Intellia completes enrolment in Phase 3 MAGNITUDE-2 trial of one-time CRISPR therapy nex-z for ATTRv-PN

What's the deal? Intellia Therapeutics announced on 4 November 2026 that it has completed patient enrolment in MAGNITUDE-2, the Phase 3 trial of its lead gene-editing candidate nexiguran ziclumeran (nex-z) in people with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN), the nerve-damaging form of a rare and progressive protein-folding disease.

Why it matters: Nex-z is an experimental one-time therapy built on CRISPR gene editing, a technique that lets scientists make precise changes to DNA. It is designed to switch off the TTR gene in the liver, stopping production of the transthyretin protein that forms damaging clumps (amyloid) in nerves and other tissues. If it works, a single infusion could halt or even reverse disease progression, offering an alternative to today's treatments, which only slow the build-up of the protein.

The trial randomised about 60 adults 1:1 to a single 55 mg infusion of nex-z or placebo. The primary endpoints are the change in a standardised neuropathy impairment score at month 18 and the change in serum TTR levels at day 29; patients can opt for a blinded crossover to nex-z after month 18. Nex-z holds US orphan-drug and regenerative medicine advanced therapy (RMAT) designations and an orphan designation in the EU, and is being developed with Regeneron Pharmaceuticals. A second Phase 3 trial (MAGNITUDE) is testing the same candidate in the heart-damaging form of the disease (ATTR-CM).

Read more: GlobeNewswire, 4 November 2026