aibioCity Therapeutics raises $200 million in upsized IPO priced at $18
The Cambridge RNAi developer sold 11.1 million shares at the midpoint of its range. Its lead drug, a Factor XI siRNA for blood clots, has more phase 1 data due in late 2026.
Key facts
- Companies
- City Therapeutics, Inc. (NASDAQ: CTY), Silence Therapeutics plc (NASDAQ: SLN)
- News type
- Financings
- Primary source
- Renaissance Capital
City Therapeutics priced its initial public offering on October 15, selling 11,111,111 shares at $18.00 each for gross proceeds of about $200 million. The stock began trading on the Nasdaq Global Market on October 16 under the ticker CTY, and the company expected the deal to close on October 19.
The price was the midpoint of the $17 to $19 range and gave the Cambridge, Massachusetts company a fully diluted market value of about $1.0 billion, according to Renaissance Capital. The shares opened at $23.00 on their first day, 27.78% above the offer price, IPO Scoop reported.
The details
City set terms on October 9 at 9.7 million shares, or about $175 million, then upsized the deal. Underwriters have a 30-day option to purchase up to 1,666,666 more shares. Goldman Sachs, Jefferies, Stifel and Oppenheimer ran the books.
The company develops RNA interference drugs. Its lead candidate, CITY-FXI, is a GalNAc-conjugated siRNA that targets Factor XI, a clotting protein, for thromboembolic diseases. A phase 1 trial started in 2026 with three single-ascending dose cohorts in healthy volunteers, and more data are due in late 2026, Renaissance said. IPO Scoop reported that a phase 2 trial in total knee replacement is expected to start in mid-2027. The other two programs are CITY-RBP4 for Stargardt disease and CITY-TFR2 for anemia of chronic disease.
City is not profitable. For the 12 months ended June 30, 2026, it reported a net loss of $87.67 million and collaboration revenue of $14.34 million.
Context
The IPO follows a $99.5 million Series B in June with new investors Viking Global, Sofinnova Investments, Casdin Capital and NYBC Ventures, with Regeneron Ventures, Arch Venture Partners and Fidelity already on the cap table. Fierce Biotech reported that the company was backed from the start by Alnylam veterans John Maraganore, Mark Keating and Tracy Zimmermann.
Its collaboration revenue comes from partners. In May 2025, Biogen agreed to pay City $16 million upfront and invest $30 million through a convertible note, with up to about $1 billion in milestones and tiered royalties for a central nervous system target. "Partnering with Biogen represents a meaningful milestone in our mission to expand the therapeutic reach of RNAi," chief executive Andy Orth said at the time. City also has a deal with Bausch + Lomb.
Interest in siRNA drugmakers stayed high after the listing. Three days later, Merck KGaA agreed to acquire Silence Therapeutics for $20 per American depositary share, or $1.3 billion, after phase 2 data for its drug divesiran in polycythemia vera.
What it means for investors
City has raised a large sum on early evidence. CITY-FXI has been tested in healthy volunteers so far, so there is no evidence yet on clotting outcomes in patients. Revenue is partnership income, not drug sales.
The base rates are sobering for a phase 1 asset. Across drugs studied from 2011 to 2020, only 7.9% of candidates that entered phase 1 reached approval, according to BIO, Informa and QLS. The Biogen and Bausch + Lomb deals give City outside validation and some cash, but its value now rests on the Factor XI program working in larger trials.
What to watch
More single-ascending dose data from the CITY-FXI phase 1 trial are expected in late 2026. The phase 2 knee replacement study is planned for mid-2027.