US FDA places clinical hold on Intellia’s gene therapy trials; shares fall

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(Reuters) -The U.S. Food and Drug Administration has placed a clinical hold on Intellia Therapeutics’ two late-stage trials testing an experimental gene therapy for a rare disease that can damage the heart and nerves, the company said on Wednesday.

Shares of the Cambridge-based company fell about 17% in extended trading.

The FDA’s decision follows a serious safety event in one of the trials, where a patient who received the therapy, called nexiguran ziclumeran (nex-z), developed Grade 4 liver enzyme elevations and increased bilirubin levels, both signs of potential liver damage.

The individual has been hospitalized and is under medical care.

The therapy is being tested as a one-time gene-editing treatment for transthyretin amyloidosis, a rare and progressive disease caused by a faulty protein that builds up in organs.

The condition can lead to cardiomyopathy (ATTR-CM), affecting the heart, or polyneuropathy (ATTR-PN), which damages nerves.

Earlier this week, Intellia paused dosing and screening in both of its late-stage trials after the adverse event.

The FDA informed the company of the clinical hold verbally and said it would issue a formal letter within 30 days. Intellia said it plans to work closely with the agency to resolve the issue as quickly as possible.

Debanjana Chatterjee, an analyst at Jones Trading, said the hold “does not have a meaningful impact” on their outlook on the stock, noting that dosing had already been paused. She added that it is “understandable that the agency would want to be cautious” while the company investigates the cause of the adverse event.

“This is not the first time Intellia has faced a regulatory hiccup,” Chatterjee said, pointing to a previous issue with the company’s hereditary angioedema program. “We remain optimistic that the trial might resume within a couple of months.”

(Reporting by Kamal Choudhury in Bengaluru; Editing by Alan Barona)