Evidence for the beneficial effects of bisphosphonates on bone resorption in multiple myeloma has been reported extensively, showing reductions in skeletal events and improvement of several biochemical variables in bone resorption. Zoledronic acid (Zometa®, CGP42446) is the most potent clinically available bisphosphonates, with the largest therapeutic ratio between the desired inhibition of calcium resorption and the unwanted inhibition of mineralization in vitro of all the bisphosphonates.