Romosozumab treatment in osteogenesis imperfecta type I: a case report

The term osteogenesis imperfecta (OI) refers to a heterogeneous group of genetic diseases characterized by defective mineralization of calcified tissues, leading to increased bone fragility and susceptibility to pathological fractures. There is currently no specific therapy for OI. Applied therapies are solely focused on alleviating symptoms, slowing disease progression, and preventing/delaying the most serious consequences of the disease. Patients with OI require life-long supplementation with calcium and vitamin D to compensate for the deficiency of these two molecules. Standard therapy consists of the administration of bisphosphonates to reduce bone resorption. Other drugs, such as denosumab or bone anabolic agents, are potential alternatives in selected patients. Additional drugs, such as anti-sclerostin agents and transforming growth factor beta antagonists, are being studied in clinical trials. We report the case of a female patient diagnosed with OI type I, due to a heterozygous germline mutation of the COL1A1 gene (c.1821+1G>A), associated with multiple fragility fractures, occurring from childhood. After treatment with bisphosphonates, denosumab, and an anabolic drug, the patient was prescribed romosozumab for 24 months, showing an improvement in the quality parameters of trabecular bone, no new fractures, a clear reduction of bone pain (not obtained with previously administered drugs), and a generally improved quality of life. KEY WORDS: Osteogenesis imperfecta, rare bone disease, fractures, bone mineral density, bisphosphonates, denosumab, teriparatide, abaloparatide, romosozumab.