Dexanabinol is the synthetic cannabinoid. It is inactive as a cannabimimetic, but exhibits pharmacological properties characteristic of an N-methyl-D-aspartate (NMDA)-receptor antagonist. It blocks NMDA-receptors stereospecifically by interacting with a site close to, but distinct from, that of uncompetitive NMDA-receptor antagonists and from the recognition sites of glutamate, glycine, and polyamines. This agent also scavenges peroxy radicals and protects neurons from the damages of reactive oxygen species. Furthermore, dexanabinol inhibits the activity of nuclear factor kappa B (NF-kB), thereby preventing the expression of NF-kB target genes, such as tumor necrosis factor alpha, cytokines and inducible nitric oxide synthase. Dexanabinol is a potent cerebroprotective agent, with a therapeutic window of about 4 h. Dexanabinol is safe, but is not efficacious in the treatment of traumatic brain injury. It was introduced into clinical trials for breast cancer and advanced solid tumors.

CI 1040 is an inhibitor of the mitogen-activated protein (MAP) kinase signal transduction pathway and has been shown to specifically inhibit MAP kinase kinase (MEK). CI 1040 was being developed by Parke-Davis (formerly a division of WarnerLambert, Now Pfizer) as an anticancer agent. It was the initial MEK inhibitor to undergo clinical evaluation based on promising preclinical activity. However, its development has been discontinued.

Tipifarnib is an oral farnesyltransferase (FTase) inhibitor which was developed by Janssen (J&J). Upon administration, tipifarnib inhibits FTase and thus suppresses the activity of downstream effectors. The drug reached phase III of clinical trials for such diseases as pancreatic cancer (terminated), colorectal cancer (terminated) and acute myeloid leukemia (in elderly patients).

Fosmidomycin (3-(formylhydroxyamino)-propylphosphonic acid mono-sodium salt, 3-(N-formyl-N-hydroxyamino)-propylphosphonic acid mono-sodium salt, FR-31564) is a potent inhibitor of P. falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (PfDXR), developed by Albert Schweitzer Hospital for P. falciparum malaria treatment. Fosmidomycin was originally isolated as natural antibiotic from Streptomyces lavendulae. Fosmidomycin is active against a broad range of enterobacteria, but not against Gram-positive organisms or anaerobes. Fosmidomycin was developed as far as an early phase II study for the treatment of urinary tract infections by Fujisawa Pharmaceutical Company (Osaka, Japan) in the early eighties, but these trials have been discontinued. In recent clinical studies, it was shown that fosmidomycin is effective in curing uncomplicated Plasmodium falciparum malaria in humans. The treatment was well tolerated and resulted in a fast parasite and fever clearance. However, the high rate of recrudescence precludes the use of fosmidomycin as a monotherapy. In drug combination studies, the synergy of fosmidomycin with clindamycin was observed. Clinical studies with a fosmidomycin-clindamycin combination are currently ongoing.

Prinomastat is a synthetic hydroxamic acid derivative with potential antineoplastic activity. Prinomastat inhibits matrix metalloproteinases (MMPs) (specifically, MMP-2, 9, 13, and 14), thereby inducing extracellular matrix degradation, and inhibiting angiogenesis, tumor growth and invasion, and metastasis. As a lipophilic agent, prinomastat crosses the blood-brain barrier. Pfizer conducted multicenter, randomized, double-bind, placebo-controlled trials to evaluate the safety and efficacy of prinomastat in combination with standard chemotherapy in patients with advanced hormone refractory prostate cancer and non-small cell lung cancer. However, this study has been terminated for the reason that Prinomastat did not improve the outcome of chemotherapy in non-small cell Lung cancer patients.

Lomeguatrib is a O6-methylguanine-DNA-methyl-transferase inhibitor which was developed by AstraZeneca for the treatment of cancer. It was tested in phase I and II of clinical trials for the treatment of colorectal cancer, melanoma and other solid tumors.

Vanoxerine, also known as GBR-12909, is a piperazine derivative exhibiting potent selective inhibition of sodium-dependent dopamine reuptake transporters. Vanoxerine has been in clinical trials for Parkinsonism, depression and cocaine addiction but lacked efficacy. Vanoxerine has also been observed as a potent blocker of the following channels: cardiac hERG/IKr potassium channel, Calcium channel, voltage-dependent, L type, alpha 1C subunit (also known as Cav1.2) and voltage-gated sodium channel Nav 1.5. Vanoxerine was studied as a potential treatment for atrial fibrillation. However, phase III clinical trials for this condition were terminated because of cardiac safety concerns. Research also indicates that vanoxerine may have additional mechanisms of action including antagonist action at nicotinic acetylcholine receptors (nAChRs).

CTS-1027 (Ro-1130830) is a hydroxamic acid matrix metalloprotease (MMP) inhibitor. CTS-1027 was originally designed as a strong inhibitor of MMP-2, -3, -8, -9, -12, -13 and -14, without inhibiting MMP-1 and MMP-7. CTS-1027 was proved to be safe in clinical trials for osteoarthritis conducted by Roche. CTS-1027 was then licensed from Roche to Conatus Pharmaceuticals and was investigated as a protector from liver fibrosis in hepatitis C virus patients. The development of the drug was discontinued due to laboratory abnormalities and adverse events in a subset of clinical trial participants.

Mureletecan is a water-soluble prodrug, consisting of camptothecin covalently linked to polymeric backbone methacryloylglycynamide, with potential antineoplastic activity. After entering tumor cells, the active moiety camptothecin is slowly released from mureletecan via hydrolysis of the ester linkage. Camptothecin, the active moiety, is an alkaloid isolatable from the Chinese tree Camptotheca acuminata. Camptothecin itself suffers from poor solubility, which is why it is often investigated with a solubilizing conjugate; such as in Mureletecan. Camptothecin binds to and stabilizes the topoisomerase I-DNA covalent complex producing potentially lethal double-stranded DNA breaks when encountered by DNA replication machinery. Camptothecin has also been shown to inhibit HIF1a. Camptothecin has been investigated with a number of solubilizing conjugates as a potential treatment in various forms of cancer.

Carboxyamidotriazole (L651582) is a carboxyamide-amino-imidazole compound originally developed as a coccidiostat, an antiprotozoal agent that acts upon Coccidia parasites. Carboxyamidotriazole (L651582) is an orally-active agent with potential antineoplastic activity. Carboxyamidotriazole binds to and inhibits non-voltage-operated Ca2 channels, blocking both Ca2 influx into cells and Ca2 release from intracellular stores and resulting in the disruption of calcium channel-mediated signal transduction and inhibition of vascular endothelial growth factor (VEGF) signaling, endothelial proliferation, and angiogenesis. This agent may also inhibit tumor cell growth, invasion, and metastasis.