MK-0557, trans-N-[1-(2-fluorophenyl)-3-pyrazolyl]-3-oxospiro [6 azaisobenzofuran-1(3H),10-cyclohexane]-40-carboxamide, is an orally available Neuropeptide Y (NPY5) receptor antagonist. MK-0557 was studied in the clinical trials for the treatment of obesity, however, MK-0557 did not significantly increase the weight loss efficacy. MK-0557 safety and effectiveness were studied in a trial for the treatment of cognitive impairment in patients with schizophrenia. It seems MK-0557 development was discontinued.

Lubazodone (YM 992) or (S)-2-[[(7-fluoro-4-indanyl)oxy]methyl]morpholine monohydrochloride, exhibited the biochemical profile of a selective serotonin (5-HT) reuptake inhibitor (SSRI) with 5-HT2A receptor antagonistic activity. It has been studied in the treatment of depression.

Farampator (CX 691, ORG 24448 or (1-(benzofurazan-5-ylcarbonyl) piperidine)) is a positive allosteric modulator of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors. Farampator exerts antipsychotic and cognitive enhancing properties.

Amiperone is a neuroleptic drug. It prolonged the latency (T) and reduced the frequency (F) of the noise escape response rate in rats. It also inhibited lever-press response and reduced the shock-avoidance rate at very low dose levels in rats.

Aloxistatin (E64d) is an irreversible and membrane-permeable cysteine protease inhibitor. Aloxistatin was developed for treating muscular dystrophy. Open trials on 73 Duchene’s muscular dystrophy patients were conducted for 3 years at four Japanese national sanatoriums and resulted in some muscle strength improvement but the results were inconclusive and final double-blind studies did not confirm the results. Taisho has discontinued development of aloxistatin for the potential treatment of muscular dystrophy. The  trials completed through Phase 3. In animal models Aloxistatin (100 mg/kg, p.o.) strongly inhibits the cathepsin B&L activities in the skeletal muscle, heart and liver of hamsters. In spinal cord injury (SCI) rats, Aloxistatin provides neuroprotection in SCI lesion and penumbra.Aloxistatin reduces brain amyloid-β and improves memory deficits in Alzheimer's disease animal models by inhibiting cathepsin B activity.

Dimenoxadol is an opioid analgesic which produces typical opioid effects such as analgesia and sedation. It is structurally similar to methadone and is a benzilic acid derivative. In the United States it is classified as a Schedule I controlled drug.

Decloxizine (UCB-1402; NSC289116) is a histamine 1 receptor antagonist. Decloxizine is a broncholyticum.

Esreboxetine (PNU-165442G) is the (S,S)-(+)-enantiomer of antidepressant reboxetine, a selective norepinephrine reuptake inhibitor. The (S,S)-enantiomer is a more potent inhibitor of norepinephrine transporter than (R,R)-enantiomer. Esreboxetine was being developed by Pfizer, primarily for the treatment of fibromyalgia.

Semagacestat (LY-450139) was a gamma secretase inhibitor being developed as a treatment for Alzheimer's disease by Eli Lilly. It was hoped that the drug would help to delay the onset of severe Alzheimer's disease, and thereby help preserve cognitive and executive functioning and in turn improve patient quality of life. Semagacestat (LY-450139) is designed to inhibit gamma secretase, an enzyme that is involved in the cleavage of APP to beta-amyloid. By decreasing production of beta-amyloid, it is hoped that gamma secretase inhibitors will exert a disease-modifying effect in Alzheimer's disease and thus slow or halt the destruction of nerve cells – the final stage in the amyloid cascade hypothesis. In March 2008 semagacestat (LY-450139) advanced to Phase III development, where it was evaluated in the IDENTITY (Interrupting Alzheimer's Dementia by EvaluatiNg Treatment of AmyloId PaThologY) trial, the first Phase III trial for this new anti-dementia drug. In August 2010, Eli Lilly announced its decision to halt the development of Semagacestat. The decision was taken after analysing the preliminary results of the second Phase III clinical trial of the drug, which indicated that semagacestat failed to slow disease progression. The drug, in fact, worsened cognition and the ability to perform day-to-day activities.

Telcagepant (MK-0974) is a calcitonin gene-related peptide receptor antagonist. Merck & Co was developing telcagepant for the treatment of pain. Telcagepant is an extremely potent CGRP antagonist with a Ki = 0.77 (0.07 nM). Telcagepant showed efficacy against acute migraines; however, different patient populations may show more beneficial effects with telcagepant versus triptans. In the acute treatment of migraine, Telcagepant was found to have equal potency to rizatriptan and zolmitriptan in two Phase III clinical trials. Merck & Co has now terminated development of the drug.