medwireNews: Patients with axial spondyloarthritis (axSpA) who continue treatment with ixekizumab are less likely to experience flares than those who discontinue the interleukin (IL)-17A inhibitor, trial results suggest.
“COAST-Y provides the first randomised withdrawal data in axSpA for an IL-17A antagonist,” and the findings “are important for clinicians when making treatment decisions regarding treatment interruption and optimising long-term management,” say Robert Landewé (Amsterdam Rheumatology and Immunology Center, the Netherlands) and co-investigators.
The phase 3 long-term extension study included 155 patients with ankylosing spondylitis or nonradiographic axSpA who had previously participated in COAST-V, COAST-W, or COAST-X. After a 24-week lead-in period, during which participants received ixekizumab 80 mg every 2 or 4 weeks, those who achieved remission were randomly assigned to continue with the same dose of ixekizumab or switch to placebo. Remission was defined as ASDAS below 1.3 points at week 16 or week 20, and below 2.1 points at both timepoints.
As reported in the Annals of the Rheumatic Diseases, a significantly higher proportion of patients who continued versus discontinued ixekizumab remained free from disease flares at the 40-week follow-up, at rates of 83.3% for both ixekizumab doses versus 54.7% for the placebo arm.
The investigators note that these findings remained consistent when patients with ankylosing spondylitis and nonradiographic axSpA were analyzed separately.
While “these findings suggest that continuous [ixekizumab] treatment is important to maintain long-term disease control for most patients,” the researchers note that “[a] substantial proportion of patients remained flare-free for a prolonged period following [ixekizumab] withdrawal, which may be important in situations where temporary treatment interruption is necessary or preferred.”
They also point out that “most patients who flared were able to recapture disease control with retreatment.” All placebo-treated patients who experienced a flare switched to open-label ixekizumab; 93% of patients with at least 16 weeks of ixekizumab retreatment achieved low disease activity (ASDAS <2.1 points), while 44% achieved inactive disease (ASDAS <1.3 points).
The team also conducted a post-hoc multivariate analysis and identified a number of predictors of flare, including withdrawal of ixekizumab, having a high (≥25.0 kg/m2) or low (<18.5 kg/m2) BMI, and having antidrug antibodies prior to week 24 of COAST-Y.
“Longer-term data from this ongoing study (with up to 80 weeks of randomised withdrawal) will likely provide additional information regarding response to retreatment with [ixekizumab], as well as predictors of flare,” conclude Landewé and team.
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