Attovia Therapeutics Raises $289M in Upsized IPO to Advance Biparatopic Nanobody Pipeline in Immunology
核心洞察
Attovia Therapeutics (搜索) priced an upsized IPO of 17 million shares at $17.00 per share, raising $289.0 million in gross proceeds on August 4, 2026.
The clinical-stage immunology company's lead asset ATTO-1310, an IL-31 (搜索)-targeting fusion protein, completed Phase I dosing in Q1 2026 with data showing favorable tolerability and rapid, deep itch relief.
Proceeds will fund clinical development of ATTO-1310 and the bispecific ATTO-2306 (搜索) targeting IL-13 (搜索) and IL-31 (搜索), with remainder allocated to the trispecific ATTO-1091 (搜索) for inflammatory bowel disease (搜索).
Attovia Therapeutics (搜索), Inc. (Nasdaq: ATTO) priced an upsized initial public offering of 17 million shares at $17.00 per share on August 4, 2026, raising $289.0 million in gross proceeds. The California-based clinical-stage immunology company, built around a biparatopic biologics platform, had previously attracted $255.8 million in private backing prior to going public. Shares were expected to begin trading on the Nasdaq Global Market on August 5, 2026 under the ticker ATTO.
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 $332.4 million if exercised in full. Morgan Stanley, Leerink Partners, Citigroup, and RBC Capital Markets acted as joint book-running managers.
The ATTOBODY Platform: Biparatopic Nanobody Engineering
Attovia was co-founded with Alamar Biosciences (搜索) 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 — connected by proprietary linkers in a biparatopic format. This approach enables the production of monospecific, bispecific, and trispecific biologics with tunable affinity, extended half-life, and manufacturability using standard biologic production processes. All pipeline candidates have been internally discovered using this platform.
Lead Asset ATTO-1310: Targeting IL-31 (搜索) in Chronic Pruritic Diseases
The company's lead asset, ATTO-1310, is a half-life extended IL-31 (搜索)-targeting fusion protein in Phase I development for chronic pruritic diseases, including chronic pruritus of unknown origin (搜索), high-itch atopic dermatitis (搜索), cholestatic pruritus, and chronic kidney disease-associated pruritus. According to the S-1 filing, Phase I dosing in healthy volunteers and patients was completed in Q1 2026, and 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.
Pipeline Expansion: Bispecific and Trispecific Candidates
Beyond ATTO-1310, Attovia is advancing two preclinical candidates. ATTO-2306 (搜索) is a bispecific ATTOBODY targeting IL-13 (搜索) and IL-31 (搜索) simultaneously, designed to treat atopic dermatitis (搜索) and other immune-mediated skin diseases. The anti-IL-13 component was derived from lebrikizumab and incorporates a YTE Fc mutation for half-life extension. ATTO-2306 is currently in IND-enabling studies, with a Phase I trial planned for the first half of 2027.
ATTO-1091 (搜索) is a trispecific construct simultaneously inhibiting TL1A (搜索), IL-23 (搜索), and integrin α4β7 (搜索) — three pathways implicated in inflammatory bowel disease (搜索). Also in IND-enabling studies, a Phase I start is planned for the first half of 2027.
Competitive Landscape and Differentiation
The atopic dermatitis (搜索) and pruritic disease space is among the most contested in immunology. Dupixent (dupilumab), co-developed by Sanofi and Regeneron Pharmaceuticals, dominates the IL-4Rα/IL-13 (搜索) segment, while Galderma's nemolizumab targets the IL-31 (搜索) receptor. Attovia's ATTO-1310 targets the IL-31 ligand directly, and ATTO-2306 (搜索) combines IL-13 and IL-31 blockade in a single molecule — a differentiation the company is advancing against existing receptor-targeted approaches. In inflammatory bowel disease (搜索), the TL1A (搜索) space is actively contested by Roche and Sanofi, among others.
Use of Proceeds and Investor Backing
The filing states proceeds will be used to advance ATTO-1310 and ATTO-2306 (搜索) through clinical development, with the remainder allocated to ATTO-1091 (搜索) and general corporate purposes. Institutional investors holding 5% or greater pre-IPO stakes include Deep Track Capital (搜索), Frazier Life Sciences (搜索), Goldman Sachs Alternatives (搜索), and venBio (搜索). Deep Track, a crossover fund active in both private and public biotech markets, is a named pre-IPO holder — a signal investors typically read as supportive of an eventual public offering.