NEW YORK – Ultragenyx on Monday said it has started dosing the second dose-escalation cohort of patients in its pivotal Phase I/II/III trial of UX701, an investigational gene therapy candidate for Wilson disease.
Novato, California-based Ultragenyx's UX701 is an adeno-associated virus serotype 9 vector-based gene therapy designed to deliver a copy of the ATP7B gene, mutations in which cause Wilson disease. Wilson disease, a rare inherited disorder, is marked by deficient production of the ATP7B protein that transports copper and prevents copper accumulation in the liver and other tissues.
UX701, administered through a single intravenous infusion, aims to provide stable expression of the ATP7B protein to normalize copper metabolism in Wilson disease patients.
For the first stage of the Cyprus2+ trial, for which the company expects to complete enrollment this year, up to three dose levels of UX701 will be evaluated for safety and efficacy over the course of 52 weeks. The gene therapy has been well tolerated in the first dose cohort with no unexpected treatment-related emergent adverse events observed as of July 11.
Investigators have dosed the first patient and screened the remaining four patients for the second cohort, in which patients will be randomized to receive either UX701 or placebo.
Ultragenyx expects to share initial data from the first stage of the Cyprus2+ trial in the first half of next year, with the primary efficacy endpoint defined as change in 24-hour urinary copper concentration and percent reduction in standard of care medications by week 52.