Intellia Therapeutics disclosed voluntary pauses in dosing and screening across its Phase III MAGNITUDE trial and a second Phase III study after a patient experienced Grade 4 transaminase elevations and hyperbilirubinemia meeting Hy’s law criteria. The FDA subsequently placed the programs on clinical hold. The safety event occurred in an older, high‑BMI patient and was identified weeks after dosing. Intellia said the patient was stable, but the regulator’s hold halts enrollment and dosing pending resolution. The trials assess an in vivo CRISPR therapy partnered with Regeneron for transthyretin amyloidosis with cardiomyopathy (ATTR‑CM). The hold spotlights risks for systemic genome‑editing therapeutics and will affect timelines, regulatory interactions, and investor expectations for in vivo CRISPR platforms.