Berubicin, an anthracycline derivative, is a DNA binding agent and potent topoisomerase II poison. Reata Pharmaceuticals were developing it as a treatment for brain cancer as it can breach the blood-brain barrier. It had also been in early clinical trials for the treatment of lung cancer and malignant gliomas. However, studies have been terminated. In October 2006, it was granted orphan drug designation from the FDA for the treatment of malignant gliomas. According to a CNS Pharmaceuticals media release in April 2018, berubicin will be studied for glioblastoma patients, these investigations will be funded in part by an equity crowdfunding campaign.

Vadimezan (5,6-dimethyl(xanthenone-4-acetic acid), ASA404, DMXAA) is a fused tricyclic analogue of flavone acetic acid with potential antineoplastic activity. In pre-clinical mouse tumour models it was demonstrated that administration of Vadimezan rapidly leads to disruption of the existing vasculature in the tumour and consequent haemorrhagic necrosis of the tumour. This was consistent with the finding that a single dose of Vadimezan induced a prolonged reduction in the growth of xenografted tumours in animal models. The ability to disrupt the vasculature in these pre-clinical models has been attributed to a rapid induction of cytokines, particularly TNFα (tumour necrosis factor α), serotonin and nitric oxide, resulting in hemorrhagic necrosis and a decrease in angiogenesis. Despite the fact that the molecular targets for the drug remained unknown, the promising pre-clinical results led to Vadimezan being selected for clinical development. Results of Phase I trials showed some restriction of tumour blood flow within 24 h of treatment, although this was not as dramatic as seen in pre-clinical models. Unlike the animal models, there was also very little evidence for the rapid death of blood vessels or for increases in TNFα levels in human tumors. No difference in antitumour activity, cytokine induction or toxicity was observed between two parallel Phase I trials, one dosed weekly and the other dosed every 3 weeks. Therefore the drug proceeded to Phase II clinical trials, dosed every 21 days in combination with chemotherapeutic agents. These trials indicated the drug had small benefits in the treatment of non-small-cell lung cancer and prostate cancer. However, a subsequent Phase III clinical trial was not able to reproduce this response and clinical development was halted.

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.

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

Veribulin is a novel microtubule destabilizer that both functions as a potent cytotoxin and acts as a vascular disrupting agent (VDA). It binds to the same (or nearby) sites on β-tubulin as colchicine. It is capable of evading multidrug resistance pumps and, thus, achieves high CNS concentrations. It is efficacious in multiple xenograft models without CNS toxicity. Veribulin had previously demonstrated pre-clinical and clinical activity in multiple tumor types. Veribulin is in phase II clinical trial for the treatment of Glioblastoma and Malignant melanoma.

L-778123 is a dual inhibitor of Farnesyl Protein Transferase (FPTase) and Geranylgeranyl Protein Transferase type-I (GGPTase-I), which can completely inhibit Ki-Ras prenylation. L-778123 has been used in phase I clinical trials to determine its effectiveness in treating patients with recurrent or refractory solid tumors. L-778123 was also studied in combination with paclitaxel to determine efficacy as a treatment for both recurrent or refractory solid tumors, and lymphomas.

Fostriecin, an antitumor antibiotic produced by Streptomyces pulveraceus, is a strong inhibitor of serine/threonine protein phosphatases type 2A and type 4, and inhibits the catalytic activity of partially purified Topo II (type II topoisomerase) in a non-competitive manner.

Fosbretabulin (Combretastatin A4 phosphate, CA4P) is the lead compound of a relatively new class of agents termed vascular disrupting agents that target existing tumor blood vessels. Rapid tumor blood flow shutdown has been demonstrated in preclinical models and patients by various techniques such as dynamic contrast-enhanced MRI, perfusion computed tomography and PET scans following CA4P infusion. CA4P typically induces rapid tumor necrosis in the center of the tumor and leaves a rim of viable cells in the periphery. In oncology, CA4P does not appear to be that active by itself, but may be more efficacious when combined with chemotherapy, antiangiogenic therapy and radiation therapy. Combretastatin was initially isolated from the root bark of the South African Bush willow Combretum caffrum in 1982 by Pettit and colleagues at the Arizona State University (AZ, USA). Combretastatin A4 phosphate binds avidly to tubulin at the colchicine-binding site to inhibit microtubule assembly and destabilize the cytoskeleton. CA4P is a tubulin-binding agent that binds at or near the colchicine binding site of β-tubulin (Kd = 0.40 uM), inhibits tubulin assembly with IC50 of 2.4 uM. Fosbretabulin has orphan drug status in the EU and the US for the treatment of ATC (Anaplastic Thyroid Cancer). Later the development of this drug was discontinued.

AT7519 is an inhibitor of Cyclin-dependent kinases (CDK). AT7519 potently inhibited CDK1,CDK2,CDK4 to CDK6, and CDK9. The compound had lower potency against other CDKs tested (CDK3 and CDK7) and was inactive against all of the non-CDK kinases tested with the exception of GSK3beta. AT7519 showed potent antiproliferative activity in a panel of human tumor cell lines. AT7519 caused cell cycle arrest followed by apoptosis in human tumor cells and inhibited tumor growth in human tumor xenograft models. AT7519 is currently being investigated in Phase 1/2 studies.

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.