Outrun Therapeutics launches to stabilize proteins

Outrun Therapeutics has launched with $10 million in seed financing. The company spun out of Satpal Virdee’s lab at the University of Dundee and is focused on stabilizing proteins, or keeping important proteins around for longer in the body, by targeting a protein class called E3 ligases.

E3 ligase is crucial in the beginning stages of the ubiquitin pathway, which is the cell’s waste disposal system. E3 tags proteins to signal that they need to be degraded.

Bringing E3 ligase to malformed and disease-causing proteins has opened a door for targeted protein degraders as a new method of treating disease. But in some cases, E3 ligase can mark necessary proteins for degradation as well.

This is where Outrun enters the picture. Instead of targeted protein degraders, Outrun is synthesizing targeted protein stabilizers—small molecules that bind to and inhibit E3 ligase, blocking it from sending beneficial proteins to the protein-shredding machinery.

Outrun’s platform uses engineered protein sensors and a fluorescence-based approach to measure the effectiveness of possible small-molecule E3 inhibitors. Carolyn Porter, the CEO of Outrun, says its platform has a competitive advantage in that it can tell whether a small molecule attached to E3 is just binding to it or actually inhibiting its activity.

The company is leading with its solid-tumor program, though it is also developing a program for neurodegenerative diseases. For solid tumors, Porter says the team is looking to stabilize proteins involved with suppressing tumors, which in some cases E3 ligase can erroneously tag for degradation.

E3 ligases are a widespread protein family, and there are hundreds of types of E3 proteins.

“We have orthogonal assays to manage off-target effects so that we’re confident that we’re designing a very specific inhibitor for the E3 ligase targets we’re pursuing,” Porter says.

Ideally, the company’s expects to release in vivo data for its lead candidate this year, and it expects to enter clinical trials in 2026 or 2027.