Clinical trials of a stromelysin inhibitor. Osteoarthritis, matrix metalloproteinase inhibition, cartilage loss, surrogate markers, and clinical implications.

Long-term trials with BAY 12-9566, a stromelysin inhibitor, have been initiated in osteoarthritis. Validation of the long-term, clinical relevance of early markers has to be tested in these and other trials. Detection of the slowing of cartilage loss (as gauged by measures of joint space narrowing and by other techniques, such as MRI) remains to be proven, but now may be possible in intervention trials.