Ultragenyx gets lift from early data on bone drug
- California-based Ultragenyx Pharmaceutical over the weekend reported positive interim results from an open-label Phase 2 trial testing its experimental drug for tumor-induced osteomalacia (TIO).
- Treatment with KRN23, a fully human monoclonal antibody licensed by Ultragenyx from Kyowa Hakko Kirin, boosted mean serum phosphorus levels and led to improvements in bone density in six of the seven patients who responded. The interim results covered the first eight patients, out of 17 currently enrolled.
- News of the positive early findings failed to lift Ultragenyx's stock much, however. Several other drugs, including KRN23 for another bone disease indication, are further along in clinical development.
Tumor-induced osteomalacia, which affects up to a thousand people in the USA, is a bone disease caused by benign tumors. This leads to hypophosphatemia, osteomalacia and fractures.
The interim data, presented at the annual meeting ot the American Society for Bone and Mineral Research, covered 24-week data from the first eight patients of the Phase 2 study, which is scheduled to last 48 weeks in total.
In addition to its development program in TIO, KRN23 is also in Phase 3 testing for X‐linked hypophosphatemia (XLH, vitamin D-resistant rickets) in adults, and in Phase 2 for a pediatric indication.
"In summary, the interim data from both XLH and TIO demonstrated KRN23 can increase and maintain serum phosphorus levels in the low normal range and may have meaningful effect on bone disease and other clinical outcomes and demonstrated safety profile consistent with what has been observed in previous analysis," said Emil D. Kakkis, president, CEO and director of Ultragenyx.
All patients experienced adverse events, including Vitamin D deficiency and dysgeusia. One patient experienced neoplasm progression, a serious adverse event, and discontinued treatment.
In adults, conditional E.U. filing for XLH is planned for the end of 2016, followed by U.S. filing sometime in 2017. The FDA also granted a breakthrough therapy designation for the drug in the pediatric indication in June 2016.
According to Kakkis, the company plans to meet with the FDA to discuss the possibility of an accelerated approval pathway.
- Ultragenyx Statement
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