Citrus/Cydonia comp. for seasonal allergic rhinitis: A randomized study to compare treatment effects of the subcutaneous and the nasal routes of administration

OBJECTIVES Allergic rhinitis is a condition characterized by sneezing, watery nasal discharge, nasal obstruction and itching. It is an increasingly prevalent condition, particularly in the Western world where it affects around 20% of the adult population. Citrus/Cydonia comp. is an anthroposophic medicine, which contains extracts of lemon (Citrus lemon) and quince (Cydonia oblongata). Several observational studies have shown that Citrus/Cydonia comp. solution either as a subcutaneous injection or as a nasal spray might be an effective treatment for seasonal allergic rhinitis (SAR) patients. In addition, in vitro is has been shown that it has a selective effect on the differentiation of T-cells by producing relatively more IL-10 than IL-12. By that, it also seems to have an effect on the induction of regulatory (IL-10 producing) T-cell subsets. Therefore, it has been concluded that Citrus/Cydonia comp., at least in vitro, is capable of neutralizing (to some extent) the changes, characteristic to allergic rhinitis, with regard to the maturation, differentiation, and activity of the immune system. The aim of the present study is to compare the efficacy and safety of subcutaneous versus nasal spray administration in SAR patients by specifically investigating which route of administration is more effective in the differentiation and inductions of (regulatory) T-cells. METHODS A national, randomized, comparative clinical trial with two parallel groups. A total of 28 patients with grass pollen SAR are recruited at primary care practices or through advertisements. After a two week run-in period without allergy medication, patients are randomized to a 6 weeks treatment period with either Citrus/Cydonia comp. 1% subcutaneous injections (2 injections per week) or Citrus/Cydonia comp. 1% nasal spray (1-2 sprays in each nostril, 4 times a day) . The primary outcome variables are changes in immunological parameters such as IL-10, IL-12 and IL-5 at week 6, as studied in PBMCs isolated from the blood of the patients. Further objectives are to investigate the influence of Citrus/Cydonia comp. subcutaneous injections versus Citrus/Cydonia comp. nasal spray on the change in clinical symptoms by means of nasal and non-nasal symptom scores. The safety and tolerability of both injections and nasal spray will be investigated by determining adverse events surveillance.