Vipadenant (V2006) is a small molecule, adenosine A2A receptor antagonist that was being investigated in Parkinson's disease. Due to safety concerns development ceased in 2010 and the rights were regained from Biogen Idec in 2011 with no further investment made. In October 2014, RedoxTherapies licensed Vipadenant as it has the potential to disrupt an immunosuppressive mechanism of tumour protection, generating improved efficacy for immunotherapies of certain cancers when used in combination with other drugs.

Tiospirone (TSP) is an atypical antipsychotic drug. Tiaspirone appeared to be a promising antipsychotic agent as it didn`t cause extrapyramidal syndromes. It has 5HT-2 antagonistic properties as well as affinity for D2, 5HT-1a, 5HT-6 and sigma receptors. Tiospirone was in phase III clinical trials for the treatment of attention hyperactivity disorder with Mead Johnson in the USA but its development appears to have been discontinued.

Ensaculin is related to naturally occurring benzopyranones like scoparone. The compound is a potent functional antagonist of excitatory amino acid-induced convulsions and mortality. In receptor-binding studies, Ensaculin showed high affinity to dopaminergic (D2, D3), serotoninergic (5-HT1A, 5-HT7), and adrenergic (A1a, A1b) receptors in the nanomolar range. Ensaculin antagonizes NMDA responses in a voltage-dependent manner. Various studies support the notion that this compound could indeed have a broad range of nootropic properties. Although few patients presented postural hypotension and dizziness after receiving ensaculin in phase I clinical trials, this drug candidate was further discontinued in phase III due to potential side effects.

Etazepine (5,6-dihydro-5-methyl-11H-11-ethoxy-dibenzo[b,e]azepin-6-one) demonstrates anticonvulsant activity in rodents. Etazepine seems to exert its anticonvulsant effects by activating the GABAergic system.

LADOSTIGIL, a rasagiline derivative, is a reversible acetylcholinesterase and butyrylcholinesterase inhibitor with neuroprotective properties. It also acts as an irreversible brain monoamine oxidases inhibitor. It is under development for the treatment of neurodegenerative disorders like dementia and Alzheimer's disease.

Pipequaline (PK-8165, 2-phenyl-4[2-(4-piperidinyl) ethyl]quinoline) is a benzodiazepine receptor partial agonist.

Gomisin A (BESIGOMSIN/GA) one of the major dibenzocyclooctadiene lignans isolated from Schisandra chinensis Baill, has proved to possess a variety of pharmacological effects. It has been found to promote hepatocyte growth factor, limit lipid peroxidation, and inhibit apoptosis in acute hepatic injury animal models. Besigomsine also acts as an anti-inflammatory by preventing the release of arachidonic acid in macrophages in vitro. Laboratory evidence suggests that Besigomsine may have anticarcinogenic effects. Chronic administration of Gomisin A had an antihypertensive effect in AngII-induced hypertensive mice. Gomisin A may exert neuroprotective effects by attenuating the microglia-mediated neuroinflammatory response via inhibiting the TLR4-mediated NF-κB and MAPKs signaling pathways. Also it induces marked protective effects against hepatic and renal injury induced by CCl(4) exposure through differential regulation of the MAPK signal transduction pathway.

Sonolisib (PX-866) is a small-molecule inhibitor of the alpha, gamma, and delta isoforms of phosphoinositide 3-kinase (PI3K) with potential antineoplastic activity. Sonolisib inhibits the production of the secondary messenger phosphatidylinositol-3,4,5-trisphosphate (PIP3) and activation of the PI3K/Akt signaling pathway, which may result in inhibition of tumor cell growth and survival in susceptible tumor cell populations. Inhibition of the PI3K pathway with Sonolisib leads to inhibition of cell growth and decreased activation of downstream targets in GBM, both in vitro and in vivo, using U87–tumor-bearing mice, including Akt, S6, and mTOR. Sonolisib was in phase II clinical trials by Oncothyreon for the treatment of glioblastoma multiforme and castration-resistant prostate cancer (CRPC). It was in phase I/II clinical trials for the treatment of malignant melanoma, non-small cell lung cancer and Head and neck cancer. In clinical trials, Sonolisib was well tolerated, with common side effects being diarrhea, nausea, vomiting, and elevated liver enzymes. However, no recent development has been reported.

Siagoside (Sygen, AGF 2) is a naturally occurring substance in the nerve cell’s membrane that is thought to play a role in cell growth, development, and repair. Siagoside completed phase 2 trials for parkinson's disease (PD) treatment. Sygen appears to be beneficial in patients with severe spinal cord injury. Treatment results in a 52% decrease in mortality 48 hours after the induction of ischemia in gerbils by permanent unilateral ligation of the common carotid artery.

Siramesine is a sigma2 opioid agonist under development by H Lundbeck as a potential treatment for anxiety. In March 1998, the compound was licensed to Forest Laboratories under a strategic alliance. In August 2000, siramesine entered phase II trials. Siramesine has been shown to trigger cell death of cancer cells and to exhibit a potent anticancer activity in vivo. Siramesine triggers cell death through destabilisation of mitochondria, but not lysosomes. Siramesine is a lysosomotropic detergent that induces cytoprotective autophagosome accumulation. Siramesine involves lysosomal leakage and oxidative stress.