Ultragenyx:Pediatric Study Shows Reduction In Bone Disease&improvement In Growth

(RTTNews) - Ultragenyx Pharmaceutical Inc. (RARE) announced positive interim data from the ongoing pediatric Phase 2 study of KRN23 for the treatment of X-linked hypophosphatemia (XLH), demonstrating that serum phosphorus levels, rickets, growth rates and other functional outcomes improved with continued KRN23 treatment. The bi-weekly dose regimen continued to show a better overall response than patients who were dosed every four weeks, and patients with higher rickets at baseline showed greater improvements in bone disease and growth velocity.

Data were also presented from the adult Phase 2 study of KRN23 for the treatment of XLH, demonstrating a significant increase in serum phosphorus levels and evidence of clinical improvement in walking, mobility, pain and stiffness at 24 weeks of treatment. Adverse events were consistent with what has been previously observed for KRN23 for the treatment of XLH.

Ultragenyx is conducting the program under a collaboration and license agreement with Kyowa Hakko Kirin to develop and commercialize KRN23. Data from the two studies were presented today at the American Society for Bone and Mineral Research (ASBMR) 2016 Annual Meeting.

Patients demonstrated increases in mean serum phosphorus, renal phosphate reabsorption (TmP/GFR) and serum 1,25 dihydroxy vitamin D levels through 64 weeks of treatment. Patients in both dosing groups had mean serum phosphorus levels in the low normal range through 64 weeks of treatment, demonstrating that phosphate wasting, the underlying cause of the disease, improved and patients were able to maintain increased serum phosphorus levels.