FDA Accepts First Gene Therapy for Huntington’s

AMT-130What to know

30-second read

For Neurology · Neurosurgery

Who

Adults with genetically confirmed, early manifest Huntington’s disease — the population enrolled in uniQure’s Phase 1/2 trials (TFC 9–13, ≥40 CAG repeats, ages 25–65).

What’s new

FDA accepted uniQure’s BLA for AMT-130, a one-time gene therapy, for Priority Review on 2 Nov 2026 under the Accelerated Approval pathway. Not yet approved.

Evidence

36-month data vs. an external Enroll-HD-matched control: 75% slower cUHDRS decline (P=.003) originally — but only 44%, not significant (P=.144), at 48 months.

What it adds

No disease-modifying HD therapy exists today; tetrabenazine/deutetrabenazine treat only chorea. AMT-130 would be the first to target the underlying biology, if the data holds.

Key consideration

No concurrent randomized control — the comparison shifts each time it’s rebuilt from natural-history data. One-time neurosurgical delivery, not an infusion-center drug.

Access

Not approved; PDUFA target action date 1 May 2027, with an FDA advisory committee meeting tentatively planned. No price, distribution or reimbursement pathway exists yet.

Practice impactNo change to practice yet

Nothing changes for patient care today. Watch the advisory committee, where FDA's reviewers will air the external-control question publicly, and the 1 May 2027 decision — counsel patients that the signal has weakened, not strengthened, over time.

Read the full physician analysis

Full analysis · 11 min readuniQure, 2 Nov 2026 FDA announcement · 48-month data update · NeurologyLive

FDA accepted uniQure’s Biologics License Application for AMT-130 (ifezuntirgene inilparvovec) on 2 November 2026 and granted it Priority Review under the Accelerated Approval pathway, setting a target action date of 1 May 2027. The therapy also holds Breakthrough Therapy, Regenerative Medicine Advanced Therapy (RMAT) and Fast Track designations — the first investigational therapy for Huntington’s disease to hold the first two. None of that is an approval. It is the start of a formal review of a therapy that, if cleared, would be the first to modify the course of a disease that today has no treatment beyond managing chorea. For neurologists, the regulatory headline matters less than what sits underneath it: a single small trial whose reported effect size has moved substantially — and, in its most recent readout, lost statistical significance — as the comparison data behind it has been updated.

A Single Trial, Three Different Readouts

uniQure’s BLA rests on 36-month data from 12 patients who received the high dose of AMT-130 in the company’s U.S. Phase 1/2 trial, compared against a propensity-score-matched external control built from the Enroll-HD natural history database — there is no concurrent, randomly assigned comparison group in this analysis. In the original version of that comparison, reported in 2025, AMT-130 patients declined 75% more slowly than matched controls on the composite Unified Huntington’s Disease Rating Scale (cUHDRS), the trial’s primary endpoint (P=.003), with a 60% slower decline on Total Functional Capacity (TFC, P=.033). After the BLA was submitted in September 2026, uniQure released an updated analysis using a refreshed pull of Enroll-HD data: 80% slowing on cUHDRS (nominal P=.005) and 67% on TFC (nominal P=.011) — numbers that were not part of the BLA itself. A further update, extending to 48 months against yet another refreshed external control, showed the cUHDRS effect fall to 44%, which did not reach statistical significance (P=.144); TFC held up better, at 61% slowing (nominal P=.008). uniQure has said part of the attenuation reflects changes in the external control population rather than a change in how its own patients fared.

Why the Comparison Keeps Moving

The swing is a direct consequence of the trial’s design, not noise in the underlying disease. Enroll-HD is an observational natural-history study, not a randomized comparator recruited alongside uniQure’s trial; every time the company draws a fresh propensity-matched subset from it, the specific patients selected as “controls” can differ, and so can the apparent treatment effect. FDA itself questioned whether this kind of single-arm, externally controlled design could serve as primary evidence for a BLA, saying so as recently as November 2025, before reversing course in June 2026 and agreeing the 36-month cUHDRS analysis could support an Accelerated Approval filing. That reversal is why a BLA exists at all — and why the agency has also required a confirmatory trial with a real randomized arm before any approval can be made permanent.

“Backed by compelling data from our phase 1/2 studies, we believe ifezuntirgene inilparvovec has the potential to become the first disease modifying treatment for Huntington’s disease.” Matt Kapusta, Chief Executive Officer, uniQure

The Neurosurgery Behind the Biology

AMT-130 is not an infusion-center therapy. It is a single administration of an AAV5 vector, carrying a microRNA designed to reduce production of the mutant huntingtin protein, delivered through MRI-guided, convection-enhanced stereotactic neurosurgery directly into the striatum — the caudate and putamen bilaterally. That places the therapy, if approved, inside a comprehensive neurosurgical and movement-disorders center rather than a community neurology practice. The safety record so far is dominated by the procedure itself: most adverse events in the Phase 1/2 program have been tied to the surgery, and in the dose-finding phase, 3 of 14 patients who received the high dose across the U.S. and European trials had serious adverse reactions severe enough to pause enrollment. An independent Data Safety Monitoring Board subsequently reviewed the program and found no ongoing safety concerns with either dose, and some patients received a short course of perioperative immunosuppression. None of that is unusual for a one-time neurosurgical gene therapy, but it is a materially different risk conversation than starting or adjusting an oral medication.

