Lilly rides TRex into regulatory T-cell space, paying $55M upfront for 3 immune-mediated disease drugs

Johnston Erwin has persuaded some old friends to up their bet on TRexBio. Twenty months after taking over as CEO of the biotech, the Eli Lilly veteran has landed a deal with his former employer that sees the trade of $55 million for exclusive rights to three regulatory T-cell (Treg) programs. 

TRexBio broke cover in the summer of 2021, simultaneously disclosing the appointment of Erwin, a pact with Lilly and the closing of a $59 million series A round. The San Francisco-based biotech attracted the attention on the strength of a platform for discovering ways to modulate Tregs, a subset of T cells that play a key role in tissue inflammation. Johnson & Johnson struck a deal with TRexBio one year ago.

At the time of its initial unveiling, TRexBio said it was collaborating with Lilly on three programs that were past the target identification stage. Now, the Big Pharma has taken up its option on the candidates, paying $55 million upfront and committing up to $1.1 billion in milestones for an exclusive license. 

“This partnership with Lilly, a global leader in the field of immunology, is important validation of our ability to identify and characterize human Treg biology pathways that are meaningful for drug discovery and advances our mission of bringing new medicines to patients,” Erwin said in a statement.

TRexBio has disclosed the names of the three candidates—TRB-031, TRB-041 and TRB-051—but details of how they work remain under wraps. The most advanced of the three programs, TRB-031, has reached the IND-enabling stage, making it the most advanced candidate in the biotech’s pipeline. The other two partnered programs are in lead optimization. 

The candidates are the fruits of a platform designed to address the challenges of studying tissue-resident immune cells, which are hard to access, operate in complex systems and can translate poorly between mouse models and humans. TRexBio’s solution is to combine high-resolution sequencing of human tissue, computational biology tools and scalable translational biology assay systems.