Evidence for AS structural control needs confirmation
Long-term anti–tumor necrosis factor therapy seemed to slow progression of sacroiliac joint damage in early axial spondyloarthritis in a German study of 42 patients.
Dr. Valeria Rios-Rodríguez
They were all part of the ESTHER trial, which found that in early axial spondyloarthritis (axSpA), active inflammatory lesions on MRI improved significantly more with etanercept (Enbrel) than with sulfasalazine-treated patients (Ann Rheum Dis. 2011 Apr 1;70[4]:590-6).
In the new work, published in the Arthritis & Rheumatology, investigators reviewed 42 ESTHER subjects who were on etanercept for up to 6 years and who also had baseline and at least one bilateral sacroiliac joint (SIJ) x-ray at 2-, 4-, or 6-year follow-up. Two blinded readers scored the x-rays, and a sacroiliitis sum score was assigned to each subject. The sum score ranged from 0, meaning no signs of sacroiliitis, to 8, meaning total ankylosis of both SIJs.
The mean progression in sacroiliitis sum score was 0.13 points from baseline to 2 years; followed by a regression of –0.27 points during years 2-4, and –0.09 points from years 4-6. There was no comparator group of untreated patients, but the authors noted that previous work would suggest a slight, but detectable, progression in joint damage over that time.
Elevated C-reactive protein and the presence of osteitis on MRI, meanwhile, were independently associated with progression.
“This is the first study to analyze the long-term (up to 6 years) progression of radiographic sacroiliitis in patients with axSpA treated with an anti-TNF agent, in this case with etanercept. Our results suggest that long-term treatment with a potent anti-inflammatory drug like a TNF inhibitor may influence the evolution of the disease by decelerating the radiographic progression of SIJ [damage] in patients with” early axSpA, wrote the investigators, led by Valeria Rios Rodriguez, MD, of the Charité Universitätsmedizin, Berlin.
Progression from nonradiographic to radiographic axSpA occurred only in the first 2 years of treatment, among 5 of 27 patients, while 2 of 15 patients who started with radiographic disease regressed to nonradiographic axSpA, yielding a net progression of 7.1%.
Although that’s higher than what’s been reported in previous studies, it might be related to greater inflammation in the SIJ at baseline in ESTHER, since active osteitis on MRI was an inclusion criteria. Also, “treatment with a TNF inhibitor ... might have triggered a faster bone repair visible on x-rays as a progression of structural damage,” the investigators said.
The results seem “congruent with the retardation of the spine progression seen in [ankylosing spondylitis] patients treated long-term with TNF inhibitors. ... Long-term treatment with TNF inhibitors could reduce ... new bone formation by preventing the development of new inflammatory lesions resulting in structural damage” of the SIJ, they said, which, in turn, “might have an impact on the functional status and spinal mobility in patients with axSpA, independently of structural damage of the spine.”
Two-thirds of the trial participants were men; the mean age was 34 years, and mean duration of symptoms 3.1 years at baseline. No information was reported on adverse events.
The work was funded by Pfizer, a marketer of etanercept. Some of the investigators disclosed consulting and other payments from the company, as well as other companies involved in marketing and/or development of drugs for axSpA. One investigator was an employee of Pfizer.
SOURCE: Rios Rodriguez V et al. Arthritis Rheumatol. 2019 Jan 9. doi: 10.1002/art.40786