Daniquidone, also known as Batracylin, is a water-insoluble heterocyclic amide with potential antineoplastic activity. Daniquidone inhibits topoisomerases I and II, thereby inhibiting DNA replication and repair, and RNA and protein synthesis. Batracylin advanced as an anticancer agent to Phase I clinical trials where dose limiting hemorrhagic cystitis (bladder inflammation and bleeding) was observed.

The new chemical entity KC12615 is a potent f neutral endopeptidase inhibitor with additional endothelin-converting enzyme (ECE)–inhibitory activity.2 KC12615 is the hydrolyzed form of the oral prodrug SLV306 (daglutril). In plasma, the compound increases natriuretic peptide levels and prevents the formation of endothelin-1 by inhibiting the degradation of its precursor, big endothelin. It is investigated for use/treatment in congestive heart failure and hypertension.

Nesbuvir (previously known as VB-19796 and HCV-796) is an inhibitor of hepatitis C NS5B RNA-dependent RNA polymerase. The drug was tested in phase II in patients with hepatitis C in combination with rebetol and peg-intron, however, its development was terminated due to safety issues.

Indibulin is a novel synthetic compound that was identified in a cell-based screening assay to discover cytotoxic drugs. Indibulin destabilizes microtubules and blocks cell cycle transition specifically at the G2-M phase. Indibulin effectively induces apoptosis through Bcl-2 phosphorylation and Bax translocation in human malignant glioma cells in a p53-independent manner. This agent has been shown to be active against multidrug-resistant (MDR) and taxane-resistant tumour cell lines. Indibulin was used in phase I/II clinical trials of patients with advanced solid tumours (metastatic breast cancer). Pharmacokinetic analysis showed a better tolerability underfeeding condition. Dose-limiting toxicities were nausea and vomiting, which seemed to be related to solvent lactic acid.

Pumosetrag is a novel, orally active and selective 5-HT 3 agonist. It is a partial agonist in rats and guinea-pig and a full agonist in the mouse, suggesting important species differences in 5-HT3 receptor structure. Pumosetrag had been in phase II clinical trials for the treatment of gastroesophageal reflux disease and irritable bowel syndrome. No serious adverse events were reported. Diarrhea was not more common on the drug and only one subject experienced pruritus. All researches on this drug candidate are discontinued.

Zosuquidar (LY-335979) is an experimental antineoplastic drug. It is is a potent modulator of P-glycoprotein-mediated multi-drug resistance with Ki of 60 nM. Zosuqidar was initially characterized by Syntex Corporation, which was acquired by Roche in 1990. Roche licensed the drug to Eli Lilly in 1997. It was granted orphan drug status by the FDA in 2006 for AML. Zosuquidar Trihydrochloride had been in phase III clinical trials by Kanisa Pharmaceuticals for the treatment of acute myeloid leukaemia. However, this research has been discontinued.

Betulinic acid (BA) is a plant-derived pentacyclic triterpenoid that exerts potent anti-cancer effects in vitro and in vivo. It`s anticancer property is linked to its ability to induce apoptotic cell death in cancer cells by triggering the mitochondrial pathway of apoptosis. In contrast to the cytotoxicity of betulinic acid against a variety of cancer types, normal cells and tissue are relatively resistant to betulinic acid, pointing to a therapeutic window. Compounds that exert a direct action on mitochondria present promising experimental cancer therapeutics, since they may trigger cell death under circumstances in which standard chemotherapeutics fail. Thus, mitochondrion-targeted agents such as betulinic acid hold great promise as a novel therapeutic strategy in the treatment of human cancers. Betulinic acid has antiretroviral, antimalarial, and anti-inflammatory properties. Betulinic acid exerts its inhibitory effect by preventing topoisomerase I-DNA interaction as a result of which the 'cleavable complex' is not formed. In consequence, it also acts as an antagonist to camptothecin-mediated cleavage. The antitumor pharmacological effects of BA consist of triggering apoptosis via the mitochondrial pathway, regulating the cell cycle and the angiogenic pathway via factors, including specificity protein transcription factors, cyclin D1 and epidermal growth factor receptor, inhibiting the signal transducer and activator of transcription 3 and nuclear factor‑κB signaling pathways, preventing the invasion and metastasis of tumor cells, and affecting the expression of topoisomerase I, p53 and lamin B1. Betulinic Acid has also been used in trials studying the treatment of Dysplastic Nevus Syndrome. Betulinic acid acts as anti-melanoma agent through inhibiting aminopeptidase N activity with IC50 of 7.3 uM. Betulinic acid is an inhibitor of HIV-1 with EC50 of 1.4 uM.

Odapipam is a benzazepine with high affinity and selectivity for D1-dopamine receptors. Labeled with C-11, it has been used as a PET radiotracer to visualize D1 receptors both in striatal and extrastriatal areas, such as the prefrontal cortex. Odapipam inhibits dopamine D1 receptor binding in vitro with low nanomolar to picomolar dissociation constants. The affinity of [11C]NNC 756 for D1 receptors is 0.18 nM. Odapipam was tested in phase I of clinical trials for the treatment of psychotic disorders, but failed.

Apricitabine (ATC) is an investigational drug that was being studied for the treatment of HIV infection. Apricitabine belongs to a class (group) of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs). NRTIs block an HIV reverse transcriptase. By blocking reverse transcriptase, NRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body. In vitro studies have shown that apricitabine appears to work on certain HIV strains against which other FDA-approved NRTIs, such as lamivudine (brand name: Epivir), may no longer work. Apricitabine shows antiviral activity in vitro against HIV-1 strains and clinical isolates with mutations in the reverse transcriptase that confer resistance to other NRTIs, including M184V, thymidine analogue mutations (TAMs), nucleoside-associated mutations such as L74V and certain mutations at codon 69. Apricitabine has shown activity in treatment-experienced HIV-1-infected patients with NRTI resistance (with M184V and up to five TAMs) as well as in treatment-naive patients. The study of apricitabine as an HIV medicine was discontinued in 2016. The company developing the drug decided to stop their clinical trials due to a lack of funding and a lack of interest in apricitabine’s early access program.

Norletimol is a Schiff base with promising anti-inflammatory properties. The time taken for elimination of 50% of the Norletimol dose in the urine was approximately five hours. As an antirheumatic agent it was tested in clinical trials in Iraq. It was used in progressive myopia in children.