5-((4-(6-Chlorothieno[2,3-d]pyrimidin-4-ylamino)piperidin-1-yl)methyl)-2-fluorobenzonitrile monofumarate (PRX-08066) is a selective 5-hydroxytryptamine receptor 2B (5-HT2BR) antagonist that causes selective vasodilation of pulmonary arteries. This drug was discovered and developed by Predix (later Epix) Pharmaceuticals and is being researched for the treatment of pulmonary arterial hypertension. 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.

Deldeprevir (Neceprevir) is a direct-acting anti-HCV drug developed by Achillion. Deldeprevir acts by inhibition of the viral NS3/4A protease. In phase 1b clinical trial for the treatment of chronic HCV infection, the drug was safe and well-tolerated and produced more than a 3 log10 mean maximum reduction in plasma HCV RNA levels in all treated groups. Despite positive results, no development of the drug was reported by Achillion since 2014.

ISPRONICLINE is a partial agonist at the a4b2 subtype of nicotinic acetylcholine receptors (nAChRs) without interaction with other nAChRs or other receptor systems. It has antidepressant, nootropic, and neuroprotective effects. It progressed to phase II clinical trials for the treatment of dementia and Alzheimer's disease but is no longer under development.

Zaurategrast (CDP323) is an ethyl ester prodrug of CT7758, a potent carboxylic acid antagonist of integrin alpha4-beta1 (α4β1) or very late antigen 4 (VLA4). CDP323 was under development with UCB and Biogen Idec for the treatment of multiple sclerosis. Its development was discontinued in 2009 based on inadequate interim efficacy data in a phase II clinical trial.

Nicocodine is an opioid related to codeine. It is also an antitussive agent. Nicocodine exhibits at least twice the potency of codeine in clinical experiments. The study of the pharmacokinetic behaviour of nicocodine by means of blood and brain level curves of rats after i .v. application showed that the penetration of the blood brain barrier seems to be favoured for nicocodine. The detected peak concentration of nicocodine in brain after i.v. application is 4.4 times higher than the blood level values at the same time - codeine the main metabolite is detected in almost equal amounts in brain and blood. A comparative assay of codeine and nicocodine after p.o. application of equimolar doses per kg body weight revealed that predominantly codeine is found in brain and its peak value after nicocodine administration is 3-fold higher than after codeine administration. Nicocodine is hydrolysable to morphine and the WHO Expert Committee on Addiction-Producing Drugs (1962) recommended its international control as a narcotic, like other convertible drugs in the morphine series.

Halethazole has been studied as an active antifungal compound.

Encaleret (JTT-305 or MK-5442) is a potent oral short-acting calcium-sensing receptor (CaSR) antagonist and transiently stimulates endogenous parathyroid hormone (PTH) secretion. CaSR antagonists stimulate endogenous PTH secretion through CaSR on the surface of parathyroid cells and thereby may be anabolic agents for osteoporosis. Japan Tobacco and Merck were developing encaleret for the treatment of osteoporosis however development has been discontinued.

Vapendavir (BTA-798) is an orally active capsid-binding inhibitor. It is a potent, orally bioavailable, broad spectrum inhibitor of the large group of HRVs. Vapendavir binds tightly to VP1s canyon and disrupts the ability of the capsid to bind to a specific cell surface receptor. This further inhibits the release of the viral RNA into the cell cytoplasm during the viral uncoating process (removing the lipid bilayer), thereby disrupting viral replication. Vapendavir is designed to be dosed orally. Vapendavir is in phase II clinical trials for the treatment of rhinovirus-induced aggravation of pre-existing asthma or COPD. Vapendavir has shown significant results in proof-of-concept studies. Thus far, from the Phase 1/2 studies conducted, vapendavir has demonstrated a desirable clinical pharmacology profile with high bioavailability, linear pharmacokinetic profile, remained unaffected by concomitant medications, and was not exclusively metabolized.