Background: Allergen-specific conjunctival challenge is a safe and reproducible experimental model to evaluate effectiveness and possible mechanism(s) of action of drugs employed in the treatment of allergic diseases.
Objective: The protective effect of oxatomide on inflammatory changes that follow allergen-specific conjunctival challenge was assessed in 20 patients with rhinoconjunctivitis due to Parietaria judaica in a double-blind study.
Methods: After a screening allergen-specific conjunctival challenge, patients were randomized into two treatment groups, each being given oxatomide (oral tablets) at 60 mg daily or matching placebo for seven days during off-pollen season. Clinical evaluation, cytologic assessment (number of inflammatory cells and ICAM-1 expression on epithelial cells) were assessed at baseline, 30 minutes, 6 hours, and 24 hours after allergen-specific conjunctival challenge, before and after treatment. In addition, electrocardiograms were obtained before and after treatment.
Results: Early phase reaction clinical events as well as total numbers of inflammatory cells were significantly reduced by oxatomide compared with placebo. Late phase reaction clinical events as well as total numbers of inflammatory cells were significantly reduced by oxatomide compared with placebo. ICAM-1 expression was significantly reduced by oxatomide in early phase reactions and late phase reactions compared with placebo. No pathologic cardiac events were detected in any subject.
Conclusions: Oxatomide has a protective effect on clinical and cellular early phase reactions and late phase reactions (including ICAM-1 expression on epithelium) induced by allergen-specific conjunctival challenge and is safe and well tolerated.