Over a year after first agreeing to a reverse merger with Pulmatrix, protein degradation biotech Cullgen has instead opted to be bought by Gyre Therapeutics in a $300 million all-stock acquisition.
San Diego-based Cullgen has been developing targeted protein degrader and degrader-antibody conjugate therapies. The biotech’s lead clinical-stage asset is CG001419, an oral pan-TRK protein degrader, which the company has touted as part of a new class of pain signaling channel modulators.
Cullgen has been aiming to move CG001419 into a phase 2 study in the U.S. for acute pain after bunion surgery in the first half of 2026, and it already has the drug in a phase 1 study for solid tumors. There’s also a GSPT1 degrader in the clinic for the treatment of blood cancers.
Back in November 2024, privately listed Cullgen announced plans to merge with Pulmatrix in order to take advantage of the inhaled therapeutics company’s Nasdaq listing.
But Cullgen’s decision this morning to instead be bought by Gyre means the Pulmatrix deal has been scrapped. Instead, the $300 million all-stock transaction will result in Cullgen becoming a subsidiary of Gyre.
Gyre, also based in San Diego, is mainly focused on developing the liver fibrosis drug hydronidone, which is being readied for an approval application in China. Through Gyre’s controlling interest in Gyre Pharmaceuticals—also known as Beijing Continent Pharmaceuticals—Gyre already markets Etuary, a capsule of the Esbriet ingredient pirfenidone, in China for idiopathic pulmonary fibrosis.
As part of Monday's deal—which is expected to close in the second quarter—Cullgen’s CEO Ying Luo, Ph.D., will move over to head up Gyre.
Luo said Cullgen “brings strong drug discovery capabilities and a solid preclinical and clinical pipeline to complement Gyre’s existing and highly efficient China-based manufacturing capabilities and sales team.”
“Following the acquisition, we will have a fully integrated biopharmaceutical company that will be capable of leveraging emerging drug discovery capabilities in China and strong clinical development in the U.S. to address unmet medical needs worldwide,” the CEO added.