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Double‐blind, placebo‐controlled, dose‐ranging study of new recombinant hypoallergenic Bet v 1 in an environmental exposure chamber
Author(s) -
Meyer W.,
Narkus A.,
Salapatek A. M.,
Häfner D.
Publication year - 2013
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/all.12148
Subject(s) - hypoallergenic , tolerability , placebo , medicine , adverse effect , dose ranging study , allergy , gastroenterology , allergen , immunology , double blind , pathology , alternative medicine
Background Recombinant allergens offer a tool for improving specific immunotherapy ( SIT ). Objective To find the optimal dose of a new hypoallergenic folding variant of recombinant Bet v 1 (rBet v 1‐FV) as SIT for patients with birch pollen allergy. Methods Before SIT , thirty‐seven adult patients were exposed for eight hours in an environmental exposure chamber ( EEC ) to birch pollen at an average concentration of 3500 ± 500 grains/m 3 , then randomized to four maintenance dose groups of rBet v 1‐FV and one placebo group: 20 μg ( n = 7), 80 μg ( n = 8), 160 μg ( n = 7), 320 μg ( n = 8), and placebo ( n = 7). Patients were treated for 10 weeks with weekly injections and then re‐exposed in the EEC . The optimal dose for SIT was assessed using efficacy results from the EEC , IgG responses, and tolerability. Results Thirty‐six patients were evaluable for efficacy assessment. The total symptom score significantly decreased in all active groups compared with placebo (−18.8% for placebo patients; −71.9%, P = 0.0022 for 20 μg; −75.6%, P = 0.0007 for 80 μg; −81.8%, P = 0.0009 for 160 μg; −78.3%, P = 0.0003 for 320 μg). IgG 1 increased significantly in all active groups compared to placebo. All four active doses were well tolerated, no serious adverse event occurred; two G rade II reactions, according to EAACI classification, were observed, one in each of the 160‐ and 320‐μg groups. Conclusions Considering efficacy, immunological response, and tolerability, a maintenance dose of 80 μg of rBet v 1‐FV appears to be the ideal dose for allergen immunotherapy in birch pollen allergic patients.