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As RNA remains hot, Flagship’s Laronde raises $440m for a new class of medicines

An image of Endless RNA, or eRNA, shows how the molecule invented at Flagship Pioneering can latch onto a ribosome to make proteins.Courtesy of Laronde

Flagship Pioneering, the Cambridge venture capital firm, brought biotech startup Laronde out of stealth mode in May, launching it with $50 million after four years of secrecy.

It was the first time Laronde disclosed its technology: a proprietary molecule its scientists call “endless RNA,” which the company hopes will allow humans to produce their own proteins for weeks or months to treat diseases. Now, three months after making its public debut, Laronde announced it has raised $440 million from investors.

It’s the third-largest biotech funding deal this year in the United States, behind Cambridge biotechs EQRx and ElevateBio, which both raised rounds topping $500 million, according to PitchBook. Investors in Laronde include Flagship, funds and accounts advised by T. Rowe Price Associates and BlackRock, Invus, Canada Pension Plan Investment Board, Fidelity Management & Research Company, and other unnamed entities.


Diego Miralles, the chief executive of Laronde, said the excitement among investors came from the amount of data that Laronde has amassed over the years in animal trials, as well as the company’s bold plan for how to generate 100 new drugs in 10 years.

“As you get the data, it becomes less of an aspiration and more of a reality,” he said. “The company has really large ambitions... and that requires a lot of capital. We want to dominate this space.”

Laronde said it has submitted “multiple” patent applications and has had two published and one granted.

In simple terms, Miralles said that endless RNA — which the company shortens to “eRNA” — will be able to do anything inside the body that a protein can do. The company hopes to achieve that by harnessing the potential of an unusual ribonucleic acid that has a circular shape, unlike the more common RNA molecule, which has a strand with two ends.


Although circular RNA can’t latch onto ribosomes — because it doesn’t have an end — Laronde tweaked the molecule so that it could work with the protein-making machinery of cells, making eRNA a potential way to make therapeutic proteins inside the body. Because of its shape, circular RNA is stable, an attribute that might allow potential therapies to be longer-lasting than other RNA medicines.

Flagship’s previous attempt at turning the human body into a type of drug-making factory led to Moderna, which now uses a synthetic version of messenger RNA to stimulate cells to produce antibodies against COVID-19.

Flagship’s Avak Kahvejian, a cofounder and board member of Laronde, said the ambition is to create a new class of medicine.

“If you are building a new drug class, you don’t make a factory for one product,” he said. “You build a factory for the future that is capable of generating many, many products with the same chemistry, the same underlying technology.”

Kahvejian said it is not a coincidence that the early days of Laronde mirror Moderna, and he thinks the eRNA startup will overcome some of its early challenges.

“Now, we have advances in the manufacturing, advances in the scale, advances in the delivery of nucleic acid medicines, and the list goes on,” he said. “For that reason, the timelines, we believe, are going to be much more quick.”

Miralles and Kahvejian are in no rush to disclose what disease areas Laronde will tackle first, but they said the opportunity is across a dozen areas including genetic diseases, oncology, and dermatology. The company also hopes its eRNA technology will make drugs easier to deliver, potentially topically or through an injection that patients could administer themselves at home.


Laronde has grown to about 70 employees and hopes to reach 100 by the end of the year, at which time it also plans to move into its two floors at the Boynton Yards campus in Somerville, a new lab space expected to open in the coming months. The nine-story building is fully leased by four Flagship companies.

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