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Major new insights into the treatment of psoriatic arthritis (PsA) dominated the headlines during the past year, with a head-to-head trial comparing interleukin (IL)-17A inhibition with tumor necrosis factor (TNF) blockade, another study considering whether methotrexate can improve outcomes with anti-TNF therapy in PsA, and an investigation into the effects of biologic therapy on bone.
These brief summaries highlight some of the important stories about PsA that MedPage Today has covered this year.
In an ongoing open-label study comparing ixekizumab (Taltz) with adalimumab (Humira), more patients with PsA who had been randomized to ixekizumab achieved both a 50% improvement on the joint symptom criteria of the American College of Rheumatology (ACR50) plus a 100% clearing on the Psoriasis Area and Severity Index (PASI100; 36% vs 27.9%) at week 24. That represented a treatment difference of 8.1% (95% CI 0.5-15.8, P=0.036) favoring the IL-17A inhibitor ixekizumab. The authors wrote, "Improvements in both joint and skin disease are necessary to achieve optimal improvement in health-related quality of life in patients with PsA, an important indicator of treatment success." The study enrolled 566 patients and is scheduled to continue to 52 weeks.
A second study evaluating IL-17A blockade with secukinumab (Cosentyx) among 177 patients with refractory PsA -- including some who had previously been given multiple courses of biologics -- found rates of remission or low disease activity in almost half by 6 months. A total of 77% had previously tried methotrexate, and two-thirds had previously used at least one other biologic, according to a presentation at the annual congress of the European League Against Rheumatism in Madrid.
In another placebo-controlled study that included more than 200 patients, the monoclonal antibody bimekizumab, which targets IL-17A and 17F, also showed success for both skin and joint outcomes. By week 48, more than 60% of patients showed ACR50 responses and 85% of patients had PASI90 responses, results that were "astonishing," one expert commented following the presentation at the annual meeting of the American College of Rheumatology in Chicago.
Treatment of early PsA with etanercept (Enbrel) was more effective than methotrexate, regardless of whether the biologic was used alone or in combination with methotrexate, which is not approved as a treatment for PsA but is widely used. In a study that included 851 patients from 17 countries, 60.9% of patients receiving etanercept monotherapy had achieved an ACR20 response at week 24, as had 65% of those given the combination, compared with 50.7% of those randomized to methotrexate alone, which were statistically significant differences. In rheumatoid arthritis, the combination therapy has demonstrated clear advantages, but this study found no advantage over the biologic alone.
And in another study, initiation of another TNF inhibitor (golimumab; Simponi) early in the course of PsA led to a doubling of the remission rate at week 22 (81% vs 42%). Unlike in rheumatoid arthritis, where an aggressive, treat-to-target approach has become standard of care, treatment of PsA has continued to rely on the older step-up model, starting with nonsteroidal anti-inflammatory drugs and nonbiologic disease-modifying antirheumatic drugs (DMARDs) such as methotrexate.
An additional benefit of the use of biologics in PsA was the salutary effects on bone. In a cross-sectional study of 165 patients with PsA, higher bone mass and increased bone strength were observed in those receiving biologics compared with those given methotrexate or no DMARDs, despite their having longer disease duration and greater corticosteroid exposure.
In the prospective Cardiovascular in Rheumatology project, 21% of patients with PsA or ankylosing spondylitis had more than one comorbidity such as hypertension, hypercholesterolemia, and obesity. Only among the PsA group, however, was the comorbidity burden independently linked with worse physical function.
Obesity was the subject of another trial that evaluated a short-term, very low energy diet among patients whose baseline body mass index was 35.2. During a period of 6 months, patients receiving a restrictive diet that included 640 kcal/day lost an average 18.6% of their body weight, and disease activity measures improved significantly in those with major weight loss. "The study supports the hypothesis that obesity is involved in the pathophysiology of PsA," the investigators commented.
Additional PsA coverage includes the following: