Astellas taps Poseida for second CAR-T deal focused on solid tumors

Astellas Pharma is signing Poseida Therapeutics to a second deal focused on developing off-the-shelf solid tumor cell therapies after the companies first teamed up in 2023.

Gary Starling

An Astellas subsidiary called Xyphos Biosciences plans to use a Poseida CAR-T construct to develop two “convertible” CAR-T therapy candidates for solid tumors. Astellas will pay Poseida $50 million upfront, with another $550 million in potential milestone payments. If a therapy is commercialized, Poseida could also receive low double-digit royalties.

Xyphos has been developing so-called convertible CAR-T therapies, which can be turned on and off using an antibody. The goal with convertible CAR-Ts is to develop a safer option compared to traditional cell therapies. This collaboration combines the Xyphos platform with Poseida’s genetic editing technology, which the company believes can make for more effective solid tumor cell therapies.

“It’s a combination of the two technologies that add a ton of power to the work that we’re doing,” Xyphos president Gary Starling told Endpoints News.

Kristin Yarema

Current CAR-T cell therapies are approved for blood cancers and use a patient’s cells. The treatments that come out of this collaboration would not only be off-the-shelf, meaning that they use T cells from healthy donors, they would also target solid tumors — an area that the CAR-T cell therapy field has yet to crack.

“We have been systematically studying the solid tumor problem in a way that maybe others have not,” Poseida president and CEO Kristin Yarema said. “In particular, we’ve been looking at the importance and role of lymphodepletion strategies in the solid tumor setting. We believe there are some differences and from [hematology] and some learnings there.”

In August, Astellas bought 8.8% of Poseida’s shares for $25 million. It paid another $25 million for the right of first refusal to license the biotech’s lead asset, an early-stage solid tumor CAR-T therapy called P-MUC1C-ALLO1. Poseida hopes the therapy can be applied to a range of cancers, including breast, colon and lung cancer, among others.

In February, Xyphos penned a partnership with Kelonia Therapeutics to research in vivo convertible CAR-T therapies.