Therini Bio raises $36 million in series A

Therini Bio has closed a $36 million series A funding round. The company will use the proceeds to advance its pipeline of drugs that aim to treat neurodegenerative and retinal diseases.

The San Francisco-based company’s hallmark approach is targeting fibrins, which are fibrous proteins that are key components of blood clots. But fibrins also have a second, more deleterious role as a driver of chronic inflammation. Damage to the blood vessels in the blood-brain barrier may lead to a buildup of fibrins. These fibrins can activate the immune system and give rise to neurological disorders such as Alzheimer’s disease and multiple sclerosis. “We believe this chronic, smoldering inflammation is driving disease,” says Therini Bio president and CEO Michael Quigley.

Fibrin’s association with disease has been known for a century, he says, but efforts to target fibrin as a treatment strategy have been mostly unsuccessful. This is because suppressing fibrin’s role in inflammation also deactivates its critical clotting function, leading to a heightened risk of bleeding.

Therini Bio’s solution to decouple fibrin’s dual roles is to inhibit the protein only when it is in the conformational state that triggers inflammation. The company’s lead asset, THN391, is an antibody that selectively binds to inflammatory fibrins and spares those in the coagulation conformation. The fibrin-targeting immunotherapy is on the verge of entering early-stage clinical trials, with an expected readout by the end of 2024. The technology is based on the work of Katerina Akassoglou, a neurologist at the University of California San Francisco.