UniQure’s Huntington’s disease gene therapy AMT-130 continued to slow disease progression at the four-year follow-up, but the magnitude of benefit declined versus earlier analyses. The update comes as the FDA begins review of UniQure’s marketing application, putting durability questions into sharper focus. Reported outcomes include a less pronounced difference on a primary measure compared with a prior one-year earlier readout, with commentary noting that secondary endpoint strength provided some ongoing investor support. Still, the headline change in effect size is likely to influence stakeholder expectations for the regulatory posture. The data also reignite broader debates on how gene therapies maintain clinical signal over time, including whether external controls and composite endpoint construction can mask or reveal true durability. For UniQure, the four-year dataset is now central to the regulatory narrative, balancing sustained slowing of progression with uncertainty about how much effect remains at later follow-up.