The usefulness of bone remodelling markers in predicting the efficacy of pamidronate treatment in SAPHO syndrome

Objectives. Pamidronate has recently been used in SAPHO syndrome due to its anti-osteoclastic effect. The aim of this study is to determine the usefulness of bone remodelling markers for determining the efficacy of pamidronate treatment. Methods. Thirteen patients with SAPHO syndrome were treated with pamidronate. The treatment evaluation was done using a visual analogue scale (VAS) and also erythrocyte sedimentation rate, C-reactive protein, serum crosslaps (sCTX) and osteocalcin initially and after 3 months. A relevant clinical response was defined as an improvement in VAS of at least 40%. Results. At 3 months, 7 of 13 patients had a good clinical response, as previously defined. Five of the seven patients maintained the good response over 6 months. Before the first perfusion 6 of the 13 patients had increased sCTX (upper 3250 pmol/l). In this small cohort we tried to analyse whether the increase in bone remodelling markers was associated with a good clinical response. In the responders group the mean levels of sCTX and osteocalcin at baseline were 6783.17 and 24.66, respectively, and in the non-responders group the levels were 2152 and 11.8, respectively. There was a significant difference in sCTX between the responders and the non-responders (P = 0.0044). Conclusion. Infusion of pamidronate is effective in SAPHO in some patients. Increased sCTX might be a prognostic marker for a good clinical response but results have to be confirmed in a larger cohort.