Intellia Therapeutics Stock Drops as Safety Fears Emerge in Drug Trial

Nex-z is the most important asset in the development pipeline at Intellia, which has no approved products. (Dreamstime)

Key Points

• Intellia Therapeutics paused two trials of its experimental gene-editing treatment, nex-z, after a patient was hospitalized with liver problems.
• Intellia shares dropped 40% following the announcement of the trial pauses for its lead pipeline asset, nex-z.
• Analysts had projected nex-z sales to reach $1.9 billion by 2030, accounting for 62% of Intellia’s estimated sales.

The gene-editing biotech Intellia Therapeutics said Monday it had paused two trials of one of its lead experimental treatments after a patient was hospitalized due to liver problems.

Intellia shares were down 40% in late morning trading. On an investor call, Intellia’s CEO, John Leonard, said that the company had learned Friday that a patient in a trial of the company’s experimental gene-editing treatment for a heart disease called ATTR-cardiomyopathy had been hospitalized after reporting stomach pain.

Leonard said that the patient was in his early 80s, and had received a dose of the gene-editing treatment, called nex-z, on Sept. 30. His blood work showed abnormally high levels of liver enzymes and of bilirubin, all signs of a liver injury.

“The patient is being closely monitored and is receiving medical intervention,” Leonard said.

The company paused the Phase 3 trial in which the patient was enrolled, called Magnitude. It also suspended a related Phase 3 trial that was testing nex-z in patients with a similar condition called ATTR-polyneuropathy.

Nex-z is the most important asset in the development pipeline at Intellia, which has no approved products. Analysts had forecast that nex-z sales would hit $1.9 billion by 2030, at which point it would account for 62% of the company’s estimated sales, according to FactSet.

In a note on Monday, Leerink Partners analyst Mani Foroohar wrote that nex-z accounts for roughly $23 per share of his $41 target price on the stock.

Details were sparse on Monday morning. “We are hopeful that the company will be able to introduce risk-mitigation strategies that will allow the programs to continue,” wrote TD Cowen analyst Joseph Thorne.

Leonard said on the investor call that including the two Phase 3 trials that have now been paused, more than 450 patients have already been treated with nex-z.

Nex-z uses a gene-editing approach called Crispr/Cas9, used in the approved sickle-cell-disease treatment Casgevy, made by Vertex Pharmaceuticals . The drug knocks out a gene that instructs the liver to make the protein transthyretin, which creates the clogs that lead to both ATTR-cardiomyopathy and ATTR-polyneuropathy.

Intellia isn’t pausing its other clinical trial, which tests a separate gene- editing treatment called NTL-2002 in a different condition. On the investor call, Intellia executives said they believed the patient’s liver issue wasn’t a result of the lipid nanoparticle wrapper used in both of its therapies, but rather was related to the specific gene that nex-z targets.

That suggests that the potential safety risk would be specific to nex-z, and not shared across Intellia’s broad platform.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com