Zag Bio launches with $80 million financing

29 October 2025

US biotech Zag Bio announced the company’s launch with $80 million in financing, including a recently closed Series A financing.

Polaris Partners founded and incubated Zag Bio and co-led the Series A financing with the T1D Fund, with participation from Mission BioCapital, AbbVie Ventures, Lightspeed Ventures, Sanofi Ventures, KdT Ventures, Regeneron Ventures, Boxer Capital and Pear VC.

Zag Bio has discovered a novel approach to deliver tolerizing antigens to the thymus to achieve durable antigen-specific central tolerance to treat autoimmune disease.

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