Third Arc Bio Closes $52M Series A Extension to Accelerate Oncology &…

Team S · 2026-02-04T14:13:44.000Z

Third Arc Bio Inc., a clinical-stage biotech company focused on developing novel multifunctional antibodies for oncology and immunology & inflammation (I&I) indications, has announced the closing of a $52 million Series A extension financing round. The new capital will fuel the company’s expansion of its I&I portfolio and advancement of additional oncology programs into clinical development, reinforcing its capabilities to address diseases with high unmet medical need. The Series A extension builds on Third Arc Bio’s earlier $165 million Series A financing and brings new investor Andreessen Horowitz (a16z) into the syndicate while continuing backing from its world-class investor base. As part of the financing, a16z General Partner Jorge Conde is joining Third Arc Bio’s Board of Directors, underscoring strong confidence in the company’s scientific platforms and strategic direction. Third Arc Bio was launched in 2022 with seed funding from Omega Funds and has rapidly assembled an experienced team with a track record of drug discovery and development. Its lead asset, ARC101, is a bispecific T cell engager targeting CLDN6 that is currently in Phase 1 dose escalation in patients with advanced solid tumors. The company’s platform technologies, including its ARCTag (Tethered Agonist) Platform, aim to precisely localize immune modulation directly to disease sites, representing a targeted advance over conventional systemic therapies. Third Arc Bio’s leadership says the new funding will maintain momentum across its expanding oncology portfolio while rapidly advancing next-generation I&I assets into first-in-human studies, enhancing its ability to generate proof-of-concept data and deliver innovative therapies for patients with significant unmet needs.

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Third Arc Bio Closes $52M Series A Extension to Accelerate Oncology &… | Newnex