Intellia Highlights Strong 2-Year Data for CRISPR Therapy in ATTRv-PN Trial

CAMBRIDGE, Mass. – May 18, 2025 – Intellia Therapeutics (NASDAQ:NTLA) reported positive two-year follow-up data from its Phase 1 trial of nexiguran ziclumeran (nex-z) for hereditary ATTR amyloidosis with polyneuropathy (ATTRv-PN) at the PNS Annual Meeting. This CRISPR-based therapy, demonstrated deep, durable (at least 24 months), and consistent reductions in serum TTR levels, along with signs of disease stability or clinical improvement in neuropathy.

The Phase 1 data showed a 90% mean TTR reduction by Day 28 in patients receiving 0.3 mg/kg or higher (n=33), with sustained levels. Notably, some patients who had progressed on other therapies showed improvement with this non-viral approach. Across 18 patients with 24-month data, 14 demonstrated clinically meaningful improvement in mNIS+7. Nex-z was generally well tolerated.

Intellia President and CEO Dr. John Leonard emphasized the growing evidence supporting a single dose of nex-z for significant and lasting TTR reduction and potential disease modification, offering an alternative to AAV-delivered gene therapies.

The pivotal Phase 3 MAGNITUDE-2 trial for nex-z in ATTRv-PN is underway. Nex-z, a CRISPR/Cas9 gene editing therapy, aims to be a one-time treatment for ATTR amyloidosis by inactivating the TTR gene, representing a different modality than AAV-based approaches. Intellia is developing nex-z with Regeneron.

ATTR amyloidosis is a rare, progressive, and fatal disease caused by misfolded TTR protein. Nex-z aims to address the underlying cause by reducing TTR production through CRISPR.