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Startup Prime Medicine emerges with $315m to pioneer a new type of gene editing

The Cambridge company was founded by David Liu, a researcher at the Broad Institute of MIT and Harvard

Keith Gottesdiener is the CEO of Prime Medicines.Courtesy of Prime Medicine

Less than two years after the discovery of a new approach to gene editing, a startup founded by David Liu, a researcher at the Broad Institute of MIT and Harvard, is coming out of stealth mode with $315 million in financing.

Cambridge-based Prime Medicine is one of many companies working on new ways to treat diseases by making changes to DNA. The firm has been operating quietly since the science behind its method, dubbed “prime editing,” was published in the scientific journal Nature in 2019.

After fielding interest from investors who had previously worked with Liu, Prime was formed shortly after the article’s publication with an initial $115 million from ARCH Venture Partners, F-Prime Capital, GV, and Newpath Partners. The company also attracted Keith Gottesdiener as its chief executive, who led Boston-based Rhythm Pharmaceuticals for nine years. He helped Prime raise another $200 million less than a year after it began operating, bringing on 10 new investors.

Some of the same investors backing Prime also placed a bet on Liu’s Beam Therapeutics, which he founded in 2017. Beam, now a publicly traded company, is centered around another technology Liu invented called base editing, which allows scientists to change individual letters of DNA.


Gottesdiener said prime editing resembles a word processor, allowing scientists to “search and replace” DNA through a variety of steps.

“If you want to find a spelling mistake, [a word processor] can find the mistake, and if you tell it how to correct it, it corrects it immediately,” he said. “When you are done, the sentence still makes sense, and nothing else has been touched in your manuscript.”

(Cambridge-based Tessera Therapeutics, which raised more than $230 million in January, is pioneering what its chief executive Geoffrey von Maltzahn calls “gene writing,” another new editing technology.)


Gottesdiener said the goal of prime editing is to halt, cure, or prevent diseases. If it works, he said, the technique could be more precise than other genome editing methods. The company plans to first advance programs for liver, eye, and brain conditions, but Gottesdiener said the technology could potentially address more than 90 percent of known disease-causing mutations, or errors in human genes.

Gottesdiener, who joined the company last summer as its third employee, said Prime aims to double its 50-person workforce by the end of the year. He said clinical trials in humans are likely a few years away.

So far, Prime has been propelled by an early partnership with Beam, which it entered to in part to make sure the companies do not interfere with each other as Prime ramps up operations, Gottesdiener said. Under that agreement, Prime gave Beam the right to use prime editing for certain therapeutic areas.

“[Beam] in turn agreed to license us all of their technology for [drug] delivery, manufacturing, assays ... all of the hard work you have to do to make something a drug,” he said. “We really got a huge jumpstart.”

Other than the agreement with Beam, Gottesdiener said, Prime would focus on developing, testing, and commercializing its own drugs, rather than licensing prime editing to other drug makers. But Gottesdiener said Prime may eventually partner with other companies that focus on gene therapy delivery to help get its therapies to patients.

Anissa Gardizy can be reached at Follow her on Twitter @anissagardizy8 and on Instagram @anissagardizy.journalism.