The findings from the C-axSpAnd study that Jonathan Kay, MD, and colleagues reported at the annual meeting of the American College of Rheumatology are not surprising. Earlier studies in patients with ankylosing spondylitis showed that short symptom duration is one of the best predictors of good treatment response to TNFi therapy. The highest response rates were obtained in studies conducted in axSpA patients with symptom duration of less than 5 years or even less than 3 years. Since nonradiographic axial spondyloarthritis (nr-axSpA) and r-axSpA are considered as two stages of one disease, it is logical that the same effect is also observed in studies in nr-axSpA. Indeed, in the first study of a tumor necrosis factor inhibitor (TNFi) in nr-axSpA (ABILITY-1), patients with symptom duration less than 5 years responded much better to the TNFi adalimumab than did those with longer symptom duration, and the delta of the response between adalimumab and placebo was much greater. All these results together indicate that early disease stage associated with favorable treatment response in axSpA is better defined by symptom duration than by the presence or absence of structural damage in the sacroiliac joints. Furthermore, these data stress the importance of the early diagnosis in axSpA.
We also know from observational studies and subanalyses from clinical trials that treatment with monoclonal antibodies against TNF is associated with reduction of uveitis flares in axSpA. However, no prospective clinical studies had been conducted with acute anterior uveitis flares as the primary outcome until the C-VIEW study, which was presented by Irene E. van der Horst-Bruinsma, MD, PhD, at ACR 2019. The results of C-VIEW are therefore the first to prospectively address the question of reduction of uveitis flares under TNFi. The main limitation of the study is the lack of a control group, which makes interpretation of the results difficult because it is not clear to what extent the natural course of the disease – which might involve very long flare-free periods lasting from months to years – contributed to the reduction of flares. A randomized, controlled study aimed at label extension is highly desired for patients with acute anterior uveitis, especially for those with a frequently relapsing course resistant to local treatment.
Dr. Denis Poddubnyy
Denis Poddubnyy, MD , is head of the rheumatology department at Charite-Universitätsmedizin Berlin. He disclosed receiving research grants from AbbVie, Lilly, Merck, Novartis, and Pfizer, as well as receiving consultancy or speaker fees from AbbVie, Bristol-Myers Squibb, Celgene, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, and UCB.