Synlogic, Inc. (SYBX)

Synlogic was a Cambridge, Massachusetts biotechnology company that worked on engineered bacteria, which it called synthetic biotic medicines, designed to carry out therapeutic functions in the body. The scientific work grew out of synthetic biology research associated with Massachusetts Institute of Technology and Boston University investigators. The company's approach was to modify probiotic bacteria so that they could consume harmful metabolites in the gut or deliver other therapeutic activity locally.

The company became public in 2017 through a reverse merger with Mirna Therapeutics, a Nasdaq-listed company, after which Synlogic's stock traded on Nasdaq under the symbol SYBX. Its early pipeline targeted metabolic diseases, including phenylketonuria, homocystinuria and enteric hyperoxaluria, and also immunological conditions and oncology. It entered collaborations with major companies, including F. Hoffmann-La Roche for inflammatory bowel disease and Ginkgo Bioworks for platform work.

Its lead candidate for phenylketonuria, SYNB1934, entered the Phase 3 Synpheny-3 trial. In February 2024, the company discontinued the trial after an internal review indicated it was unlikely to meet its primary endpoint, a decision it said was not based on safety or tolerability. The setback led the company to stop development of its metabolic programs, cut staff, and begin a review of strategic alternatives as it conserved cash.

As its operations were wound down, Synlogic reduced its workforce to a handful of people and sought a transaction, such as a merger or sale, that could create value for stockholders. On November 21, 2025, Nasdaq staff notified the company that it no longer met the requirements for continued listing under Listing Rule 5101, with the staff reasoning that the company had become a public shell. Synlogic appealed the determination on November 28, 2025 to a Nasdaq Listing Qualifications Hearings Panel.

On January 16, 2026, the Panel issued its decision and the staff determination became final, and trading in Synlogic's common stock was suspended on Nasdaq effective January 21, 2026. The shares began trading on the OTC markets under the same symbol, SYBX. Nasdaq then filed with the SEC to complete the removal of the stock from listing, and the delisting took effect at the opening of trading on May 28, 2026.

As of its first-quarter 2026 report, Synlogic continued to file reports with the SEC and reported about $14.1 million in cash and equivalents, a single remaining full-time employee supported by consultants, and an accumulated deficit of about $442 million. It stated that it was pursuing a strategic process that could include a merger or sale, with no assurance that a transaction would result, and it did not report a definitive agreement.