Abstract
The classification of inflammatory arthritis incorporates a sharp divide between diseases of childhood onset, grouped together as juvenile idiopathic arthritis, and diseases such as rheumatoid arthritis that begin by definition in adulthood. An important consequence of this divide is that regulatory authorities and many rheumatologists regard pediatric and adult arthritides as truly different, with the implication that drugs should be evaluated separately for each category. However, it is now clear that most forms of arthritis transcend the pediatric/adult boundary and that agents generally exhibit comparable success irrespective of age of onset, offering new opportunities in drug development and regulation focused on pharmacology and safety rather than efficacy. This paradigm shift will enable advances in arthritis treatment, originating either with adults or children, to translate more rapidly across the age spectrum.