Tariquidar, a non-competitive, specific P-glycoprotein (Pgp) inhibitor, is an anthranilamide derivative with multidrug resistance properties. Tariquidar binds to the ATP-binding cassette (ABC) transport protein Pgp, thereby inhibiting transmembrane transport of anticancer drugs resulting in their increased intracellular concentrations augmenting cytotoxicity of an anticancer drug. Tariquidar was discovered by Xenova Group and was developed for the treatment of multidrug resistance in cancer. In October 2002 the US Food and Drug Administration (FDA) has granted fast track review status to tariquidar for the treatment of multi-drug resistance in first-line treatment of non-small cell lung cancer (NSCLC) patients. Tariquidar is still undergoing research as an adjuvant against multidrug resistance in cancer.

Tanespimycin (17-allylamino-17-demethoxygeldanamycin, 17-AAG) is a synthetic analogue of geldanamycin, an antibiotic first purified in 1970 from Streptomyces hygroscopicus. Tanespimycin is an Hsp90 inhibitor that has demonstrated the potential to disrupt the activity of multiple oncogenes and cell signaling pathways implicated in tumor growth, including HER2, a key pathway in breast cancer. Tanespimycin was being under development by Kosan Biosciences. It was in phase 3 clinical development with bortezomib for the treatment of multiple myeloma (MM). However, in 2010 the company halted development of tanespimycin, during late-stage clinical trials as a potential treatment for multiple myeloma. While no definitive explanation was given, it has been suggested that Bristol-Myers Squibb halted development over concerns of the financial feasibility of tanespimycin development given the 2014 expiry of the patent on this compound, and the relative expense of manufacture.

Ridogrel is a dual action drug used for the prevention of systemic thrombo-embolism and as an adjunctive agent to thrombolytic therapy in acute myocardial infarction. Ridogrel, a combined thromboxane synthase inhibitor, and receptor antagonist is used with streptokinase as an adjunctive therapy to reduce the formation and size of blood clots. Blood clots can cause ischemic cardiac events (heart attacks). Ridogrel has the dual property of inhibiting the synthesis of thromboxane and blocking the receptors of thromboxane/prostaglandin/endoperoxides. It has been shown to accelerate the speed of recanalization and to delay or prevent reocclusion during systemic thrombolysis with tissue plasminogen activator (streptokinase). Ridogrel is a more potent antiplatelet agent than aspirin and might offer an advantage over aspirin as an adjunct to thrombolysis in patients suffering from acute myocardial infarction. While aspirin inhibits cyclooxygenase, the enzyme responsible for producing thromboxane, ridogrel inhibits thromboxane synthesis directly. Ridogrel has been studied primarily as an adjunctive agent to thrombolytic therapy in acute MI (AMI). Despite positive results from initial pilot studies, the largest clinical study, the Ridogrel versus Aspirin Patency Trial (RAPT) failed to demonstrate any advantage with this agent over aspirin. In the study of 907 patients with AMI, there was no difference in the primary endpoint of infarct vessel patency rate between those randomized to ridogrel (72.2%) or aspirin (75.5%). Various mechanisms are likely responsible for the results seen with ridogrel in clinical trials, including potentially ineffective thromboxane receptor inhibition with the concentrations of ridogrel used in human studies. As such, there currently are no clinical indications for preferential use of ridogrel over aspirin.

Licofelone (ML 3000) is a pyrrolizine derivative originally discovered by Merckle GmbH and developed by EuroAllaince with a unique pharmacological profile, which comprises optimal gastrointestinal tolerability and high analgesic and anti-inflammatory activity. These effects are due to balanced and selective inhibition of both cyclo-oxygenase and 5-lipoxygenase. Inhibition of 5-lipoxygenase may reduce the gastrointestinal toxicity associated with other non steroidal anti-inflammatory drugs, which only inhibit cyclooxygenase. Licofelone also has antipyretic and antiaggregatory properties. Clinical and preclinical trials were also undertaken for osteoarthritis, rheumatoid arthritis, asthma, pain and inflammation. However, development for these indications appear to have been discontinued.

