Ixekizumab Shows Promise Treating Psoriatic Arthritis

The IL-17 inhibitor reduced the number of tender and swollen joints in at least 20% of patients with PsA.

In a pivotal phase 3 clinical trial, patients with psoriatic arthritis (PsA) who did not gain long-lasting benefit from standard of care treatments experienced a reduction in symptoms, including joint tenderness and swelling, after receiving treatment with ixekizumab (Taltz).

Ixekizumab is an injectable monoclonal antibody designed to block interleukin-17 (IL-17). It received FDA approval in March 2016 to treat adults with moderate to severe plaque psoriasis.

The randomized, double-blind, placebo-controlled SPIRIT-P2 trial was conducted at 109 centers in 10 countries. Included in the study were 314 adults with PsA, for whom available biological drugs lost their efficacy or were unsuccessful to begin with.

For a 24-week period, 109 patients received regular injections of ixekizumab every 2 weeks, 94 received a placebo every 2 weeks, and 111 alternated every 2 weeks between receiving injections of ixekizumab and placebo.

The results of the study, published in The Lancet, showed that more than 50% of patients in the ixekizumab arm experienced at least a 20% reduction in the number of tender and swollen joints. Ixekizumab significantly outperformed the placebo arm, according to the authors.

Psoriatic arthritis is an inflammatory autoimmune disease that causes stiffness, pain, and swelling of joints. The disease typically emerges between the ages of 30 and 50 years.

Three of the top 10 selling drugs in the United States—–in dollar sales––are biologics to treat psoriatic arthritis and the more common rheumatoid arthritis. Adalimumab, etanercept, and infliximab are designed to block the tumor necrosis factor (TNF), which stimulates the immune response and inflammation.

Despite this, TNF inibitor medications are not as successful in patients with psoriatic arthritis.

“Only about half of psoriatic arthritis patients who are given TNF inhibitors get better,” said senior author Mark Genovese, MD.

Although the cause of the disease remains unknown, researchers believe ixekizumab has potential.

In an earlier phase 3 trial, ixekizumab demonstrated efficacy for patients with PsA who had not received prior treatment with TNF inhibitors.