Insogna KL, Rauch F, Kamenický P, et al. - In adults with X-linked hypophosphatemia (XLH) who have not been treated for at least 2 years prior to registration, researchers conducted this phase 3, single-arm, international trial to test the effectiveness of 1.0 mg/kg subcutaneous burosumab, a fully human monoclonal antibody against FGF23, administered every 4 weeks to improve osteomalacia. Fourteen individuals were recruited, 13 finished 48 weeks, and 11 finished paired biopsies. Investigators found that burosumab significantly improved osteomalacia in adults with XLH by normalizing phosphate homeostasis, which most likely accounts for improved fracture healing and skeletal complications. It was noted that most adverse events were mild to moderate. There have been no deaths or hyperphosphatemia events.