What Today's Standard of Care Doesn't Do

The reason this filing matters despite the unsettled data is that the bar it is trying to clear is low: nothing currently approved for Huntington’s disease changes the course of the illness. Tetrabenazine, approved by FDA in 2008, and deutetrabenazine, approved later, both treat chorea — the involuntary movements associated with HD — and neither has evidence of a disease-modifying effect. Cognitive decline, psychiatric symptoms and functional loss progress regardless. A 2022 Movement Disorder Society evidence review found no treatment, pharmacologic or otherwise, with data supporting a disease-modifying effect in either premanifest or manifest HD. That is the gap AMT-130 is aimed at, and it is why a single-arm, externally controlled trial with a shrinking effect size is still generating this much attention: for a devastating, genetically certain disease with no real treatment, even a contested signal is more than exists today.

What AMT-130 would add to Huntington's disease management

	AMT-130 (if approved)	Tetrabenazine / deutetrabenazine (today)
What it targets	The underlying mutant-huntingtin biology, via one-time gene therapy	Chorea symptoms only, via VMAT2 inhibition
Disease-modifying evidence	Contested: 44%–80% slowing of cUHDRS/TFC decline depending on which external-control analysis is used; not yet statistically robust at 48 months	None; no evidence of altering disease course
Administration	One-time MRI-guided stereotactic neurosurgery into the striatum	Daily oral tablets, titrated and continued indefinitely
Where it's delivered	A comprehensive neurosurgical/HD center, if approved	Any prescriber comfortable managing chorea
Regulatory status	BLA under FDA Priority Review; decision due 1 May 2027	FDA-approved since 2008 (tetrabenazine) and 2017 (deutetrabenazine)

AMT-130's disease-modifying claim rests on a single-arm trial with an externally matched, not randomized, control; cross-analysis comparisons here are uniQure's own reported figures, not independently verified by Regulatory News.

The Confirmatory Trial Is the Real Test

Accelerated Approval, if AMT-130 receives it, would be conditional rather than final. FDA requires a confirmatory trial to verify the clinical benefit that the accelerated pathway only presumes, and uniQure has described a planned randomized study of roughly 200 patients, assigned 2:1 to AMT-130 or standard of care, with TFC at 36 months as the primary endpoint — the first time the therapy will be tested against a concurrent control rather than a historical one. Kapusta has said the company expects to begin screening patients for that trial around the end of 2026, with the study underway well before any approval decision. If the confirmatory trial does not verify benefit, FDA has the authority to withdraw an accelerated approval already granted — a real, if uncommon, outcome elsewhere in gene and cell therapy, and the central uncertainty hanging over this filing regardless of what the May 2027 decision says.

• Do not refer patients for treatment yet. AMT-130 is not approved anywhere, has no access pathway, and FDA's acceptance of the BLA is a review step, not an authorization.
• Know the eligibility hallmarks for counseling. The trials enrolled genetically confirmed early manifest HD: Total Functional Capacity 9–13, ≥40 CAG repeats, ages 25 to 65 — a narrower population than all HD patients.
• Represent the evidence honestly. The reported effect has weakened, not strengthened, as the comparator data matured — from 75% slowing with P=.003 at 36 months to 44% slowing, not statistically significant, at 48 months. Patients and families will have read about this; don't let hope outrun the data.
• Watch for the advisory committee date. FDA has tentatively planned a public advisory committee meeting, likely its Cellular, Tissue and Gene Therapies Advisory Committee, where the external-control methodology will be debated by the agency's own reviewers before the May 2027 decision.
• Flag interested patients for the confirmatory trial once it is listed. uniQure says screening is expected to begin around year-end 2026; that trial, not any early-access route, is the near-term way an eligible patient could receive AMT-130.
• There is no pricing, coverage or coding information to give patients yet — nothing has been approved, and none of that is set until it is.

From a questioned trial design to a review clock

1. Nov 2022

   uniQure's first approved gene therapy

   Hemgenix, licensed to CSL Behring, becomes the first FDA-approved gene therapy for hemophilia B.

2. Nov 2025

   FDA questions the trial design

   FDA says single-arm, externally controlled Phase 1/2 data may not be adequate as primary BLA evidence.

3. Jun 2026

   FDA reverses course

   Agency agrees the 36-month cUHDRS analysis, vs. an Enroll-HD external control, can support an Accelerated Approval filing.

4. 2 Sep 2026

   BLA and UK filing submitted

   uniQure files the BLA under Accelerated Approval and a parallel Marketing Authorisation Application with the UK's MHRA.

5. 2 Nov 2026

   FDA accepts the BLA

   Priority Review granted; PDUFA target action date set for 1 May 2027.

6. Ahead

   Confirmatory trial and advisory committee

   Screening for the ~200-patient randomized confirmatory trial expected to begin around year-end 2026; an FDA advisory committee meeting is tentatively planned ahead of the May 2027 decision.

Frequently asked questions

Can I refer a patient for AMT-130 right now?

No. AMT-130 is not approved anywhere and has no commercial access pathway. FDA's acceptance of the BLA for Priority Review only starts a formal review clock toward a decision targeted for 1 May 2027. uniQure says it expects to begin screening patients for the required randomized confirmatory trial around the end of 2026 — that trial, once listed on ClinicalTrials.gov, will be the only route to AMT-130 before any approval.

Why do the reported efficacy numbers keep changing?

Because the pivotal comparison has no concurrent control arm. Each time the external Enroll-HD comparison group has been refreshed with newer data, the apparent treatment effect has shifted — from 75% slowing of cUHDRS decline at 36 months (P=.003) to 44% at 48 months, no longer statistically significant (P=.144). That reflects a moving comparator, which is the exact limitation FDA flagged before reversing itself in June 2026.

What does accelerated approval mean here, and what happens if the confirmatory trial doesn't confirm benefit?

It would let FDA authorize AMT-130 based on a clinical-scale effect the agency judges reasonably likely to predict benefit, before that benefit is definitively proven, conditioned on a confirmatory trial — a planned randomized study of roughly 200 patients measuring Total Functional Capacity at 36 months. If that trial fails to verify benefit, FDA can withdraw the approval.