DEnosumab for the Treatment of FIbrous Dysplasia/McCune-Albright Syndrome in Adults (DeFiD)

Fibrous Dysplasia/McCune-Albright syndrome (FD/MAS) is a rare disease, consisting of the replacement of normal bone tissue with fibrous tissue. FD lesions may be isolated in one or more bones or may be associated with endocrinopathies in McCune-Albright syndrome. Bone lesions constitute of weak bone tissue, leading to higher risk of fractures, pain and decreased quality of life. There is no cure for FD lesions and current therapies failed to soothe patients' complaints or to display any effect on progression of the lesions on imaging. However, the RANKL-inhibitor Denosumab demonstrated encouraging results in mouse models and in off-label clinical use, leading to clinical, biochemical and radiographical improvements.

Study's aim is to investigate whether 3-monthly Denosumab will improve the clinical, radiological and biochemical manifestations of FD bone lesions.