Phase 3 Trial of Ixekizumab Reports Positive Results

Topline results from the phase 3 COAST-X trial of ixekizumab (Taltz) in patients with non-radiographic axial spondyloarthritis show that the primary and major secondary endpoints were met.

At weeks 16 and 32, the proportion of patients receiving ixekizumab who achieved Assessment of Spondyloarthritis International Society 40 (ASAS40) response was statistically significant compared to placebo, meeting the primary endpoint.

The study evaluated the safety and efficacy of ixekizumab for the treatment of non-radiographic axial spondyloarthritis (nr-axSpA) in patients who have not previously received a biologic disease-modifying anti-rheumatic drug (bDMARD).

"Non-radiographic axSpA is a challenging diagnosis that is not only missed in clinics, but also has limited treatment options for physicians to offer patients," said Atul Deodhar, MD, professor of medicine, Oregon Health & Science University and clinical investigator for the COAST program. "The COAST-X results offer compelling evidence that Taltz could provide a much-needed new alternative if approved for this patient population."

The 52-week study included 305 patients with non-radiographic axial spondyloarthritis who were bDMARD-naïve. Participants were randomized to receive subcutaneously either ixekizumab every 2 weeks (Q2W), ixekizumab every 4 weeks (Q4W) or placebo every 2 weeks.

Ixekizumab demonstrated statistically significant improvement in Ankylosing Spondylitis Disease Activity Score (ASDAS), significant improvement in Bath Ankylosing Spondylitis Disease Activity (BASDAI), proportion of patients achieving low disease activity (ASDAS <2.1), significant improvement in sacroiliac joint inflammation (SIJ) as assessed by MRI (week 16), and significant improvement in 36-Item Short Form Health Survey (SF-36) Physical Component Summary (PCS) Score. These major secondary endpoints were met at 16 and 32 weeks.

The company reported a safety profile consistent with previous phase 3 studies, and no new safety signals were noted during the trial. The most common reported adverse reactions associated with ixekizumab are injection site reactions, upper respiratory tract infections, nausea, and tinea infections.

"We're encouraged by the results of the COAST-X trial, which support our belief that Taltz could become the first IL-17A antagonist to be approved in the US for people with non-radiographic axSpA," said Christi Shaw, president, Lilly Bio-Medicines. "The COAST-X data add to the growing body of evidence from our COAST program, which demonstrates that Taltz may work across the axSpA disease spectrum."

Ixekizumab is currently under regulatory review with the US Food and Drug Administration (FDA) for the treatment of radiographic axSpA, with a decision expected later this year. Based on the COAST-X study results, Eli Lilly and Company intends to apply for an indication for nr-axSpA in 2019.

Ixekizumab is currently approved by the FDA for plaque psoriasis, psoriatic arthritis, and genital area psoriasis.