LAVOLTIDINE, also known as loxtidine, is a highly potent and selective histamine H2-receptor antagonist. It is a member of triazoles. It produces gastric carcinoid tumors in rodents that is why its clinical development was discontinued.

Carubicin (also known as Carminomycin) is an anthracycline antineoplastic antibiotic isolated from the bacterium Actinomadura carminata. Carubicin intercalates into DNA and interacts with topoisomerase II, thereby inhibiting DNA replication and repair and RNA and protein synthesis. The drug is active against a variety of experimental tumors. Pharmacology studies in animals revealed that the drug bound largely to serum proteins and that it was widely distributed. In clinical trials The main toxic effect was myelosuppression but gastrointestinal intolerance and alopecia were also reported. Objective partial responses were seen in two of seven previously untreated patients with non-small cell lung cancer and one of three patients with squamous cell carcinoma of the head and neck previously untreated with chemotherapy.

Triciribine is a purine analogue which inhibits DNA and protein synthesis, it is a synthetic tricyclic nucleoside which acts as a specific inhibitor of the Akt signaling pathway. It selectively inhibits the phosphorylation and activation of Akt1, -2 and -3 but does not inhibit Akt kinase activity nor known upstream Akt activators such as PI 3-Kinase and PDK1. It inhibits cell growth and induces apoptosis preferentially in cells that express aberrant Akt1. In whole cells triciribine is phosphorylated by adenosine kinase which may be necessary for its activity. Triciribine is a cancer drug which was first synthesised in the 1970s and trialled clinically in the 1980s and 1990s without success. Following the discovery in the early 2000s that the drug would be effective against tumours with hyperactivated Akt, it is now again under consideration in a variety of cancers. As PTX-200, the drug is currently in two early stage clinical trials in breast cancer and ovarian cancer being conducted by the small molecule drug development company Prescient Therapeutics.

Semapimod (CNI-1493) is a cytokine inhibitor and synthetic guanylhydrazone mitogen-activated protein kinase blocker, is being developed by Cytokine PharmaSciences as a potential treatment for Crohn's disease and other inflammatory conditions. As of December 2001, a phase I study demonstrating the safety of the compound had been completed and phase II trials for psoriasis and Crohn's disease were ongoing. In April 2003, preclinical and early clinical studies were underway for a variety of indications, including congestive heart failure and pancreatitis. Semapimod inhibits activation of p38 MAPK and NF-κB and induction of cyclooxygenase-2 by TLR ligands, but not by IL-1β or stresses. Semapimod inhibits TLR4 signaling (IC50 ≈0.3 umol) and acts by desensitizing cells to LPS; it fails to block responses to LPS concentrations of ≥5 ug/ml. Semapimod had been in phase II clinical trials by Ferring Pharmaceuticals for the treatment of Crohn's disease. However, this research has been discontinued. Semapimod is in phase I clinical trials for the treatment of autoimmune disorders and inflammation.

Brequinar is a synthetic quinolinecarboxylic acid analogue with antineoplastic properties. Brequinar inhibits the enzyme dihydroorotate dehydrogenase, thereby blocking de novo pyrimidine biosynthesis. This agent may also enhance the in vivo antitumor effect of antineoplastic agents such as 5-FU. Brequinar had been in phase II clinical trials by Bristol-Myers Squibb for the treatment of cancer and transplant rejection. However, this research has been discontinued. Brequinar had been also in preclinical studys for the treatment of cytomegalovirus infections. However, this research has been discontinued.

Cemadotin (LU103793) is a cytotoxic water-soluble pentapeptide analogue of dolastatin 15. The dolastatin peptides were originally isolated from the shell-less mollusc Dolabella auricularia. Cemadotin blocks cells at mitosis. It exerts its antitumor activity by suppressing spindle microtubule dynamics through a distinct molecular mechanism by binding at a novel site in tubulin. Cemadotin was in phase II clinical trials as a promising cancer chemotherapeutic agent. However, this agent appears to be inactive in the treatment of advanced non-small-cell lung cancer and other tumors and this research has been discontinued.

