Ultragenyx, Kyowa Kirin announce FDA approval for label update for Crysvita
Ultragenyx Pharmaceutical and Kyowa Kirin announced that the U.S. Food and Drug Administration (FDA) has approved a label expansion for Crysvita. The label has been updated to include new clinical data demonstrating superiority of treatment with Crysvita versus oral phosphate and active vitamin D in pediatric patients with XLH, and improvement in stiffness, and maintenance of efficacy of Crysvita in adult patients with longer-term treatment. The indication has also been expanded to include infants as young as six months of age. Crysvita is an antibody that binds to and inhibits the biological activity of fibroblast growth factor 23, restoring renal phosphate reabsorption and increasing the serum concentration of 1,25 dihydroxy vitamin D. It was first approved in the U.S. in April 2018 for the treatment of XLH in adult and pediatric patients one year of age and older. For the pediatric XLH population, the U.S. label update is based on 64-week efficacy and safety data from the randomized active-controlled Phase 3 study of Crysvita compared with oral phosphate and active vitamin D in 61 children with XLH. The results showed that Crysvita was superior to conventional therapy for all key efficacy endpoints, showing a meaningful improvement in rickets severity, lower limb deformity and growth. The 64-week safety profile was similar to that observed at 40 weeks and in other Crysvita pediatric XLH studies. For the adult XLH population, the label update incorporates results from the open-label treatment period of the Phase 3 study in 134 adult patients with XLH through week 48, demonstrating that serum phosphorus levels were maintained with no evidence of loss of effect. The updated label also includes results demonstrating the continued healing of fractures and pseudofractures at week 48 and improvement in the patient-reported outcome of stiffness at week 24. The safety profile is consistent with what has been previously observed in this study, with no new adverse reactions identified during the extended treatment period.