Namitecan (ST1968) is a camptothecin analogue being developed by sigma-tau (a subsidiary of Alfasigma) in Switzerland for the treatment of cancer. Namitecan, a novel hydrophilic camptothecin analog of the 7-oxyiminomethyl series, was selected for clinical development on the basis of its promising preclinical efficacy. Namitecan is a topoisomerase I inhibitor. Namitecan exhibited an acceptable toxicity profile, with neutropenia being the dose-limiting toxic effect, and clinical benefit was appreciable in patients with different tumor types, particularly bladder and endometrium carcinomas.

Furafylline is a methylxanthine derivative that was introduced as a long-acting replacement for theophylline in the treatment of asthma, it was a bronchodilator with extended duration compared to theophylline, but then subsequently reported the adverse side effects the inhibition of the oxidation of caffeine, a reaction catalyzed by CYP1A2. Furafylline is now widely used in biochemical studies as a selective mechanism-based inhibitor of cytochrome p450 1A2.

The dihydrochloride salt of nolatrexed, a water-soluble lipophilic quinazoline folate analog with antineoplastic activity. Nolatrexed occupies the folate binding site of thymidylate synthase, resulting in inhibition of thymidylate synthase activity and thymine nucleotide synthesis with subsequent inhibition of DNA replication, DNA damage, S-phase cell cycle arrest, and caspase-dependent apoptosis. This agent also exhibits radiosensitizing activity. Orphan designation of nolatrexed was granted in the Unites States of America for treatment of hepatocellular carcinoma.

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.

Tozasertib, originally developed as VX-680 by Vertex (Cambridge, MA) and later renamed MK-0457 by Merck (Whitehouse Station, NY), was the first aurora kinase inhibitor to be tested in clinical trials. The drug, a pyrimidine derivative, has affinity for all aurora family members at nanomolar concentrations with inhibitory constant values (Ki(app)) of 0.6, 18, and 4.6 nM for aurora A, aurora B, and aurora C, respectively. Preclinical studies confirmed that tozasertib inhibited both aurora A and aurora B kinase activity, and activity has been reported against prostate, thyroid, ovarian, and oral squamous cancer cell lines. Upon treatment with tozasertib, cells accumulate with a 4N DNA content due to a failure of cytokinesis. This ultimately leads to apoptosis, preferentially in cells with a compromised p53 function. Tozasertib is an anticancer chemotherapeutic pan-aurora kinase (AurK) inhibitor that also inhibits FMS-like tyrosine kinase 3 (FLT3) and Abl. Tozasertib is currently in clinical trials as a potential treatment for acute lymphoblastic leukemia (ALL). In cellular models of cancer, tozasertib activates caspase-3 and PARP and decreases expression of HDAC, increasing apoptosis and inhibiting cell growth. In other cellular models, tozasertib inhibits cell proliferation and metastasis by blocking downstream ERK signaling and downregulating cdc25c and cyclin B. This compound also decreases tumor growth in an in vivo model of prostate cancer.

Saterinone, a dual-action drug combines both alpha-1 blocking vasodilatory property and phosphodiesterase III (PDE III) inhibition--mediated inotropism. PDE III inhibitors are well established in the acute intravenous treatment of patients with decompensated chronic congestive heart failure. Saterinone was demonstrated to be a safe and potent drug on short-term application without major changes in myocardial oxygen consumption. Saterinone was studied in phase II trials in Germany for the treatment of heart failure. However, the development of this drug has been discontinued.

Aranotin, a metabolite of Arachniotus aureus, possesses the antiviral and antibiotic properties. It inhibits viral RNA synthesis against strains of rhino-, coxsackie, polio- and parainfluenza viruses.

Revamilast is an orally active, potent and selective phosphodiesterase 4 (PDE 4) inhibitor that is being studied for its potential in treatment of inflammatory disorders. PDE 4 inhibitors attenuate the inflammatory response and suppress many cytokines, including TNF-α production in mononuclear cells. Initial studies showed no serious adverse events in healthy volunteers and phase II studies have evaluated the effect of revamilast on long function and rheumatoid arthritis.

Sparfosate (PALA) is a stable transition state analogue for an aspartate transcarbamylase- cartalyzed reaction with antineoplastic activity. PALA is a potent inhibitor of aspartate transcarbamylase (Ki about 10(-8) M for ACTases of various origins), which in whole cells blocks the de novo synthesis of pyrimidines. Thus PALA inhibits de novo pyrimidine biosynthesis and increases the extent to which fluorouracil metabolites are incorporated into RNA. In vivo, low doses of PALA inhibit whole body pyrimidine synthesis. While this action is cytotoxic in vitro, extensive human testing demonstrates that PALA alone is devoid of selective antitumor activity. Interest in the therapeutic action of PALA derives from the demonstration that its action potentiates the cytotoxicity of several cytotoxic drugs, notably 5-fluorouracil (5-FU). Development of Sparfosate for cancer and Hepatitis B treatment is assumed to have been discontinued.

Seliciclib (CYC202, R-roscovitine) is a second-generation orally available cyclin-dependent kinases (CDKs) inhibitor that competes for ATP binding sites on these kinases. It is a direct inhibitor of cyclin CDK2/E, CDK2/A and it has inhibitory effects on cyclin H/CDK7, CDK5, and CDK9. CDKs are enzymes that are central to the process of cell division and cell cycle control and play pivotal roles in cancer cell growth and DNA damage repair. Seliciclib exerts an anti-proliferative effect via several key mechanisms: selective downregulation of proliferative and survival proteins and upregulation of p53, leading to growth arrest or apoptosis. The second one is decreasing phosphorylation of Rb and modulating E2F transcriptional activity leading to growth arrest or apoptosis. Seliciclib is currently in phase II clinical trial as a drug candidate for the treatment of Cushing's disease and as a potential therapeutic agent for the treatment of cystic fibrosis (CF). In addition, it is in Phase II trials for non-small cell lung cancer and nasopharyngeal carcinoma.