Doctors can now treat children living in the EU with the rare, chronic progressive musculoskeletal disorder X–Linked Hypophosphataemia with Kyowa Kirin/Ultragenyx’ Crysvita following its conditional approval in the region.

In children, the condition causes skeletal disease, leading to lower-extremity deformity and diminished height. Conventional treatment consists of multiple daily doses of phosphate and active vitamin D to counteract the excess effects of FGF23, but does not correct the underlying disease.

Crysvita (burosumab), an anti-FGF23 fully human monoclonal antibody, is the first treatment to target the underlying pathophysiology of XLH.

The conditional approval allows its use to treat XLH with radiographic evidence of bone disease in children one year of age and older and adolescents with growing skeletons.

The drug’s clearance “brings hope to people affected by XLH in Europe, and it’s exciting that Europe is the first global regulatory approval for Crysvita,” said Dr Tom Stratford, Kyowa Kirin International’s president and chief executive. “We will now focus our efforts on working with health authorities to ensure patient access in European countries.”

The firm also said it intends to continue working with healthcare providers and patients to further develop understanding of the real-world experience of people affected by XLH.

“This will help to ensure appropriate patient identification and diagnosis and improve standards of care for this rare condition,” Dr Stratford noted.