Ultragenyx announces data demonstrating treatment with UX111

Ultragenyx Pharmaceutical announced data demonstrating treatment with UX111 AAV gene therapy resulted in rapid and sustained decreased levels of heparan sulfate in cerebrospinal fluid in patients with Sanfilippo syndrome type A, and that sustained reduction in CSF HS exposure over time was correlated with improved long-term cognitive development. These data are from the modified intention to treat group in the pivotal Transpher A study. Following treatment with UX111, levels of CSF-HS decreased within the first month post treatment in all patients. 8 of 17 patients in the mITT group who reached 24 months post-treatment achieved an overall mean percent reduction from baseline of 51%. An alternative way to assess CSF-HS is to look at the reduction in CSF HS exposure over time post-administration of UX111 using time-normalized area under curve. The 17 patients in the mITT group had a mean follow-up duration of 29 months. There was a mean reduction in CSF HS exposure of 63% using time-normalized AUC. Cognitive function was measured using Bayley-III cognitive raw scores and an estimated yearly rate of change was calculated to reflect a patient-specific rate of change in BSITD-III cognitive raw scores after UX111 treatment. At the time of the data cut-off, the individual EYC in cognitive raw scores showed a positive rate of change indicating either stability or gains from baseline in 16 of the 17 patients during the expected window of plateau into decline, defined as greater than30 months of age.