Clinical trials of bisphosphonates in multiple myeloma.

More than 80% of patients with multiple myeloma (MM) have osteolytic bone disease, which increases the risk of skeletal-related events (SREs) such as pathologic fracture, spinal cord compression, and the need for radiotherapy or surgery. Bone disease is primarily due to increased osteoclastic activity and impaired osteoblast activity. Bisphosphonates are pyrophosphate analogues with high bone affinity that can inhibit osteoclastic activity. Pamidronate and zoledronic acid are the most commonly used bisphosphonates in multiple myeloma. Other agents include ibandronate and clodronate. Bisphosphonates are associated with several adverse events, such as renal toxicity and osteonecrosis of the jaw. The optimal duration of bisphosphonate therapy has yet to be determined. Clinical trials are investigating tailored approaches to management based on treatment-related changes in levels of bone resorption markers.