Tubulozole is a stereospecific microtubule inhibitor. Structurally it is related to the benzimidazole carbamates by its carbamate moiety, which is essential for the activity of both types of compounds. The compound exists as a cis-isomer called tubulozole-C (R 46 846) and as a trans-isomer called tubulozole-T. The cis-isomer appears to be a potent and specific microtubule inhibitor, the trans-isomer being inactive at 100 times higher concentrations. At low concentrations, both isomers of tubulozole (C, T) inhibit Plasmodium falciparum but only tubulozole C inhibits mammalian cells. Since tubulozole C prevents polymerization of mammalian tubulin whereas tubulozole T does not, the antimalarial action of tubulozoles may not involve microtubules. Tubulozole-C, a new synthetic anticancer drug, interfered with the structure and function of microtubules in both interphase and mitotic cells. The activity of Tubulozole-C in experimental tumor systems can be explained partly by a direct antimitotic effect and partly by the disintegration of the normal subcellular organization of the nondividing cells. At concentrations which affect the microtubule system, tubulozole-C arrested directional migration of transformed cells and malignant invasion in a three-dimensional organ culture system. Investigations in vivo show that malignant L1210 leukemia cells are more susceptible to the antimicrotubular effect of tubulozole-C than are the normal leukocytes of the host. The trans-isomer of tubulozole (tubulozole-T, R 48 265), which has no antitumor activity in vivo, did not affect the microtubule system of cells in vitro or their capacity for directional migration or for malignant invasion.

Indotecan (LMP400) is a novel indenoisoquinoline derivative with specific topoisomerase I inhibition activity, developed by Division of Cancer Treatment and Diagnosis National Cancer Institute for cancer treatment. In preclinical studied Indotecan inhibited the cell growth of established mouse pheochromocytoma cell lines and primary human tumor tissue cultures. Low doses of Indotecan decreased the protein levels of hypoxia-inducible factor 1 (HIF-1α), one of a family of factors studied as potential metastatic drivers in these tumors. In vitro, Indotecan showed an increase in the growth-inhibitory effects in combination with other chemotherapeutic drugs that are currently used for the treatment of pheochromocytoma. Recently Indotecan has entered Phase I clinical trials for the treatment of cancer patients at the National Cancer Institute, and definite plans are being formulated to commence Phase II clinical trials.

Morazone is is a nonsteroidal anti-inflammatory drug (NSAID), originally developed by the German pharmaceutical company Ravensberg in the 1950s. Morazone was used as a moderately strong analgesic but was discontinued due to high abuse potential

Indimitecan, also known as LMP776, is a novel topoisomerase I inhibitor. A substance being studied in the treatment of cancer. It blocks certain enzymes that break and rejoin DNA strands. These enzymes are needed for cells to divide and grow. Blocking them may cause cancer cells to die. Indimitecan (LMP776) also helps anticancer drugs kill cancers that are resistant to some other drugs. LMP776 is a type of indenoisoquinoline and a type of topoisomerase inhibitor. In vitro, LMP776 induces TOP 1 cleavage at unique genomic positions and causes cell cycle arrest in both S and G (2)-M phases. Protein linked DNA breaks were observed in cells treated with nanomolar concentrations of LMP776.

Mocetinostat is an rationally designed, orally available, Class 1-selective, small molecule, 2-aminobenzamide HDAC inhibitor with potential antineoplastic activity. Mocetinostat binds to and inhibits Class 1 isoforms of HDAC, specifically HDAC 1, 2 and 3, which may result in epigenetic changes in tumor cells and so tumor cell death; although the exact mechanism has yet to be defined, tumor cell death may occur through the induction of apoptosis, differentiation, cell cycle arrest, inhibition of DNA repair, upregulation of tumor suppressors, down regulation of growth factors, oxidative stress, and autophagy, among others. It is undergoing clinical trials for treatment of various cancers including bladder cancer, diffuse large B cell lymphoma, follicular lymphoma, myelodysplastic syndromes, non-small cell lung cancer. Fatigue, weight loss or anorexia were most common treatment-related adverse events.

There is no much available information related to the biological and pharmacological application of imidoline, but this compound has been found to be as potent as chlorpromazine in increasing striatal DOPA accumulation and prolactin secretion in vivo. Imidoline exhibited only weak inhibitory activity towards dopamine-sensitive adenylate cyclase and 3H-spiroperidol binding to striatal membranes in vitro. A proposed active conformation involves intramolecular hydrogen bonding between the protonated dimethylamino group and the oxygen of the imidazolidinone ring. The spatial relationship between the amine nitrogen and phenyl ring in this conformation allows proper fit of imidoline with key dimensions described for the dopamine receptor.

