Taprostene (also known as CG 4203), a stable prostacyclin (PGI2) analog was developed by Gruenenthal as a selective agonist of the prostanoid receptor IP1. Taprostene was studied in a clinical trial in patients with acute myocardial infarction, where it was shown that the drug could be a useful adjuvant to thrombolytic agents in acute myocardial infarction. In addition, taprostene participated in a clinical trial for the treatment of critical limb ischemia, where the drug was safe and effective. Besides taprostene was studied in patients with advanced peripheral arterial disease. However, further development of the drug was discontinued.

Brofezil (ICI 54594) is an ibuprofen derivative with anti-inflammatory and analgesic activity.

Ralinepag is a cyclohexyl amide derivative patented by Arena Pharmaceuticals, Inc. as agonists of the human prostacyclin (PGI2) receptor useful for the treatment of pulmonary arterial hypertension. Ralinepag shows selectivity in both binding and functional assays with respect to most members of the prostanoid receptor family and a more modest 30-50-fold selectivity over the EP3 receptor. Ralinepag had an excellent PK profile across species. Enterohepatic recirculation most probably contributes to a concentration-time profile after oral administration in the cynomolgus monkey that showed a very low peak-to-trough ratio. Phase III clinical trial is currently ongoing.

FGF-401 is an inhibitor of human fibroblast growth factor receptor 4 (FGFR4), with potential antineoplastic activity. Upon administration, FGF401 binds to and inhibits the activity of FGFR4, which leads to an inhibition of tumor cell proliferation in FGFR4-overexpressing cells. FGFR4 is a receptor tyrosine kinase upregulated in certain tumor cells and involved in tumor cell proliferation, differentiation, angiogenesis, and survival. FGF-401 is an FGFR4 inhibitor in phase I/II clinical studies at Novartis for the treatment of positive FGFR4 and KLB expression solid tumors and hepatocellular carcinoma.

Ralinepag is a cyclohexyl amide derivative patented by Arena Pharmaceuticals, Inc. as agonists of the human prostacyclin (PGI2) receptor useful for the treatment of pulmonary arterial hypertension. Ralinepag shows selectivity in both binding and functional assays with respect to most members of the prostanoid receptor family and a more modest 30-50-fold selectivity over the EP3 receptor. Ralinepag had an excellent PK profile across species. Enterohepatic recirculation most probably contributes to a concentration-time profile after oral administration in the cynomolgus monkey that showed a very low peak-to-trough ratio. Phase III clinical trial is currently ongoing.

Imiclopazine is a phenothiazines derivative patented by Asta-Werke A.-G. as strong sedative and antiemetic agent. Imiclopazine was studied for treatment of schizophrenia but was never marketed.