Berlin, Germany—The biologic drug ustekinumab (Stelara), which is already approved for use in patients with moderate-to-severe plaque psoriasis, has demonstrated promise in treating psoriatic arthritis, according to data from the late-stage PSUMMIT-1 clinical trial. Lead investigator Iain B. McInnes, MD, PhD, Director of the Institute of Infection, Immunity, and Inflammation at the University of Glasgow, Scotland, discussed these results at the 2012 European League Against Rheumatism Congress.
“There are a number of patients with psoriatic arthritis who do not respond to currently available treatment options, including biologic medicines targeting tumor necrosis factor,” said Dr McInnes. “As physicians, we struggle to manage such people as well as we would like, so the development of this new medicine is a welcome step forward.”
Dr McInnes emphasized that the importance of new treatment options in this setting cannot be understated. Approximately 10% to 15% of patients with psoriasis go on to develop inflammation of the synovium, enthesis, and periosteum, resulting in deforming and debilitating arthritis.
To investigate the use of ustekinumab in patients with psoriatic arthritis, the PSUMMIT-1 investigators recruited 615 patients with the disease who were still experiencing active disease despite treatment
with disease-modifying antirheumatic drugs, including biologics. Patients randomized to 45 mg of ustekinumab, 90 mg of ustekinumab, or to placebo. Treatments were administered at the beginning of the trial, again at week 4, and then every 12 weeks thereafter. Patients in any of the treatment groups were allowed to use concomitant methotrexate as needed.
If no therapeutic response was observed at 16 weeks, patients were allowed to switch to another treatment arm in a blinded fashion.
Results for PSUMMIT-1 showed Results for PSUMMIT-1 showed that both doses of ustekinumab were superior to placebo at 24 weeks,
with significant improvements in ACR20 (American College of Rheumatology criteria 20% response to treatment), ACR50, and the most favorable outcome of ACR70. An ACR50 response was seen in 24.9% of patients receiving the 45-mg dose and in 27.9% of patients receiving 90 mg of ustekinumab compared with 8.7% of those given placebo. ACR70 responses were seen in 12.2% and 14.2% for the 45-mg and 90-mg ustekinumab groups, respectively, compared with 2.4% of patients in the placebo group.
For skin involvement—a condition that precedes joint disease in patients with psoriatic arthritis, often by years—patients in the active-treatment arms experienced a 57.2% and a 62.4% improvement in Psoriasis Area and Severity Index (PASI) scores for 45 mg and 90 mg of ustekinumab, respectively.
“The improvement in Psoriasis Area and Severity Index was expected,” said Dr McInnes, “because ustekinumab is already licensed and in clinical use for psoriasis. The real test in this trial was whether the treatment also worked in the joints, and the answer, at least in comparison with placebo, was that it does.”
Through week 16, the proportion of patients experiencing ≥1 adverse events was similar between all treatment groups, with infection being the most common side effect (>2%). No malignancies, serious infections, tuberculosis, opportunistic infections, or deaths occurred during the course of the trial.
“These results highlight not only ustekinumab’s efficacy, but also its promising safety profile. We look forward now to seeing how it compares in trials with standard treatments.”—NC