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FDA blocks UniQure Huntington disease gene therapy, demands sham surgery-controlled Phase 3 despite prior alignment on Phase 1/2 data
UniQure disclosed today that FDA meeting minutes from a January 30 Type A meeting confirm the agency cannot agree that Phase 1/2 data for AMT-130, compared to an external control from the Enroll-HD natural history dataset, are sufficient to support a marketing application. The FDA “strongly recommended” UniQure conduct a prospective, randomized, double-blind, sham surgery-controlled study — a significant escalation that would require drilling holes in control patients’ skulls without delivering the therapy. UniQure’s stock plunged 35% on the news. The Phase 1/2 trial had shown a 75% slowing of disease progression at 3 years in high-dose patients, data that researchers and investors had called game-changing for the first genetic disease ever mapped to a specific chromosome. UniQure had been aligned with the FDA on using external controls as the basis for a BLA as recently as June 2025. The reversal adds to a pattern of FDA regulatory shifts under current leadership that has affected Regenxbio, Capricor, Biohaven, and others. Leerink Partners called the update the “worst case scenario for many investors,” while Truist analysts noted the FDA’s position is “inconsistent with regulatory flexibility the FDA professes it will exercise in reviewing rare disease drugs.” UniQure plans to request a Type B meeting in Q2 2026 to discuss Phase 3 design, but CEO Matt Kapusta acknowledged the company did not reach alignment on a submission pathway.
FDA lifts Intellia MAGNITUDE clinical hold in ATTR-CM as in vivo CRISPR editing resumes Phase 3 enrollment after cardiac event review
The FDA cleared Intellia’s MAGNITUDE Phase 3 trial to resume enrollment after a clinical hold triggered by a serious cardiac adverse event in November 2025. The trial evaluates NTLA-2001, an in vivo CRISPR-Cas9 therapy targeting TTR gene silencing in patients with transthyretin amyloid cardiomyopathy, a rare inherited condition affecting an estimated 300,000-500,000 patients globally across wild-type and hereditary subtypes. This is the first cardiovascular in vivo gene editing program to reach Phase 3, positioning a one-time editing approach against Alnylam Pharmaceuticals’ chronic RNAi therapies ONPATTRO and AMVUTTRA. The hold resolution provides a counterpoint to the broader FDA rejection trend in gene therapy: while some programs face increased scrutiny, others are advancing through regulatory milestones. The MAGNITUDE readout, expected in late 2027, will test whether durable TTR reduction and functional cardiac benefit can differentiate CRISPR editing from chronic silencing in ATTR-CM, a market where treatment sequencing between wild-type and hereditary subtypes presents distinct positioning considerations.
Rare Disease Day 2026 mobilizes 106 countries amid growing tension between FDA innovation promises and approval reality
The 19th annual Rare Disease Day, observed February 28 under the theme “More Than You Can Imagine,” brought together advocates, families, and researchers across 106 countries with over 600 registered events. The Global Chain of Lights illuminated landmarks worldwide in solidarity with the estimated 300 million people living with more than 6,000 identified rare diseases, 72% of which are genetic in origin with 70% presenting in childhood. NIH held its annual Rare Disease Day event at the Natcher Conference Center on February 27, featuring panel discussions, patient stories, and scientific posters. This year’s observance carried particular urgency given the widening gap between FDA rhetoric and action on rare disease therapies. While FDA Commissioner Makary and CBER Director Prasad have announced new frameworks including the plausible mechanism pathway and one-trial policy, the agency has simultaneously rejected or reversed course on gene therapies from UniQure, Regenxbio, Capricor, Biohaven, and Saol Therapeutics over the past year. Rare disease advocates have described “whiplash” over shifting FDA positions, even as the community continues to celebrate milestones including the Baby KJ personalized CRISPR therapy anniversary and Waskyra’s approval for Wiskott-Aldrich syndrome.
Pipeline Watch
The FDA’s demand for a sham surgery-controlled trial raises significant ethical and practical questions. AMT-130 is delivered through intracranial surgery involving drilling small holes in patients’ skulls; a sham arm would require the same invasive procedure without delivering therapy. Stifel analysts noted the study design “introduces meaningful risk,” while Truist flagged the inconsistency with the FDA’s stated commitment to regulatory flexibility for rare diseases. UniQure plans a Type B meeting in Q2 2026 to discuss alternative Phase 3 designs. Huntington disease advocates may attempt to pressure the FDA, as the Duchenne community did for Sarepta’s Elevidys, but whether opposition can reach sufficient scale remains uncertain.
