Markers useful in enrichment strategies for the treatment of osteoarthritis

A method for treating a subject with an FGF-18 compound having a cartilage disorder characterized by articular cartilage injury or loss of articular cartilage, comprising the following steps:

• a) determining, from a sample from said subject, the quantity of neo-epitope of Collagen type II (ProC2), and a measurement of the joint space width (JSW) in at least one knee of said subject, wherein said quantity of ProC2 and the joint space width are predictive about the subject's risk for having good sensitivity or intermediate sensitivity to a treatment with said FGF-18 compound,
• b) selecting the subject having:
• good sensitivity to treatment with an FGF-18 compound as determined by the presence of (i) lower than 4.2±2SD ng/mL of ProC2, and (ii) JSW lower than or equal to 3.5±2SD mm,
• intermediate sensitivity to treatment with an FGF-18 compound as determined by the presence of (i) lower than 4.2±2SD ng/mL of ProC2, and (ii) JSW higher than 3.5±2SD mm, or
• intermediate sensitivity to treatment with an FGF-18 compound as determined by the presence of (i) higher than 4.2±2SD ng/ml of ProC2, and (ii) JSW lower than 3.5±2SD mm, and
• c) administering intraarticularly said FGF-18 compound to said selected subject,
• wherein the FGF-18 compound comprises amino acid residues 28-196 of SEQ ID NO:
• 1, optionally fused to a heterologous protein or chemical compound.