SYNLOGIC, INC.

We are a biopharmaceutical company that previously developed new treatments for serious diseases, specifically rare metabolic disorders. Our main program, labafenogene marselecobac (SYNB1934), was being studied in Synpheny-3, a global, pivotal Phase 3 study for patients with phenylketonuria (PKU). We also had SYNB1353, a potential treatment for homocystinuria (HCU). Both PKU and HCU are metabolic disorders that require new treatment options due to current limitations in effectiveness and safety. In February 2024, we decided to stop the Synpheny-3 study for labafenogene marselecobac (SYNB1934) for PKU. This decision was made after an internal review, ahead of an independent Data Monitoring Committee (DMC) assessment, indicated that the trial was unlikely to achieve its primary goal. The decision was not related to safety or tolerability concerns. Our current strategy focuses on exploring strategic options to increase stockholder value, such as a merger or selling the company. This process is active and ongoing, involving discussions with potential transaction partners. On November 21, 2025, we received a letter from The Nasdaq Stock Market LLC stating their belief that we were a "public shell," and therefore, our securities' continued listing was no longer justified.