Adalimumab Improves Symptoms of Axial Spondyloarthritis

Alice Goodman

November 10, 2011

November 10, 2011 (Chicago, Illinois) — Adalimumab significantly improved signs and symptoms of axial spondyloarthritis in patients without classic radiographic criteria, according to results of the ABILITY-1 phase 3 study reported here at the American College of Rheumatology (ACR) 2011 Annual Meeting.

More than one third of patients treated with adalimumab had at least 40% improvement on the standard Assessments in Ankylosing Spondylitis (ASAS40) measure compared with 14.9% of placebo recipients (P < .001).

"We showed that on standard measures, 36% of patients achieved a good response at week 12," said study coauthor Philip Mease, MD, director of rheumatology research at the Swedish Medical Center and clinical professor at the University of Washington, Seattle. "This study suggests that we need to treat these patients early before they develop radiographic evidence of disease, and we need to keep in mind that there are some axial spondyloarthritis patients who will remain in a chronic inflammatory state for years and not develop radiographic evidence."

Classic axial spondyloarthritis diagnostic criteria, developed in 1984, required radiographic evidence of sacroiliac damage. Over the years, it has become clear that many patients with axial spondyloarthritis may have symptoms without evidence of sacroiliac damage for up to 10 years. These patients may have significant pain and disability, and may be underdiagnosed and undertreated, Dr. Mease said. New criteria developed by the ASAS international working group include patients with magnetic resonance imaging (MRI) evidence of edema long before structural damage appears, with at least 1 clinical symptom of axial spondyloarthritis or a positive HLA-B27 test result and at least 2 clinical features of axial spondyloarthritis.

In ABILITY-1, 192 patients who fulfilled the new ASAS criteria for nonradiographic axial spondyloarthritis were randomly assigned to receive adalimumab, 40 mg, every other week or placebo for 12 weeks, followed by a 92-week open-label extension phase.

Positive MRI criteria fulfilling ASAS imaging criteria were present in 51% of the adalimumab group and 46% of the placebo group. The remaining patients in each group fulfilled the ASAS clinical criteria (positive HLA-B27 test result and at least 2 clinical features of the disease).

Joachim Siefer, MD, a rheumatologist at Charité Universitätsmedizin, Berlin, Germany, presented 12-week outcome data from ABILITY-1 here at ACR 2011.

The primary endpoint (ASAS40 at 12 weeks) and the clinical and imaging endpoints were significantly in favor of adalimumab. At least a 50% improvement on the Bath Ankylosing Spondylitis Disease Activity Index was reported in 35.2% of the adalimumab group vs 14.9% of the placebo group (P = .001). ASAS inactive disease was observed in 24% and 4.3% of the 2 groups, respectively (P < .001).

In an interview with Medscape Medical News, Dr. Mease said a subgroup analysis identified factors that predicted achievement of ASAS40: age younger than 40 years, symptom duration of less than 5 years, and elevated C-reactive protein level.

He noted that axial spondyloarthritis expresses itself in a slightly different way in women, who have less proclivity for radiographic evidence and may just present with back pain that shows inflammation on MRI or signs of elevated C-reactive protein.

"This study suggests that treatment should be initiated earlier and in a broader range of patients with axial spondyloarthritis [those with no radiographic evidence of disease]. Some of these patients have been hiding in the bushes," Dr. Mease stated. "Axial spondyloarthritis can occur at a relatively young age and be very aggressive, especially in males. In my career, the only 2 suicides I've seen were in young males diagnosed in their early 30s with axial spondyloarthritis."

"This is the first large randomized trial to show in population of axial spondyloarthritis patients with no x-ray changes but symptoms of inflammatory back pain that the response to adalimumab is equivalent to that seen in patients who do have x-ray evidence. All TNF [tumor necrosis factor]-inhibitors have the same magnitude of response in patients with axial spondyloarthritis who have x-ray changes," said Eric Ruderman, MD, professor of medicine at Northwestern University Feinberg School of Medicine in Chicago, Illinois.

"Axial spondyloarthritis is a challenging disease and patients can be miserable due to their symptoms. I can see dramatic relief with treatment with a TNF inhibitor. This is a registry trial and the data can now be submitted to the FDA [Food and Drug Administration] as part of the company's labeling. If the drug is approved for this indication, I will be able to use it in axial spondyloarthritis patients without having to provide evidence of x-ray damage for [insurance] coverage," Dr. Ruderman commented.

Dr. Sieper receives financial support from Abbott, Merck, Pfizer, UCB. Dr. Mease receives financial support from Abbott, Amgen, Bristol-Myers Squibb, Novartis, Centocor, Genentech, Biogen IDEC, Lilly, and Pfizer. Dr. Ruderman receives financial support from Abbott, Amgen, Bristol-Myers Squibb, Pfizer, Genentech, UCB, and CVS CareMark.

American College of Rheumatology 2011 Annual Meeting; Abstract #2486A. Presented on November 8, 2011.

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