FRI0419 OUTCOMES OF DOSE REDUCTION OF TNF-INHIBITORS IN AXIAL SPONDYLOARTHRITIS AT 24 MONTHS
Authors: Liz Van Rossen, Claire Harris, Annie Gilbert, Raj Sengupta, Cathal Boyle, Karl Gaffney, Pedro Machado, Andrew Keat
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Some patients with inflammatory arthritis who respond well to TNF inhibitor (TNFi) treatment continue to do so after dose reduction. In Axial Spondyloarthritis (axSpA) dose optimisation is desirable but the extent of benefit is unclear and predictors of therapeutic response to dose reduction are unknown. <h3>Objectives</h3> To observe responses to dose reduction of TNFi treatment in axSpA patients and to seek preliminary predictors of low-dose therapeutic response. <h3>Methods</h3> AxSpA Patients at 4 UK centres were allowed to reduce their doses of TNFi therapy if they had met UK (NICE) response criteria and remained well for at least 6 months and wished to do so. There was no predetermined dose-reduction schedule. The proportion of dose reduction was calculated as a percentage, in mg per month, of the original, standard dose. All patients completed BASDAI and BASFI questionnaires at each visit with annual BASMI measurement. CRP levels were measured frequently. Individuals who continued to take reduced-dose treatment throughout the 24-month period were designated "Remainers" (REM) and those who reverted to full-dose treatment were designated "Reverters" (REV). Data were collected at 6 timepoints; 1: immediately before starting TNFi therapy; 2: at the point of dose reduction; 3: at the point of reversion to full-dose treatment (REV only); 4: 6 months after dose reduction; 5:12 months after dose reduction; 6: 24 months after dose reduction. <h3>Results</h3> 58 patients (86%male) who had reduced their dose of TNFi treatment were observed for 24 months. 47 (81%) were REM and 11 (19%) were REV. Mean disease duration prior to biologic therapy was 22.6 years for remainers and 18.6 years for reverters. Mean dose reduction was 38% and 41%, respectively. These 47 REM (85%male) were of mean age 53.6 (range 36 to 71) years, compared with the 11 REV (63.6%male) whose mean age was 51.9 (range 39 to 71) years. Mean BASDAI, BASFI and BASMI scores and CRP levels at the designated time points are shown in table1. REM mean BASDAI scores reduced from 1.9 to 1.4 (28%) from dose reduction to 24 months whereas REV mean BASDAI scores increased from 1.8 to 2.4 (34%) from dose reduction to dose reversion. REM mean BASFI scores reduced from 2.5 to 1.4 (43%) from dose reduction to 24 months whereas REV mean BASFI scores increased from 2.6 to 3.0 (17%) from dose reduction to dose reversion. REM mean BASMI scores reduced from 3.4 to 2.3 (32%) from dose reduction to 24 months whereas REV mean BASMI scores increased from 2.8 to 3.3 (19%) from dose reduction to dose reversion. REM mean CRP scores decreased from 4.1 to 0.7mg/dl (83%) from dose reduction to 24 months and REV mean CRP scores also decreased from 4.7 to 3.5mg/dl (25%) from dose reduction to dose reversion. <h3>Conclusion</h3> Amongst these selected patients with axSpA 85% continued to respond to TNFi treatment in spite of 38% dose reduction. Reverters were more likely to be female and to have relatively low CRP levels at the initiation of TNFi treatment; reversion was preceded by modest rises in BASDAI, BASFI and BASMI but by continued fall in CRP levels. There is a need for randomised dose-reduction studies in axSpA and further research to understand the factors that lead to dose-reversion. <h3>Disclosure of Interests</h3> Liz Van Rossen Grant/research support from: UCB, Abbvie, Consultant for: Novartis, Speakers bureau: Abbvie, UCB, Novartis, Claire Harris Consultant for: Abbvie, Speakers bureau: Abbvie, Annie Gilbert Consultant for: Boehringer, Raj Sengupta Grant/research support from: AbbVie, Celgene Corporation, Merck Sharp &amp; Dohme, Novartis, Pfizer, and UCB, Speakers bureau: AbbVie, Celgene Corporation, Merck Sharp &amp; Dohme, Novartis, Pfizer, and UCB, Cathal Boyle: None declared, Karl Gaffney Grant/research support from: Abbvie, Pfizer, Consultant for: Abbvie, Lilly, Novartis, UCB, Speakers bureau: Abbvie, Biogen, Gilead, Lilly, Novartis, UCB, Pedro Machado Consultant for: Abbvie, BMS, Celgene, Janssen, MSD, Novartis, Pfizer, Roche and UCB, Speakers bureau: Abbvie, BMS, Celgene, Janssen, MSD, Novartis, Pfizer, Roche and UCB, Andrew Keat: None declared