Intellia: Patient who experienced Grade 4 liver safety event has passed away

Intellia provided an update on the MAGNITUDE and MAGNITUDE-2 Phase 3 clinical trials of nexiguran ziclumeran. “We were deeply saddened to learn that the patient who experienced Grade 4 liver transaminase elevations and increased total bilirubin following a dose of nex-z in the MAGNITUDE Phase 3 clinical trial, as reported on October 27, 2025, passed away last night,” said Intellia President and CEO John Leonard, M.D. “We have been advised by the treating physician that this is a case with complicating comorbidities, and it is being further evaluated. As we await the FDA’s clinical hold letter, we are working with clinical investigators and external experts to better understand the liver-related events that have been observed within MAGNITUDE and to develop our risk mitigation plan. We continue to believe in nex-z’s potential to address important unmet needs for patients with ATTR amyloidosis. Regarding our other late-stage investigational product for the treatment of HAE, lonvo-z, we have made considerable progress over the course of 2025. Enrollment was completed in the HAELO Phase 3 clinical trial of lonvo-z in September, less than nine months after we dosed our first patient in the trial, putting us on track to share topline data by mid-2026. We look forward to presenting longer-term data from our Phase 1/2 clinical trial of lonvo-z on Saturday at ACAAI.”