Rare Daily Staff


Ultragenyx Pharmaceutical said it has sold to Royalty Pharma a royalty right due to Ultragenyx from Kyowa Kirin for the net sales of its X-linked hypophosphatemia drug Crysvita in the European Union, the United Kingdom, and Switzerland for $320 million.

XLH is a rare, hereditary, progressive, and lifelong skeletal disorder characterized by renal phosphate wasting caused by excess production of phosphaturic hormone fibroblast growth factor 23 (FGF23). FGF23 is a hormone that reduces serum levels of phosphorus and active vitamin D by regulating phosphate excretion and active vitamin D production by the kidney. It affects both children and adults. In children, XLH causes rickets that leads to lower-extremity deformity, delayed growth, and decreased height. Adults with XLH have an increased risk of fractures.

Crysvita has received conditional marketing authorization in Europe for the treatment of X-linked hypophosphatemia (XLH) with radiographic evidence of bone disease in children who are at least 1 year old and adolescents with growing skeletons, and an application for the expanded use in adults with XLH is currently under review by the European Medicines Agency.  

Crysvita (burosumab) is a recombinant fully human monoclonal IgG1 antibody that binds to and inhibits the biological activity of FGF23, restoring renal phosphate reabsorption and increasing the serum concentration of 1,25 dihydroxy vitamin D. By blocking excess FGF23 in patients, Crysvita is intended to increase phosphate reabsorption from the kidney and increase the production of vitamin D, which enhances intestinal absorption of phosphate and calcium.

The agreement will automatically expire in the event aggregate royalty payments received by Royalty Pharma are equal to or greater than 1.9 times the purchase price prior to December 31, 2030, or in the event aggregate royalty payments are equal to or greater than 2.5 times the purchase price if the prior threshold is not met by the end of 2030. Once the threshold amount has been met, the royalty payments will revert to Ultragenyx.

“This non-dilutive royalty financing provides Ultragenyx with capital to support our strong launches of Crysvita in North America and Latin America and Mepsevii worldwide, as well as the advancement of our clinical and translational research programs,” said Shalini Sharp, chief financial officer of Ultragenyx.

Photo: Shalini Sharp, chief financial officer of Ultragenyx

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