September 01, 2014
By Will Boggs MD
NEW YORK - Very few patients with early axial spondyloarthritis (axSpA) who take etanercept continuously for three years develop new osteitis on MRI, according to data from the ESTHER trial.
Several clinical studies have demonstrated significant reductions in active inflammation on MRI of the spine and/or sacroiliac joints after TNF-alpha inhibitor treatment. But there are few data about the course of fluctuating MRI inflammation in patients with axSpA, researchers write in Rheumatology, online August 19.
Dr. Joachim Sieper from Charite Medical University, Berlin, Germany and colleagues provide data on the course of osteitis on MRI of the SI joints in a long-term study of 61 patients.
MRI results were available for 41 patients for all three assessments (baseline, two years and three years), according to the Pfizer-sponsored study.
During treatment, the mean MRI SI joint score decreased from 7.1 at baseline to 2.0 at year 2 and 2.2 at year 3, while the MRI osteitis spine score decreased from 1.7 at baseline to 0.7 at year 2 and 0.9 at year 3.
Inflammation disappeared from 68 (47.2%) of the 144 SI joint quadrants at year 2 and from 56 (38.9%) of 144 quadrants at both year 2 and year 3, the researcher say.
Similarly, osteitis resolved in 25 (62.5%) of 40 vertebral units at year 2 and in 20 (50%) of 40 vertebral units at both year 2 and year 3.
Even in the joints where inflammation persisted, MRI joint scores decreased from baseline to year 2 and year 3.
Five (3.8%) of 131 SI joint quadrants developed new osteitis at year 2, and 2 (1.5%) of 131 developed new osteitis at both year 2 and year 3. Seven (0.8%) of 862 vertebral units developed new osteitis at year 2, and 3 (0.4%) of 862 developed new osteitis at both year 2 and year 3.
"Our data clearly show that there is a consistently small amount of osteitis on MRI of the SI joints and spine in patients with early axSpA compared with baseline values and only a very low rate of new-onset osteitis during 3 years of continuous treatment with etanercept," the researchers conclude.
"It has been proposed that bony inflammation precedes structural damage in axSpA, including new bone formation, and that effective and consistent suppression of inflammation is mandatory in preventing new bone formation," they explain. "If the proposed sequence of events is true, this should result in a reduction in new bone formation during TNF blocker therapy over time, which has to be shown by longer follow-ups in the current and other cohorts."
Two of the authors are Pfizer employees, and six others reported various ties to the company.
Dr. Sieper did not respond to a request for comments.
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