Atrium emerged as a spinout from Novartis’s $12 billion acquisition of Avidity Biosciences with $270 million in funding and two preclinical cardiovascular programs. Novartis retained Avidity’s lead muscular dystrophy assets while spinning out cardiology candidates, illustrating selective asset prioritization in platform deals. Atrium’s antibody-oligonucleotide conjugate candidates target rare cardiac conditions, combining tissue-targeting antibodies with RNA therapeutics. The funding positions the company to advance through IND-enabling studies without immediate dilution.
United Therapeutics achieved a 55% reduction in clinical worsening risk versus placebo in a Phase 3 pulmonary arterial hypertension trial, an orphan disease affecting approximately 40,000 US patients. The company plans to file for FDA approval this year, competing with J&J’s OPSUMIT and existing endothelin receptor antagonists in a market where chronic combination therapy is standard and annual treatment costs range from $50,000 to over $200,000. United already markets TYVASO and other PAH therapies.
Disc Medicine last month received a complete response letter for bitopertin, proposed to treat erythropoietic protoporphyria, a rare disease characterized by extreme, painful sunlight sensitivity. The CRL follows rejections for Regenxbio’s Hunter syndrome gene therapy and UniQure’s Huntington program, bringing the count of FDA rare disease setbacks under current leadership to at least six. The pattern raises questions about whether the agency is applying a higher evidentiary bar than its public guidance suggests, particularly for therapies relying on novel endpoints or external controls.
Competitive Landscape
UniQure’s AMT-130 rejection adds to a growing list of gene therapy and rare disease programs that have faced FDA reversals or rejections under the current leadership, despite the agency’s stated commitment to regulatory flexibility. The trend creates a credibility gap that affects deal valuations, investor confidence, and developer willingness to pursue accelerated approval pathways for rare diseases.
| Company | Program | Disease | FDA Action |
|---|---|---|---|
| UniQure | AMT-130 | Huntington Disease | Sham Ph3 Required |
| Regenxbio | RGX-121 | Hunter Syndrome | CRL (Feb 2026) |
| Disc Medicine | Bitopertin | Erythropoietic Protoporphyria | CRL (Feb 2026) |
| Capricor | CAP-1002 | DMD | Reversed Course |
| Biohaven | Troriluzole | Spinocerebellar Ataxia | CRL |
| Saol | PDCD Candidate | Pyruvate Dehydrogenase Deficiency | Rejected (Sep 2025) |
Intellia’s MAGNITUDE trial resumption after clinical hold resolution positions in vivo gene editing to compete against Alnylam’s chronic RNAi therapies in ATTR-CM. The one-time editing approach offers potential durability advantages, but regulatory scrutiny of cardiac safety remains a key risk factor. Notably, Intellia’s hold lift demonstrates that the FDA is not uniformly blocking gene therapy programs — the distinction appears to hinge on trial design rigor, particularly around control groups and endpoint validation.
| Company | Modality | Status | Dosing |
|---|---|---|---|
| Intellia (NTLA-2001) | In Vivo CRISPR | Phase 3 | One-time |
| Alnylam (ONPATTRO) | RNAi IV | Approved | Q3W Chronic |
| Alnylam (AMVUTTRA) | RNAi SubQ | Approved | Q3M Chronic |
The $12 billion Avidity acquisition and Atrium spinout illustrate how big pharma buyers are narrowing rare disease focus to indications with established precedents. Novartis retained Duchenne and myotonic dystrophy AOC candidates while spinning out cardiovascular programs, suggesting that for BD teams, platform deals increasingly require indication-specific diligence rather than wholesale portfolio valuation.
Forward Looking
- UniQure Type B meeting with FDA in Q2 2026 will determine whether a feasible Phase 3 design for AMT-130 can be negotiated; the sham surgery question raises both ethical and enrollment viability concerns for a Huntington disease trial requiring intracranial delivery
- Intellia MAGNITUDE Phase 3 readout expected late 2027 will test whether one-time CRISPR editing can demonstrate durable TTR reduction and functional cardiac benefit versus chronic RNAi silencing in ATTR-CM
- The cumulative impact of six-plus FDA rare disease rejections on developer investment decisions and deal flow will become measurable at upcoming conferences; watch for shifts in licensing activity and accelerated approval strategy adjustments across the gene therapy sector
- Atrium Therapeutics IND filings for cardiovascular antibody-oligonucleotide conjugates will test whether the Avidity-derived modality can expand beyond muscular dystrophy into rare cardiac indications with distinct regulatory pathways