Assessment of the efficacy of pamidronate in ankylosing spondylitis: an open prospective trial.

INTRODUCTION Bisphosphonates have anti-inflammatory properties in arthritic conditions. This study was conducted to assess the therapeutic potential of intravenous pamidronate in nonsteroidal anti-inflammatory drug (NSAID) refractory/intolerant cases of ankylosing spondylitis (AS). METHODS A total of 35 NSAID refractory/intolerant AS patients with Bath AS Disease Activity Index (BASDAI) score 4 or above were recruited for the study. Monthly pamidronate infusions (60 mg) were administered to the patients for six months. Treatment outcomes were assessed by comparing baseline values with the values after six infusions using BASDAI, Bath AS Functional Index (BASFI), Metrology Index (BASMI) and Global Score (BAS-G), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). An improvement was defined according to the Assessments in Ankylosing Spondylitis (ASAS)-20 and BASDAI-50. RESULTS 26 patients received all the six infusions. Of these, 22 (85 percent) achieved ASAS-20 and 20 (77 percent) achieved BASDAI-50 responses. Decrements were noted in the mean BASDAI (56.4 percent), BASFI (52.66 percent), BASMI (55.72 percent), BAS-G (66.71 percent), ESR (52.12 percent) and CRP (72.84 percent) after six months. The tender and swollen joint counts of 14 (54 percent) patients with peripheral arthritis were respectively reduced to a mean value of 0.85 and nil, from the baseline of 2.57 and 1.2. Early feel good response was noted in 16 (62 percent) patients within 48 hours of the first infusion. Fever, arthralgia and myalgia were observed in six cases after the first infusion, and in one case, after the second infusion. These symptoms resolved spontaneously within 24 hours. CONCLUSION Intravenous pamidronate has good efficacy for the treatment of AS.