EU Expands Use of XLH Therapy Crysvita to Include Older Adolescents, Adults

The European Commission (EC) has expanded the approval of Crysvita (burosumab) to treat all adolescents and adults with X-linked hypophosphatemia (XLH).

The decision follows a recommendation by the Committee for Medicinal Products for Human Use, an arm of the European Medicines Agency. Crysvita, developed by Kyowa Kirin and Ultragenyx Pharmaceutical, had been approved previously for use in children ages 1 and up and in adolescents with growing skeletons. Notably, Crysvita now is available to all adolescents with evidence of bone disease, regardless of their skeletal growth.

“Today’s decision from the European Commission is a significant milestone for the management of XLH,” Abdul Mullick, president of Kyowa Kirin International, said in a press release. “With this approval, older adolescents and adults with XLH will also be able to benefit from treatment with CRYSVITA, the only therapy that targets the underlying pathophysiology [disease process] of this disease.”

“We now will focus on ensuring access for as many people as possible in this expanded group of eligible patients,” Mullick added.

XLH is characterized by muscle, joint, and bone abnormalities, including rickets and osteomalacia (soft, weak bones), resulting from low phosphate levels in the blood. Phosphate, which necessary for normal bone growth and function, is absorbed in the gut in a process stimulated by vitamin D. In people with XLH, excess levels or overactivity of the hormone fibroblast growth factor 23 (FGF23) disrupts vitamin D metabolism and prevents proper phosphate absorption, increasing its excretion in urine.

Crysvita is a monoclonal antibody that acts by binding to and blocking FGF23, thereby promoting phosphate absorption and increasing vitamin D production. The treatment is given as a subcutaneous (under-the-skin) injection.

The expansion of Crysvita’s approval was based on data from two Phase 3 clinical studies, UX023-CL303 (NCT02526160) and UX023-CL304 (NCT02537431). Collectively, the trials demonstrated the safety and effeciveness of Crysvita in adults with XLH, restoring blood phosphate levels to a normal range, reduced osteomalacia, and improved mobility by alleviating pain and stiffness.

Crysvita also has been approved to treat children and adults with XLH by the U.S. Food and Drug Administration and Health Canada in 2018, and by Swissmedic (in Switzerland) earlier this year. In 2019, Crysvita was approved in Japan for treating rickets and osteomalacia related to FGF23.