The FDA lifted clinical holds on Intellia’s Phase 3 Magnitude and Magnitude‑2 trials of in‑vivo CRISPR candidate nexiguran ziclumeran (nex‑z), allowing enrollment to resume under new safety restrictions. Regulators required tighter liver‑function monitoring, exclusion criteria for patients with certain hepatic or cardiovascular instability, and steroid guidance for enzyme elevations. Intellia said the agency and company aligned on measures intended to enhance patient safety while permitting continued evaluation of nex‑z in transthyretin amyloidosis with cardiomyopathy (ATTR‑CM) and polyneuropathy (ATTRv‑PN). The decision follows a prior pause after a participant experienced fatal liver toxicity. CRISPR in‑vivo editing therapies deliver gene disruption directly inside patients and carry unique organ‑specific safety profiles; the FDA’s conditional restart signals cautious openness to gene editing but emphasizes rigorous hepatic surveillance and tighter eligibility criteria.