Gestaclone was developed as a progesterone receptor agonist; however, this compound has never been marketed. Information about the current use of this compound is not available.

1H-2-BENZOPYRAN-3-ACETIC ACID, 8-HYDROXY-6-METHOXY-Α-METHYL-1-OXO- (NM-3) is an orally bioavailable antiangiogenic isocoumarin with potential antineoplastic activity. NM-3 inhibits vascular endothelial growth factor (VEGF), a pro-angiogenic growth factor, thereby inhibiting endothelial cell proliferation. NM-3 induces apoptosis by a mechanism involving reactive oxygen species. In human MCF-7 and ZR-75-1 breast cancer cells, NM-3 induces the p21 cyclin-dependent kinase inhibitor, cell cycle arrest at G1-S-phase, and necrotic cell death. NM-3 has been used in trials studying the treatment of solid tumours.

HSD-016 was discovered as an orally efficacious 11β-hydroxysteroid dehydrogenase type 1 inhibitor for the treatment of diabetes. The phase I in clinical trials for the drug was completed; however, information about further studies is not available.

Temiverine was developed as an antimuscarinic and calcium-antagonist agent for the treatment of overactive bladder. Temiverine participated in clinical trials; however, the development of the drug was discontinued on the pre-registration stage.

NPV-LEQ506 is an orally bioavailable small-molecule Smoothened (Smo) antagonist with potential antineoplastic activity. NPV-LEQ506 selectively binds to the Hedgehog (Hh)-ligand cell surface receptor Smo, which may result in the suppression of the Hh signaling pathway, thereby inhibiting tumor cell growth. NPV-LEQ506 is a second-generation inhibitor of smoothened (Smo) with IC50s of 2 and 4 nM in human and mouse, respectively. NPV-LEQ506 has been in clinical trials with Novartis studying the treatment of advanced solid tumors, recurrent or refractory medulloblastoma, and locally advanced or metastatic basal cell carcinoma.

Foxy-5, a wingless-type mammary tumor virus integration site 5A (WNT5A)-mimicking peptide, was studied for the treatment of cancer. Foxy-5 is participating in phase II clinical trial as neo-adjuvant therapy for the treatment of patients with wnt-5a low colon cancer. Besides, Foxy-5 was used in phase I clinical trial, for the treatment of prostate cancer patients with tumors exhibiting absent or low WNT5A expression.

Oleandrin is a toxic cardiac glycoside found in oleander (Nerium oleander L.). Along with neandrin it is primarily responsible for the toxicity of the sap of oleander. Oleandrin has been used for many years in China and Russia for its properties as a cardiac glycoside, for both suicidal and therapeutic purposes as in treatment of cardiac insufficiency. Because of its properties as a cardiac glycoside, oleandrin interferes in some essential processes within the cell, the most important of these being the inhibition of the Na-K ATPase. This protein enables the cell to exchange the cations Na+ and K+ between the intercellular and extracellular spaces by which, for instance, electronic signaling is made possible in nerve cells. Oleandrin binds to specific amino acids in the protein, causing it to lose its function. After depolarization of the cell in which Na+ flows into the cell, the Na+ cannot be transported back into the extracellular membrane, causing the sodium gradient to disappear. This gradient is the driving force for other transport proteins, such as the sodium-calcium exchanger, which plays an important role in cardiomyocytes. To make muscle contraction possible, a calcium influx from the extracellular fluid into the cell is crucial. After the muscle contraction, the calcium is normally pumped out of the cell and exchanged for sodium. When the sodium gradient is depleted, calcium cannot be pumped back and, as a consequence, accumulates in the cardiomyocyte. As a result of the high calcium concentration, actin and myosin filaments will bind stronger, unable to relax properly to make a new contraction possible. This may result in cardiac arrhythmias, in the worst case decreasing cardiac output and causing a shortage in oxygen supply in vital tissues. Apart from being a potent toxic compound, it may also be used in therapeutic ways. Both oleandrin and oleandrigenin, as well as their relatives, may be able to inhibit proliferation of tumor cells and stimulate their apoptosis as a result of the high concentration of intracellular calcium. In addition, it inhibits excretion of fibroblast growth factor 2 through membrane interaction and through inhibition of the Na,K-ATPase pump. However, there are no results from clinical testing on humans that support any use as a cancer treatment. Oleandrin has been reported to be lethal, but exact dosages are not fully documented. The fatal blood concentration of oleandrin has been estimated for humans to be approximately 20 ng/ml in decreased blood by extrapolation of intoxication symptoms. Symptoms present in poisoned animals include bloody diarrhea and colic, the latter especially in horses. Because the leaf itself is quite bitter, only starving animals will be likely to eat the plant. The lethal dosage for animals is estimated to be about 0.5 mg/kg.

Vatiquinone is the international non-proprietary name for Edison Pharmaceuticals’ EPI-743, an orally bioavailable small molecule being developed by the company for inherited mitochondrial diseases. EPI-743 is a member of the para-benzoquinone class of drugs. The mechanism of action of EPI-743 involves augmenting the synthesis of glutathione, optimizing metabolic control, enhancing the expression of genetic elements critical for cellular management of oxidative stress, and acting at the mitochondria to regulate electron transport. EPI-743 is a compound being developed by BioElectron (previously known as Edison Pharmaceuticals) to treat Friedreich’s ataxia (FA), a rare, autosomal recessive genetic disorder. The regulation of oxidative stress is disturbed in people with FA. EPI-743 targets NADPH quinone oxidoreductase 1 (NQO1), helping to increase the biosynthesis of glutathione, a compound essential for the control of oxidative stress. The drug does not target any FA-specific biochemical pathways directly, but helps to improve the regulation of cellular energy metabolism in general. Vatiquinone has been investigated for the treatment and prevention of retinopathy, rett syndrome, parkinson's disease, noise-induced hearing loss, and methylmalonic aciduria and homocystinuria, Cblc type. The FDA previously granted orphan drug designation for Edison’s EPI-743 to treat inherited respiratory chain diseases of the mitochondria and Friedreich’s ataxia. The company received orphan drug designation for EPI-743 from the Japanese Ministry of Health, Labour and Welfare and European Medicines Agency Committee on Orphan Products for the treatment of Leigh syndrome.