City Therapeutics, a young biotechnology firm working on new RNA interference therapies, has banked $99.5 million to fund further testing of its medicines, the company said Tuesday.
Dubbed “CITY-FXI,” City’s lead program targets a critical blood-clotting protein called Factor XI and recently entered Phase 1 testing for thromboembolic conditions such as pulmonary embolisms, strokes and deep vein thrombosis. The treatment is designed to reduce the risk of bleeding, which CEO Andy Orth said could make it an ideal drug for patients who can no longer take, or are not qualified to receive, available blood-thinning drugs. Factor XI is the target of multiple therapies that are already in late-stage testing.
Behind CITY-FXI is a second experimental medicine called “CITY-RBP4,” which is expected to enter human testing later this year for Stargardt disease, a genetic eye condition that is the focus of several other medicines in development.
Some companies are working on gene therapies or RNA editing treatments to correct the underlying genetic defects linked to Stargardt. City is instead using RNA interference to reduce expression of a liver protein called RBP4 that ferries vitamin A to the eye. In Stargardt, this process goes haywire, leading to the toxic accumulation of vitamin A byproducts in the eye. Silencing the gene that produces RBP4 might prevent that from happening.
