Adult and pediatric clinical trials of sublingual immunotherapy in the USA.

Specific allergen immunotherapy has been practiced for allergic rhinoconjunctivitis for over 100 years and is the only treatment option that is disease modifying. In the USA, immunotherapy is usually administered via subcutaneous injection; this is the only route with a US FDA-approved formulation. There is growing interest in developing US-standardized formulations for the sublingual route, but up until recently there have been few US trials.