-controlled trial

Glutaraldehyde-modified, tyrosine-adsorbed ragweed extract (GTR) is a modijication of allergen extract to reduce allergenic@ but retain immunogenicity. We evaluated the clinical efficacy and immunologic changes associated with the administration of GTR (16,350 protein nitrogen units) or placebo to a group of 100 atopic subjects with ragweed hay fever. The study was carried out in a double-blind, placebo-controlled fashion. Clinical response was measured by daily symptom diaries, physician evaluations, and patient responses. Changes in ragweed-spec$c IgE and IgG antibody were evaluated with an amphped enzyme-linked immunosorbent assay (a-ELBA) and were compared with measurements by RAST and a protein A-binding assay for IgG antibody. Treatment with GTR resulted in a sixfold increase in blocking IgG antibody and a small increase in IgE-specific antibody. No changes occurred in the placebo treated group. Mild immediate local reactions occurred after 74% of injections, and late-onset local reactions occurred after 62% of injections in the treated group. The placebo-treated group experienced immediate or late local reactions after only 12% of injections. There were two mild late-onset urticarial reactions of a generalized nature in the treatment group. The treatment group e,xperienced significantly fewer symptoms than the placebo group throughout the season (p < 0.02), although the diSference was not dramatic. The results showed that GTU could be safely given in jive preseasonal injections, with retained immunogenicity but less potential for generalized reactions. GTR is an improved method of allergy immunotherapy with the potential for clinical benejit when used in a brief preseasonal treatment regimen. (J ALLERGY CLIN IMMUNOL 68:442, I981 .)