Challenges faced in clinical trials for chronic allergic conjunctivitis

Allergic conjunctivitis is an inflammatory disorder at the ocular surface that affects 40% of Americans with allergic symptoms. Treatment of chronic ocular allergy is currently limited and is often associated with severe side effects. Development of new therapeutics to address this unmet need has proved challenging due to the highly variable nature of this disorder. Historically, clinical studies for the evaluation of pharmacological agents for the treatment of ocular allergy relied on seasonal and/or chamber models, both of which are associated with a number of limitations resulting in inconsistent and, oftentimes, non-reproducible study conditions. The development of the conjunctival allergen challenge model in 1990 provided a highly effective means for the study of ocular allergy. Recently, modifications to this model with multiple successive allergen challenges have shown to mimic the chronic allergic response and will likely be pivotal in the development of new therapeutics for chronic allergic conjunctivitis.