Prime editing deal flurry to nail down patent rights

Tome Biosciences came out of stealth mode on 12 December with a haul of over $200 million to develop the company’s gene editing platform. Tome’s first order of business was to snap up Replace Therapeutics to expand its toolkit to one equipped to make gene edits in DNA sequences big and small.

Tome’s own genomic technology, mediated by an integrase, is well suited to large DNA up to tens of thousands of kilobases long. Replace’s CRISPR–Cas9 ligase-mediated platform, by contrast, is adept at inserting and deleting small DNA sequences of 10–100 base pairs. Having both of these technologies in its pocket, says Tome CEO Rahul Kakkar, means that the company can potentially replace an entire gene with a wild-type version rather than correct a defective version, and without requiring double-stranded breaks in DNA.

The merger, worth $65 million up front and potentially up to $185 million total for Replace, is one of the largest acquisitions in the booming prime editing field. Although Kakkar says that the acquisition was driven not by patent coverage but to expand Tome’s gene editing toolkit...