prx-08066

PRX‑08066 is a potent and selective small molecule antagonist of the serotonin 5‑HT₂B receptor. It was discovered and developed by Predix (later Epix) Pharmaceuticals for the treatment of pulmonary arterial hypertension (PAH) and chronic obstructive pulmonary disease (COPD) with associated pulmonary hypertension. The drug acts by selectively blocking the serotonin 5‑HT₂B receptor, which is upregulated in patients with PAH and contributes to vasoconstriction, smooth muscle proliferation, and right ventricular hypertrophy. By antagonizing this receptor, PRX‑08066 causes selective vasodilation of diseased pulmonary arteries without affecting systemic blood pressure. In preclinical studies, it reduced key indicators of PAH and improved cardiac output with efficacy similar to established therapies such as bosentan or sildenafil. Clinical development reached Phase II trials for both PAH and COPD-associated PH but has since been discontinued[1][6][7][8].

Other names

5-((4-(6-chlorothieno(2,3-d)pyrimidin-4-ylamino)piperidin-1-yl)methyl)-2-fluorobenzonitrile5-((4-(6-chlorothieno[2,3-d]pyrimidine-4-yamino)piperidin-1-y)methyl)-2-fluorobenzonitrile monofumarate