Psoriatic arthritis has many faces. Patients may present with various combinations of clinical manifestations, such as arthritis, spondylitis, enthesitis or dactylitis. While enthesitis is considered a key pathophysiologic feature in PsA, it has traditionally been assessed as a secondary outcome in clinical trials evaluating the efficacy of newer agents for active PsA.
Recent data suggest that IL-23 plays an important role in the development of enthesitis, which raises the question whether patients who have a predominantly "entheseal phenotype" would benefit more from medications targeting this pathway. The ECLIPSA study attempts to answer this question and may be the first step in a "personalized medicine" approach in guiding the selection of biologic medications in PsA.
The ECLIPSA study compared the efficacy of treatment with ustekinumab (UST) vs. TNF inhibitors (TNFi) in clearing enthesitis in patients with active PsA.
The study was a prospective randomized-controlled, open-label study. Patients with PsA with active enthesitis were randomized to receive UST (n=23) or TNFi (n=24). Enthesitis was assessed only clinically. The primary outcome was a complete clearance of enthesitis as measured by the SPARCC index after 6 months.
Overall 47 patients were included in the study with a mean SPARCC score at baseline of 4.9. Arthritis measures (tender and swollen joint counts) improved to a similar degree in both treatment arms. In contrast, the improvement in enthesitis score was more significant in the UST group compared with TNFi. In addition, more patients treated with UST also achieved an enthesitis-free state.
This is one of the first clinical trials that assessed enthesitis as a primary outcome in patients with PsA. The study is limited by its small sample size, the lack of blinding for the study drug, and the lack of imaging data to confirm enthesitis. However, it suggests that subphenotypes of PsA may respond differently to various biologic agents. With the growing number of available classes of biologic drugs for PsA, similar studies assessing the efficacy of these drugs in different subphenotypes of PsA are needed.
Dr. Lihi Eder is an Assistant Professor of Medicine at the University of Toronto and Staff Rheumatologist and Director of the Psoriatic Arthritis Research Program at Women’s College Hospital. Dr. Eder is a Scientist at Women’s College Research Institute and associate member of the graduate faculty at the Institute of Medical Science.View Full Bio