Background:TNF inhibitors have been largely demonstrated to be effective and reasonably safe for the treatment of psoriatic arthritis (PsA). Current EULAR guidelines recommend the use of an anti-TNF as first choice treatment in patients with PsA for whom a synthetic DMARD (usually methotrexate or leflunomide) is not efficacious or not well tolerated [1]. In a scenario where biologic treatments are easily available, and the treat to target strategy is widely accepted, a complete disease remission or at least a minimal disease activity are considered realistic goals to be achieved in a growing proportion of patients [2]. However, there remains very little research regarding anti-TNF discontinuation in patients who achieved a complete remission [3-5].Objectives:The primary aim of this study was to measure the disease-free interval after anti-TNF discontinuation, secondary it was investigated whether the use of Power Doppler Ultrasound (PDUS) and Contrast Enhanced Ultrasound (CEUS) could improve the diagnostic accuracy in the recognition of the relapse. Finally, we wanted to characterize the clinical features of the disease recurrence.Methods:From June 2018, 35 patients with PsA (27 males and 8 female) treated with anti-TNF, in stable remission were prospectively monitored for 1 year after treatment discontinuation. Remission was defined as documented absence of clinical and ultrasonographic signs of arthritis or enthesitis. Complete rheumatological and dermatological examinations were performed in all participants, at baseline and every 8-12 weeks: American College of Rheumatology (ACR) 66-68 joint count; Psoriasis Area Severity Index (PASI); patient pain visual analog score (VAS); patient global disease activity VAS; Health Assessment Questionnaire (HAQ); Leeds Enthesitis Index (LEI); Bath Ankylosing Spondylitis Disease Activity Index (BASDAI); Bath Ankylosing Spondylitis Functional Index (BASFI); Power Doppler Ultrasound (PDUS) of the involved joints and entheses, Contrast Enhanced Ultrasound (CEUS) of a selected joint or enthesis and laboratory inflammation tests.Results:31 out of the 35 enrolled patients, experienced a disease recurrence with an average disease-free interval of 27.9±21.1 weeks (Figure 1). In 3 patients the treatment was restored for a relapse of the skin psoriasis, 8 patients reported only axial symptoms of disease relapse and 20 patients had both axial and peripheral joints involvement (average DAPSA score of 23.6±11.1; average BASDAI score of 4.7±2.6; average BASFI score 4.5±2.9). In all cases the disease flare was moderate and all patients promptly regained remission after restarting the treatment. Both PDUS and CEUS were safe and reliable showing a good percentage of accordance (95,4%) in detecting synovitis and enthesitis.Conclusion:The rate of disease relapse of PsA after anti-TNF discontinuation is relevant. However the disease-free interval was not short. Retreatment with the same anti-TNF was effective and safe.References:[1]Gossec L, Baraliakos X, Kerschbaumer A, et al. EULAR recommendations for the management of psoriatic arthritis with pharmacological therapies: 2019 update. Ann Rheum Dis. 2020 Jun;79(6):700-712.[2]Dures E, Shepperd S, Mukherjee S, et al. Treat-to-target in PsA: methods and necessity. RMD Open. 2020 Feb;6(1):e001083.[3]Stober C, Ye W, Guruparan T, et al. Prevalence and predictors of tumour necrosis factor inhibitor persistence in psoriatic arthritis. Rheumatology (Oxford). 2018 Jan 1;57(1):158-163.[4]Huynh DH, Boyd TA, Etzel CJ, et al. Persistence of low disease activity after tumour necrosis factor inhibitor (TNFi) discontinuation in patients with psoriatic arthritis. RMD Open. 2017 Jan 16;3(1):e000395.[5]Ye W, Tucker LJ, Coates LC. Tapering and Discontinuation of Biologics in Patients with Psoriatic Arthritis with Low Disease Activity. Drugs. 2018 Nov;78(16):1705-1715.Disclosure of Interests:None declared.
Treat-to-target in PsA: methods and necessity