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.

Epetirimod (S-30563 or TAK-851) is an immunostimulant. The compound is structurally related to the marketed topical imidazoquinoline drug, imiquimod, an agonist of Toll-like receptor 7. Epetirimod was under development with Takeda Pharmaceutical as a topical treatment for cervical high-risk HPV infection and cervical dysplasia. Takeda has discontinued epetirimod development as it did not meet the predefined efficacy end points in a US Phase II trial.

Lividomycin is the antibacterial agent produced by Streptomyces lividus. It is aminoglycoside antibiotic. Lividomycin binds to bacterial ribosomes and inhibits protein synthesis. In vitro development of resistance to lividomycin in P. aeruginosa and M. tuberculosis was much slower than that to kanamycin, but was comparable in Staphylococcus aureus. Lividomycin showed a positive protecting effect for the experimental infections in mice with several bacteria such as S. aureus, P. aeruginosa, Klebsiella pneumoniae and Escherichia coli. It was fairly effective for the experimental infection with the kanamycin-resistant strains of E. coli and P. aeruginosa producing the kanamycin-phosphorylating enzyme.

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.

Linifanib (ABT-869) is a structurally novel, receptor tyrosine kinase (RTK) inhibitor that is a potent inhibitor of members of the vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptor families, but has much less activity against unrelated RTKs, soluble tyrosine kinases, or serine/threonine kinases. Linifanib (ABT-869) does not have a general antiproliferative effect due to its high dose requirement. However, it may exhibit potent antiproliferative and apoptotic effects on tumor cells whose proliferation is dependent on mutant kinases, such as FMS-related tyrosine kinase receptor-3 (FLT3). Linifanib (ABT-869) was in phase III clinical trial for the treatment of hepatocellular carcinoma, but the study failed to meet the primary end point.

Ritanserin (INN, USAN, BAN) is a serotonin receptor antagonist which was never marketed for clinical use but has been used in scientific research. In humans, ritanserin increases deep slow-wave sleep, improved liveliness in a variety of psychiatric disorders and facilitated participation in behaviour therapy. During clinical trials, unexpected observations indicated that ritanserin may be of value in treating obsessive-compulsive disorder, acute mania, negative symptoms of schizophrenia, drug addicts, etc. Clinical observations confirmed the efficacy of ritanserin in the chronic withdrawal phase after detoxification from ethanol. Ritanserin had been in phase III clinical trials by Janssen L.P. for the treatment of anxiety disorder and major depressive disorder. However, the clinical development of ritanserin was discontinued.

Dimiracetam is a nootropic drug of the racetam family. Dimiracetam inhibited the NMDA-induced increase of [3H]D-Asp release from hippocampal synaptosomes. The increased potency and longer duration of action of dimiracetam, together with the potential cognition enhancing property makes it a very promising and safe for the treatment of neuropathic pain conditions for which there are very limited therapeutic options. Dimiracetam is in Phase II clinical trials for the treatment of HIV-associated pain and in phase I clinical trials for the treatment of osteoarthritis pain.

Enalkiren (A-64662) is a potent, dipeptide renin inhibitor, mimics the transition state of the human renin substrate, angiotensinogen. The results of clinical trials with enalkiren suggest that renin inhibitors may be safe, useful therapeutic agents in the management of hypertension. In addition, it exerts intraocular pressure lowering pressure. Enalkiren development for the treatment of glaucoma, heart failure, hypertension has been discontinued.

Spirorenone is an androstadienone derivative patented by Schering A.-G as a highly effective aldosterone antagonist. Spirorenone is 8.6 times as potent as spironolactone, but showed a lower affinity for the mineralocorticoid receptors. In phase I clinical trials Spirorenone was absorbed with a half-life of 20-30 min, achieving maximum concentrations of about 100 ng/ml (10 mg) and 260 ng/ml (40 mg) after 1-2 h. Disposition of the parent drug was biphasic with half-lives of 50-60 min (distribution) and 5-6 h (elimination). Neither significant accumulation nor enzyme induction was observed after prolonged treatment.