Amonafide L-malate (AS1413, Xanafide) is a DNA intercalator and topoisomerase II inhibitor that induces apoptosis by disrupting chromatin organisation independently of ATP. This is different from classical topoisomerase II inhibitors which induce apoptosis by causing extensive DNA damage. Amonafide L-malate is also able to evade P-glycoprotein and related transporters that contribute to multi-drug resistance. AS1413 had orphan drug status in both the U.S. and the E.U. for the treatment of AML and also received Fast Track status from the U.S. FDA for the treatment of secondary AML. Amonafide L-malate was originated by Xanthus Pharmaceuticals. It was added to Antisoma's pipeline through the acquisition of Xanthus Pharmaceuticals, Inc. in June 2008. Antisoma discontinued development of Amonafide L-malate after data from the open-label, international Phase III ACCEDE trial in over 420 patients showed that 600 mg/m 2 IV amonafide for 5 days plus cytarabine missed the primary endpoint of significantly improving initial remission rate, defined as the proportion of patients who achieve CR or CRi, vs. daunorubicin plus cytarabine.

Nolpitantium (SR-140333) is a highly selective nonpeptide antagonist of neurokinin-1 (NK1) receptor. Nolpitantium potently, selectively and competitively inhibited substance P binding to NK1 receptors from various animal species, including humans. In vitro, it was a potent antagonist in functional assays for NK1 receptors such as [Sar9, Met(O2)11]substance P-induced endothelium-dependent relaxation of rabbit pulmonary artery and contraction of guinea-pig ileum. Up to 1 mkM, Nolpitantium had no effect in bioassays for NK2 and NK3 receptors. The antagonism exerted by Nolpitantium toward NK1 receptors was apparently non-competitive, with pD2' values between 9.65 and 10.16 in the different assays. Nolpitantium also blocked in vitro [Sar9, Met(O2)11]substance P-induced release of acetylcholine from rat striatum. In vivo, Nolpitantium exerted highly potent antagonism toward [Sar9, Met(O2)11]substance P-induced hypotension in dogs, bronchoconstriction in guinea-pig) and plasma extravasation in rats. Nolpitantium was found to be effective in the modulation of the inflammatory response and airway remodeling in mice. Nolpitantium is reported to cause antagonism of the SP-induced relaxations of human isolated intralobar pulmonary arterial rings. Nolpitantium also blocked the activation of rat thalamic neurons after nociceptive stimulation. Nolpitantium has been shown to reduce the severity of inflammation in trinitrobenzene sulfonic acid-induced colitis in the rat colon. Nolpitantium inhibited mustard oil-induced plasma protein extravasations in the dorsal skin of the rat hind paw. Nolpitantium had been in some phase II clinical trials but further studies were discontinued.

Combretastatin A4 is a vascular disrupting agent (VDA) that targets tumor vasculature to inhibit angiogenesis. Combretastatin A4 is a tubulin-binding agent that binds at or near the colchicine binding site of β-tubulin and inhibits tubulin assembly. This tubulin-binding agent was originally isolated from an African shrub, Combretum caffrum. Combretastatin A4 is cytotoxic to umbilical-vein endothelial cells (HUVECs) and to a range of cells derived from primary tumors and these cytotoxicity profiles have been used to assess several novel analogs of the drug for future development. Combretastatin A4 has antitumor activity by inhibiting AKT function. The inhibited AKT activation causes decreased cell proliferation, cell cycle arrest, and reduced in vitro migration/invasiveness and in vivo metastatic ability. Several studies in mice have shown that a single administration of combretastatin A4 (100 mg/kg) does not significantly affect primary tumor growth. However, repeated administration (12.5 – 25.0mg/kg twice daily) for periods of 10 – 20 days resulted in approximately 50% retardation of growth of ectopic Lewis lung carcinoma and substantial growth delay of T138 spontaneous murine breast tumors. In clinical studies, Combretastatin A4 has been well tolerated in patients at doses up to 56 mg/m2, following a protocol of five daily 10-minute intravenous infusions every 21 days. The disodium combretastatin A4 phosphate prodrug is currently undergoing clinical trials in the UK and USA.