City Therapeutics, one of BioSpace’s NextGen companies for 2026, was started by RNA royalty John Maraganore, former CEO of Alnylam.
City Therapeutics is beefing up its bank account with a fresh infusion of $99.5 million that it will use to advance its pipeline of RNA interference medicines.
The biotech’s lead asset is CITY-FXI, which is designed to prevent the formation of dangerous blood clots while also avoiding increasing the risk of bleeds. CITY-FXI, which targets the coagulation protein Factor XI, is in Phase 1 development for thromboembolic diseases.
City is also working on a therapy for Stargardt disease and three other undisclosed targets, according to the company’s pipeline page, though all of its other programs have yet to enter the clinic.
Aside from building out its pipeline, City will also use some of the new series B haul for its next-generation RNAi engineering platform and for other “business development activities”—though the biotech didn’t say if it had any major deals in the works at the moment.
City launched in October 2024 with $135 million in series A firepower and a mission to advance the field of RNA interference, developing next-generation siRNA medicines for diseases that don’t typically fall within the ambit of RNAi approaches.
The biotech made it to BioSpace’s NextGen class of 2026, ranking among the industry’s most exciting and promising early-stage players. That much is no surprise, given that City was launched by John Maraganore, former CEO of Alnylam and a well-known name not just in the RNA field but also across biotech more broadly. Maraganore is City’s co-founder and executive chairman.
“This Series B financing reflects the exceptional progress our team has made in delivering on our mission to lead the next generation of RNAi-based medicines,” Maraganore said in a prepared statement. “The advances our team is making with our next-generation RNAi platform speak to the breadth of what is possible beyond traditional RNAi.”
In particular, City’s platform relies on so-called trigger molecules, which the biotech pairs with precise targeting ligands that can bring these payloads to a wide range of tissue types—expanding the coverage of RNAi medicines beyond just the liver and, potentially “fueling a new era of therapeutic discovery,” according to the company’s website.
In May 2025, Biogen bought into the potential of City’s platform, betting up to $1 billion in a research partnership to develop an RNAi therapy for an undisclosed central nervous system disease.
City’s series B round counts among its backers Regeneron Ventures, ARCH Venture Partners and Rock Springs Capital, according to a news release. City has also won over two new big-name investors in Sofinnova Investments and Viking Global Investors.
Correction (June 8): This story has been updated to avoid implying that John Maraganore is City Therapeutics’ CEO. That role belongs to Andy Orth, while Maraganore is City’s co-founder and executive chairman. Additionally City Therapeutics is based in Cambridge, Mass., not California. BioSpace regrets the errors.
