Kyowa Kirin gets EC approval for CRYSVITA (burosumab) to treat X-Linked hypophosphataemia in older adolescents and adults

Kyowa Kirin announced that the European Commission (EC) has approved CRYSVITA (burosumab) for use in older adolescents and adults with the rare disease X-linked hypophosphataemia (XLH). CRYSVITA was previously approved for the treatment of XLH with radiographic evidence of bone disease in children one year of age and older and adolescents with growing skeletons. With this expanded approval, all adolescents with radiographic evidence of bone disease, regardless of growth status, as well as adults with XLH are now also eligible for treatment with CRYSVITA.

XLH is a life-long and progressive disease that typically presents in early childhood, causing lower limb deformities, stunted growth, and bone and joint pain. Symptoms such as dental abscesses, osteoarthritis, enthesopathy (issues with the tendons), and hearing loss may also develop during adulthood. As a result of the disease, some adults may require special equipment to improve their mobility. The physical limitations as well as pain and stiffness caused by XLH can affect people’s ability to work and socialise, their emotional wellbeing, and their capacity for self-care.⁹

The application to expand the marketing authorisation was based on data from two Phase 3 studies: the Phase 3 UX023-CL303 study, a randomised, double-blind, placebo-controlled trial investigating the safety and efficacy of burosumab in adults with XLH, and the Phase 3 UX023-CL304 study, an open-label, single-arm study investigating the effects of burosumab on osteomalacia (softening of the bones) in adults with XLH. These two studies found that burosumab increased and maintained serum phosphate levels in the normal range, helped to heal pseudofractures and fractures related to osteomalacia, and improved osteomalacia. Other endpoints showed that patients had less pain and stiffness, and their physical functioning and mobility improved with time. The safety profile of burosumab was consistent with that observed in other burosumab studies, with adverse events including injection site reactions, hyperphosphataemia and hypersensitivity. There were no treatment-related serious adverse events.