Osteoarthritis and its associated cartilage pathology affects 30 million people in the U.S., but no disease-modifying treatments have yet reached the clinic. A recent multicenter trial evaluating the safety and efficacy of a truncated, recombinant human fibroblast growth factor-18 (FGF18) protein analogue (rhFGF18) demonstrated a dose-dependent improvement in cartilage thickness relative to a placebo.