Synlogic, Caldera Therapeutics Announce All-Stock Merger
Cambridge, Massachusetts — Synlogic, Inc. and Caldera Therapeutics, Inc. have agreed to merge in an all-stock transaction that will create a publicly traded biotechnology company developing therapies for inflammatory bowel disease and other immune-mediated disorders.
The merged company will operate under the Caldera Therapeutics name and intends to seek a listing on the Nasdaq Capital Market under the ticker “CALD.”
Alongside the merger, Caldera has obtained commitments for a $278 million private placement involving healthcare-focused institutional investors and mutual funds. The financing, combined with cash held by the companies at closing, is expected to support operations into 2029.
Caldera plans to use the proceeds primarily to advance Phase 2 clinical trials of its lead candidate, CLD-423, in ulcerative colitis and Crohn’s disease.
Investors participating in the private placement include Bain Capital Life Sciences, TCGX, Atlas Venture, venBio Partners, Omega Funds, Blackstone Multi-Asset Investing, Wellington Management, Janus Henderson Investors and Vivo Capital, among others.
“In just over a year, we’ve shown our team’s ability to open up a lead with compelling data from a molecule poised to deliver the next horizon of I&I therapy,” Caldera Chief Executive Officer Praveen Tipirneni, M.D., MBA, said. “These transactions provide the capital and public company platform to advance our vision as we move into Phase 2 development in IBD and continue exploring the potential of CLD-423 across additional immune-mediated diseases.”
CLD-423 is an experimental bispecific antibody designed to block both the TL1A and IL-23p19 pathways. Caldera believes that simultaneously targeting the two pathways could produce stronger results than treatments directed at only one of them.
The drug is currently being studied in a Phase 1 trial involving healthy volunteers in Australia. The trial began in January 2026 and has completed dosing.
According to Caldera, results from the first four single ascending-dose groups showed that CLD-423 was generally well tolerated and produced no dose-limiting toxicities.
The candidate also demonstrated a serum half-life exceeding 40 days within the expected therapeutic exposure range and about 80% bioavailability following subcutaneous administration.
Caldera said the results could support maintenance dosing every eight or 12 weeks for patients with inflammatory bowel disease. The company expects to release additional findings from all five single-dose groups and the multiple-dose portion of the study later in 2026.
Caldera holds exclusive global rights to develop and commercialize CLD-423 through a licensing agreement with Qyuns Therapeutics Co., Ltd.
“Following our evaluation of strategic alternatives, we believe this transaction represents the best path forward for our shareholders and an exciting opportunity to support the advancement of an innovative program with the potential to break through the current efficacy ceiling in inflammatory bowel disease,” Synlogic Principal Executive Officer and Principal Financial Officer Mary Beth Dooley said.
Under the agreement, current Synlogic shareholders are expected to own about 2.3% of the combined company. Existing Caldera shareholders will hold approximately 62.8%, while investors participating in the private placement will own about 34.9%.
The final ownership stake for Synlogic shareholders could change depending on Synlogic’s estimated net cash balance before the transaction closes.
The boards of directors of both companies have approved the merger. The transaction is expected to be completed by early 2027, subject to shareholder approvals, the effectiveness of a registration statement filed with the U.S. Securities and Exchange Commission and other customary closing conditions.
Tipirneni will serve as chief executive officer of the combined company, while Caldera’s current directors will join the board of the merged organization.
