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.

CI 1040 is an inhibitor of the mitogen-activated protein (MAP) kinase signal transduction pathway and has been shown to specifically inhibit MAP kinase kinase (MEK). CI 1040 was being developed by Parke-Davis (formerly a division of WarnerLambert, Now Pfizer) as an anticancer agent. It was the initial MEK inhibitor to undergo clinical evaluation based on promising preclinical activity. However, its development has been discontinued.

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.

Nefiracetam is a cyclic derivative of gamma-aminobutyric acid (GABA). It is thought to act by normalising dysfunctional acetylcholine, GABA and possibly monoamine neurotransmitter systems, but it may also facilitate N/L-type calcium channel opening. Nefiracetam has received attention as a treatment for seizures, depression, and dementia. Nefiracetam was found to be extremely testicular toxic in both rats and dogs; it was found to significantly decrease the levels of testicular testosterone leading to atrophy and malformation of sperm.

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.

AMG-487 is a potent and selective orally bioavailable chemokine (C-X-C motif) receptor 3 (CXCR3) antagonist that displays dose- and time-dependent pharmacokinetics in human subjects after multiple oral dosing. AMG-487 is an 8-azaquinazolinone, it can prevent the chemokines I-IP-10 and I-ITAC from binding to CXCR3. The preclinical properties of AMG487 has been extensively studied. The compound displays a greater than 1000-fold selectivity for CXCR3 versus a panel of other receptors, including 11 chemokine receptors. The safety profile of AMG487, as assessed by various genotoxicity and cardiotoxicity assays, revealed no major concerns. The ability of AMG487 to inhibit inflammatory cell migration in vivo was confirmed in a mouse model of bleomycin-induced cellular recruitment, where AMG487 significantly reduced infiltration of macrophages and lymphocytes into the lungs in CXCR3-KO mice. In a mouse model for idiopathic pneumonia syndrome (IPS), AMG487 reduced recruitment of donor T cells to the lung after allogeneic stem cell transplantation, leading to improved survival rates. Likewise, reductions in inflammation, pannus formation, and cartilage damage were observed upon administering AMG487. The preclinical studies convincingly paved the way for clinical studies on two inflammation-related diseases: psoriasis and rheumatoid arthritis. In 2003, results of a Phase I trial on AMG487 were disclosed. The compound was assessed for safety and pharmacokinetics in 30 healthy males in a randomised, double blind, placebo-controlled dose-escalation study. Generally, the compound was well tolerated and adverse events were mild to moderate. Disappointingly, no significant differences in the endpoints (psoriasis severity index or physician global assessment scores) were seen between patient groups. AMG-487 progressed to Phase II clinical trials but has been withdrawn because of lack of efficacy.