Circulating serum interleukin-6, serum chitinase-3-like protein-1, and plasma vascular endothelial growth factor are not predictive for remission and radiographic progression in patients with early rheumatoid arthritis: post-hoc explorative and validation studies based on the CIMESTRA and OPERA trials

Objective: To investigate serum interleukin-6 (IL-6), serum chitinase-3-like protein-1 (YKL-40), and plasma vascular endothelial growth factor (VEGF) as measures of disease activity and predictors of clinical remission and radiographic progression in two early rheumatoid arthritis (RA) randomized controlled trials (RCTs).Method: Treatment-naive patients with early RA (< 6 months’ duration) and active disease, participating in two investigator-initiated RCTs, were treated according to a predefined treat-to-target algorithm aiming at inflammatory control, using methotrexate (MTX) + cyclosporine versus MTX + placebo (CIMESTRA study, n = 150, 5 year follow-up) or MTX + adalimumab versus MTX + placebo (OPERA study, n = 180, 2 year follow-up). The 28-joint Disease Activity Score (DAS28) and conventional radiography [bilateral hands and feet at baseline, 2 years and 5 years (only CIMESTRA)] were obtained at baseline and during follow-up. Serum IL-6, serum YKL-40, and plasma VEGF were measured in baseline blood s...