Clinical efficacy of oral alendronate in ankylosing spondylitis: a randomised placebo-controlled trial

A prospective, double blind, randomised, placebo controlled trial over 2 years was performed to test the efficacy of alendronate, an oral aminobisphosphonate, in improving symptoms and arrest disease progression in patients with mild to severe ankylosing spondylitis (AS). 180 patients with AS were randomised to receive weekly alendronate 70 mg or placebo (1:1 randomisation). BAS-G was the primary outcome measure with Bath indices as secondary outcomes. Vertebral x-rays were performed at 0 and 24 months. Biomarkers (including CRP, IL-1beta, IL6, VEGF, MMP-1, and MMP-3) were collected during the first 12 months. There was no significant difference between the placebo and treatment groups in any of the recorded outcomes over the 2 years including clinical indices, biomarkers, and radiology. The change in BAS-G, the primary outcome measure, was -0.21 for the treatment group and -0.42 for the placebo group p=0.57. Change in all other clinical outcome measures were also non-significant; BASDAI p=0.86, BASFI p=0.37, BASMI p=0.021. Sub-group analysis of those subjects with a baseline BASDAI >4 were also non-significant. This prospective study demonstrates that alendronate 70mg weekly for 2 years was no more efficacious than placebo in improving clinical or laboratory measures of disease activity or measures of physical impact in subjects with mild to severe active AS. ID SRCTN12308164, registered on 15.12.2015.