BISCHOFBERGER NORBERT W → Kronos Bio, Inc.

Item 4 of the Original Schedule 13D is hereby amended and supplemented by adding the following paragraph at the end of Item 4: On June 20, 2025 (the "Effective Time") the Issuer completed the transactions contemplated by the Agreement and Plan of Merger, dated as of May 1, 2025 (the "Merger Agreement") by and among the Issuer, Concentra Biosciences, LLC ("Concentra") and Concentra Merger Sub IV, Inc., a wholly owned subsidiary of Concentra (the "Merger"). Pursuant to the Merger, the Issuer became a wholly-owned subsidiary of Concentra. In addition, pursuant to the Merger Agreement, at the Effective Time, Norbert Bischofberger, Ph.D. ceased to be a director of the Issuer. At the Effective Time of the Merger each issued and outstanding share of the Issuer's Common Stock was automatically converted into the right to receive (i) $0.57 in cash, without interest (the "Per Share Cash Consideration") and (ii) one contractual contingent value right pursuant to the CVR Agreement in the form attached as Exhibit A to the Merger Agreement (a "CVR" and together with the Per Share Cash Consideration, the "Merger Consideration"). Each CVR represents the right to receive certain contingent cash payments. In addition, pursuant to the Merger Agreement, immediately prior to the Effective Time, each outstanding stock option to purchase shares of the Issuer's Common Stock (each, a "stock option") became immediately vested and exercisable in full. At the Effective Time, each outstanding stock option was cancelled and converted into the right to receive the equivalent Merger Consideration. Accordingly, as of June 20, 2025, the Reporting Persons ceased to have beneficial ownership of any shares of Common Stock.