CAMBRIDGE, Mass., Sept. 25, 2025 — Intellia Therapeutics announced positive longer-term Phase 1 data for its investigational CRISPR-based therapy nexiguran ziclumeran (nex-z) in patients with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN). A single dose of nex-z produced rapid, deep, and durable transthyretin (TTR) reductions of ≥90%, sustained for up to three years, alongside stabilization or improvement in clinical measures.
Science Significance
The findings confirm that CRISPR gene editing can deliver long-lasting therapeutic effects after just one infusion. In Phase 1, patients maintained significant TTR reduction with evidence of improved neuropathy scores, quality of life measures, and biomarker stability. These results suggest that a one-time treatment could halt or even reverse disease progression in ATTRv-PN, a fatal and debilitating disorder with limited options.
Regulatory Significance
The data support advancement to Phase 3 MAGNITUDE-2, a global, randomized, placebo-controlled trial already enrolling patients, with completion expected in 2026. Intellia aims to submit a Biologics License Application (BLA) by 2028, which could establish nex-z as the first approved CRISPR-based one-time therapy for ATTR amyloidosis.
Business Significance
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This milestone strengthens Intellia’s leadership in gene editing therapeutics and validates its clinical pipeline. A positive Phase 3 outcome would open significant commercial potential in a rare disease affecting 50,000 hereditary and up to 500,000 wild-type patients worldwide. It also reinforces industry confidence in CRISPR-based medicines as scalable business opportunities in rare and genetic diseases.
Patients’ Significance
For patients living with ATTR amyloidosis, characterized by nerve damage, heart complications, and progressive disability, nex-z offers hope for a transformative treatment. Unlike current chronic therapies that slow disease progression, a one-time infusion with durable efficacy could provide sustained quality-of-life benefits and reduce the burden of lifelong medication.
Policy Significance
The results highlight the growing importance of policies that enable rapid adoption of breakthrough genetic therapies. Given ATTR’s rarity and severity, regulatory frameworks like accelerated approval pathways and orphan drug policies will be critical to ensuring timely patient access to innovative CRISPR-based treatments.
The sustained efficacy and safety of nexiguran ziclumeran in Phase 1 mark a turning point for ATTR amyloidosis care. With regulatory pathways advancing and pivotal trials underway, nex-z could become the first approved one-time CRISPR therapy, reshaping treatment standards and offering long-term hope to patients facing a devastating disease.
Source: Intellia Therapeutics Press Release
