I’ve been poring over the news around Intellia Therapeutics’ NTLA-2001, an in vivo CRISPR-Cas9 therapy to inactivate the TTR gene in two sets of transthyretin amyloidosis patients. On October 27, 2025, Intellia reported that an 80-year-old trial participant treated with NTLA-2001, also known as nexiguran ziclumeran (nex-z), had Grade 4 liver transaminases and increased total bilirubin, requiring hospitalization. The FDA placed a clinical hold on NTLA-2001, the 650+-patient MAGNITUDE trial, and MAGNITUDE-2 (NCT06672237), a 47-patient Phase III study, while the company and authorities investigated.

For days, I and others have wondered: What happened to the patient? What caused the serious adverse event? What does this mean for the company’s future?

While waiting for Intellia to re

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