Zenazocine is an opioid analgesic that mixes both agonist/antagonist activities. This compound participated in phase II clinical trial, however, the further development was ultimately halted and it has never been marketed.

ABT-639 is a T-type calcium (Cav3.2) channel antagonist that was in development with AbbVie for the treatment for pain. ABT-639 is a potent and selective T-type calcium channel blocker. ABT-639 effectively reduces nociceptive and neuropathic pain in rats. ABT-639 produces robust antinociceptive activity in experimental pain models at doses that do not significantly alter psychomotor or hemodynamic function in the rat. ABT-639 blocks recombinant human T-type (Cav3.2) Ca2+ channels in a voltage-dependent fashion (IC50=2 uM) and attenuates low voltage-activated (LVA) currents in rat DRG neurons (IC50=8 uM). ABT-639 was significantly less active at other Ca²⁺ channels (e.g. Ca(v)1.2 and Ca(v)2.2) (IC₅₀ > 30 uM). ABT-639 has high oral bioavailability (%F = 73), low protein binding (88.9%) and a low brain:plasma ratio (0.05:1) in rodents.

DCFBC F-18 is a radioconjugate containing a low molecular weight tracer, DCFBC, specific for prostate-specific membrane antigen (PSMA) and labeled with the positron-emitting isotope fluorine F 18 with potential prostate tumor imaging upon positron emission tomography (PET). Upon administration, the DCFBC moiety of fluorine F 18 DCFBC specifically targets and binds to the tumor-associated antigen PSMA, thereby allowing the visualization of tumor cells expressing PSMA upon PET. F 18 DCFBC is investigated in phase 2 clinical trials in patients with prostate cancer.

LX6171 is an orally-delivered, small molecule inhibitor of SLC6A7, a high-affinity L-proline transporter found in the brain. SLC6A7 is a member of the gamma-aminobutyric acid (GABA) neurotransmitter transporter family, and is expressed in regions of the brain that are known to be involved in learning and memory. In preclinical studies, mice treated with LX6171 displayed improved performance in tests of learning and memory, corroborating observations in knockout mice lacking SLC6A7. In the completed Phase 2a clinical trial, daily doses of LX6171 or placebo were given to 121 healthy elderly subjects with age-associated memory impairment (AAMI). The study evaluated safety, tolerability, and cognitive effects of LX6171 over four weeks. Although LX6171 was well tolerated at all doses evaluated, the trial did not result in significant effects on parameters of attention or memory that would justify further studies in therapeutic indications prioritized by the company.

Fluoroazomycin Arabinoside F-18 (18F-FAZA) is a radiofluorinated 2-nitroimidazole derivative with hypoxia (low oxygen)-specific tracer activity. 18F-FAZA is reduced under hypoxic conditions, forming highly reactive intermediates. In its reduced form, 18F-FAZA covalently binds to macromolecules, thereby accumulating in hypoxic cells (e.g. malignant tumors) and allowing radioisotopic imaging of these particular cells with positron emission tomography (PET). (18)F-FAZA shows superior biokinetics and is, thus, a promising PET tracer for the visualization of tumor hypoxia. Clinical evaluation of 18F-FAZA is currently ongoing, and early results have been reported for head and neck, lung, prostate, and rectal cancers.

(R)-Mequitazine or V0162 (10-[(3R)-1-azabicyclo[2.2.2]oct-3-ylmethyl]-10H-phenothiazine) is an anticholinergic enantiomer of mequitazine, an existing oral racemic antihistamine commercialized for over 30 years. (R)-Mequitazine was found to be an antagonist at muscarinic acetylcholine receptors behaving as an inverse agonist. (R)-Mequitazine was investigated in clinical trials for the treatment of chronic obstructive pulmonary disease, asthma and urinary incontinence.

GET-73 (N-[(4-trifluoromethyl)benzyl]4-methoxybutyramide) is a compound with a structure related to that of gamma-hydroxybutyric acid (GHB), which is used in the treatment of alcohol withdrawal. Like GHB, GET-73 has the capacity to reduce alcohol intake in rats. GET-73 also exerts anxiolytic effects in rats and seemed to improve memory in a water maze test. Although the exact mechanism of GET-73 action is still unknown, it was suggested that an allosteric modulation of metabotropic glutamate receptor 5 (mGlu5 receptor) by GET-73 may represent the mechanism underlying the effects of the compound. GET73 was suggested to have a multifaceted pharmacological profile, importantly including the capacity to reduce alcohol drinking and anxiety-related behaviors. A phase II study was completed in November 2018, in which physical effects and changes in cognitive performance as a result of GET-73 administration were studied in alcohol-dependent individuals.

IQP-0528 is an antiretroviral pyrimidinedione derivative with activity against human immunodeficiency virus (HIV) in the nanomolar range. It is a non-nucleoside reverse transcriptase inhibitor that also inhibits HIV entry through an unknown mechanism thought to target a conformational epitope formed prior to the fusion of the viral envelope with the host cellular membrane. IQP-0528 is under clinical development for HIV prevention.

Merck was developing MK 8245, an orally active inhibitor of stearoyl CoA desaturase for the treatment of type-2 diabetes mellitus. MK-8245 is a liver-targeting inhibitor of stearoyl-CoA desaturase (SCD) with IC50 of 1 nM for human SCD1 and 3 nM for both rat SCD1 and mouse SCD1, with anti-diabetic and anti-dyslipidemic efficacy. It is in Phase 2 clinical studies for type 2 diabetes mellitus.

D-Fagomine (1,2-dideoxynojirimycin) is a six-membered ring iminocyclitol that was first isolated from seeds of buckwheat (Fagopyrum sculentum Moench, Polygonaceae) and is also present in other plant sources such as mulberry (Morus Alba, Moraceae) leaves and gogi (Lycium chinense) roots. D-fagomine is present in common buckwheat-based foodstuffs in amounts ranging from 1 to 25 mg/kg or mg/L, it is stable during boiling, baking, frying and fermentation, and it is biosynthesised upon sprouting. The estimated total intake of D-fagomine resulting from a diet that includes such foodstuffs would be between 3 and 17 mg per day (mean for both genders; range from P5 to P95). In animal studies D-Fagomine lowers postprandial blood glucose. D-fagomine agglutinated Enterobacteriaceae (Escherichia coli, Salmonella enterica serovar Typhimurium), while it did not show this effect on Bifidobacterium spp. or Lactobacillus spp. D-fagomine significantly inhibited the adhesion of Enterobacteriaceae and promoted the adhesion of Lactobacillus acidophilus to intestinal mucosa. D-Fagomine did not show any effect on bacterial cell viability. D-fagomine may be used as a dietary ingredient or functional food component to reduce the health risks associated with an excessive intake of fast-digestible carbohydrates, or an excess of potentially pathogenic bacteria.