aibioGyre Therapeutics agrees to acquire Cullgen in all-stock deal valued at about $300 million
Tickers GYRE
Gyre Therapeutics agreed to buy privately held Cullgen in an all-stock deal valued at about $300 million, issuing common stock and Series B convertible preferred. Until stockholders approve the conversion, Gyre may not issue more than 19.99% of its stock, and Cullgen's lead drug has completed only a Phase 1 trial.
Key facts
- Company
- Gyre Therapeutics, Inc. (NASDAQ: GYRE)
- News type
- Financings
- Primary source
- GYRE THERAPEUTICS, INC. Form 8-K filed March 2, 2026 (SEC EDGAR)
Gyre Therapeutics, Inc. (Nasdaq: GYRE) agreed on March 2, 2026 to acquire Cullgen Inc. in an all-stock transaction that values Cullgen at approximately $300 million. The company disclosed it in a Form 8-K filed the same day. The deal has not closed; the companies expect it to close early in the second quarter of 2026, subject to customary conditions and US regulatory approvals.
How the deal is built
Under the merger agreement, Helix Merger Sub Corp., a wholly owned Gyre subsidiary, will merge into Cullgen, which will survive as a wholly owned Gyre subsidiary.
Cullgen shares convert into Gyre stock at an exchange ratio of 0.4753. Certain designated Cullgen holders receive Gyre Series B Convertible Preferred Stock, equal to the exchange ratio divided by five for each Cullgen common share. All other holders receive Gyre common stock. Each Series B share converts into five common shares after a Gyre stockholder vote the filing calls the Conversion Proposal.
The merger requires approval by the requisite Cullgen stockholders and a filing under the Hart-Scott-Rodino Antitrust Improvements Act. The merger itself does not need Gyre stockholder approval; only the preferred conversion goes to a Gyre vote.
The 19.99% cap
Until the Conversion Proposal is approved, Gyre may not issue more than 19.99% of its outstanding common stock or its voting power. Gyre will hold a stockholder meeting on converting the preferred into common stock under Nasdaq rules and intends to file a proxy statement.
Certain Gyre officers, directors and stockholders signed support agreements to vote for the Conversion Proposal. The filing does not say how much stock they hold. Certain executives, directors and stockholders of both companies also signed lock-up agreements. Subject to exceptions, they may not transfer their Gyre shares for 180 days after closing for one-third of their shares, for twelve months for another third and for eighteen months for the last third. At closing Gyre will sign a Registration Rights Agreement and must file a resale registration statement within 45 calendar days, then use reasonable best efforts to have it declared effective within 90 business days, or 120 calendar days after a full SEC review.
What Cullgen has
The release describes Cullgen as a privately held, clinical-stage company developing targeted protein degrader and degrader antibody conjugate therapies. Its lead candidate, CG001419, has completed a Phase 1 trial in acute post-operative pain. Cullgen recently submitted an investigational new drug application for a Phase 2 trial in acute pain.
The release says Cullgen released "positive top-line results" from that trial in late 2025 but gives no efficacy or safety numbers. The drug is an oral pan-TRK degrader also in a Phase 1 solid tumor trial. Its second candidate, CG009301, is a GSPT1 degrader in a Phase 1 trial for blood cancers. Nothing in the release shows a Cullgen drug past Phase 1.
Gyre's business and its China products
Gyre calls itself a commercial-stage biopharmaceutical company "dedicated to advancing fibrosis-first therapies." Its annual report for 2024 says it develops and commercializes small-molecule anti-inflammatory and anti-fibrotic drugs, built on ETUARY (pirfenidone).
The release says ETUARY is on the market in China for the treatment of lung fibrosis. It also says the company plans to submit a new drug application for Hydronidone for conditional approval in the first half of 2026.
Leadership and advisers
Directors Thomas Eastling and Songjiang Ma will resign from the Gyre board immediately before the effective time, and Ma will also leave his post as Gyre's President. The board will shrink to seven directors. Ying Luo, Ph.D., age 60, Cullgen's chairman and chief executive since 2018, will become Gyre's Chief Executive Officer and President and a Class I director. The release says Ping Zhang, interim chief executive and Executive Chairman, will remain Executive Chairman.
Moelis & Company LLC is financial advisor to the special committee of Gyre's board. Gibson, Dunn & Crutcher LLP is Gyre's legal counsel. Mintz, Levin, Cohn, Ferris, Glovsky & Popeo, P.C. is legal counsel to Cullgen.
What is not disclosed
The 8-K and the release give no Gyre cash, loss or share-count figures, so the $300 million value cannot be set against Gyre's finances or its dilution at signing.