UT-231B is an iminosugar that was under development by United Therapeutics Corporation as an oral drug for the treatment of hepatitis C virus (HCV). UT-231B completed acute and chronic Phase I dosing studies in early 2003. A Phase II proof-of-concept study for UT-231B in patients infected with hepatitis C who have failed conventional therapies was started, but the development of drug seemed to be discontinued.

Dilmapimod is a potent p38 mitogen-activated protein kinase (MAPK) inhibitor. It was investigated for its anti-inflammatory effect in non-head injury trauma patients at risk for developing acute respiratory distress syndrome. IL-1β was identified as a gene regulated by dilmapimod that could influence c-reactive protein levels. Dilmapimod had been in phase III clinical trials by GlaxoSmithKline for the treatment of rheumatoid arthritis, neuropathic pain, coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD). However, these studies were discontinued.

Pimilprost (SM-10902) and its free acid, SM-10906 are new stable 3-oxa-methano prostaglandin (PG) I1 analogs, SM-10902 is a prodrug of SM-10906. SM-10906, but not SM-10902 was demonstrated to be an agonist for IP receptors. SM-10906 was shown to exert its anti-platelet and vasodilatory activities through the increase of the cAMP level. Pimilprost was being developed by Dainippon Sumitomo Pharma (formerly Sumitomo Pharmaceuticals) in Japan for the treatment of skin ulcers. In Japan, an NDA was filed for pimilprost and was awaiting registration. However, development appears to have been discontinued.

Etorphine was the first potent opiate agonist employed primarily for use in non-domestic and wild species. Etorphine was 500 times as potent as morphine, with a very rapid onset and short duration of action. In morphine-dependent subjects, etorphine suppressed abstinence but for a shorter period than morphine. Etorphine is a full opiate agonist and binds to multiple opiate sites in the central nervous system. It is believed to produce its clinical effects through binding the µ-, δ-, and κ- opiate sites. It has a potent effect on depressing the respiratory centers of the CNS thus resulting in apnea being commonly seen in immobilized animals. Etorphine revolutionized the ability of biologists and veterinarians to safely capture and restrain many species that previously could not be handled. Etorphine is not currently commercially available due to lack of production by the manufacturer.

Ipexidine is a biologically active carbamimidoylurea derivative

Corticosterone is an adrenocortical steroid, the major glucocorticoid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. Corticosterone is of minor importance in humans but is known, that it has a profound effect on the structure and function of the hippocampus. Brain corticosterone may involve memory storage and emotional stress might cause increases in plasma corticosterone.

Oxilorphan (also known as levo-BC-2605) was developed as a long-acting, narcotic antagonist that has agonist properties. Oxilorphan is a partial agonist at the kappa-opioid receptor and antagonist of the mu-opioid receptor. During clinical trials, oxilorphan had led to dysphoria, which combined with its hallucinogenic effects, serves to limit its clinical usefulness. As a result, many patients who experienced these side effects refused to take additional doses in clinical trials.

Berupipam (also known as NNC 22-0010), a dopamine antagonist with a high affinity and selectivity for D1 receptor has been studied for patients with psychotic disorders. Berupipam participated in phase I clinical trials; however, further development of this drug was discontinued

Faxeladol (GRT9906) is a μ-opioid receptor agonist and inhibitor of noradrenalin/serotonin re-uptake. Faxeladol was being studied in the treatment of fibromyalgia and neuropathic pain, however its development has been discontinued.

Banoxantrone (formally known as AQ4N), a bioreductive drug that is irreversibly converted to AQ4, a stable DNA affinic cytotoxic compound. Banoxantrone is activated by haem-containing reductases such as inducible nitric oxide synthase (iNOS). In hypoxic cells, AQ4N is reduced to the topoisomerase II inhibitor AQ4. By inhibition of topoisomerase II within these hypoxic areas, AQ4N has been shown to sensitize tumors to existing chemo- and radiotherapy treatments. Novacea, the company which was responsible for clinical trials for banoxantrone had decided to scale back on its clinical development, including discontinuing the clinical trial in acute lymphoblastic leukemia and delaying the planned clinical trial in B-cell lymphoma. The company decided to continue enrollment in an ongoing Phase 1b/2a clinical trial in patients with glioblastoma multiforme. However, further information about these clinical trials are not available. Some recent experiments have shown that targeting hypoxic tumors with high levels of iNOS with a combination of AQ4N and radiotherapy could be a useful clinical therapeutic strategy.