Antiinflammatory treatment with bisphosphonates in ankylosing spondylitis

Bisphosphonates are antiosteoclastic agents widely used in the treatment of bone diseases. They also have antiinflammatory properties suggested by a clinical amelioration in animal models of arthritis. Bisphosphonates act on cells from the monocyte/macrophage lineage and may modulate the generation of proinflammatory cytokines. Ankylosing spondylitis is characterized by bone marrow subchondral inflammation with the presence of T cells and macrophages, and osteoporosis is a well known complication of the disease. Thus, bisphosphonates may be reasonably used as a therapeutic agent in ankylosing spondylitis.

Different open trials have shown that the amino bisphosphonate pamidronate ameliorated the clinical symptoms of ankylosing spondylitis, mainly axial disease, and in one study, peripheral arthritis. Laboratory parameters of inflammation were, in general, not influenced while biochemical markers of bone turnover fell significantly under pamidronate. Imaging modifications of the inflammatory lesions using MRI were also improved with pamidronate. A dose-controlled study demonstrated a higher efficacy for 60 mg pamidronate compared with a 10 mg dose.

The amino bisphosphonate pamidronate has shown clinical and radiological amelioration in ankylosing spondylitis patients, although this improvement is mild and transient. Additional studies are required to better define the real impact of pamidronate on ankylosing spondylitis and its place among the different treatment options for the disease.