San Diego-based Gyre Therapeutics (Nasdaq: GYRE) has completed the acquisition of Cullgen Inc., a privately held, clinical-stage biopharmaceutical company focused on targeted protein degradation, operating out of Shanghai and the US. The all-stock transaction is valued at approximately USD 300 million, and creates a dual US-China integrated biotech company spanning commercial, Phase III, and early-stage programs across fibrosis, inflammatory diseases, and oncology.
Cullgen becomes a wholly owned subsidiary of Gyre following the close, with Cullgen's former chief executive officer Dr. Ying Luo appointed President and Chief Executive Officer of the combined entity and added to Gyre's Board of Directors. The combined company continues to trade on the Nasdaq Capital Market under the ticker GYRE.
Platform and Pipeline: Cullgen's technical core
Cullgen's primary contribution to the combined entity is its targeted protein degrader platform and a clinical-stage pipeline built on that foundation. The lead Cullgen asset, CG001419, is an oral pan-TRK degrader currently in Phase I/II evaluation across two indications: acute post-operative pain and solid tumors harboring NTRK abnormalities. A second named program, CG009301, was also referenced in the transaction announcement, alongside earlier-stage degrader-antibody conjugate programs.
Degrader-antibody conjugates, or DACs, combine the target-selectivity of monoclonal antibodies with intracellular protein degradation via the ubiquitin-proteasome system, enabling delivery of degrader payloads to specific cell populations. This approach addresses a key limitation of conventional small-molecule targeted protein degraders, which lack cell-type selectivity. Cullgen's platform, designated ULF-PROTAC, underpins both its small-molecule TPD and DAC programs.
Gyre's own lead asset, F351 (hydronidone), a structural analogue of pirfenidone, anchors the combined company's near-term regulatory pipeline. F351 received priority review designation from China's National Medical Products Administration Center for Drug Evaluation in March 2026 for its NDA in chronic hepatitis B-associated liver fibrosis, following a pivotal Phase III trial that demonstrated statistically significant fibrosis regression at 52 weeks. Gyre has also indicated it is evaluating F351 development in ex-China territories, including the United States.
The commercial layer of the combined entity rests on Etuary (pirfenidone), marketed in China through Gyre Pharmaceuticals, a subsidiary in which Gyre Therapeutics holds a 69.7% equity interest. Etuary was the first approved treatment for idiopathic pulmonary fibrosis in China and has maintained commercial presence since 2011. Enrollment has been completed in a 52-week Phase III trial of Etuary for pneumoconiosis, and the first patient has been enrolled in a Phase III study evaluating the drug in radiation-induced lung injury with or without immune checkpoint inhibitor-related pneumonitis.