Objectives : The aim of the present study was to compare the efficacy of three anti-TNF agents (adalimumab, infliximab and etanercept ) in patients with ankylosing spondylitis (AS) at 24 weeks .
Methods : We achieved a retrospective descriptive and comparative monocentric study, on 23 patients, with AS (according to Amor criteria, ASAS 2009) who were handled during 12 years (2004-2015). The patients were treated with at least one anti-TNF, during at least 6 months. Disease activity was assessed by the BASDAI, ASDAS, ESR and CRP. To compare mean differences between time points (week 0 versus week 24), a Wilcoxon test was applied. To compare efficacy between the 3 anti-TNF, a Mann-Whitney test was applied.
Results: Twenty three patients were evaluated (19 men). The mean age was 40,7 years ±9,6. The median age at disease onset was 28,52±11,36 years. The mean disease duration was 9,6 (±7,17) years. Twelve patients received etanercept (ETN), 6 Infliximab (IFX) and 5 adalimumab (ADA). At six Months, the 3 anti-TNF showed improvement in the disease activity scores: BASDAI (p<0,0001), ASDAS CRP (p<0,0001), ESR (p=0,002) and CRP (p=0,001). Seventy percent of the patients have reached BASDAI 50 response at 6 months.
Table : Summary of median change  from baseline to week 24 in clinical  outcomes
	                        Week 0	                    Week 24	                         p
BASDAI                	6,13±2,2	            2.36 ±2,2	                 <0,0001
ASDAS CRP  	4,03 ±0,97	            2,06±1,18	                 <0,0001
CRP (mg/l)	        29,77±24,14	            9,1±10,09	                  0,001
ESR (mm)	        53,5 ±34,8	            23,15±15,36	          0,002
BASDAI : Bath Ankylosing Spondylitis Disease Activity Index,ASDAS : Ankylosing Spondylitis Disease Activity Score ,C-Reactive protein,ESR : Erythrocyte Sedimentation Rate
At week 24, patients on ETN achieved more frequently a significant reduction of ASDAS (-2,5 vs. -1,17; p < 0.04) and  ESR (-44,5 vs. -13,3; p=0,01) than IFX. The “Face to Face” comparison ADA vs IFX and ADA vs ETN had shown no significant efficacy differences. 
Conclusion: Our results showed a BASDAI 50 response in 70 % of patients. The comparison between the three biologics was consistent with a better efficacy of  the ETN.

DIRECT COMPARISON OF THE EFFECTS OF ANTI-TNF BIOLOGICAL AGENTS IN PATIENTS WITH ANKYLOSING SPONDYLITIS