Objective: The aim of the current study was to evaluate the short-term effects of anti-tumour necrosis factor alpha (infliximab) therapy on serum cartilage oligomeric matrix protein (COMP) levels, a possible biomarker of cartilage destruction.
Methods: Nine consecutive patients with active psoriatic arthritis (PsA) were treated with infliximab for 6 weeks. Serum COMP levels were measured and correlated to pre-established disease activity outcome variables: pain as assessed by the patient, using the 100 mm visual analogue scale (VAS), duration of morning stiffness (MGST), swollen joint count (SJC), tender joint count (TJC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).
Results: Significant improvements in MGST, VAS, SJC and TJC values were observed after 6 weeks of therapy. Similar significant improvements were demonstrated in the ACR response rate and in eight (89%) patients the ACR20 was achieved. ESR and CRP decreased significantly over 6 weeks. Serum COMP levels also decreased significantly after 6 weeks of treatment (12.99 +/- 1.71 baseline, 10.22 +/- 1.1 after 6 weeks, P < 0.008).
Conclusion: The results of our study suggest that short-term therapy with infliximab leads to decreased COMP levels in patients with PsA. COMP seems to be a good candidate for a biomarker reflecting cartilage response to this treatment in PsA patients.