Onset of action of etanercept in rheumatoid arthritis based on patient-reported outcomes.

Background: Onset of action is considered to be a key characteristic of the treatment of rheumatoid arthritis. The efficacy of TNF blockers is usually evaluated after 2 to 4 weeks of therapy. EULAR-RAID is a valid patient-reported outcome composite index.

Objectives: To evaluate the onset of action of etanercept in rheumatoid arthritis patients according to the EULAR-RAID score.

Methods: An open-label, single-arm (etanercept 50 mg/week), 12-week study was carried out in patients with active rheumatoid arthritis. Patients were asked to fill in the RAID score questionnaire each day for the first 14 days of the study and at the 4-week and 12-week visits. Onset of action was evaluated by considering: a) changes over time of the EULAR-RAID score; b) the percentage of patients achieving an 'acceptable' condition according to the EULAR-RAID score (e.g. a score ≤3.00).

Results: Of the 120 screened patients, 108 (female: 75%), age 54±13 years, disease duration 8±7 years) were enrolled. At baseline, patients had active rheumatoid arthritis (DAS: 5.4±0.8; CRP: 18.±30mg/l). Eleven patients dropped out of the study. A statistically significant decrease in the EULAR-RAID score was observed by day 1 of therapy. Kaplan-Meier estimates of the proportion of patients achieving an acceptable RAID score were 29.8 [% 95% C.I. 23.8-X42.6], 50 % [95% C.I. 41-60.9], 51.9% [95% C.I. 43.8-63.7], 56% [95% C.I. 49.5-69.1, after 1, 2, 4 and 12 weeks of therapy respectively. The median time to achieve an acceptable EULAR-RAID score was 14.5 days.

Conclusions: This open-label study suggests that patients can perceive a clinically relevant improvement by the first week of etanercept therapy.