Bisphosphonates in multiple myeloma.

Bone disease is a frequent manifestation of multiple myeloma, and results in considerable morbidity. In this review we summarise the current theories as to the mechanism of bony destruction in this disease and discuss the interrelationships between the malignant plasma cells and those cells responsible for bone remodelling, i.e. the osteoclasts and osteoblasts. The bisphosphonates are a long established group of drugs known to have inhibitory effects on osteoclast activity, and in common use for osteoporosis and Paget's disease. Their role in myeloma is less clear. Several clinical studies, including phase III randomised placebo controlled trials, have been reported in recent years. Although these have tended to show a benefit for bisphosphonate treatment, we have not yet identified the most appropriate use of these agents. Two of the clinical trials have suggested that bisphosphonates may also have a beneficial effect on the underlying disease, a tantalizing theory which has been supported with some early laboratory data.