AB0632 EFFECTIVENESS OF ETANERCEPT BIOSIMILARS IN REACTIVE ARTHRITIS: RETROSPECTIVE CASE CONTROL
Authors: S. Ahmed, P. Padhan
Journal: Annals of the Rheumatic Diseases (2020)

Background: There is a paucity of evidence based therapies for reactive arthritis(ReA). Data is limited for anti-TNF drugs usage [Table 1] with even less data on biosimilars. Objectives: To find out the outcomes of etanercept biosimilars (ETN-b) use in ReA Methods: A retrospective review of patients meeting the Braun criteria 5 for probable ReA helped identify patients on ETN-b. Patients with less than 1 year follow-up and those who had received less than 5 doses of ETN were excluded. Biological naïve patients who had completed at least 1 year follow-up were included as controls. Baseline and current status was compared between these two groups. Results: Of 94 identified ReA patients, 11(11.7%) had received ETN-b and 10 met the case definition. Five each had received one of two ETN-b. 30 were available as controls. All cases had been documented as refractory ReA. Amongst cases, 7 patients had resolution of ReA; 2 had relapsing courses and 1 persistent arthritis. Four were in remission off all drugs. Controls has similar proportions [Table 2]. There were no infections or adverse effects recorded during follow-up. Table 1. Anti-TNF use in reactive arthritis Place (year) Anti-TNF N Outcomes Remarks Pennsylvania, USA (2005) Etanercept 16 10 completed trial: 9 responders Synovial histology improvement but not normalized Strasbourg, France (2011) Infliximab(5) Etanercept(4) Adalimumab(1) 10 Rapidly effective in 9 patients (90%) 5 had DFR Relapses responded to re- initiation Besançon, France (2016) Etanercept (9) infliximab (3) Adalimumab(3) 15 5 had DFR 9 developed chronic SpA Delhi, India (2019) Infliximab(10), Adalimumab(3) Etanercept(1) 9 At median of 3.5 months: 4 had remission, 3 relapse, 1 adverse reaction Biologicals were not given regularly Current study Etanercept biosimilars 10 At median 7 months: 6 had DFR All patients responded DFR: drug free remission Table 2. Comparison between etanercept group and biological naїve group Etanercept group (n=10) Non-etanercept group (n=30) Non parametric tests of significance Age at presentation (years) 27(17.2-34.2) 25(19-34.2) NS Males 10 (100%) 22 (55%) NS Follow-up (months) 27(15-71.7) 27(15-79.5) NS Preceding infection Diarrhoea= 6 Diarrhoea= 23 NS UTI= 4 UTI= 7 Inflammatory backache 3 11 NS Small joint involvement 4 11 NS Monoarticular/ oligoarticular/ polyarticular 3/3/4 10/8/12 NS Average intra-articular injections 1.9 0.3 NS Sulfasalazine 9 22 NS Methotrexate 1 1 NS Disease outcome Resolved = 7 Resolved = 19 NS Relapsing = 2 Relapsing = 9 Persistent = 1 Persistent = 2 Drug free remission 4 (40%) 12(40%) NS BASDAI at last follow-up 0.3(0-0.8) 0(0-1.4) NS HAQ-DI at last follow-up 0(0-0.15) 0.05(0-0.3) NS BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; HAQ-DI: Health Assessment Questionnaire Disability Index; NS: not significant Conclusion: All 10 patients responded. 40% achieved drug free remission. Thus, ETN-b appear safe and effective for ReA refractory to conventional therapy. References: [1]Flagg SD, Meador R, et al. Decreased pain and synovial inflammation after etanercept therapy in patients with reactive and undifferentiated arthritis: an open-label trial. Arthritis Rheum. 2005;53(4):613-7 [2]Meyer A, Chatelus E, et al. Safety and efficacy of anti-tumor necrosis factor α therapy in ten patients with recent-onset refractory reactive arthritis. Arthritis Rheum. 2011 May;63(5):1274-80 [3]Brinster A, Guillot X, et al. SAT0387 Anti Tnf Treatment of Reactive Arthritis. A Monocentric Experience. Ann Rheum Dis 2016;75:808 [4]Gupta V, Mohta P, et al. A retrospective case series of 12 patients with chronic reactive arthritis with emphasis on treatment outcome with biologics. Indian J Dermatol Venereol Leprol. 2019 [in print] [5]Braun J, Kingsley G, et al. On the difficulties of establishing a consensus on the definition of and diagnostic investigations for reactive arthritis. 1999. J Rheumatol . 2000;27(9):2185-92 Disclosure of Interests: None declared