Background Clinical trial data suggest that the duration of rheumatoid arthritis (RA) may influence response, but most trials have been conducted in patients with severe disease. Less attention has been paid to patients with moderately active RA, who represent a larger group of patients treated in rheumatology clinics.

Objectives The objective of this post hoc analysis from the PRESERVE trial was to determine the relationship between RA duration and the efficacy of combination ETN–MTX therapy in patients with moderately active RA.

Methods Enrolled subjects had DAS28 >3.2 and ≤5.1 despite stable oral MTX doses and received open-label ETN 50 mg QW plus MTX for 36 wks. Subjects (n=832) were stratified into disease duration subgroups (≤2 y vs >2 y) and analyzed in a one-way analysis of variance for demographic/baseline (BL) disease variables and for BL/Wk 36 mean weekly MTX doses, and in regression models for Wk 36 annualized radiographic and clinical treatment responses.

Results Significant differences (P<0.05) between subgroups with disease duration ≤2 y or >2 y were observed for: age (46.5 vs 49.1 y, mean); racial distribution (Asian, 16.8% vs 10.9%); RF+ (62.7% vs 76.7%); and aCCP+ (67.4% vs 81.7%). Disease duration was not significantly associated with mean weekly dosage of MTX at BL or Wk 36. No significant differences were observed between subgroups in the proportions of subjects achieving ACR20/50/70, DAS28 or SDAI low disease activity or remission, normal HAQ (≤0.5), or normal CRP (≤ULN) at Wk 36. Subjects in the >2 y subgroup were significantly more likely to achieve radiographic non-progression (Δ in mTSS ≤0.0; OR 1.76, 95% CI 1.11-2.77), but the estimated mean (SD) BL annual rate of progression was significantly lower in this group (6.0 [6.6] vs 16.6 [39.2], P<0.001).

Conclusions ETN-MTX therapy was effective in improving RA signs and symptoms in subjects with moderately active RA and an inadequate response to MTX, regardless of disease duration. Subjects with longer disease duration were significantly more likely to achieve non-progression and experienced a lower mean rate of progression. Among subjects with shorter duration, a lower proportion were RF+ and aCCP+; further analyses are planned to examine the distribution of these markers.

Disclosure of Interest S. Hall: None Declared, A. Szumski Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., A. Koenig Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., T. Jones Shareholder of: Pfizer Inc., Employee of: Pfizer Inc.