Positive results help Ultragenyx recover after prior failure
- After a mid-stage failure for its lead candidate, Ultragenyx announced a win on Tuesday for one of its earlier pipeline candidates, KRN23 (burosumab).
- The topline results of the Phase 3 study showed burosumab produced a statistically significant improvement in serum phosphorous levels, with a 94% of the 134 patients achieving normal levels compared with only 8% on placebo.
- Burosumab is being investigated as a treatment for adults with X-linked hypophosphatemia, a rare rickets disorder. It was discovered by Kyowa Hakko Kirin and it targets the phosphaturic hormone fibroblast growth factor 23 (FGF23).
The positive data sent Ultragenyx stock up nearly 9%, or about $5, in early morning trading on Wednesday to reach $65 per share. The company's stock had taken a major hit earlier this year when Ultragenyx reported a Phase 2 failure for UX007, or triheptanoin, which did not meet its primary endpoint of reducing the frequency of seizures compared to placebo in patients with glucose transporter type-1 deficiency syndrome (Glut1 DS).
"These data demonstrate a clinical improvement in patients treated with burosumab and support the potential for treatment of adults," said Emil Kakkis, president and CEO of Ultragenyx. "When combined with a favorable safety profile and a strong serum phosphorus response, we believe these clinical data should support regulatory submissions in adults with XLH, and we look forward to discussing our filing plans with the U.S. FDA."
Burosumab has been a bright spot for Ultragenyx as its later stage assets flounder. The company has also announced positive mid-stage results for burosumab in tumor-induced osteomalacia (TIO).
The company is expected to file for approval of the drug this year in both adults and pediatric patients, and analysts estimate the drug could reach peak sales of $1 billion.
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