Dexniguldipine (B8509-035, (-)-(R)-niguldipine) is a new dihydropyridine derivative, that exerts selective antiproliferative activity in a variety of tumor models and, in addition, has a high potency in overcoming multidrug resistance. Dexniguldipine is ( - )-(R)-enantiomer of niguldipine, of which the ( )-(S)-enantiomer shows pronounced cardiovascular hypotensive activity due to its high affinity for the voltage-dependent Ca2 channel. As compared with the (S)-enantiomer, the (R)-enantiomer has a 40-fold lower affinity for the Ca 2 channel and, accordingly, only minimal hypotensive activity in animal pharmacology models. Dexniguldipine have shown antiproliferative activity in several tumor cell lines, but the concentrations necessary to inhibit growth have varied by several orders of magnitude between cell lines. Initial results of preclinical investigations for the evaluation of the mechanism of its antiproliferative activity demonstrate that dexniguldipine interferes with intracellular signal transduction by affecting phosphoinositol pathways, protein kinase C expression, and intracellular Ca 2 metabolism. In a series of human tumor xenografts in vitro, dexniguldipine demonstrated selective antiproliferative activity against several tumor types, e.g., melanoma and renal-cell carcinoma. Striking results were obtained in a hamster model, in which neuroendocrine lung tumors could be completely eradicated by 20 weeks of oral treatment with 32.5mg/kg dexniguldipine, whereas Clara-cell-type lung tumors were not affected. In in vitro studies, dexniguldipine has been found to bind to P-glycoprotein (P-gp) and to enhance the cytotoxicity of chemotherapeutic agents such as doxorubicin and etoposide in several cell lines The synergistic effect may well be associated with the reversal of multidrug resistance (MDR) related to the activity of P-gp. In the clinical therapy of cancer, resistance to many cytostatic drugs is a major cause of treatment failure. However, the high potency of dexniguldipine (about 10-fold as compared with that of verapamil in vitro) and its low cardiovascular activity provide the opportunity to achieve blood or tumor concentrations that might be high enough to overcome Mdr 1 resistance in patients without producing dose-limiting cardiovascular effects.

Liarozole is an imidazole-containing compound that inhibits the cytochrome P-450-dependent metabolism of all-trans-retinoic acid (RA). Liarozole, a retinoic acid (RA) metabolism-blocking agent (RAMBA) in clinical development, has been granted orphan drug designation for congenital ichthyosis by the European Commission and the U.S. Food and Drug Administration. Later, based on the mixed results from a phase II/III trial of liarozole for the treatment of ichthyosis, Barrier decided to discontinue the development of liarozole. Liarozole displays antitumor activity against androgen-dependent and independent rat prostate carcinomas.A large phase III international study was completed comparing liarozole 300 mg twice daily with cyproterone acetate (CPA) 100 mg twice daily in a total of 321 patients with metastatic prostate cancer in relapse after first-line endocrine therapy. The results indicate that liarozole might be a possible treatment option for prostate cancer (PCA) following failure of first-line endocrine therapy.

CGC-11047 is a polyamine analog designed to halt cell growth and induce apoptosis of cancer cells. In preclinical models CGC-11047 significantly inhibited tumor development in both lung and prostate cancer models when administered as a single agent. In the lung cancer model, CGC-11047 potentiated the antitumor effect of cisplatin. Although potent activity was observed with CGC-11047 and bevacizumab when administered as single agents in the prostate cancer model, the combination arm significantly enhanced antitumor activity compared with either agent alone. In all experiments, CGC-11047 was well tolerated with no adverse effects on bodyweight gain.

Obatoclax (GX15-070) is a novel BH3 mimetic pan Bcl- 2 inhibitor. The clinically studied formulation is as obatoclax mesylate (Box 1), a salt. It is only under study as an intravenous preparation. It functions to block BH3-mediated binding of Bcl-2, Bcl-XL, Mcl-1 and A1 to Bax and Bak. Bax and Bak thus are unopposed and able to dimerize to allow initiation of intrinsic apoptosis. Preclinically, obatoclax has been shown to reverse inhibition of Bax or Bak by Bcl-2, Bcl-XL, Bcl-w and Mcl-1. Obatoclax was discovered by Gemin X, which was acquired by Cephalon, which has since been acquired by Teva Pharmaceuticals. Obatoclax had been in phase III clinical trials by Gemin X Biotechnologies (subsidiary of Teva) for the treatment of non-small lung cancer (NSCLC). The compound received orphan drug designation in the U.S. in 2004 for the treatment of chronic lymphocytic leukemia (CLL). However, Teva discontinued the development of obatoclax in 2013.