Ombrabulin is an experimental drug candidate discovered by Ajinomoto and further developed by Sanofi-Aventis for cancer treatment. Ombrabulin is a synthetic water-soluble analog of combretastatin A4, derived from the South African willow bush (Combretum caffrum), with potential vascular-disrupting and antineoplastic activities. Ombrabulin binds to the colchicine binding site of endothelial cell tubulin, inhibiting tubulin polymerization and inducing mitotic arrest and apoptosis in endothelial cells. As apoptotic endothelial cells detach from their substrate, tumor blood vessels collapse; the acute disruption of tumor blood flow may result in tumor necrosis. Ombrabulin has been used in trials studying the treatment of Sarcoma, Neoplasms, Solid Tumor, Neoplasms, Malignant, and Advanced Solid Tumors, among others. In January 2013, Sanofi said it discontinued development of Ombrabulin after disappointing results from phase III clinical trials.

Talarozole (formerly R115866) is a new highly potent and selective azole derivative, which inhibits cytochrome-P450-dependent all-trans-retinoic acid catabolism by blocking the cytochrome P450 enzyme isoform CYP26, a retinoic acid hydroxylase. It is in clinical development for the treatment of psoriasis and acne. However, no local pharmacokinetic data on the diffusion behaviour of talarozole in the skin itself are available. As topical application might be an interesting alternative to oral therapy because of the reduced systemic side effects. The distribution of talarozole within the skin was investigated: 80% was located in the epidermis, while the remaining 20% was found in the dermis. The epidermal concentration of talarozole achieved after a single topical application was sufficiently high to enable the potential induction of local retinoid-like effects.

Misonidazole is a nitroimidazole with radiosensitizing and antineoplastic properties. Exhibiting high electron affinity, misonidazole induces the formation of free radicals and depletes radioprotective thiols, thereby sensitizing hypoxic cells to the cytotoxic effects of ionizing radiation. This single-strand breaks in DNA induced by this agent result in the inhibition of DNA synthesis. The drug also possesses a substantial cytotoxic effect, independent of radiation, which is selectively expressed in hypoxic cells. Misonidazole may be cytotoxic to the normal hypoxic tissues in the human body, making this became a major concern in the clinical application of the drug. Misonidazole leads to strand breaks in cellular DNA and those cells which fail to survive also fail to repair these strand breaks. Misonidazole depletes intracellular glutathione and is more toxic in glutathione depleted cells.

NMS-P937 is a selective PLK1 inhibitor. It was developed by Nerviano Medical Sciences and tested in phase I clinical trials.

Andrographolide, a diterpenoid, is known for its anti-inflammatory effects. It can be isolated from various plants of the genus Andrographis, commonly known as 'creat'. Andrographolide has been tested for its anti-inflammatory effects in various stressful conditions, such as ischemia, pyrogenesis, arthritis, hepatic or neural toxicity, carcinoma, and oxidative stress. Apart from its anti-inflammatory effects, andrographolide also exhibits immunomodulatory effects by effectively enhancing cytotoxic T cells, natural killer (NK) cells, phagocytosis, and antibody-dependent cell-mediated cytotoxicity (ADCC). The properties of andrographolide, such as its ability to induce apoptosis of cancer cells and inhibition of DTH, its anti-oxidative and cytoprotective effect, and its ability to enhance CTLs and NK cell activation makes it a potent antiviral agent. Andrographolide inhibited the growth of human breast, prostate, and hepatoma tumors. Andrographolide could be a potent anticancer agent when used in combination with other chemotherapeutic agents.

Japan Tobacco developed JTV-519 (known also as K201) as an antiarrhythmic agent. This drug was in Phase II trials for the potential treatment of Atrial Fibrillation, but study was terminated. In experimental myofibrillar overcontraction models, JTV-519 demonstrated greater cardioprotectant effects than propranolol, also, this drug investigated against heart failure, but then these researches have been discontinued. In addition, K201 was in phase II clinical trial for investigation its topical implementation for Atopic Dermatitis. The mechanism of its action is both complex and controversial, known that it is a non-specific blocker of sodium, potassium and calcium channels (multiple-channel blocker). It is believed to stabilize the closed state of the RyR2 (cardiac ryanodine receptor) by increasing its affinity for the FKBP12.6 (12.6 kDa FK506 binding protein), in addition was suggested, that suppression of spontaneous Ca2 release and the activity of RyR2 contributes, at least in part, to the anti-arrhythmic properties of K201.

