Pulse Pamidronate therapy in NSAID refractory ankylosing spondylitis. Is it effective?–An open label study

ObjectiveTo assess the efficacy of pulse Pamidronate therapy in NSAID refractory ankylosing spondylitis (AS).PatientsFifty two patients of ankylosing spondylitis (fulfilling modified New York criteria), refractory to NSAID and having active disease were enrolled. Active disease was defined as BASDAI = 4 and/or early morning stiffness = 45 minutes despite NSAID therapy.InterventionMonthly intravenous Pamidronate infusions (60 mg) for a period of 6 months along with current NSAID. Primary outcome measure was improvement in BASDAI at the end of therapy. Secondary outcome measures included improvement in BASDAI = 25%, BASFI, metrology parameters, visual analogue scales for pain and global assessment of disease, ESR, CRP, MMP-3 and quality of life domains.ResultsOut of 52 patients enrolled [47 men; mean age 36.2 years (range 22-53 years) and mean disease duration 7.2 years (3-25 years)], 47 patients completed the study. At 6 months, there were significant improvement in BASDAI (P < 0.005), BASFI (P < 0.005), pain (P < 0.005) and patient global assessment of disease (P < 0.005) and lateral flexion (P<0.05). However, BASDAI >25% reduction was seen in 29.6% patients only. In addition, quality of life, HAQ and serological markers MMP-3, ESR and CRP were not significantly altered. Most common adverse effects included arthralgias and myalgias, 22.5% each, following initial infusions. There were five withdrawals; two defaults and one for hip joint replacement and two for asymptomatic rise in serum creatinine.ConclusionPamidronate has modest efficacy in improving the patient reported outcome variables in NSAID refractory AS.