Background:In ankylosing spondylitis (AS) patients with lack of response to a first line of biologic disease modifying antirheumatic drugs (bDMARD), switching to another bDMARD is recommended, aiming either to the same or different therapeutic target. In several previous studies a decrease in drug survival has been noted when tumor necrosis factor alfa inhibitors (TNFai) are used as second or third treatment line (1,2).Objectives:Primary endpoint: To evaluate survival of bDMARD as second line treatment in patients with AS non responding to TNFai either because of lack or loss of efficacy. Secondary: To evaluate the impact on drug survival of several variables such as sex, HLA, peripheral arthritis, radiologic sacroiliitis, CRP, BASFI, BASDAI or bDMARD class.Methods:Observational, longitudinal and retrospective observational study. We included 67 patients diagnosed with AS who received treatment on second line with bDMARD (TNFai or anti IL7) after discontinuation of TNFai as first line of treatment. We analyze patients older than 18 yo, with at least 3 months of continuous treatment before and after switch, seen in our Hospital from 2006 to 2019. Data were collected regarding to demographics, HLA B27 positivity and functionality and activity index, CRP and treatment with cDMARDs.Results:All 67 patients included were still on follow up after switching to second bDMARD. Median age was 37 yo, 56.7% were male and 31%, smokers. 35.8% patients had axial AS; 1.5% peripheral arthritis; 62.7%, mixed and 9%, dactilitis. 76.1% had radiographic sacroiliitis and 74.6%, HLA B 27+. As first bDMARD, the most common was Infliximab (IFX) (47.8%), followed by Adalimumab (ADA) (19.4%) and Etanercept (ETN 14.9%). Mean survival was 32.4 months (IFX, 37 months; ETN, 45; Golimumab, 32.3 and ADA, 24.1). The commonest cause of treatment suspension was loss of efficacy (LoE) (56.7%), followed by lack of efficacy (LaE) (17.6%) and adverse effects (AE) (16.4%).As second bDMARD the most frequent was ADA (35.8%), followed by ETN (34.3%), Golimumab (9%), IFX (7.5%) and Secukinumab (6%) with a mean survival of 45 months (ETN 63.8, ADA 45.7, Golimumab 32). Treatment was discontinued in 47.8% of patients because of LoE (17.9%), LaE (17.9%) and EA (11.9%). A total of 16 AE were recorded, of which 6% were infections and 9%, allergic reactions. Regarding the analysis of the impact of other variables on drug survival, there was statistically significant differences on HLA B 27 carrier status (p=0.012), in which we observed an increase on survival when the patient is HLA B27 + and in whom BASDAI is higher before switching (p=0.02).Conclusion:In our study, we did not observe differences in survival of second line bDMARD in patients with AS regarding type of TNFai, case of discontinuation or type of radiographic involvement in the first line of treatment. Patients with HLA B27+ and high value of BASDAI at the beginning of second bDMARD showed an increased on drug survival. Contrary to literature, we did not see significant differences regarding CRP.References:[1]Glintborg B, Østergaard M, Krogh NS, Tarp U, Manilo N, Loft AGR, et al. Clinical response, drug survival and predictors thereof in 432 ankylosing spondylitis patients after switching tumour necrosis factor α inhibitor therapy: results from the Danish nationwide DANBIO registry. Ann Rheum Dis. 2013 Jul;72(7):1149–55.[2]Deodhar A, Yu D. Switching tumor necrosis factor inhibitors in the treatment of axial spondyloarthritis. Semin Arthritis Rheum. 2017 Dec;47(3):343–50.Disclosure of Interests:None declared
