City Therapeutics, a Cambridge RNAi startup co-founded by former Alnylam CEO John Maraganore, has snagged $99.5 million in a Series B round to push its next-generation RNAi programs into the clinic and beef up its Kendall Square footprint. The money lands as the company advances a blood-clotting candidate toward first-in-human testing and continues hiring locally, not a bad trajectory for a company that launched less than two years ago.
Funding and investors
According to the Boston Business Journal, the Series B came to $99.5 million and is earmarked for clinical programs, platform engineering and business development. BioSpace reports that the round brought back existing investors including Regeneron Ventures, ARCH Venture Partners and Rock Springs Capital, while adding new backers such as Sofinnova Investments and Viking Global Investors.
The company formally debuted in October 2024 with a $135 million Series A led by ARCH Venture Partners, as reported by STAT. That initial haul allowed City to bring in scientists and start assembling a pipeline aimed at taking RNAi beyond the liver into tissues such as the eye and the central nervous system.
Pipeline and clinical timeline
In a press release, City Therapeutics said it has submitted a Clinical Trial Application for CITY-FXI, an investigational RNAi therapeutic that targets Factor XI, and plans to start a Phase 1 study. “This CTA filing marks our transition to a clinical-stage company,” Chief Executive Andy Orth said in the release, underscoring the company’s shift from preclinical work into human testing.
Local impact and lab expansion
The new funding also tightens City’s grip on Kendall Square real estate. The Boston Business Journal notes the company has grown to roughly 75 employees in Cambridge and has been adding lab space while it builds out clinical, regulatory and manufacturing capabilities. That expanding footprint places City among a cluster of well-funded Cambridge startups racing to turn early RNA technologies into clinic-ready drugs.
What’s next
Investors will be watching to see whether this fresh capital speeds up IND filings and early clinical readouts. BioSpace notes that City plans to use the Series B proceeds to advance its clinical programs and further develop its next-generation RNAi engineering platform. The company is positioning itself to push additional IND-stage filings and to generate early human data from CITY-FXI as it works to turn preclinical momentum into concrete clinical milestones.
