Bavisant (also known as JNJ-31001074 or BEN-2001), a highly selective, active antagonist of the human H3 receptor that was invented by Johnson & Johnson for the treatment of attention-deficit hyperactivity disorder (ADHD). However, the result of clinical trials did not display significant clinical effectiveness in the treatment of adults with ADHD. BenevolentAI has started phase II clinical trials where investigated bavisant for ameliorating the excessive daytime sleepiness in patients with Parkinson’s disease, using one of the drug side effects is dose-dependent insomnia.

Imiloxan is a highly selective alpha2B adrenoceptor antagonist and was developed for depression in the 1980s. In Phase 1 clinical trials imiloxan dosing led to hypersensitivity reactions; the molecule's development was discontinued.

Elarofiban is a novel nonpeptide glycoprotein IIb/IIIa (GPIIb/IIIa) antagonist. It inhibits thrombin-induced platelet aggregation in human gel-filtered platelets and platelet aggregation in human platelet-rich plasma (PRP) in response to collagen, arachidonic acid, ADP, and SFLLRN-NH(2). Elarofiban had adequate oral pharmacokinetics in dogs and excellent oral pharmacodynamics. Elarofiban has been in phase II clinical trials for the treatment of myocardial infarction and thrombosis. However, this research has been discontinued.

Isamoltan (CGP 361A) is a β-adrenoceptor and serotonin 1B receptor antagonist. Isamoltane has reported activity as an anxiolytic in man. Isamoltan had been in phase III clinical trials for the treatment of anxiety. However, this research has been discontinued.

Omtriptolide (previously known as PG490-88 or F60008), an immunosuppressant that has been shown to be the safe and potent antitumor agent and it has been approved entry into Phase I clinical trial for the treatment of prostate cancer in the USA. In addition, the drug is participating in phase I clinical trial for the treatment of myeloid leukemia. Experiments on animals have shown omtriptolide was highly effective in the prevention of murine graft-versus-host disease (GVHD). The immunosuppressive effect of the drug was mediated by inhibition of alloreactive T cell expansion through interleukin-2 production. However, this study was discontinued. Recently published article has shown omtriptolide possesses the potential as a prophylactic agent to prevent ischemia/reperfusion (I/R)-induced lung injury.

Hydroxytamoxifen (Afimoxifene) is an active metabolite of tamoxifen exerting estrogen receptor modulatory function. In addition, hydroxytamoxifen binds to regulates transcriptional activity of the estrogen-related receptor gamma. ASCEND Therapeutics, Inc. was developing TamoGel (4-hydroxytamoxifen gel) for a variety of estrogen-dependent conditions, including breast cancer, cyclic breast pain and gynecomastia.

FLAVODILOL is an antihypertensive agent.

Acolbifene, the active metabolite of EM-800, was identified as a pure antagonist that acts on both activation domains of the ERs. It is in Phase III clinical trials for the prevention of breast cancer and vasomotor symptoms (Hot flush) in postmenopausal women. Most commonly reported adverse events included irregular menses, leg/muscle cramps, diarrhea, and hot flashes. No serious adverse events were reported.

Zolertine is an alpha-adrenergic receptor antagonist that acts as an antihypertensive agent. Its effect was studied in animals in vivo and in vitro. Zolertine considerably decreased systemic blood pressure in mecamylamine hypertensive dogs in a dose-related fashion. Using the intravital microscopic method in rat's mesocygeus microvasculature a direct relationship between zolertine dosage and blockade was demonstrated as well as an inverse relationship between time of action of zolertine and percentage of vasoconstriction caused by noradrenaline. When only zolertine was applied, it caused a small vasoconstriction that decreased as its concentration increased which could be due to its ability to antagonize alpha receptor responses, but not beta responses. Zolertine is a more active alpha blocker than azapetin, a blocker used in medical practice. Competition binding experiments using the alpha1-adrenoceptor antagonist [3H] prazosin showed a zolertine pKi of 6.81 +/- 0.02 in rat liver (alpha1B-adrenoceptors) and 6.35 +/- 0.04 in rabbit liver (alpha1A-adrenoceptors) membranes. Zolertine showed higher affinity for alpha1D-adrenoceptors compared to alpha1A-adrenoceptors, while it had an intermediate affinity for alpha1B-adrenoceptors. The ability of the alpha1-adrenoceptor antagonist zolertine to block alpha1D-adrenoceptor-mediated constriction in different vessels of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats may explain its antihypertensive efficacy despite its low order of potency.

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.