Arena BioWorks, a Boston research institute launched in 2024 with $500 million from a group of billionaire backers, confirmed an abrupt shutdown after investors cited deteriorating biotech macro conditions. The closure affects roughly 50 staff remaining after earlier layoffs; Arena will cease internal research and transfer scientific discoveries back to individual scientists for potential follow‑on development. The funders framed the decision as necessary given policy uncertainty and weak funding markets; Arena’s prior workforce reduction and reprioritization of programs foreshadowed the move. STAT and Endpoints reported that the institute had pursued projects across oncology, immunology, and brain health but will halt centralized R&D operations. The shutdown highlights the fragility of privately financed, long‑horizon research models when capital markets tighten, and raises questions about stewardship of in‑progress science and how investigators will translate assets forward.