As Biosimilar Adalimumab Gains Ground in Europe, Ixekizumab Shows Superiority to Humira in PsA

Eli Lilly and Company have announced findings from the phase 3b/4 SPIRIT trial, a head-to-head comparison of ixekizumab (Taltz) and adalimumab (Humira) in patients with psoriatic arthritis (PsA).

The study met its primary end point of superiority of ixekizumab to adalimumab in the proportion of patients who achieved American College of Rheumatology criteria for 50% improvement (ACR50) and complete skin clearance as measured by the Psoriasis Area and Severity Index (PASI 100).

The assessor-blinded, randomized controlled trial in 566 patients (234 of whom were randomized to receive ixekizumab and 231 of whom were randomized to receive adalimumab) was the first head-to-head study to use on-label dosing for both agents and to allow for concomitant treatment with conventional disease-modifying antirheumatic drugs. Patients received their assigned treatment for 52 weeks, with the primary analysis taking place at week 24.

At week 24, the proportion of patients who had achieved both ACR50 and PASI 100 was 36% in the ixekizumab arm versus 28% in the adalimumab arm (P <.05). The trial also met key secondary end points, including noninferiority of ixekizumab to adalimumab in the percentage of patients achieving ACR50 and superiority to adalimumab in the percentage of patients achieving PASI 100.

The safety profile of ixekizumab was also consistent with previously reported data, with the most commonly reported adverse events being infections, injection-site reactions, hypersensitivity reactions, and cerebrocardiovascular events. No new safety signals were detected.

In a statement, Philip Mease, MD, Swedish Medical Center, Providence St. Joseph Health, and the University of Washington, said that “head-to-head data like these are significant and help inform treatment decisions. This study underscores that Taltz is an important option for healthcare providers to consider for their patients."

These results showing that ixekizumab has outperformed the once-dominant Humira come as biosimilars of adalimumab have gained significant ground in the European context. Since their arrival in the marketplace in October 2018, biosimilar adalimumab options have secured a majority of the market share in a number of nations through national tenders.

Given the head-to-head data from the SPIRIT trial, Humira maker AbbVie may face even further challenges in trying to maintain its sales as newer products like ixekizumab advance in such therapeutic areas as PsA.