Ocinaplon is anxiolytic in rodents and primates, including humans, with a magnitude of effect comparable to benzodiazepines. It was evaluated to treat Generalised anxiety disorder. The mechanism of action by which ocinaplon produces its anxiolytic effects is by allosteric modulating of GABA-A receptors. The serious adverse event detected in the ocinaplon group was icterus following transaminase elevations. Due to liver complications that occurred in Phase III, development of ocinaplon is discontinued.

Lubeluzole is a medication, developed by Janssen Research Foundation for the treatment of acute ischemic stroke. The drug action is discussed to involve the inhibition of NMDA receptor and sodium channels.

Enciprazine also known as WY-48624 or, D-3112 is a GABA A receptor agonist which was in the phase III of clinical trial for the treatment of anxiety disorders. Enciprazine was well tolerated, with low levels of sedative and asthenic side effects reported. However, research was discontinued.

Indole-3-carbinol (I3C), a common phytochemical in cruciferous vegetables, and its condensation product, 3,3'-diindolylmethane (DIM) exert several biological activities on cellular and molecular levels, which contribute to their well-recognized chemoprevention potential. ndole-3-carbinol is used for prevention of breast cancer, colon cancer, and other types of cancer. The National Institutes of Health (NIH) has reviewed indole-3-carbinol as a possible cancer preventive agent and is now sponsoring clinical research for breast cancer prevention. Indole-3-carbinol is also used for fibromyalgia, tumors inside the voice box (laryngeal papillomatosis) caused by a virus, tumors inside the respiratory tract (respiratory papillomatosis) caused by a virus, abnormal cell growth in the cervix (cervical dysplasia), and systemic lupus erythematosus (SLE). Indole-3-carbinol scavenges free radicals and induces various hepatic cytochrome P450 monooxygenases. Specifically, this agent induces the hepatic monooxygenase cytochrome P4501A1 (CYP1A1), resulting in increased 2-hydroxylation of estrogens and increased production of the chemoprotective estrogen 2-hydroxyestrone. Accumulating evidence indicates that the antitumor activity of indole-3- carbinol is attributable to its ability to interfere with multiple oncogenic signaling pathways governing cell cycle progression, survival, invasion, and other aggressive phenotypes of cancer cells. Reported signaling targets of indole-3- carbinol in various cancer cell lines include EGFR/Src, Akt/NF-B, stress responses, elastase, and Rho kinase. Moreover, indole-3-carbinol functions as a negative regulator of estrogen action in hormonesensitive cancer cells through the inhibition of estrogen receptor (ER)-alpha signaling and/or induction of cytochrome P-450-mediated estrogen metabolism, suggesting its clinical use in hormone-sensitive cancers.

Nefiracetam is a cyclic derivative of gamma-aminobutyric acid (GABA). It is thought to act by normalising dysfunctional acetylcholine, GABA and possibly monoamine neurotransmitter systems, but it may also facilitate N/L-type calcium channel opening. Nefiracetam has received attention as a treatment for seizures, depression, and dementia. Nefiracetam was found to be extremely testicular toxic in both rats and dogs; it was found to significantly decrease the levels of testicular testosterone leading to atrophy and malformation of sperm.

Meclinertant (SR-48692) is the first non-peptide antagonist of neurotensin receptors. It is potent and selective vs the high-affinity binding sites and with a small activity on the levocabastine-sensitive binding sites. It is active on several species including man without partial agonist properties. In vivo, it is active by oral route with a long duration of action and it is able to cross the blood-brain barrier. Meclinertant may be considered a powerful tool for investigating the role of neurotensin in physiological and pathological processes. Meclinertant has been developing for the treatment of anorexia nervosa; colorectal cancer; irritable bowel syndrome; pain; pancreatic cancer; prostate cancer; schizophrenia; small cell lung cancer however its development was discontinued.