Disease response in rheumatoid arthritis across four biologic therapies associates with improvement in paraoxonase-1 activity and oxylipins.

Objective: Paraoxonase-1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme, that has been implicated as a biomarker of cardiovascular risk in patients with rheumatoid arthritis (RA). We aimed to investigate how different biologic therapies affect levels of PON1 and oxylipins.

Methods: 1213 adult patients with RA in the Comparative Effectiveness Registry to study Therapies for Arthritis and Inflammatory CoNditions cohort study with moderate-to-high disease activity (Clinical Disease Activity Index (CDAI) >10) who initiated a new biologic (tocilizumab (TCZ), n=296; abatacept, n=374; tumour necrosis factor inhibitors, n=427; rituximab, n=116) were followed prospectively with serum specimens analysed for PON1 activity by arylesterase (ARYL), lactonase (LAC) and PON assays at baseline and after 6 months of biologic therapy. A targeted panel of oxylipins was evaluated by liquid chromatography-mass spectrometry/mass spectrometry in a subset of patients with the lowest and highest 6-month Disease Activity Score 28 (DAS28)-C reactive protein (CRP) responses in each treatment group.

Results: PON1 activity generally increased in the entire cohort after 6 months of new biologic therapy, showing the greatest, most consistent increases in the TCZ group. Increases in all three PON1 domains associated with significant decreases in disease activity in DAS28-CRP/CDAI (p<0.05), and increases in LAC/ARYL were significantly associated with the American College of Rheumatology 20/50/70 responses (OR (95% CI) of 1.12 (1.04, 1.22) and 1.13 (1.04, 1.23), p<0.01, respectively), after controlling for other RA disease characteristics. Some oxylipins, including 12-hydroxyeicosatetraenoic acid correlated with RA disease activity measures.

Conclusion: Improvement in disease activity across four classes of biologics is associated with enhanced PON1 activity, which has significant implications for cardiovascular safety.