prx-08066 prx-08066 prx-08066 is a drug discovered and developed by predix (later epix) pharmaceuticals , which acts as a potent and selective antagonist at the serotonin 5-ht2b receptor, with a 5-ht2b binding affinity (ki) of 3.4nm, and high selectivity over the closely related 5-ht2a and 5-ht2c receptors and other receptor targets. prx-08066 and other selective 5-ht2b antagonists are being researched for the treatment of pulmonary arterial hypertension, following the discovery that the potent 5-ht2b 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. prx-08066identifiers iupac name 5-((4-(6-chlorothienopyrimidin-4-ylamino)piperidin-1-yl)methyl)-2-fluorobenzonitrile cas number866206-54-4 ypubchem cid11502243chemspider9677045unii82sk298ebucomptox dashboard (epa)dtxsid60235710 chemical and physical dataformulac19h17clfn5smolar mass401.89 g·mol−13d model (jsmol)interactive image smiles s3c2ncnc(c2cc3cl)nc4ccn(cc4)cc(ccc1f)cc1c#n