Treatment adherence, efficacy, and safety of etanercept in patients with active psoriatic arthritis and peripheral involvement in Belgium for 66 months (PROVE study).

Objectives: To describe the long-term adherence, efficacy, and safety in patients with psoriatic arthritis (PsA) treated with etanercept (ETN) in a daily clinical setting in Belgium.

Methods: The PROVE study was a prospective, multi-centre, open-label, observational study in patients with active PsA who had previously failed disease-modifying anti-rheumatic drugs. Patients were treated with ETN prescribed by their physician and adherence was monitored over 66 months.

Results: A total of 303 patients were enrolled (polyarticular-type n=264; oligoarticular-type n=39). 156 (51.5%) patients adhered to the treatment until the end of the study. The mean study duration was 4.0 (SD, 1.9) years. The most common reasons for discontinuing were non-response (35.9%), patient lost to follow-up (20.7%), and reasons unrelated to ETN (20.0%). Males adhered to treatment significantly longer than females (5.0 vs. 3.9 years; p<0.0001). After 6 months, 49.0% of patients with active synovitis at the start of the study had zero joints with synovitis, and this proportion increased to 77.6% by month 66 (p<0.001 for all time points vs. baseline). In polyarticular-type patients, the mean total Health Assessment Questionnaire (HAQ) score (0-60) decreased from 27.0 (95% CI 25.9-28.1) to 9.7 (8.5-10.9; 64.8% improvement; p<0.001) after 6 months and to 7.7 (6.2-9.3; 66.6% improvement; p<0.001) after 66 months. Treatment-related adverse events were reported in 177 (58.8%) of patients, and 53 (17.6%) patients reported serious adverse events related to treatment.

Conclusions: In these patients with active PsA from daily clinical practice, adherence to ETN was high observed over 5.5 years and it was well tolerated.