Objective: To compare the efficacy of adalimumab versus placebo in reducing spinal and sacroiliac (SI) joint inflammation, by magnetic resonance imaging (MRI) in patients with active ankylosing spondylitis (AS).
Methods: This was a randomized, multicenter, double-blind, placebo-controlled study. Patients (n = 82) received 40 mg adalimumab or placebo every other week during an initial 24-week double-blind period. MRIs of both the spine and SI joints were obtained at baseline, week 12, and week 52. Spinal and SI joint inflammation were measured using the Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index.
Results: The spine SPARCC score in placebo-treated patients increased by a mean of 9.4% from baseline, compared with a mean decrease of 53.6% in adalimumab-treated patients (P < 0.001); the SI joint SPARCC score decreased by a mean of 12.7% from baseline in placebo-treated patients and by 52.9% in adalimumab-treated patients (P = 0.017). The response in adalimumab-treated patients was maintained at week 52. Placebo-treated patients were switched to open-label adalimumab treatment at week 24 and experienced similar reductions in spinal and SI joint inflammation by week 52. Similar large reductions in the spine and SI joint SPARCC scores were noted, even in patients who failed to meet the ASsessment in Ankylosing Spondylitis (International Working Group) criteria (nonresponders) at 12 weeks. In adalimumab-treated patients, a reduced C-reactive protein concentration at week 12 was significantly associated with improvement in the spine SPARCC score (P = 0.018).
Conclusion: Adalimumab significantly reduced both spinal and SI joint inflammation in patients with active AS after 12 weeks of treatment, and these improvements were maintained for up to 52 weeks.
Trial registration: ClinicalTrials.gov NCT00195819.