PRX 08066

PRX-08066 is a drug discovered and developed by Predix (later Epix) Pharmaceuticals [Dale S. Dhanoa et al. Patent US 7,030,240 B2], which acts as a potent and selective antagonist at the serotonin 5-HT_2B receptor, with a 5-HT_2B binding affinity (K_i) of 3.4nM, and high selectivity over the closely related 5-HT_2A and 5-HT_2C receptors and other receptor targets. PRX-08066 and other selective 5-HT_2B antagonists are being researched for the treatment of pulmonary arterial hypertension, following the discovery that the potent 5-HT_2B agonist norfenfluramine produces pulmonary arterial hypertension and subsequent heart valve damage. In animal studies, PRX-08066 has been found to reduce several key indicators of pulmonary arterial hypertension and improved cardiac output, with similar efficacy to established drugs for this condition such as bosentan, sildenafil, beraprost and iloprost. It is also being researched for potential anti-cancer applications, due to its ability to inhibit fibroblast activation.