Alendronate to Treat Polyostotic Fibrous Dysplasia and McCune-Albright Syndrome

Polyostotic fibrous dysplasia (PFD) is a sporadic disorder which affects multiple sites in the skeleton. The bone at these sites is rapidly resorbed and replaced by abnormal fibrous tissue and mechanically abnormal bone. PFD may occur alone or as part of the McCune-Albright Syndrome (MAS), a syndrome originally defined by the triad of PFD, cafe-au-lait pigmentation of the skin, and precocious puberty. The bony lesions are frequently disfiguring and painful, and depending on the location of the lesion, they can cause significant morbidity. Lesions in weight-bearing bones can lead to disabling fractures, while lesions in the skull can lead to compression of vital structures such as cranial nerves. Currently there are no clearly-defined systemic therapies for this bone disease. Small, uncontrolled trials using the second generation bisphosphonate, pamidronate, suggest that bisphosphonates may be effective. This study is a phase 2, controlled, double blinded trial of the third generation oral bisphosphonate, alendronate for the treatment of fibrous dysplasia. We propose to show that treatment with alendronate will improve bone quality, decrease bone pain, decrease fractures, and, if the patient is referred to the companion bone grafting protocol, will allow for the regeneration of better quality bone.