Ultragenyx Pharmaceutical Inc. and Kyowa Hakko Kirin Co. Ltd. said Crysvita met its main goal in a phase 3 study for treating children with a rare musculoskeletal disorder.
The drug has gained conditional approval in Europe to treat children at least one year old and adolescents with X-linked hypophosphatemia, or XLH, which is characterized by low phosphate levels in the blood.
XLH leads to an increased risk of fractures in adults and rickets in children, resulting in lower-body deformity, delayed growth and decreased height.
The study showed that Crysvita was better than the conventional therapy of oral phosphate and active vitamin D in improving rickets in children with XLH after 40 weeks.
The companies said the study, which enrolled 61 patients, will serve as a confirmatory study in Europe and was not required for the regulatory application in the U.S. The study also showed improvement in important metabolic and functional measures with Crysvita treatment and a safety profile similar to that observed in other Crysvita pediatric XLH studies.
Ultragenyx and Kyowa have completed two phase 2 studies among children and adolescents. The European Medicines Agency required the completion of three ongoing studies to further test the safety and efficacy of the drug.
Crysvita was approved by the U.S. Food and Drug Administration in April to treat XLH among adults and children one year of age and older.
