Objective: The objective of this study was to evaluate if the anti-inflammatory properties of bisphosphonates and their effect on bone turnover could be useful in the treatment of AS.
Methods: Sixty patients were consecutively assigned in a 1:1 ratio in a 6-month open-label, single-centre study on active AS to receive monthly i.v. neridronate (100 mg) or standard infliximab (5 mg/kg) therapy.
Results: A significant reduction in the mean BASDAI was observed over 6 months of either neridronate (-1.72) or infliximab (-1.62) administration. The BASFI decreased significantly at 3 and 6 months in the neridronate arm, while in the infliximab group a significant reduction at 3 months but not 6 months was observed. The 10-cm visual analogue scale for axial pain decreased significantly and comparably at 3 and 6 months in both groups. No significant differences between treatment arms for all these changes were observed at both 3 months and the final assessment. The BASMI was not significantly modified in the neridronate or infliximab group. No significant variations of BMD were observed in the infliximab group, while in patients treated with neridronate a significant increase was observed at the lumbar spine.
Conclusion: High i.v. doses of the amino-bisphosphonate neridronate are as effective as infliximab therapy in reducing disease activity in AS patients, with additional benefits on BMD changes. Further studies to confirm these results over a longer time frame are warranted together with the possibility to explore the long-term efficacy of a combination of lower anti-TNF doses with bisphosphonates.
Keywords: ankylosing spondylitis; bisphosphonates; infliximab; neridronate.