ACR2012 Highlights: Ankylosing Spondylitis

In reports to the American College of Rheumatology meeting in Washington last month, there were reports on a phase III trial of a new treatment, studies showing failed and useful measures for severity analysis and diagnosis, and a new study on risk of fractures. (Click on the abstract numbers to read the abstract of the presentation online.)

•   Certolizumab pegol, a monoclonal antibody to TNF, reduced signs and symptoms of axial spondyloarthritis, including spinal mobility. The RAPID-axSpA phase III trial is following 325 patients for 158 weeks, and was placebo-controlled for 24 weeks. By week 12, 63.6% of higher-dose certolizumab patients, vs. 38.3% placebo, had a response of ASAS20 (the primary endpoint). By week 24, the response was 70.1% vs. 29.0%, respectively. ASAS40 and partial remission rates were also higher with certolizumab. Improvements were confirmed by MRI at baseline and week 12. Response was similar in ankylosing spondylitis and non-radiographic axial spondyloarthritis. Serious infections occurred in 1.1% of certolizumab patients, but no deaths, TB or cancers. (Abstracts #777  and #1705)

•  After axial spondyloarthritis has been diagnosed with MRI of the sacroiliac joints, an additional MRI of the spine has little value.  After 130 consecutive patients with back pain were assigned by clinical examination and pelvic radiology as either non-radiographic axial spondyloarthritis, ankylosing spondylitis,, or mechanical back pain, they and 20 healthy controls were given sacroiliac joint and spinal MRIs. Three blinded readers assessed the sacroiliac joint MRI alone, the spinal MRI alone, and both together. Only two (4%) of the patients who were negative on sacroiliac joint MRI were reclassified as non-radiographic axial spondyloarthritis with the addition of spinal MRI, but three (15%) of healthy controls were rated as having spondyloarthritis based on spinal MRI scan alone. (Abstract #778)

•  Patients with ankylosing spondylitis are at 18% higher risk of osteoporotic fracture related to oral corticosteroids, and at almost twice the risk of clinical spine fractures. The Spanish SIDIAP database contains anonymized medical and pharmacy records of more than 4.9 million people (80% of the population). A European group identified 6,474 patients 15 years or older who had a diagnosis of ankylosing spondylitis, as well as 32,346 controls, and followed them for a median of six years. Osteoporotic and clinical spine fracture rates per 1,000 person-years were 9.64 and 2.12, respectively, among ankylosing spondylitis patients, compared to 8.05 and 1.05 among controls. (Abstract #781)

•  Elevated vascular endothelial growth factor (VEGF) is highly predictive of new syndesmophyte formation in ankylosing spondylitis. Fifty-four patients from the German Spondyloarthritis Inception Cohort had plain X-rays and serum VEGF levels taken at baseline and after two years. At baseline, syndesmophytes were present in 25 patients, and after two years they were present in six more. Baseline VEGF was significantly higher (544 vs. 296 pg/ml) in patients who developed new syndesmophytes. A threshold of 500 pg/ml predicted radiographic progression with sensitivity of 83% and specificity of 92%. (Abstract #2496)