Long-Term Safety and Efficacy of Ixekizumab in Patients With Axial Spondyloarthritis: 3-year Data From the COAST Program

Objective. To report safety and efficacy of ixekizumab (IXE) from the COAST program at 3 years, including 1 year from the originating studies (COAST-V, COAST-W, and COAST-X), and 2 years from COAST-Y. Methods. In COAST-Y, patients continued with the dose received at the end of the originating study at week 52: 80 mg IXE either every 4 weeks (Q4W) or every 2 weeks (Q2W). Placebo-treated patients from COAST-X received IXE Q4W in COAST-Y. Starting at week 116 (week 64 of COAST-Y), patients receiving IXE Q4W could be escalated to Q2W. Safety for patients receiving ≥ 1 dose of IXE and efficacy for patients receiving ≥ 1 dose of IXE Q4W was assessed. Data are summarized as observed. Results. For the 932 patients who received ≥ 1 dose of IXE (Q2W or Q4W) through 3 years, treatment-emergent adverse events (TEAEs) occurred at an incidence rate (IR) of 38.0 per 100 patient-years (PYs). The most frequently reported were infections (IR 25.7 per 100 PYs) and injection site reactions (IR 7.4 per 100 PYs); the majority of TEAEs were mild or moderate in severity. In total, 7.1% of TEAEs led to discontinuation (IR 3.1 per 100 PYs). All patient groups receiving IXE Q4W assessed through 3 years saw sustained improvements in Ankylosing Spondylitis Disease Activity Score, clinically important improvement, and other efficacy end points. Conclusion. The 3-year safety profile of IXE in the COAST program is consistent with the previously established long-term safety profile. IXE Q4W provided sustained improvement of disease activity in patients who received treatment through 3 years.