Ustekinumab Effective in Treatment of Psoriatic Arthritis With Spondylitis

Ustekinumab, an anti-interleukin (IL)-12 and IL-23 antibody approved for the treatment of psoriatic arthritis, shows significant improvement in patients with psoriatric arthritis who also have spondylitis and peripheral joint involvement, according to results of a post-hoc, subgroup analysis presented at the 2015 Annual Congress of the European League Against Rheumatism (EULAR).

IL-23 is believed to possibly be implicated in spondylitis, explained lead author Arthur Kavanaugh, MD, University of California - San Diego, San Diego, California, speaking here on June 12. Dr. Kavanaugh and colleagues evaluated a subset of patients with spondylitis who were enrolled in phase 3 trial called PSUMMIT-1.

PSUMMIT-1 enrolled 615 adult patients with active psoriatic arthritis despite treatment with disease-modifying anti-rheumatic drugs and/or non-steroidal anti-inflammatory drugs. From this group, Dr. Kavanaugh and colleagues identified 186 subjects (mean age 45.6 years) with spondylitis and peripheral joint involvement as their primary arthritis presentation. These patients included 116 individuals who received dosing of ustekinumab 45 mg or 90 mg at Weeks 0, 4 and 12, and 70 subjects who received placebo.

Patients in the placebo group crossed over to the ustekinumab 45-mg group at Week 24. At that time, greater proportions of patients treated with ustekinumab in both treatment groups demonstrated improvements in dactylitis and enthesitis, as well as the Health Assessment Questionnaire-Disability Index (HAQ-DI) and American College of Rheumatology (ACR20/50/70) responses compared with subjects receiving placebo. These improvements were sustained, in general, through Week 100.

A greater proportion of ustekinumab-treated patients achieved 20% improvement in the Bath Ankylosing Spondylitis Disease Activity Index criteria (BASDAI20) at Week 24 compared with subjects receiving placebo (54.1% vs 26.2%), as well as BASDAI50 (27.9% vs 13.1%), and BASDAI70 (14.4% vs 0.0%).

Among 135 patients with 3% or more body surface-area involvement and spondylitis with peripheral arthritis at baseline, the percentage of patients who achieved a 75% or more reduction in their Psoriasis Area and Severity Index score from baseline (PASI 75) -- were also maintained through Week 100.

Rates of adverse events were similar between the placebo and ustekinumab-treated groups, and safety events were consistent with the overall population of patients with psoriatic arthritis.

Patient characteristics were similar to those of the overall population, but with a psoriatic-arthritis duration of 6.3 years.