Intellia voluntarily paused dosing and screening in its Phase III MAGNITUDE trial and a second Phase III study after a patient experienced Grade 4 transaminase elevations and hyperbilirubinemia consistent with Hy’s law. The safety signal prompted the FDA to impose a clinical hold on the INDs for both trials testing nexiguran ziclumeran (nex‑z/NTLA‑2001), an in vivo CRISPR therapy partnered with Regeneron for ATTR‑CM. More than 450 patients had been dosed across programs; regulators and the company are reviewing causality and next steps.