uniQure Announces Updated Preliminary AMT-191 Phase I/IIa Data Showing Sustained Increases in α-Gal A Enzyme Activity in Patients with Fabry Disease

Core Insights - The article discusses updated preliminary safety and exploratory efficacy data from uniQure's Phase I/IIa trial of AMT-191, a gene therapy for Fabry disease, presented at the WORLDSymposium [1][7] Group 1: Efficacy Data - All 11 patients in the trial exhibited elevated α-galactosidase A (α-Gal A) activity across three dosing cohorts [2] - Dose-dependent increases in α-Gal A activity were observed, ranging from 0.34- to 82.2-fold at the lowest dose, 1.6- to 312.52-fold at the mid dose, and 27.7- to 223.7-fold at the highest dose, with durability noted over follow-up periods [3] - Six out of 11 patients discontinued enzyme replacement therapy after meeting pre-specified criteria, including elevated α-Gal A activity, while stable plasma lyso-Gb3 levels were maintained post-dose across all cohorts [4] Group 2: Safety Profile - The safety profile of AMT-191 was manageable, with no serious adverse events (SAEs) related to the therapy observed at the lower doses [5] - Two patients at the mid dose experienced asymptomatic Grade 3 liver enzyme elevations, confirmed as dose-limiting toxicity, leading to a pause in additional dosing in mid- and high-dose cohorts [5][6] - At the highest dose, five SAEs were reported, including two unrelated to AMT-191, and one patient experienced an asymptomatic Grade 3 liver enzyme elevation that resolved with corticosteroid therapy [6] Group 3: Clinical Trial Overview - The Phase I/IIa trial is a multi-center, open-label study in the U.S. with three dosing cohorts, exploring safety, tolerability, and early efficacy signs [8] - Patients were not excluded based on pre-existing neutralizing antibodies to AAV5 and will be followed for 24 months [8] - AMT-191 has received Orphan Drug and Fast Track designations from the U.S. FDA, indicating its potential significance in treating Fabry disease [9] Group 4: Background on Fabry Disease - Fabry disease is an X-linked genetic lysosomal storage disorder caused by α-Gal A deficiency, leading to toxic accumulation of lyso-Gb3, which can damage various organs [10] - The current standard treatment involves bi-weekly enzyme replacement therapy, which has limited effectiveness due to poor cross-correction and substrate clearance [10] Group 5: Company Overview - uniQure is focused on advancing gene therapies for severe diseases, with a history of significant achievements in the field, including a gene therapy for hemophilia B [11] - The company is developing a pipeline of gene therapies for various conditions, including Fabry disease, and aims to deliver potentially curative treatments [11]