WASHINGTON, DC — Treatment of psoriatic arthritis (PsA) with ixekizumab (IXE)—an IgG4 monoclonal antibody—significantly improves arthritis, dactylitis and enthesitis at 52-weeks, according to research presented at the 2016 American College of Rheumatology Annual Meeting.
Philip J Mease, MD, at the Swedish Medical Center and the University of Washington, and colleagues conducted a phase 3 study (A Study of Ixekizumab in Participants With Active Psoriatic Arthritis SPIRIT P1, ClinicalTrials.gov NCT01695239) to evaluate the efficacy and safety IXE use over 52 weeks in patients with active PsA.
The trial enrolled 417 biologic disease-modifying antirheumatic drug (bDMARD)-naïve patients with active PsA. During the double-blind treatment period (weeks 0-24), patients received either IXE 80 mg once every 4 weeks or once every 2 weeks, including a 160 mg loading dose; 40 mg adalimumab (ADA); or placebo.
At the conclusion of the double-blind treatment period, 381 participants were eligible to enter the extension period (weeks 24-52), and were assigned to receive either 80 mg IXE once every 4 weeks or once every 2 weeks.
Primary efficacy measures included American College of Rheumatology 20/50/70 Indices, Health Assessment Questionnaire-Disability Index (HAQ-DI) Score, Disease Activity Score 28 diarthrodal joint count based on C-reactive protein (DAS 28-CRP), Psoriasis Area and Severity Index 75, 90, 100 (PASI 75/90/100), Leeds Enthesitis Index (LEI), and Leeds Dactylitis Index-Basic (LDI-B).
In total, 304 patients completed the extension period. Researchers observed improvements from baseline in all primary efficacy measures at week 52, with a similar rate of adverse events as occurred during the double-blind treatment period. Twelve patients experience serious adverse events, but no deaths occurred among the extension period population.
“IXE demonstrated a clinically significant improvement in signs and symptoms of PsA including arthritis, dactylitis, and enthesitis, as well as skin manifestations across treatment groups in the [extension period],” the researchers concluded.
“The safety profile of IXE observed in the [extension period] was similar to that observed in the [double-blind treatment period] and other phase 3 studies of IXE in patients with plaque psoriasis.”
Mease PJ, Okada M, Kishimoto M, et al. Efficacy and safety of ixekizumab in patients with active psoriatic arthritis: 52 week results from a phase 3 study. Presented at: 2016 ACR/ARHP Annual Meeting; November 11-16, 2016; Washington, D.C. Abstract no. 959.