Desperately looking for the right target in osteoarthritis: the anti-IL-1 strategy.

Blocking IL-1 in patients with knee osteoarthritis is an attractive strategy. Cohen and colleagues report a randomised, placebo-controlled, multiple-dose trial using a monoclonal antibody blocking IL-1 type 1 receptor. They failed to show any positive results in terms of evolution of pain for up to 12 weeks, in line with the former trials using intraarticular injections of IL-1 receptor antagonist. A trend was observed, however, in a subgroup of patients with high level of pain at baseline. Although these data may suggest cessation of IL-1 therapy in osteoarthritis, other methods such as limited intraarticular anti-IL-1 delivery should still be considered.