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document
Double-blind , placebo-controlled , dose-ranging study of new recombinant hypoallergenic Bet v 1 in an environmental exposure chamber . 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 ) . IgG1 increased significantly in all active groups compared to placebo . All four active doses were well tolerated , no serious adverse event occurred ; two Grade 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 .
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Intervention_Control
placebo-controlled
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Intervention_Pharmacological
recombinant hypoallergenic Bet v 1
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Intervention_Pharmacological
recombinant Bet v 1 ( rBet v 1-FV )
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Intervention_Physical
environmental exposure chamber
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Outcome_Physical
symptom score
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Outcome_Other
well tolerated
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Outcome_Adverse-effects
serious adverse
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Outcome_Adverse-effects
Grade II reactions
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Participant_Condition
birch pollen allergy