TNF and ankylosing spondylitis: In the BIOBADASER registry, among 4706 patients with chronic arthritis—including RA, PsA, and ankylosing spondylitis (AS)—10% had been treated with more than one anti-TNFα over a 4-year period [41]; 88% of PsA patients continued with their first anti-TNFα drug for 12 months vs. 83% of RA patients [26].