Organization

Synlogic, Inc., together with its wholly owned and consolidated subsidiaries (Synlogic or the Company), is a biopharmaceutical company that previously advanced novel therapeutics to transform the care of serious diseases. The Company focused on rare metabolic disorders, with its lead program, labafenogene marselecobac (SYNB1934), studied in Synpheny-3, a global, pivotal Phase 3 study for patients with phenylketonuria (PKU), and SYNB1353, a potential treatment for homocystinuria (HCU). Both PKU and HCU are caused by inborn errors of metabolism, and present significant need for innovation due to limitations of both efficacy and safety in the currently available medical treatment options. Since incorporation, the Company has devoted substantially all of its efforts to the research and development of its product candidates.

In February 2024, the Company and its board of directors decided to discontinue the Synpheny-3 trial and to conduct a comprehensive review of strategic alternatives. The Company also announced a corporate restructuring that resulted in a reduction in its workforce, leaving one remaining full-time employee. In addition, the Company engaged consultants to, among other things, support the strategic review process and current business operations.

On July 28, 2026,the Company entered into an Agreement and Plan of Merger (the Merger Agreement) with Caldera Therapeutics, Inc. (Caldera), a privately-held company based in Cambridge, Massachusetts, and certain newly formed subsidiaries of the Company. Pursuant to the Merger Agreement, and upon the terms and subject to the satisfaction or waiver of the conditions described therein, Synlogic will be merged with and into a merger subsidiary of a newly formed parent company, Sonic Holdco, Inc. (Parent), with Synlogic surviving as a wholly owned subsidiary of Parent, and Caldera will be merged with and into a separate merger subsidiary of Parent, with Caldera surviving as a wholly owned subsidiary of Parent. Upon completion of the transaction, the combined company is expected to operate under the name Caldera Therapeutics, Inc. and focus primarily on advancing Caldera’s development of CLD-423, a potential first-in-class bispecific antibody targeting the clinically validated IL-23p19 and TL1A pathways for the treatment of inflammatory bowel disease (IBD) and other immune-mediated diseases. Closing of the planned mergers (the Caldera Mergers) is subject to certain closing conditions, including, among others, approval by the stockholders of each company, the effectiveness of a registration statement filed with the U.S. Securities and Exchange Commission (the SEC) to register the securities to be issued in connection with the Caldera Mergers and the satisfaction of other customary closing conditions. The percentage of the combined company that pre-closing Synlogic security holders will own as of the closing of the Caldera Mergers is subject to adjustment based on the valuation of Synlogic immediately prior to the closing.

Going Concern and Liquidity

The Company’s interim unaudited consolidated financial statements have been prepared assuming it will continue as a going concern. The going concern assumption contemplates the continuity of operations, and the realization of assets and the satisfaction of liabilities in the ordinary course of business. The Company has historically generated negative cash flows from operations and has an accumulated deficit of $442.5 million at June 30, 2026. At June 30, 2026, the Company had $13.2 million in unrestricted cash and cash equivalents. The Company has determined its current cash and cash equivalents as of June 30, 2026 will be sufficient to fund its operations at the current levels for at least the next 12 months from the date of this filing.