Monoclonal antibody anti-sclerostin for treatment of pelvic insufficiency fractures in adult hypophosphatasia: A case report

Hypophosphatasia is a rare inherited metabolic disease leading to inhibition of bone and teeth mineralization that can be complicated by multiple insufficiency fractures. Treatment is currently limited to enzyme replacement therapy using bone-targeting recombinant human alkaline phosphatase, or asfotase alfa. Romosozumab is a monoclonal anti-sclerostin antibody originally indicated for the treatment of osteoporosis in postmenopausal women with high-risk of fracture. Recently its indication had been expanded to other metabolic bone disorders such as osteogenesis imperfecta. We report a unique case of a 67-yer-old female with hypophosphatasia complicated by multiple delayed-union and nonunion insufficiency fractures of the pelvis. After 12-month therapy with Romosozumab to address her osteoporosis, the patient healed her fractures and increased her bone mass density. Our case report shows interesting effects of Romozumab in an adult patient with hypophosphatasia. It not only helped increase bone density, but also help in the healing process of delayed-union and nonunion insufficiency fractures of the pelvis and prevented the occurrence of new fractures during the treatment period. To our knowledge, this is the first report describing the potential effect of Romosozumab on insufficiency fractures in patients with hypophosphatasia.