California-based Attovia Therapeutics, Inc. (Nasdaq: ATTO) priced an upsized initial public offering of 17 million shares at USD 17.00 per share on August 4, 2026, raising USD 289.0 million in gross proceeds. The clinical-stage immunology specialist is centered around a biparatopic biologics platform that has attracted USD 255.8 million in private backing prior to going public.
The offering was upsized from its original filing, with underwriters holding a 30-day option to purchase up to an additional 2,550,000 shares at the offering price, which would bring total gross proceeds to approximately USD 332.4 million if exercised in full. Shares were expected to begin trading on the Nasdaq Global Market on August 5, 2026 under the ticker ATTO. Morgan Stanley, Leerink Partners, Citigroup, and RBC Capital Markets acted as joint book-running managers.
Attovia raised USD 255.8 million in private capital since its founding in 2023, according to its S-1 filing. Institutional investors holding 5% or greater pre-IPO stakes include Deep Track Capital, Frazier Life Sciences, Goldman Sachs Alternatives, and venBio.
Attovia was co-founded with Alamar Biosciences Inc, which licensed its ATTOBODY platform to the company as the basis for its therapeutic pipeline. The ATTOBODY platform engineers molecules using paired heavy-chain antibody variable domains — known as VHHs or nanobodies — in a biparatopic format, enabling the production of monospecific, bispecific, and trispecific biologics. All pipeline candidates have been internally discovered using this platform.
The company's lead asset, ATTO-1310, is a half-life extended IL-31-targeting fusion protein in Phase I development for chronic pruritic diseases, including chronic pruritus of unknown origin and high-itch atopic dermatitis. The filing states that Phase I dosing in healthy volunteers and patients was completed in Q1 2026, and that initial data demonstrated favorable tolerability, low immunogenicity, and pharmacokinetic and target engagement profiles consistent with a potential quarterly subcutaneous dosing regimen; rapid, deep itch relief was also reported in patient cohorts, according to the S-1.