medwireNews: The interleukin (IL)-17A inhibitor ixekizumab improves the signs and symptoms of nonradiographic axial spondyloarthritis (axSpA) relative to placebo, indicate findings from the phase III COAST-X trial.
These results “demonstrate for the first time that blocking IL-17A is a potential treatment option for patients with [nonradiographic] axSpA,” Atul Deodhar (Oregon Health & Science University, Portland, USA) told delegates at the 2019 ACR/ARP Annual Meeting in Atlanta, Georgia, USA.
The 1-year study included 303 patients with nonradiographic axSpA and no prior exposure to biologic DMARDs who were randomly assigned to receive ixekizumab at a dose of 80 mg every 2 weeks or every 4 weeks, or to receive placebo.
Participants had an average symptom duration of around 10 years, and the average ASDAS score at baseline was approximately 3.8. All patients had objective signs of inflammation at baseline (sacroiliitis on magnetic resonance imaging or C-reactive protein levels >5 mg/L).
The investigators found that a significantly higher proportion of patients treated with ixekizumab every 2 weeks or every 4 weeks versus placebo achieved an ASAS40 response at week 16, with rates of 40% and 35% versus 19%, respectively. These differences remained statistically significant at the 1-year follow-up, with corresponding rates of 31% and 30% versus 13%.
Deodhar said that all major secondary endpoints were met; participants in the ixekizumab arms had significantly greater improvements in ASDAS, BASDAI, and BASFI scores, as well as Spondyloarthritis Research Consortium of Canada magnetic resonance imaging sacroiliac joint scores, compared with those in the placebo group at both 16 weeks and 1 year.
In all, 77.5% of patients given ixekizumab every 2 weeks, 65.6% of those given the IL-17A inhibitor every 4 weeks, and 57.7% of participants in the placebo group experienced treatment-emergent adverse events. The corresponding rates of serious adverse events were 1.0%, 2.1%, and 1.0%, while 1.0% of patients in both ixekizumab groups and 1.9% of those given placebo discontinued treatment due to adverse events.
“There were no unexpected safety findings,” summarized Deodhar.
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Arthritis Rheumatol 2019; 71 (suppl 10)
ACR/ARP 2019; Atlanta, Georgia, USA: 8–13 November