First, a quick note -- if you've registered for XLH Day (or plan to) and don't have your hotel reservations yet, make them now. The discounted rate is only good through September 5. Also, if you'd like to apply for financial assistance with the hotel cost, apply before September 5. Instructions for both hotel reservations and hotel stipend here: http://xlhday.com/?page_id=220
Now for the news: Ultragenyx Pharmaceutical has released some very encouraging results from the clinical trial involving bone biopsies of patients before and after treatment with KRN23/burosumab. Note that the results from after treatment are only for two patients, an obviously tiny sample size!
Here's the summary from a recent press release:
Bone biopsy results from the first two adults in the bone quality study will be included in the burosumab BLA. In this study, baseline biopsies obtained from 11 patients confirmed that a majority of the patients had severe osteomalacia with a mean osteoid volume/bone volume of 26% vs. normal range of 0.3%-3.1%. These data verify that adult XLH patients have severe underlying bone disease even many years past puberty. Follow-up biopsies after 48 weeks of burosumab treatment are available from the first two patients. For these two patients, osteoid volume/bone volume was decreased from 24% and 29% to 9% and 7%, respectively. Osteomalacia was characterized by the pathologist as improving from severe to mild disease. Additionally, a post-hoc statistical analysis of bone fracture healing in the recently announced adult Phase 3 placebo-controlled study showed an odds ratio of 7.76 for complete healing of fractures and pseudofractures in the burosumab group compared to the placebo group (p=0.0004) at 24 weeks.
You can read the entire press release here: