Intellia Therapeutics (NASDAQ:NTLA) shares plummeted 50% on Monday after the company announced a temporary halt to patient dosing and screening in its Phase 3 trials of nex-z, citing a serious liver-related safety incident. Shares of CRISPR Therapeutics (NASDAQ:CRSP) also slid 10% following the news.
The biotech company paused its MAGNITUDE and MAGNITUDE-2 studies, which target patients with transthyretin amyloidosis with cardiomyopathy (ATTR-CM) and polyneuropathy (ATTR-PN). The decision followed a case reported on October 24, in which a participant in the MAGNITUDE trial who received nex-z on September 30 experienced Grade 4 liver transaminase elevations and increased total bilirubin — triggering the trial’s protocol-defined safety pause.
“In line with our commitment to patient safety, we have taken immediate action to temporarily pause enrollment in MAGNITUDE and MAGNITUDE-2 as we investigate this recent event,” said Intellia President and Chief Executive Officer John Leonard, M.D. “As we focus on ensuring the health of this patient, we also are engaging with regulatory authorities and other stakeholders globally to develop a strategy to resume enrollment as soon as appropriate.”
The patient has been hospitalized and is undergoing treatment while under close observation. Intellia said it is consulting with independent experts, evaluating mitigation strategies, and coordinating with regulators as it works to determine next steps.
Before the pause, MAGNITUDE had enrolled more than 650 participants with ATTR-CM, while MAGNITUDE-2 included 47 patients with ATTR-PN. An estimated 450 patients had already received doses of nex-z.
The safety setback has sent shockwaves through the gene editing sector, weighing on related companies such as CRISPR Therapeutics that rely on similar technology platforms.