Gyre picks up Cullgen for its degraders

The fibrosis specialist Gyre Therapeutics is branching out into degraders, buying the private US and China-based group Cullgen in an all-stock deal worth $300m. Cullgen is developing various degraders and degrader-antibody conjugates in oncology, although it also has a presence in inflammatory diseases and pain, which might have tempted Gyre.

Cullgen’s lead cancer assets are CG001419 and CG009301, degraders of TRK and GSPT1 respectively. Both went into human trials in China in the past few years.

Although Cullgen will be run as a subsidiary of Gyre, in some ways this deal looks more like a merger. Cullgen’s current chief executive officer, Ying Luo, is set to lead the new company, while Gyre’s chief exec, Ping Zhang, will become executive chairman.

Different TRK

NTRK genes encode the tropomyosin receptor kinase (TRK) proteins, and inhibitors of NTRK are already FDA-approved, such as Roche’s Rozlytrek and Bayer/Lilly’s Vitrakvi. However, no other TRK degraders are in development, according to OncologyPipeline, and toxicities associated with this target will have to be closely watched with CG001419.

Meanwhile, there’s more activity in GSPT1 degradation, with Monte Rosa Therapeutics looking the most advanced. That company has said it plans to start a phase 2 study this year of its molecular glue degrader MRT-2359 in combination with a second-generation AR-inhibitor in patients with metastatic castrate-resistant prostate cancer and AR mutations.

Notably, Cullgen is investigating CG009301 in haematologic malignancies, while most of its rivals are aiming at solid tumour indications.

Another approach here comes from Bristol Myers Squibb, whose BMS-986497 is a degrader-antibody conjugate targeting CD33, and uses a GSPT1 degrader payload. The project went into the clinic in 2024 and came via a deal with Orum Therapeutics. However, Orum last year terminated a phase 1 trial of its HER2-targeting, GSPT1 degrader-based ORM-5029.

Degrader-antibody conjugates

Cullgen hasn’t said much about its own degrader-antibody conjugates, apart from that they target undisclosed epigenetic and transcriptions factors.

The company’s cancer portfolio is rounded out by a CDK2 degrader – a field that also features BeOne and NiKang.

Cullgen also has a collaboration with Astellas dating back to 2023, covering multiple targeted protein degraders. Not much information has been released, but Astellas’s latest earnings presentation notes a Cullgen-partnered cell cycle protein degrader in cancer at the discovery stage.

This isn’t the first time Cullgen, which is headquartered in San Diego but also has operations in China, has been on the auction block. In late 2024 the company announced a proposed merger with Pulmatrix, but this wasn’t cleared by Chinese regulators, and last December the companies granted each other a waiver to explore other deals.

Now Cullgen has found a buyer in San Diego-based Gyre. It could soon become apparent how interested its suitor is in the oncology programmes.

Cullgen’s cancer pipeline

Notes: *also hits SALL4 & NEK7; **NiKang also has CDK2/4 degrader, NKT5097. Source: company website & OncologyPipeline.