Ultragenyx and Kyowa Kirin Announce FDA Approval of Crysvita® (burosumab-twza) for the Treatment of Children and Adults with X–Linked Hypophosphatemia (XLH)
First Approved Therapy for XLH in the U.S.; Only Treatment that Targets the Underlying Cause of this Rare, Hereditary, Lifelong Disease
Ultragenyx to Host Conference Call Today at 4:30 pm Eastern Time
Novato, Calif., Tokyo, Japan, and London, UK, April 17, 2018: Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE), a biopharmaceutical company focused on the development of novel products for rare and ultra-rare diseases, Kyowa Hakko Kirin Co. Ltd (Kyowa Hakko Kirin), and Kyowa Kirin International PLC (Kyowa Kirin International) today announced that the U.S. Food and Drug Administration (FDA) has approved Crysvita® (burosumab-twza) for the treatment of X-linked hypophosphatemia (XLH) in adult and paediatric patients one year of age and older. Crysvita is an antibody that blocks fibroblast growth factor 23 (FGF23), a hormone that causes phosphate urinary excretion and suppresses active vitamin D production by the kidney.
“Patients now have an approved breakthrough therapy that can help correct the underlying disease, transforming the treatment of XLH and reducing related bone disease in both children and adults living with this disease,” said Emil D. Kakkis, M.D., Ph.D., Chief Executive Officer and President of Ultragenyx. “This milestone represents Ultragenyx’s second approved therapy in less than six months and validates our strategy to rapidly transform good science into effective therapies for rare diseases. This approval would not have been possible without the patients, their families and clinicians who participated and I would like to thank them for their commitment and dedication.”
XLH is a rare, hereditary, progressive and lifelong skeletal disorder characterised by renal phosphate wasting caused by excess FGF23 production. 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 is designed to bind the excess FGF23 in these patients, normalising phosphorus levels, improving bone mineralisation, improving rickets in children and healing fractures in adults.
“The approval of Crysvita is truly a watershed moment for patients with X-linked hypophosphatemia as it is the first therapy directed toward correction of renal phosphate wasting,” said Tom Carpenter, M.D., the lead study investigator, Director of the Yale Center for X-Linked Hypophosphatemia, and Professor of Pediatric Endocrinology at Yale University School of Medicine. “By targeting this mechanism Crysvita leads to sustained improvements in phosphate metabolism with concurrent repair of the skeleton, even after prior treatment with conventional approaches. Most importantly, the dosing regimen for Crysvita is far less burdensome than for currently available therapies and should be readily acceptable by families. I expect it to revolutionise the care of patients with XLH.”
Dr Tom Stratford, President and Chief Executive Officer of Kyowa Kirin International, said: “This is excellent news for people affected by XLH and their families. Coming close behind the granting of a European Marketing Authorisation for Crysvita in children, this means that even more patients who suffer from this often debilitating condition can benefit from this medicine.”
The FDA previously granted Crysvita a Breakthrough Therapy Designation for the treatment of XLH in paediatric patients one year of age and older, and evaluated Crysvita with Priority Review, which is reserved for drugs that treat a serious condition and, if approved, would provide a significant improvement in safety or effectiveness.
With this approval, the FDA issued a Rare Pediatric Disease Priority Review Voucher, which confers priority review to a subsequent drug application that would not otherwise qualify for Priority Review. The Rare Pediatric Disease Priority Review Voucher programme is designed to encourage development of new drugs and biologics for the prevention or treatment of rare paediatric diseases.
In order to support patients, Ultragenyx has launched UltraCare™, a support service that will provide ongoing support to patients and caregivers. UltraCare will help patients understand insurance coverage and assist in finding financial support for both medication and administration of medication. Dedicated in-house UltraCare Guides are available Monday through Friday from 9 a.m. to 8 p.m. Eastern Time at 888-756-8657 to assist patients and their families.
Kyowa Hakko Kirin, Kyowa Kirin International, a wholly owned subsidiary of Kyowa Hakko Kirin, and Ultragenyx have been collaborating in the development and commercialisation of Crysvita globally, based on the collaboration and licence agreement between Kyowa Hakko Kirin and Ultragenyx.
Efficacy Results in Clinical Studies
For the paediatric XLH population, the FDA approval is supported by 64-week data from Study CL201, a randomised, open-label study in 52 patients ages 5 to 12, which showed that treatment with Crysvita improved rickets, increased serum phosphorus levels, decreased serum alkaline phosphatase activity, and increased growth. The indication is also supported by 40-week data from Study CL205, an open-label study in 13 patients ages 1 to 4. In these patients, Crysvita improved rickets and lower-limb deformity, increased serum phosphorus levels and decreased serum alkaline phosphatase activity.
For the adult XLH indication, the FDA approval is supported by 24-week data from Study CL303, a randomised, double-blind, placebo-controlled study in 134 adult XLH patients. Crysvita treatment resulted in a higher proportion of patients achieving serum phosphorus levels above the lower limit of normal, and a higher rate of complete healing of active fractures and pseudofractures, compared to placebo. The adult indication is also supported by data from the 48-week, open-label, single-arm bone biopsy study in 14 adult XLH patients, which showed healing of osteomalacia as demonstrated by decreases in osteoid volume/bone volume, osteoid thickness and mineralisation lag time.
