Intellia Therapeutics paused enrollment and dosing in two phase 3 trials of its in vivo CRISPR candidate after a participant was hospitalized with severe liver injury. The company halted screening and dosing while it investigates the hepatic safety signal and develops revised monitoring and dosing controls. Intellia executives briefed investors and suspended recruitment in Magnitude/Magnitude-2 programs targeting transthyretin amyloidosis with its nexiguran (nex‑z) candidate. The pause triggered a sharp share decline and prompted industry-wide scrutiny of liver toxicities seen in in vivo gene‑editing programs. Regulators and competitors will be watching for Intellia’s root-cause analysis and any protocol amendments; the episode highlights the narrow safety margins for gene-editing therapeutics administered systemically and may reshape risk management in similar development programs.