Ultragenyx Pharmaceutical entered a collaboration and license agreement with Kyowa Hakko Kirin (KHK) to develop and commercialize KRN23, a recombinant fully human monoclonal IgG1 antibody intended to treat the rare metabolic bone disorder X-linked hypophosphatemia (XLH). KHK is currently completing a Phase I/II study in adults with XLH in the United States and Canada, and the two companies are planning to initiate a pediatric XLH program in 2014.
Per the agreement, Ultragenyx and KHK will work together to develop KRN23 for the United States, Canada, and the European Union, with Ultragenyx leading development efforts in the XLH indication. If KRN23 is approved, Ultragenyx and KHK will share commercial responsibilities and profits in the United States and Canada, KHK will commercialize KRN23 in the European Union, and Ultragenyx will develop and commercialize KRN23 in Mexico as well as Central and South America. KHK will manufacture and supply KRN23 for clinical and commercial use globally.
According to KHK, XLH patients have low serum phosphate levels due to high levels of FGF23, a hormone that represses the reabsorption of phosphate from the urine. KRN23 is intended to bind to FGF23 and render it inactive, leading to an increase in kidney tubular absorption of phosphate and increased serum phosphate levels. KHK says that KRN23 is potentially the first specific treatment that addresses the problem of excess FGF23 production in XLH.
“We believe that the collaboration with Ultragenyx will accelerate the development and commercialization of KRN23 and maximize its value in global markets,” said Yoichi Sato, executive managing officer, vp, and head of the development division at KHK, in a statement. “Through the collaboration, Kyowa Hakko Kirin will continue to use its best efforts to bring KRN23 to XLH patients who need the new therapy the most.”