Background/Purpose: Anti-TNF treatment has demonstrated its effectiveness in axial ankylosing spondylitis (AS) patients with inadecuate response to traditional NSAIDs (tNSAIDs) therapy (>=2 tNSAIDs), but also aspects such as potential adverse events and cost must be considered. Etoricoxib(a selective COX-2 NSAID) has proved more efficacy than naproxen in these patients, and in an open label study up to 40% of patients refractory to tNSAIDs achieved a good clinical response with etoricoxib.

Objective: To evaluate the proportion of patients with axial AS with inadecuate response to tNSAIDs which achieve a good clinical response to etoricoxib after 4 weeks of treatment. To assess the proportion of these patients that mantain the good clinical response at 6 months follow-up. To analyze the effect of etoricoxib on the different clinical and biological parameters determined at 4 weeks and 6 months. 

Methods: Open label, multicentric (12 centers) randomized, prospective (4 weeks with a 6-month  open extension), non-controlled study, with inclusion period of approximately 2 years (mid 2010-2012).  57 axial AS patients with inadequate response to tNSAID following the consensus and guidelines previously published for the initiation of  anti-TNF treatment were included. Patients who achieved a good clinical response at week 4 were followed in an open extension study for 6 moths. Variables analyzed at baseline, 2, 4 weeks and 6 months included:  BASDAI,  clinical symptoms such as back and nocturnal back pain, global patient and physician assessment of disease (VAS score), disability (BASFI),  and biological parameters (CRP mg/dl) . We also evaluated both the proportion of patients who achieved good clinical response defined as patients who did not fulfill anti-TNF therapy criteria after etoricoxib treatment,  and ASASBIO response (50% in BASDAI and VAS physician global assessment improvements).

Results: 26/57 patients (46% , CI 34-58) achieved a good clinical response and 11/57 patients (19%, CI 8-31) achieved an ASASBIO response. 17/26 (65%) of patients included in the extension study maintaned the good clinical response and did not fulfill criteria of anti-TNF treatment  at the end of 6 moths follow-up, representing 30%(CI 18-43) of the total of patients included . Moreover, 13/57 (23%,CI 11-36) achieved an ASASBIO  response at 6-months follow-up.  Only 17/57 (30%) showed a good clinical response at week 2.  A discordant good clinical response between week 2 and 4 was observed in 9 patients, one of them losing response and the remaining 8 achieving response at week 4.  All individual clinical variables analyzed improved significatively after 2 wks achieving around 30% of mean reduction after  4 wks of treatment (p<0.001  in all variables). The mean BASFI score significatively improved in the same range that clinical variables, however the improvement of CRP did not reach  statistical significance (1.1 to 0.83 p=ns), although about 30% of patients with a good clinical response were showed with CPR normalization.

Conclusion: Etoricoxib treatment should be tried in axial AS patients before prescription of antiTNF treatment because around a third of patients achieved a good 6-months clinical response. Response at week 2 did not appear to predict response at week 4.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/is-there-a-role-for-etoricoxib-in-patients-with-axial-ankylosing-spondylitis-refractory-to-traditional-nsaid/