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.

Perzinfotel (EAA-090) is a novel squaric acid amide derivative that has been identified as a potential treatment for ischemic brain damage resulting from stroke. EAA-090 is a competitive inhibitor at the NMDA-selective subtype of the glutamate receptor. The compound demonstrates potent inhibitory activity in both in vitro and in vivo models of NMDA-induced excitotoxicity and provides neuroprotective efficacy in several animal models of stroke. EAA-090 is unique among competitive NMDA antagonists in displaying a clear separation between predicted efficacious dose and doses that induce PCP-like psychotomimetic side effects in both animals and humans. This unique profile makes EAA-090 an exciting candidate for assessing the neuroprotective potential of the competitive NMDA mechanism.

AEE-788 is an orally available anticancer agent that was being developed by Novartis. AEE-788 is a dual family epidermal growth factor receptor/ErbB2 and vascular endothelial growth factor receptor tyrosine kinase inhibitor with antitumor and antiangiogenic activity. At the enzyme level, AEE-788 inhibited EGFR and VEGF receptor tyrosine kinases in the nm range (IC(50)s: EGFR 2 nm, ErbB2 6 nm, KDR 77 nm, and Flt-1 59 nm). In cells, growth factor-induced EGFR and ErbB2 phosphorylation was also efficiently inhibited (IC(50)s: 11 and 220 nm, respectively). AEE-788 demonstrated antiproliferative activity against a range of EGFR and ErbB2-overexpressing cell lines (including EGFRvIII-dependent lines) and inhibited the proliferation of epidermal growth factor- and VEGF-stimulated human umbilical vein endothelial cells. These properties, combined with a favorable pharmacokinetic profile, were associated with a potent antitumor activity in a number of animal models of cancer, including tumors that overexpress EGFR and or ErbB2. Oral administration of AEE-788 to tumor-bearing mice resulted in high and persistent compound levels in tumor tissue. Moreover, AEE-788 efficiently inhibited growth factor-induced EGFR and ErbB2 phosphorylation in tumors for >72 h, a phenomenon correlating with the antitumor efficacy of intermittent treatment schedules. AEE-788 has potential as an anticancer agent targeting deregulated tumor cell proliferation as well as angiogenic parameters. AEE-788 had been in phase Ⅱ clinical trials by Novartis for the treatment of glioblastoma multiforme. However, this research has been discontinued.

Clorotepine (aka octoclothepin or octoclothepine) is an antipsychotic from the tricyclic group derived from perathiepin. It was originally developed in 1965 and marketed in the Czech Republic by Spofa in or around 1971 for the treatment of schizophrenic psychosis. Clorotepine has a high affinity for the dopamine (D1, D2, D3, D4), receptors the serotonin 5-HT (2A, 2B, 2C, 6, 7) receptors, the alpha-adrenergic receptors (1A, 1B, 1D), and the histamine H1 receptors. In most instances, it acts as an antagonist (or inverse agonist). Clorotepine will also block the reuptake of norepinephrine by inhibiting the norepinephrine transporter.

Metrenperone, a 5-hydroxytryptamine blocker, is used in veterinary as an antimyopathic agent. Experiments on rabbits have shown that the drug had positive effects on collagen turnover, remodeling, and organization during acute inflammation and fibroplasia.

Nanofin is a ganglion blocker alkaloid having nicotinic acetylcholine receptor antagonist action. It has an antihypertensive effect used for mild to moderate hypertension. It was also used for the treatment of eczema and neurodermatitis.

Eticlopride {2S(−)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamide} is an antagonist at dopamine D2 and D3 receptors. It is widely used for in vivo, in vitro, and ex vivo examination of D2/D3 receptors densities and function. Eticlopride exerts antipsychotic activity in animals.

Prosulpride is an aminosulfonylbenzamide derivative with potent neuroleptic activity. Prosulpride selectively blocks the presynaptic dopaminergic receptors and antagonize apomorphine-induced stereotyped behavior, circling behavior, climbing behavior, increased motor activity and some other apomorphine-induced effects related to stimulation of postsynaptic dopaminergic receptors.

Pruvanserin (EMD 281014, LY-2422347) is a selective serotonin 5-HT2A receptor antagonist. Pruvanserin was originated by Merck KGaA. Eli Lilly had been developing pruvanserin, under a global licence from Merck KGaA, for the treatment of primary insomnia and major depressive disorder. Phase II trials were completed in the US, Hungary and Spain. However, development appears to have been discontinued.

CGP-36742 (3-Aminopropyl-n-butyl-phosphinic acid) is one of the first GABAB receptor antagonists that can penetrate the blood-brain barrier after peripheral administration. Although its affinity for GABA B binding sites labeled with a tritiated agonist is modest, being in the low micromolar range, it displays significant pharmacological activity when administered either orally or parenterally. CGP 36742 was effective in the learned helplessness paradigm in rats, dose-dependently improving the escape failures induced by the inescapable shocks, suggesting that it may have an antidepressant profile. CGP36742 displays pronounced cognition enhancing effects in Rhesus monkeys in active and passive avoidance paradigms, in an eight-arm radial maze and a Morris water maze and in a social learning task. CGP36742 blocks the late inhibitory postsynaptic potential and the paired-pulse inhibition of population spikes recorded from CA1 pyramidal neurons of the hippocampus of rats in vitro and in vivo. CGP36742 significantly enhances the release of glutamate, aspartate, glycine and somatostatin in vivo. Chronic administration of CGP36742 causes an up-regulation of GABA(B) receptors in the frontal cortex of rats. The effects of CGP36742 on cognition were investigated in a double-blind, placebo-controlled study undertaken as the first assessment of the efficacy of CGP36742 in 110 patients age 59–85 years with Mild cognitive impairment. The results showed significant improvement in working memory, psychomotor speed and attention with SGS742 as compared with placebo. SGS742 appeared to be safe and well tolerated in this study.