June 23, 2010 (Rome, Itlay) — Etanercept achieved significantly more improvement in magnetic resonance imaging (MRI)-detected active inflammatory lesions of the spine than sulfasalazine in patients with early active axial spondyloarthritis (SpA), according to the results of the 48-week randomized controlled ESTHER trial, which were reported here at the European League Against Rheumatism (EULAR) Congress 2010.
"The significant effect of etanercept on inflammation that we saw on MRI had a good correlation with clinical data. No correlation was seen between MRI findings and clinical data for those treated with sulfasalazine," lead author In-Ho Song, MD, from the Department of Rheumatology at Charité University Hospital in Berlin, Germany, told meeting attendees.
The study involved 76 patients with early axial SpA refractory to nonsteroidal anti-inflammatory drugs. They were randomized in a 1:1 ratio to etanercept 25 mg subcutaneously twice weekly or daily oral sulfasalazine 2 to 3 g.
All patients had a disease duration of less than 5 years, a diagnosis of axial SpA, a Bath Ankylosing Spondylitis Disease Activity Index score of 4 or higher, and positive MRI scans for inflammatory lesions at baseline.
Mean age was 33.7 years, mean disease duration was 2.9 months, about 58% were male, and 81.6% were positive for human leukocyte antigen B27. At baseline, 92% of patients had active MRI-detected inflammation in the sacroiliac joint and 41% had it in the spine. Only 5% had such lesions detected in the spine and not in the sacroiliac joints.
Dr. Song reported that in most clinical trials of patients with long-standing ankylosing spondylitis, the percentage of patients with spine inflammation is much higher. In this study of patients with early disease, there was more inflammation in the sacroiliac joints than in the spine. According to Dr. Song, this supports the concept that the disease originates in the sacroiliac joints and spreads to the spine.
At week 48, etanercept reduced the mean sacroiliac joint MRI score from 7.8 at baseline to 2.4; sulfasalazine reduced the mean score from 5.4 at baseline to 3.5. The difference between the 2 groups was significant and in favor of etanercept after adjustment for differences in baseline MRI scores between the 2 groups (P = .003). The highest possible MRI score is 24, Dr. Song noted.
At 48 weeks, etanercept reduced the baseline MRI spine score from 2.3 to 1.4; whereas with sulfasalazine, the score rose from 1.0 to 1.3 (P = .0024).
"At the end of the study, there was nearly no inflammation in patients treated with etanercept; this was not true of those treated with sulfasalazine," Dr. Song told meeting attendees.
Clinical data showed that 50% of the etanercept group was in partial remission by the end of the study, according to Assessment of SpondyloArthritis scores, compared with 19% of the sulfasalazine group. "This is comparable to what is reported with infliximab," Dr. Song said. He also said the MRI evaluation was blinded, but the clinical evaluation was unblinded, and that the study will continue on an open-label basis for 1 year.
Session chair Joachim Sieper, MD, also from the Department of Rheumatology at the Charité University Hospital, said that this study was encouraging for etanercept because of the good correlation between low MRI scores and achievement of partial remission. Dr. Sieper was senior author of the study.
"This is a very interesting study and the first trial to report on the efficacy of etanercept in early axial SpA. It confirms that there is a window of opportunity to achieve higher remission rates in early disease, as has previously been reported with infliximab and adalimumab using clinical and imaging outcomes," said Helena Marzo-Ortega, MD, in an interview with Medscape Rheumatology. Dr. Marzo-Ortega is consultant rheumatologist at United Leeds Teaching Hospitals NHS Trust and honorary senior lecturer at Leeds Institute of Molecular Medicine, University of Leeds, United Kingdom.
She said that the main shortcoming of this study was the lack of a third placebo control group, which would have allowed for the assessment of the effectiveness of sulfasalazine in these patients.
"Looking at the current data, it is clear that patients receiving sulfasalazine achieved a clinical response, although this was not mirrored on the MRI finding," Dr. Marzo-Ortega noted.
The study was funded by a grant from Wyeth Pharmaceuticals. Dr. Song and Dr. Sieper have disclosed no relevant financial relationships. Dr. Marzo-Ortega reports receiving grants, speaker, or advisory fees from Wyeth, Pfizer, Schering-Plough, Abbott, and Centocor.
European League Against Rheumatism (EULAR) Congress 2010: Abstract OP0022. Presented June 18, 2010.
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