Tomeadds California biotech

CEO foresees ‘quantum leap’ in genomic editing

Tome Biosciences, a Watertown company that emerged from stealth mode last month with $213 million in funding and a novel approach to gene editing, said Tuesday that it will buy a San Francisco biotech to augment its technology.

The acquisition of Replace Therapeutics, which has explored ways to cure diseases by making small but precise DNA edits, will complement Tome’s own MIT-licensed technology, which can modify larger sequences of genetic code, said Tome chief executive Rahul Kakkar.

“Our technology is remarkably flexible,” Kakkar said in an interview. “This represents a maturation of gene editing where we can move from the early drugs for rare diseases to applications for more common diseases. We can create the full panoply of genomic medicines.”

The formal launch of Tome and its buyout of Replace come just as regulators in the United States and Europe have approved the first gene-editing drug. That treatment, for sickle cell disease, was developed by Boston’s Vertex Pharmaceuticals and CRISPR Therapeutics, a Swiss biotech that does much of its research in South Boston.

That first therapy uses an enzyme known as CRISPR-Cas9, which works like a pair of molecular scissors to cut out a gene in patients’ cells. Tome’s technology, working alongside CRISPR-Cas9, can add and replace DNA sequences rather than simply snipping them out.

The technology was discovered by Tome cofounders Jonathan Gootenberg and Omar Abudayyeh, both protegees of CRISPR pioneer Feng Zhang at the Broad Institute of MIT and Harvard. Their approach promises a “quantum leap” in gene editing, Kakkar said.

Replace’s technology, meanwhile, combines CRISPR-Cas9 with another enzyme to precisely manipulate small

sequences of DNA. Under the purchase agreement announced Tuesday, venture-backed Tome will pay $65 million upfront for Replace along with up to $185 million more if its technology meets certain milestones.

Kakkar likened the two companies’ research tools to the iPhone and Apple Watch, saying Tome hopes to amass a portfolio of technologies that can be effective against a broad range of maladies. He declined to specify the experimental drugs in its pipeline, however, promising that Tome will disclose its lead drug candidates later in 2024.

When the company came out of stealth mode, it had already been working on drug discovery for two years, assembling a team of 140 scientists, researchers, and manufacturing specialists operating out of converted space in the old Watertown Arsenal. Kakkar said the research done by Replace will be transferred from San Francisco to Watertown.

Tome’s investors are a mix of local venture firms, such as Longwood Fund and Polaris Partners, and Silicon Valley heavyweights, such as Andreessen Horwitz and GV Management. Other backers include ARCH Venture Partners, Fujifilm, Alexandria Venture Investments, and Brucker Corp.