Lometrexol, formerly known as DDATHF; LY 264618; T-64 was the first glycinamide ribonucleotide formyl transferase (GARFT) inhibitor to be investigated clinically. Lometrexol had been in phase II clinical trial for the treatment non-small cell lung cancer (NSCLC). However, the studies have been discontinued by Tularik Inc, because Company had suggested, that drug would face competition from other companies in the indication

Ganetespib (formerly called STA-9090) is a novel, injectable resorcinolic triazolone small molecule inhibitor of Hsp90, developed by Synta Pharmaceuticals. Ganetespib inhibits the growth of many tumor types in vitro and in vivo including AML, ALL, CML, NHL, neuroblastoma, Ewing sarcoma, rhabdoid cancer, rhabdomyosarcoma, melanoma, and carcinomas of the breast, lung, prostate, bladder and colon7-10,14-27. Ganetespib has being studied in multiple adult oncology indications. The 50% inhibitory concentrations (IC50) for Ganetespib against malignant mast cell lines are 10-50 times lower than that for 17-AAG, indicating that triazolone class of HSP90 inhibitors likely exhibits greater potency than geldanamycin based inhibitors. Ganetespib inhibits MG63 cell lines with IC50 of 43 nM. Ganetespib binds to the ATP-binding domain at the N-terminus of Hsp90 and serves as a potent Hsp90 inhibitor by causing degradation of multiple oncogenic Hsp90 client proteins including HER2/neu, mutated EGFR, Akt, c-Kit, IGF-1R, PDGFRα, Jak1, Jak2, STAT3, STAT5, HIF-1α, CDC2 and c-Met as well as Wilms' tumor 1. Ganetespib, at low nanomolar concentrations, potently arrests cell proliferation and induces apoptosis in a wide variety of human cancer cell lines, including many receptor tyrosine kinase inhibitor- and tanespimycin-resistant cell lines. Ganetespib exhibits potent cytotoxicity in a range of solid and hematologic tumor cell lines, including those that express mutated kinases that confer resistance to small-molecule tyrosine kinase inhibitors. Ganetespib has been studied in 5 completed Synta-sponsored clinical trials (Studies 9090-02, 9090-03, 9090-04, 9090-05, and 9090-07) and 3 completed Synta-sponsored studies in normal healthy volunteers (9090-12, 9090-13, and 9090-15). Ganetespib is currently being studied in 6 Synta-sponsored clinical trials. Studies include: one Phase 1 study, three Phase 2 studies, one Phase 2b study, and one Phase 3 study. Ganetespib is also being studied in 24 Investigator Sponsored Trials (ISTs)

Barasertib (AZD1152) is a dihydrogen phosphate prodrug of a pyrazoloquinazoline Aurora kinase inhibitor [AZD1152–hydroxyquinazoline pyrazol anilide (HQPA)] and is converted rapidly to the active AZD1152-HQPA in plasma. AstraZeneca was developing the aurora kinase inhibitor, barasertib (AZD 1152) as a therapeutic for cancer. AZD1152-HQPA is a highly potent and selective inhibitor of Aurora B (Ki, 0.36nmol/L) compared with Aurora A (Ki, 1,369nmol/L) and has a high specificity versus a panel of 50 other kinases. Consistent with inhibition of Aurora B kinase, addition of AZD1152-HQPA to tumour cells in vitro induces chromosome misalignment, prevents cell division, and consequently reduces cell viability and induces apoptosis. Barasertib (AZD1152) potently inhibited the growth of human colon, lung, and haematologic tumour xenografts (mean tumour growth inhibition range, 55% to ≥100%; P < 0.05) in immunodeficient mice. Detailed pharmacodynamic analysis in colorectal SW620 tumour-bearing athymic rats treated i.v. with Barasertib (AZD1152) revealed a temporal sequence of phenotypic events in tumours: transient suppression of histone H3 phosphorylation followed by accumulation of 4N DNA in cells (2.4-fold higher compared with controls) and then an increased proportion of polyploid cells (>4N DNA, 2.3-fold higher compared with controls). Histologic analysis showed aberrant cell division that was concurrent with an increase in apoptosis in AZD1152-treated tumours. Bone marrow analyses revealed transient myelosuppression with the drug that was fully reversible following cessation of Barasertib (AZD1152) treatment. Barasertib (AZD1152) was in phase III for the treatment of Acute myeloid leukaemia, but later these studies were discontinued.

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.