Astellas shells out $35M upfront to Cullgen in protein degrader development deal

Astellas is expanding its mark in the growing protein degradation space with a potential $1.9 billion deal with San Diego and Shanghai-based Cullgen.

Cullgen, which closed a $50 million Series B round in 2021 to develop its protein degradation platform and pipeline, will get an upfront payment of $35 million from the pharma giant. An additional $85 million is at stake if Astellas uses a license option for the already-identified lead program: a cell cycle protein degrader for the treatment of breast cancer and other solid tumors.

Total compensation to Cullgen “could exceed” $1.9 billion if Astellas exercises all license options and a candidate hits all milestones. Cullgen is also eligible to receive royalty payments for any commercial sales of a finished product.

Cullgen and Astellas will develop multiple targeted protein degrader candidates collaboratively by combining Cullgen’s platform featuring E3 ligands, dubbed uSMITE, with Astellas’ drug discovery expertise.

Targeted protein degradation is a primary focus for the Japanese drugmaker “and will ultimately lead to the expansion of Astellas’ portfolio and development of new therapeutics for patients with significant unmet medical needs,” Astellas chief strategy officer Adam Pearson said in a statement.

Astellas could exclusively license the rights for development and commercialization of the protein degrader compounds, though Cullgen could also get a piece of the pie with an option to participate equally in the costs, profits and losses during the first stages of clinical development. Cullgen and Astellas may also co-promote any US products developed for the solid tumor-focused lead program.

Ying Luo

“We are excited to enter into this strategic collaboration with Astellas using our novel E3 ligands, which we discovered in-house,” Cullgen president and CEO Ying Luo said in a statement.

The protein degradation space has erupted in the last few years, with investors goggling at the idea of eliminating problematic proteins via the body’s natural garbage disposal system. Big Pharmas have taken note.

Pfizer shelled out $1 billion upfront in 2021 to collaborate with Arvinas on a breast cancer candidate. Arvinas was the first drugmaker to reach the clinic with a targeted protein degrader back in 2019, which led Bayer to wager $115 million on the company that year on the potential of Arvinas’ tech platform, which uses an E3 ligase to tag target proteins with a ubiquitin, flushing these disease culprits down the cell’s natural “garbage disposal.”

In March, Gilead exercised its option to exclusively license Nurix’s investigational targeted protein degrader molecule NX‑0479. The protein degrader is the first development candidate resulting from the companies’ collaboration to develop protein degradation therapies.

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