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Keywords:

  • clinical trial;
  • house dust mite allergy;
  • immune modulator;
  • toll-like receptor 9;
  • virus-like particle

Summary

Background Allergic symptoms are generally caused by exposure to substances to which people have become sensitized. Associated with this is an ‘unbalanced’ Th1/Th2 immune response with T cell responses skewed towards the production of Th2 cytokines, IL-4, 5, and 13 and high levels of IgE antibodies. Current immune modulating therapies require the use of allergens, carrying the risk to induce potentially severe allergic reactions.

Objective Goal of the present study was to assess the safety and efficacy of an allergen-free immune modulator in patients suffering from perennial allergy.

Methods In order to be protected from immediate degradation upon injection, a toll-like receptor 9 (TLR9) agonist was packaged into virus-like particles. These nanoparticles loaded with TLR9 ligands (CYT003-QbG10) were injected six times, at weekly intervals, into patients with house dust mite allergy in an attempt to ameliorate allergic symptoms by modifying the immune response towards allergens. Two different doses were compared against placebo in this double-blind, randomized phase IIb study (n=299). Public trial registry: http://clinicaltrials.gov (NCT00800332).

Results The treatment was safe and generally well tolerated. Rhinoconjunctivitis symptoms were significantly lower in patients treated with high dose of CYT003-QbG10 as compared with placebo (scores 0.31 vs. 0.52, P=0.04) based on a standardized average combined symptom and medication score. Furthermore, patients in the high dose group reported a significantly better quality of life score post-treatment than patients on placebo (scores 0.71 vs. 1.21, P=0.02). The conjunctival provocation test revealed a median 10-fold increase in allergen tolerance in the high dose group while in the placebo group it remained unchanged.

Conclusion and Clinical Relevance Treatment with high-dose CYT003-QbG10 improved disease symptoms and reduced medication use in allergic individuals thus providing first evidence for a new potential immunotherapeutic.

Cite this as: L. Klimek, J. Willers, A. Hammann-Haenni, O. Pfaar, H. Stocker, P. Mueller, W. A. Renner and M. F. Bachmann, Clinical & Experimental Allergy, 2011 (41) 1305–1312.