A Large Proportion of Suboptimal Responders With Axial Spondyloarthritis Remain on Anti-TNF Agents

Using anti—tumor necrosis factor (anti-TNF) agents in the treatment of axial spondyloarthritis (axSpA) is associated with good efficacy and improvements in pain, disease activity, and physical function. However, some patients do not have a good response to anti-TNF therapies, and in a recent study, researchers found that a significant proportion of patients with axSpA continue with anti-TNF therapy despite their suboptimal outcomes.

The researchers performed a retrospective analysis of 499 patients with axSpA who were treated at 2 centers in the United Kingdom between 2002 and 2016.

The proportion of patients who had a suboptimal response to anti-TNFs—classified as having a 2-point or higher reduction in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score without reaching BASDAI criteria for a 50% improvement and with BASDAI remaining at a score of 4 or above at 6 months—was 16.4%.

In this group, 78% were male, 95.1% had ankylosing spondylitis, and 82.1% were positive for Human leukocyte antigen B27. Mean (SD) time to diagnosis was 10 (8.6) years, age at diagnosis was 37 (11.7) years, and age at starting the index anti-TNF agent was 48 (11.1) years. Univariate and multivariate analyses of suboptimal responders showed that older age at starting anti-TNF therapy was the best predictor of suboptimal response.

The anti-TNF agents used in this group of suboptimal responders were adalimumab (50%), etanercept (32.9%), infliximab (6.1%), golimumab (3.7%), and certolizumab pegol (7.3%).

At 6 months and 1 year, respectively, survival rates among the suboptimal responders who stayed on their index anti-TNF agent were 90.2% and 85.1%. The rate of attrition was greater among suboptimal responders at 2 years and 5 years, but at 10 years, there was no difference between responders and suboptimal responders (67.6% and 68.4%; P = .064).

Notably, although more than 90% of patients with a suboptimal response remained on their index anti-TNF therapy at 6 months, the option for switching to different anti-TNF agents was available in both of the 2 centers where the patients were treated.

According to the authors, “a significant proportion of patients continued [anti-TNFs] despite demonstrating a sub-optimal response,” and further studies will be needed to understand suboptimal response among patients with axSpA, as well as to investigate the best treatment choices for this group of patients.

Reference

Yahya F, Gaffney K, Sengupta R. Exploring sub-optimal response to tumour necrosis factor inhibitors in axial spondyloarthritis. Rheumatol Adv Pract. 2019;3(1):rkzo12. PMCID: PMC6649897.