Post-Hoc Analysis of Ustekinumab Efficacy in PsA Patients With Spondylitis

Patients with peripheral arthritis associated with psoriatic arthritis (PsA) and physician-reported spondylitis treated with ustekinumab had significant improvements in axial symptoms, according to research published in Annals of Rheumatic Disease. 

Arthur Kavanaugh, MD, from the University of California-San Diego, and colleagues, performed a post-hoc analysis of a subset of study participants from the P-SUMMIT clinical trials (Phase 3 Multicenter, Randomized, Double-blind, Placebo-controlled Trial of Ustekinumab, a Fully Human Aanti-IL-12/23p40 Monoclonal Antibody, Administered Subcutaneously, in Subjects With Active Psoriatic Arthritis, ClinicalTrials.gov Identifiers: NCT01009086, NCT01077362).

Adult patients with active PsA enrolled in the clinical trial were randomly assigned to receive either ustekinumab 45 mg, ustekinumab 90 mg , or placebo at week 0, week 4, and then every 12 weeks thereafter.  A subset of study participants with physician-diagnosed spondylitis had outcomes tested utilizing the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score C-Reactive Protein (ASDAS-CRP).

After 24 weeks of treatment, more PsA patients with physician-diagnosed spondylitis assigned to receive ustekinumab achieved BASDAI scores of 20 (54.8% vs 32.9%), BASDAI scores of 50 (29.3% vs 11.4%), and BASDAI scores of 70 (15.3% vs 0%) when compared to placebo. Twenty seven percent of study participants with spondylitis in the ustekinumab treatment group achieved mean percentage improvement in ASDAS-CRP scores when compared with placebo (3.9%; P < .001).

“Comparable to the overall study population, significant improvements were also achieved in psoriasis, peripheral arthritis, enthesitis, dactylitis, physical function and peripheral joint radiographs in the spondylitis subset,” the authors found.

Summary and Clinical Applicability

Patients with comorbid active PsA and physician-reported spondylitis treated with ustekinumab had improvements in axial signs and symptoms at 24 weeks post-treatment initiation.

Limitations

Study participants included in the spondylitis group were physician-diagnosed, as baseline axial radiographs were not available for all patients. 

Reference

Kavanaugh A, Puig L, Gottlieb AB, et al. Efficacy and safety of ustekinumab in psoriatic arthritis patients with peripheral arthritis and physician-reported spondylitis: post-hoc analyses from two phase III, multicentre, double-blind, placebo-controlled studies (PSUMMIT-1/PSUMMIT-2). Ann Rheum Dis. 2016; [Epub ahead of print] April 20, 2106 doi: 10.1136/annrheumdis-2015-209068.