Bisphosphonates as anti-inflammatory agents in ankylosing spondylitis and spondylarthropathies

NSAIDs remain the cornerstone of the treatment of ankylosing spondylitis (AS) and spondylarthropathies (SpA), and have been successfully used for a long time in these diseases. However, some patients remain refractory or intolerant to NSAIDs and new effective treatments have recently emerged, namely TNF-alpha-blocker agents. Other therapeutic options targeting the bone, such as bisphosphonates, have also been tried in refractory AS or SpA patients. The anti-inflammatory properties of bisphosphonates give the rationale for the use of these compounds in AS and SpA, and include the inhibition of antigen presenting cells, the modulation of pro-inflammatory cytokine generation, and also a decreased bone mass in AS. Open trials using pamidronate gave favourable results, and one controlled study comparing the efficacy of pamidronate 10 versus 60mg showed that the 60mg dose was effective in AS. Further studies are required to confirm these preliminary data and to better determine the optimal regimen (dosage and rhythm) of administration.