THU0422 Effectiveness of Dose Reduction of TNF Inhibitors in Maintaining Low Disease Activity in Severe Psoriatic Arthritis
Authors: W. Fong, C. Holroyd, B. Davidson, R. Armstrong, N. Harvey, E. Dennison, C. Cooper, C.J. Edwards
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> Disease relapse can occur in psoriatic arthritis (PsA) when tumour necrosis factor inhibitor (TNFi) therapy is withdrawn. Dose reduction of TNFi whilst maintaining disease control may be possible. <h3>Objectives</h3> To determine feasibility of TNFi dose reduction in severe PsA patients in a real world setting. <h3>Methods</h3> 83 PsA patients were identified from a Biologics Therapy Clinic database. Severe PsA was defined as patients with ≥3 tender joints and ≥3 swollen joints, and active arthritis despite adequate trials of ≥2 disease-modifying antirheumatic drugs (DMARDs). Using standardised questionnaires, rheumatologists recorded clinical characteristics, laboratory results, disease activity, medications and clinical outcomes. Criteria for dose reduction of TNFi therapy included DAS28-ESR ≤3.2 (low disease activity) for ≥6 months and patient agreement. TNFi dose was reduced by one-third [Adalimumab (ADA) 40mg 3 weekly; Etanercept (ETN) 50mg every 10 days; Infliximab (INF) 5mg/kg 3 monthly; Certolizumab (CER) 200mg 3 weekly; Golimumab (GOL) 50mg 6 weekly]. Patients were seen 12 weeks after starting TNFi therapy, then 24 weekly. Failure of dose reduction was defined as DAS28-ESR &gt;3.2 or patient-defined disease recurrence. Patients who flared were reviewed and re-escalated to standard treatment dose. <h3>Results</h3> All 83 patients had a clinical diagnosis of PsA by a consultant rheumatologist (96% satisfied CASPAR). 64% were males. 93% were Caucasian. Mean age was 52.3±12.1 years. Mean age of diagnosis was 40.6±12.1 years. Patients were diagnosed with PsA for mean of 11.3±6.6 years. 46% tried ≥3 DMARDs prior to biological therapy. 45% were current or ex-smokers. 63%, 24%, 11%, 2% were on their 1st, 2nd, 3rd and 4th biologic respectively. Mean DAS28-ESR prior to starting TNFi therapy was 4.2±1.0. Methotrexate (76%) was the most common DMARD used. Biologics used in order of frequency were: ADA (42%), ETN (25%), INF (15%), CER (8%) and GOL (7%). 18% (15/83) fulfilled criteria for TNFi dose reduction and had their TNFi reduced. 60% (9/15) successfully maintained TNFi dose reduction for a mean of 1.2±0.8 years. Disease activity prior to TNFi dose reduction was lower in patients successful in maintaining dose reduction compared to failures of TNFi dose reduction [mean DAS28-ESR 1.1±0.5 vs 2.1±0.9 respectively (p=0.021)]. Of those who failed dose reduction (6/15), re-instating standard dose of TNFi therapy re-captured low disease activity in all patients by 12 weeks, but with significantly higher disease activity compared to patients successfully maintained on TNFi dose reduction [mean DAS28-ESR 2.7±0.6 vs 1.3±0.5 respectively (p≤0.001)]. <h3>Conclusions</h3> Real world experience suggests that about 60% of individuals with severe PsA who achieve low disease activity, can be maintained on a reduced dose of TNFi therapy for 1 year. PsA patients with lower disease activity are better able to maintain dose reduction of TNFi therapy. Re-instating standard dose of TNFi therapy in those who flare can rapidly control disease activity again. <h3>Disclosure of Interest</h3> None declared