OARSI-FDA initiative: defining the disease state of osteoarthritis.

OBJECTIVE: To respond to a pre-specified set of questions posed by the United States Food and Drug Administration (FDA) on defining the disease state to inform the clinical development of drugs, biological products, and medical devices for the prevention and treatment of osteoarthritis (OA). METHODS: An Osteoarthritis Research Society International (OARSI) Disease State working group was established, comprised of representatives from academia and industry. The Working Group met in person and by teleconference on several occasions from the Spring of 2008 through the Autumn of 2009 to develop consensus-based, evidence-informed responses to these questions. A report was presented at a public forum in December 2009 and accepted by the OARSI Board of Directors in the Summer of 2010. RESULTS: An operational definition of OA was developed incorporating current understanding of the condition. The structural changes that characterize OA at the joint level were distinguished from the patients' experience of OA as the 'disease' and 'illness', respectively. Recommendations were made regarding the evaluation of both in future OA clinical trials. The current poor understanding of the phenotypes that characterize OA was identified as an important area for future research. CONCLUSIONS: The design and conduct of clinical trials for new OA treatments should address the heterogeneity of the disease, treatment-associated structural changes in target joints and patient-reported outcomes.