Triapine (3-aminopyridine-2-carboxaldehyde thiosemcirbazone, (3-AP; NTO-1151; OCX-0191) is a novel small molecule ribonucleotide reductase inhibitor that acts on the M2 (R2) subunit. Ribonucleotide reductase is an enzyme involved in the de novo synthesis of deoxyribonucleotides, which are critical for DNA replication and DNA repair. Triapine has been used in trials phase II studying the treatment of Lung Cancer, Kidney Cancer, Prostate Cancer Pancreatic Cancer, among others. Recently was published the article describing, that the triple combination triapine-cisplatin-paclitaxel was safe and provided a rational basis for a follow-up phase II trial to evaluate the efficacy and progression-free survival in women with metastatic or recurrent uterine cervix cancer.

Tipifarnib is an oral farnesyltransferase (FTase) inhibitor which was developed by Janssen (J&J). Upon administration, tipifarnib inhibits FTase and thus suppresses the activity of downstream effectors. The drug reached phase III of clinical trials for such diseases as pancreatic cancer (terminated), colorectal cancer (terminated) and acute myeloid leukemia (in elderly patients).

R-etodolac (SDX-101) is the non-cyclooxygenase 2-inhibiting R-enantiomer of the non-steroid anti-inflammatory drug etodolac (1,8-diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid). The absolute configuration of the enantiomer is R-(-)-etodolac. R-etodolac specifically bound retinoid X receptor (RXRalpha), inhibited RXRalpha transcriptional activity, and induced its degradation by a ubiquitin and proteasome-dependent pathway. In addition R-etodolac can disrupt the beta-catenin signaling pathway. R-etodolac exerts antineoplastic properties. R-etodolac was in phase 2 studies for the treatment of hematologic malignancies however development was discontinued.

Rabusertib is a Chk1 kinase inhibitor which was developed by ICOS for the treatment of cancer. The drug was tested in phase II of clinical trials for pancreatic cancer and non small cell lung carcinoma, but its development was discontinued. Now the drug is undergoing phase I trial in Japanese patients with solid tumors.

GV 150526A (gavestinel) is an investigational drug for a neuroprotective therapy of acute ischemic stroke within 6 hours of symptom onset. It is a potent and selective non-competitive antagonist at the glycine site of the N-methyl-D-aspartate receptor (NMDA) which reduces infarct volume in experimental stroke models. Gavestinel acts at the strychnine-insensitive glycine binding site of the NMDA receptor-channel complex with nanomolar affinity (pKi = 8.5), coupled with high glutamate receptor selectivity. Gavestinel displays higher than 1000-fold selectivity over NMDA, AMPA and kainate binding sites and is orally bioavailable and active in vivo. GV 150526A inhibited convulsions induced by NMDA in mice, when administered by both IV and po routes (ED50 = 0.06 and 6 mg/kg, respectively). The safety and efficacy of GV150526 were studied in two phase III randomized placebo-controlled clinical trials of acute ischemic stroke patients within 6 h from onset [The Glycine Antagonist in Neuroprotection (GAIN) International and GAIN Americas Trials] sponsored by GlaxoSmithKline. The results of these trials suggested that gavestinel was not of substantial benefit or harm to patients with primary intracerebral hemorrhage.

Idalopirdine (Lu AE58054) is a Serotonin 6 receptor (5-HT6) antagonist. Idalopirdine exrets good oral bioavailability and robust efficacy in a rat model of cognitive impairment in schizophrenia. In rats idalopirdine potentiates the effects of acetylcholinesterase inhibitor donepezil on two pharmacodynamic biomarkers associated with cognition, i.e. neuronal oscillations and extracellular ACh levels in the hippocampus. Such potentiation could contribute to the procognitive effects of idalopirdine observed in donepezil-treated Alzheimer's disease patients. The compound is being developed by Lundbeck as an adjunctive therapy with acetylcholinesterase inhibitor donepezil, and is in phase III development for the treatment of Alzheimer's disease in multiple countries worldwide. A phase II trial for the treatment of cognitive impairment associated with schizophrenia was conducted; however no recent reports of development for idalopirdine have been identified.

Sanguinarine is an extract of the bloodroot plant Sanguinaria canadensis, a member of the poppy family. It is an inhibitor of protein phosphatases PP1, PP2C and PP2B in vitro. Also inhibits mitogen-activated protein kinase phosphatase-1 (MKP-1) and other enzymes. Sanguinarine exerts a protective effect in cerebral ischemia, and this effect is associated with its anti-inflammatory and anti-apoptotic properties. It was clinically tested as an agent against gingivitis and tooth plaques.

18alpha-Glycyrrhetinic acid (18-GA), a derivative of enoxolone, is used to inhibit gap junctions and furthermore, it has anti-proliferative properties against various cancer types by affecting the cell cycle proteins. 18alpha-Glycyrrhetinic acid, is a non-selective inhibitor of 11beta-hydroxysteroid dehydrogenases isozymes and results in increased whole body insulin sensitivity and decreased glucose production.

Mertansine (Maytansine) is a 19–member ansa macrolide structure attached to a chlorinated benzenering. It was originally isolated from the shrub Maytenus ovatus. Mertansine (DM1) is a tubulin inhibitor, it inhibits the assembly of microtubules by binding to tubulin, with a linker structure can create an antibody-drug conjugate (ADC). Mertansine is a potent microtubule-targeted compound that induces mitotic arrest and kills tumor cells at sub-nanomolar concentrations. The antimitotic effect of maytansine has been attributed to its ability to inhibit microtubule assembly by binding to tubulin with a KD of ~ 1 umol/L, at or near the vinblastine-binding site. Experimental ADCs with the SPP-DM1 design include lorvotuzumab mertansine. DM1 can also be linked to an antibody using the SMCC (4-(3-mercapto-2,5-dioxo-1-pyrrolidinylmethyl)-cylohexanecarboxylic acid) linker, in which case the International Nonproprietary Name of the conjugate formed contains the word emtansine. DM1 and its attachment via these linkers result from ImmunoGen Inc research. Trastuzumab emtansine (T-DM1) is an anti-HER2/neu antibody-drug conjugate.

Cinobufagin is a bufadienolide compound extracted from the dried venom secreted by the parotid glands of toads and one of the glycosides in the traditional Chinese medicine ChanSu, with potential antineoplastic activity. Cinobufagin has been shown to have clinical applications in cancer treatment as well as immunomodulatory and analgesic properties. Cinobufagin induces apoptosis of osteosarcoma cells through inactivation of Notch signaling. Cinobufagin induces autophagy-mediated cell death in human osteosarcoma U2OS cells through the ROS/JNK/p38 signaling pathway. Cinobufagin significantly relieved cancer pain in mice and raised their pain threshold, mainly upregulating the expression levels of beta-Endorphin and μ- opioid receptor in the hind paw tumor and adjacent tissue. In combination with gemcitabine-oxaliplatin cinobufagin was used in clinical trial for the treatment of locally advanced or metastatic gallbladder carcinoma.