Biologic agents in osteoarthritis: hopes and disappointments.

New treatment options are needed for osteoarthritis (OA) to slow down the structural progression of the disease; current therapies mostly target pain and function with minimal effectiveness. OA results from an imbalance between catabolic and anabolic factors, and biologic agents either target specific catabolic proinflammatory mediators, such as cytokines, nitric oxide synthesis, or affect anabolism more generally. Biologic agents have dramatic effects in other rheumatic inflammatory diseases such as rheumatoid arthritis; they were hoped to have similar effects in the treatment of OA. In this Review, we will discuss the three main types of cytokine blockers used in knee and hand OA, which target β-nerve growth factor (β-NGF), IL-1β or TNF. We will also discuss inhibitors of nitrogen oxide production and the use of growth factors to treat OA. Among the targeted agents, anti-β-NGF therapy has shown promising results, although cases of rapid destructive arthropathy caution against its widespread use. The future of therapies targeting cytokines, nitrogen oxide synthesis and growth factors in OA is questionable, as results from clinical trials have been repeatedly negative. Strategies in OA therapy need to be reconsidered. New molecules emerging from preclinical data should focus on treating the early phase of the disease where damage may be reversible, and treatment should be modified to fit each patient.