Tonabersat is a unique compound with demonstrated activity as a gap-junction inhibitor in animal studies. In preclinical and clinical trials, tonabersat was well tolerated, with no cardiovascular effects; the pharmacokinetic profile suggested its usefulness in the prophylaxis of migraine. The basis of its high efficacy is inhibiting neuronal hyperexcitability and trigeminal nerve stimulated neurogenic inflammation in rodent models. Tonabersat inhibits the CSD (cortical spreading depression) that is believed to underlie the aura of migraine.

Cutamesine, an agonsit of brain sigma 1 receptors, was developed by Santen Pharmaceutical for the treatment of cognitive diseases. The drug was tested in phase II in patients with major depressive disorders and for recovery of patients with stroke, however its development was terminated for the given conditions. Currently M's science corporation is developing cutamesine for Amyotrophic lateral sclerosis and Retinitis pigmentosa as more suitable target diseases.

Schering published xanthine PDE5 inhibitors with amino substituents in the imidazole 2-position, such as Dasantafil. Dasantafil, also known as SCH-446132, is a PDE5A inhibitor potentially for the treatment of erectile dysfunction. It had been in phase II clinical trials but there is no report for this compound recently.

Dipraglurant (ADX48621) is a novel, potent mGluR5 negative allosteric modulator that reduced the severity of drug-induced dyskinesia in Parkinson's disease. Dipraglurant pharmacokinetic variables were similar to those of levodopa, suggesting that both drugs can be co-administered simultaneously in further studies. Dipraglurant might be useful in torsion dystonia treatment also. Detected adverse events are: sweating, dyskinesia, nausea, dizziness, and anxiety. One serious adverse event described as possible syncope.

Altinicline (SIB-1508Y, SIB-1765F) is a drug which acts as an agonist at neural nicotinic acetylcholine receptors with high selectivity for the α4β2 subtype. It stimulates release of dopamine and acetylcholine in the brain in both rodent and primate models, and progressed as far as Phase II clinical trials for Parkinson's disease, where "no antiparkinsonian or cognitive-enhancing effects were demonstrated", although its current status is unclear.

Elinogrel, previously known as PRT060128 or PRT128, is a direct-acting, reversible P2Y12 inhibitor for both intravenous and oral administration. Elinogrel has been tested in 2 phase II studies for the treatment of acute coronary syndrome, myocardial infarction and prevention of secondary thrombotic events. Elinogrel therapy was associated with an increased incidence of dyspnea and incidence of elevated liver transaminases. The development of the drug was terminated in January 2012 by Novartis.

Indoximod is an orally available Indoleamine 2,3-dioxigenase inhibitor. It shows higher potency in reversing IDO-mediated T cell suppression. Indoximod improves the efficacy of multiple chemotherapeutics agents and some immunological checkpoints mediators in Phase I/II clinical studies for metastatic breast cancer, metastatic melanoma, non-small cell lung cancer, primary malignant brain tumors, metastatic pancreatic cancer, as well as metastatic prostate cancer.

Pozanicline is an alpha4-beta2 neuronal nicotinic receptor partial agonist. It had been in phase II clinical trials for the treatment of attention hyperactivity disorder and Alzheimer’s disease. It was tested for the treatment of schizophrenia too. All these studies were discontinued. Modulation of hippocampal learning and memory using Pozanicline in animal model was effective as novel therapeutic strategies for nicotine addiction. However future clinical trial was terminated.

Fostedil (KB-944) is a phosphonic acid derivative with potent vasodilator activity. KB-944 has been demonstrated to produce long lasting coronary vasodilator and hypotensive effects in conscious and anesthetized dogs; increase coronary blood flow in isolated, blood perfused heart preparations of dogs; and reduce systemic pressure in conscious normotensive and hypertensive rats. Slow channel calcium entry blockade is thought to contribute to the vasodilator activity of KB-944. Fostedil is longer acting in hypertensive animals than either nifedipine or diltiazem suggesting a potential clinical advantage for this compound. Unexpectedly, fostedil was shown to produce atrial fibrillation in 3 of 10 hypertensive patients in a placebo controlled study. Fostedil had been in phase II clinical trials for the treatment of angina pectoris. However, this research has been discontinued.

Sobetirome (3,5-dimethyl-4[(4'-hydroxy-3'-isopropylbenzyl)-phenoxy] acetic acid, also known as GC-1 and QRX-431, is a member of a class of compounds known as selective thyromimetics. It was firstly developed by Thomas Scanlan’s group at the University of California-San Francisco (UCSF) in 1995. Sobetirome binds selectively to the main hepatic form of thyroid hormone (TH) receptor, TRβ1, compared to TRα1, which is principally responsible for thyrotoxic effects on heart, muscle and bone. Sobetirome also preferentially accumulates in liver. It was originally envisaged that sobetirome could be used to stimulate hepatic pathways that lower cholesterol without harmful side effects and might be used in conjunction with statins. Indeed, sobetirome progressed through preclinical animal studies and Phase I human clinical trials with excellent results and without obvious harmful side effects. Sobetirome had been in phase I clinical trials for the treatment of lipid metabolism disorders and obesity. However, this research has been discontinued.