ROME -- Patients with psoriatic arthritis who also have axial involvement experienced significant benefits with treatment with ustekinumab (Stelara), a post-hoc analysis of three randomized trials found.
On the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) at week 24, the percentages of patients receiving ustekinumab in doses of 45 mg or 90 mg who had a 20% improvement in spinal symptoms were 49% and 58.3%, respectively, compared with 26.2% of those receiving placebo, reported Arthur Kavanaugh, MD, of the University of California San Diego.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
And the percentages who had a 50% improvement on the BASDAI at that time point were 23.5% and 31.7% for the 45-mg and 90-mg groups, respectively, compared with 13.1% of the placebo patients, he said at the European League Against Rheumatism annual meeting.
About one-third of patients who have psoriatic arthritis also have spondyloarthritis along with their typical skin symptoms and peripheral arthritis.
"Ustekinumab is a monoclonal antibody that targets the interleukin (IL)-12/23 pathways. In addition to an established role in psoriasis and an increasing role in psoriatic arthritis, recent data have suggested that IL-23 also may be involved in the pathogenesis of spondyloarthritis," Kavanaugh said.
To explore the possibility that blocking this cytokine pathway might benefit the subgroup of patients with psoriatic arthritis plus spine inflammation, he and his colleagues analyzed data from the three PSUMMIT studies, identifying 186 out of 615 patients with physician-diagnosed inflammatory back pain.
Patients' mean age was 45, and all had active peripheral arthritis at baseline. Patient characteristics at baseline were similar to those in the overall patient cohorts. Those with previous exposure to anti-TNF therapies were excluded, but methotrexate was permitted.
Ustekinumab or placebo was given at days zero and 14, and then every 12 weeks through week 100. Those who had less than a 5% reduction in tender and swollen joints were allowed rescue at week 16, and all patients were switched to the active treatment at week 24.
Along with improvements in BASDAI, patients receiving the active treatment also had greater responses for enthesitis/dactylitis, skin scores, and radiographic changes.
For instance, at week 24, the change in enthesitis score from baseline in the combined ustekinumab groups was -46.14 compared with -5.81 in the placebo group (P=0.009). At week 24, the percentage of patients in the combined ustekinumab groups who had achieved a 75% reduction in skin scores was 66.3% compared with 11.5% in the placebo group (P<0.001).
And by week 100, the change in radiographic scores among patients who initially had been randomized to placebo and subsequently switched to the 45-mg dose was 4.28 compared with 1.45 in the combined ustekinumab groups.
"This was quite an impressive difference in skin response between the placebo and active treatment groups, and the improvement was maintained through 2 years," Kavanaugh said.
As to safety, there were very few major cardiac events or infections, and the treatment was tolerated quite well overall, he said.
"These data suggest that IL-23 may have a role in the immunopathogenesis of spondyloarthritis and that there may be a potential therapeutic role for IL-23 inhibition," he concluded.
A limitation of the study was that the axial involvement was diagnosed clinically, not with imaging.
Disclosures
The PSUMMIT studies were sponsored by Janssen.
Kavanaugh and the co-authors disclosed relevant relationships with Janssen and a number of other companies.
Primary Source
European League Against Rheumatism
Source Reference: Kavanaugh A, et al "Efficacy and safety of ustekinumab in psoriatic arthritis patients with spondylitis and peripheral joint involvement: results from a phase 3, multicenter, double-blind, placebo-controlled study" EULAR 2015; Abstract OP174.