Long-Term Ixekizumab Safe and Effective for Treatment of Axial Spondylarthritis

Treatment with ixkizumab (IXE) provided sustained disease activity improvement with a favorable safety profile over a 3-year period among patients with axial spondyloarthritis (axSpA), according to study results published in The Journal of Rheumatology.

Researchers performed a long-term extension study (COAST-Y; ClinicalTrials.gov Identifier: NCT03129100) following 3 originating studies: COAST-V (ClinicalTrials.gov Identifier: NCT02696785), COAST-W (ClinicalTrials.gov Identifier: NCT02696798), and COAST-X; (ClinicalTrials.gov Identifier: NCT02757352) to report the safety and efficacy of IXE treatment among patients with radiographic axSpA (r-axSpA) and nonradiographic axSpA (nr-axSpA) through 156 weeks.

A total of 932 patients received at least 1 dose of IXE between week 0 of the originating study and week 156. Of these, 773 moved on to enter COAST-Y after completing the originating studies.

In COAST-X, 40 patients received IXE dose escalation from every 4 weeks to every 2 weeks, with the same escalation occurring among 86 patients in COAST-Y. The safety analysis only counted this total of 126 patients once in the total safety population.

Treatment-emergent adverse event (TEAE) analysis was conducted, including 932 patients with axSpA who had received at least 1 dose of IXE over 156 weeks­ (52 weeks of the original study and 104 weeks of COAST-Y). Of these, 454 patients received IXE every 4 weeks and 604 patients received IXE every 2 weeks, comprising a total of 2097.7 patient-years (PYs).

The incidence rates for TEAEs were 43.3 per 100 PYs among patients receiving IXE every 4 weeks and 37.9 per 100 PYs among those treated every 2 weeks. Adverse events (AEs) leading to discontinuation occurred at a rate of 3.0 per 100 PYs among patients treated with IXE every 4 weeks and 3.3 per 100 PYs among those treated every 2 weeks.

The majority of TEAEs were mild to moderate in severity and 7.1% led to discontinuation. Injection site reactions and infections were the most frequently reported AEs, also considered mild to moderate in severity.

At week 156, 75% of patients from COAST-V, 39% of patients from COAST-W, and 66% of patients from COAST-X who received IXE every 4 weeks throughout the study period achieved either Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease or ASDAS low disease activity. Over half of the patients from COAST-V, COAST-W, and COAST-X achieved ASDAS clinically important improvement, sustained through week 156.

Patients with r-axSpA who were biologic disease-modifying antirheumatic drug (bDMARD)-naïve, tumor necrosis factor inhibitor-experienced, and those with nr-axSpA who were bDMARD-naïve all showed sustained clinical efficacy outcomes for up to 3 years.

Study limitations included dose escalation performed at the investigator’s discretion without predefined criteria and exclusion of data during these dose escalations from the main results.

The study authors concluded, “These results provide additional evidence to support the fact that patients with axSpA receiving IXE experience long-term safety and sustained improvements in efficacy and patient-reported outcomes at 3 years.”

Disclosure: This research was supported by Eli Lilly and Company. Please see the original reference for a full list of disclosures.