STAT+: Intellia plays down concerns about accidental germline transmission in CRISPR trial

Earlier this month, Intellia Therapeutics announced it was scrapping plans to include U.S.-based sites in one of its mid-stage CRISPR trials after the Food and Drug Administration requested additional data to support including female patients of childbearing potential. The move left many researchers wondering whether the specter of accidental germline transmission — which haunted early gene therapy trials — had now risen over the field of gene editing.

Over the weekend, Intellia sought to assure the gene editing community that no such thing is happening. At a meeting at Cold Spring Harbor Laboratory that drew more than 400 of the field’s top scientists, the company shared more detailed information about studies it has conducted to assess the risks that renegade CRISPR components could be getting into an egg or sperm. These studies demonstrate “that there’s no evidence of vertical germline transmission of those edits,” Jonathan Phillips, head of pharmacology and toxicology at Intellia, said during a presentation Saturday.

Intellia is one of the leading companies working to advance in vivo gene editing therapies. In a landmark study published in the New England Journal of Medicine in 2021, Intellia revealed data from six patients in its trial for a transthyretin amyloidosis therapy — showing for the first time that it was possible to precisely alter the DNA of particular cells within the human body to treat disease with a one-time infusion of CRISPR. Included in the supplementary material was a redacted version of the company’s package requesting authorization to start its clinical trial. It noted that during toxicology studies in non-human primates, Intellia scientists discovered that editing had taken place at low levels in organs other than the liver, including the spleen and adrenal glands. In three out of 12 female monkeys, they also found editing in the animals’ ovaries.

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