The effect of zoledronic acid on serum osteoprotegerin in early stage multiple myeloma.

We evaluated the effect of zoledronic acid (ZA) on serum levels of osteoprotegerin (OPG) and the ligand for receptor activator of nuclear factor kappaB (RANKL) in patients with smoldering myeloma. In treated subjects we found an increase of OPG accounting for an effect of ZA on osteoblast and/or bone marrow stromal cells together with the direct effect on osteoclasts.