Improvement in Disease Activity With Long-Term Ixekizumab in axSpA

In patients with axial spondyloarthritis (axSpA), long-term treatment with the monoclonal antibody ixekizumab was found to improve disease activity, according to study findings published in The Journal of Rheumatology.

In the COAST program, ixekizumab showed efficacy at week 16 in patients with radiographic axSpA (r-axSpA) and nonradiographic (nr-axSpA), with efficacy maintained through 2 years and no new safety signals reported.

Eligible participants in the current study completed 1 of the 2 original studies in r-axSpA (COAST-V; ClinicalTrials.gov Identifier: NCT02696785 or COAST-W; ClinicalTrials.gov Identifier: NCT02696798) or the original study in nr-axSpA (COAST-X; ClinicalTrials.gov Identifier: NCT02757352) and were permitted to enroll in COAST-Y (ClinicalTrials.gov Identifier: NCT03129100).

Participants in COAST-Y had r-axSpA and were biologic disease-modifying antirheumatic drug (bDMARD)-naive (COAST-V) or tumor necrosis factor inhibitor (TNFi)-experienced (COAST-W), along with those with nr-axSpA who were bDMARD-naive (COAST-X). Participants were able to receive treatment with ixekizumab 80 mg every 2 weeks or every 4 weeks, for up to a total of 156 weeks (52 weeks of treatment in the original study plus 104 weeks of treatment in COAST-Y).

In the current analysis, the subgroup of patients who received at least 1 dose of ixekizumab during the 3-year COAST program was assessed to evaluate the efficacy and safety of ixekizumab.

Overall, 932 participants received at least 1 dose of ixekizumab between week 0 and 156. Among these individuals, 82.9% (n=773) entered COAST-Y following completion of the original COAST studies, with 67.7% (n=631) completing a total of 3 years of the COAST program.

A total of 414 individuals received treatment with at least1 dose of ixekizumab every 4 weeks, with 288 (67.9%) of these participants completing 3 years of the COAST program.

Results of the study showed that treatment-emergent adverse events (TEAEs) were reported at an incidence rate (IR) of 38.0 per 100 patient-years (PYs). The IRs for TEAEs with ixekizumab every 4 weeks and every 2 weeks were 43.3 and 37.9 per 100 PYs, respectively.

Infections (IR, 25.7 per 100 PYs) and injection-site reactions (IR, 7.4 per 100 PYs) were the most frequently reported TEAEs. Of note, the majority of TEAEs were mild or moderate in severity, with 7.1% associated with discontinuation of the study drug (IR, 3.1 per 100 PYs). Overall, 3 deaths were reported.

More than half of the participants from COAST-V, COAST-W, and COAST X who received ixekizumab every 4 weeks attained Ankylosing Spondylitis Disease Activity Score (ASDAS) clinically important improvement by week 52, which was sustained through week 156.

A key limitation of the study was the escalation of patients who received ixekizumab every 4 weeks to receiving it every 2 weeks, which was performed strictly at the investigator’s discretion, with no specific or predefined criteria.

The researchers also noted, “Almost 70% of patients in the COAST program remained on [ixekizumab] treatment through 3 years.”

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.