uniQure N.V. (NASDAQ: QURE) released updated clinical data from its ongoing Phase I/II studies of ifezuntirgene inilparvovec, a gene therapy candidate for Huntington's disease, showing continued slowing of disease progression at 36 and 48 months.

In 15 high-dose patients at 36 months, the composite Unified Huntington's Disease Rating Scale (cUHDRS) showed 80% slowing of disease progression compared to an external control (nominal p=0.005), while Total Functional Capacity (TFC) showed 67% slowing (nominal p=0.011). In 12 high-dose patients at 48 months, cUHDRS showed 44% slowing of disease progression, a result that did not reach statistical significance (p=0.144), while TFC showed 61% slowing (nominal p=0.008).

The data cutoff was June 30, 2026. Outcomes were compared to propensity score-matched external controls drawn from the ENROLL-HD natural history dataset. uniQure noted that missing data reached 53% in the updated matched controls at 48 months and that patients who discontinued follow-up were progressing faster than those who remained, which the company said likely understated the treatment effect at that timepoint. A post hoc sensitivity analysis using a prior external control showed 54% slowing on cUHDRS (nominal p=0.041) and 68% on TFC (nominal p=0.001) at 48 months.

At 48 months, high-dose patients showed a mean cUHDRS change from baseline of -0.91, compared to -1.94 in low-dose patients, consistent with a dose-dependent effect.

The therapy was described as generally well-tolerated. Five high-dose participants (17%) experienced a treatment-related serious adverse event involving central nervous system inflammation, all of which resolved. One suicide in a low-dose patient occurred approximately five years after treatment and was assessed as unrelated to treatment by the study investigator.

uniQure submitted a Biologics License Application (BLA) to the FDA under the accelerated approval pathway, based on 36-month data from 12 high-dose patients. The FDA communicated at a June 2026 Type B meeting that this data would be acceptable as the primary basis for the submission. The data announced were not part of that submission.