THU0357 No specific impact of concomitant fibromyalgia on the anti tnf treatment effect in axial spondyloarthritis patients without radiographic structural damage or objective signs of inflammation

Background Currently, the European Medicine Agency (EMA) is recommending the use of anti-TNF in case of active NSAID refractory axial (ax) spondyloarthritis (SpA) only in the presence of either structural radiographic damage of the sacroiliac Joints (SIJ) or objective signs of inflammation (either elevated CRP or inflammation at MRI-SIJ) probably mainly because of the fear of a concomitant fibromyalgia (FM). Objectives To evaluate the interaction of a concomitant FM on the anti-TNF response with regard to the application of the EMA recommendation Methods Study design: Prospective, multicenter, longitudinal (12 weeks) open trial (Predict-SpA, ClinicalTrials.gov: NCT03039088). Patients (pts): axSpA requiring an anti-TNF. Data collected: At baseline, 1/Radiographic SIJ damage 2/ MRI-SIJ inflammation 3/ Elevated CRP 4/ FM according to the FiRST (Fibromyalgia Rapid Screen Test) questionnaire. At baseline and after 12 weeks of therapy: BASDAI. Statistical analysis: Non Responder Imputation (NRI), Baseline Carried Forward Technic (BOCF) in case of missing data. Interaction test between the presence of FM and the fulfillment of the EMA recommendation (defined by the presence of either structural radiographic damage of the SIJ or objective signs of inflammation (either elevated CRP or inflammation at MRI-SIJ)) on the anti TNF treatment response (BASDAI50) Results Of the 508 enrolled pts (females: 46.7%, age: 41.4+11.6 years old, HLA B27 positive: 57.5%, X-Ray sacroiliitis: 53.2%, inflammation at MRI-SIJ: 52.0%), only 59 had no structural damage at SIJ-X-Rays and no inflammation at MRI-SIJ (12%). A concomitant FM was noticed in 42% vs 37% of pts treated in accordance vs not with the EMA recommendation, respectively (p=0.44). The anti-TNF treatment effect was higher in the groups of pts treated in accordance (vs not) with the EMA recommendation (BASDAI 50: 52% vs 39%, respectively; p=0.054). There was a trend (but not statistically significant) suggesting an interaction of the concomitant FM on the anti TNF treatment response with regard to the application of the EMA recommendation (interaction p value=0.140). In the 59 pts not treated in accordance with the EMA recommendation, the treatment effect in the sub-groups of pts without ( vs with) concomitant FM was 38% vs 40% respectively, p=0.891. In the 449 pts treated in accordance with the EMA recommendation, the treatment effect in the sub-groups of pts without ( vs with) concomitant FM was 56% vs 46%, p=0.042). Conclusions This study suggests that 1/ French rheumatologists are applying the EMA recommendation in daily practice 2/ these recommendations result in a better outcome in terms of short term symptomatic treatment effect. In this study, concomitant FM was not more frequently observed in patients without ( vs with) objective sign of structural damage or inflammation and the impact of a concomitant FM was not more pronounced (or even lower) in pts without (vs with) objective sign of structural damage or inflammation. References Perrot S, et al. Development and validation of the Fibromyalgia Rapid Screening Tool (FiRST). Pain.2010;150:250–6. Acknowledgements This study was conducted thanks to an unrestricted grant from MSD. Disclosure of Interest None declared