Dinaciclib (SCH 727965) is a small molecule inhibitor of cyclin-dependent kinases. Dinaciclib demostrates potent and selective inhibition of CDK2, CDK5, CDK1, and CDK9 activity. Dinaciclib inhibits cell cycle progression and proliferation in various tumor cell lines in vitro. Dinaciclib is a product of a drug discovery collaboration between Pharmacopeia (later Ligand Pharmaceuticals) and Schering-Plough (later Merck & Co.) that began in 1998. Dinaciclib showed promising effect in treating haematological malignancies and solid tumors.

Meisoindigo ((E)-1,1'-dimethyl-[3,3'-biindolinylidene]-2,2'-dione) is a derivative of Indigo Naturalis, that has been used in China for chronic myeloid leukemia. In vitro cell line studies have shown that this agent might induce apoptosis and myeloid differentiation of acute myeloid leukemia (AML). Meisoindigo has been a routine therapeutic agent in the clinical treatment of chronic myelogenous leukemia (CML) in China since the 1980s. In phase III clinical trial of Meisoindigo involving 402 patients, it was shown that Meisoindigo was equally efficient for both newly diagnosed and previously treated CML patients after oral administration. The hematological complete response (CR) and partial response (PR) rates, respectively, were 45.0 and 39.3% for newly diagnosed patients and 35.9 and 41.4% for previously treated patients. Meisoindigo was generally well tolerated. The most frequent side‑effects were bone, joint and/or muscle pain of varying degrees when the dosage was more than the suitable one.

Volasertib (BI 6727), a dihydropteridinone derivative, is a small-molecule cell cycle inhibitor of polo-like kinase-1 (PLK-1). Volasertib induces G2-M arrest and induction of apoptosis in cancer cells and potently inhibits tumor growth in xenograft models. Boehringer Ingelheim is developing intravenously administered volasertib for the treatment of acute myeloid leukaemia (AML), myelodysplastic syndromes (MDS), chronic myelomonocytic leukaemia (CMML), non-small cell lung cancer, urogenital cancer, ovarian cancer and solid tumours.

Dofequidar (MS-209), a quinolone-derived sphingomyelin synthase inhibitor that blocks P-glycoprotein and multidrug resistance-associated protein-1, is under development by Schering for the potential treatment of multidrug resistant tumors. MS-209 had been in phase III clinical trials for the treatment of breast cancer and non-small lung cancer. But this research was discontinued in 2004. Detected adverse events are: nausea, vomiting, leukopenia, neutropenia, anorexia, constipation.

Avosentan is an oral endothelin receptor A antagonist which was developed by Roche and then licensed by Speedel (now Novartis). The drug was tested in phase III of clinical trials in patients suffering from diabetic nephropathy, however drug development was terminated due to safety reasons: avosentan caused severe heart failure and even deaths.

Fedotozine [(1R)-1-phenyl-1-[(3,4,5-trimethoxy) benzyloxymethyl]-N,N- dimethyl-n-propylamine, (2S,3S-tartrate], derived from the arylacetamide series, is an opioid drug which acts as a selective agonist for kappa(1a)-opioid receptor. Pharmacological studies have shown that fedotozine exerts a peripheral antinociceptive action, comparable with that of other kappa-agonists. Results of Phase III trials of fedotozine against irritable bowel syndrome and dyspepsia have ultimately been disappointing and was lack of efficacy in subsequent studies.

Volinanserin (MDL-100,907) is a highly selective 5-HT2A receptor antagonist. It is widely used in scientific research to investigate the function of the 5-HT2A receptor. Volinanserin is also being trialed as a potential antipsychotic, antidepressant and treatment for insomnia. Volinanserin (M-100907) was in phase III trials for chronic schizophrenia. In August 1999, development was discontinued for acute schizophrenia (schizoaffective disorder) on the basis of poor results. M-100907 is also active in animal models involving blockade of NMDA glutamatergic channel receptors, an effect known to resemble some behavioral symptoms of schizophrenia in man. M-100907 is also claimed in other patents for the treatment of thromboembolic disorders, for the treatment of various developmental neurological disorders such as autism and attention deficit hyperactivity disorder.

Veliparib (ABT-888) is a potent inhibitor of PARP, has good oral bioavailability, can cross the blood-brain barrier, and potentiates temozolomide, platinums, cyclophosphamide, and radiation in syngeneic and xenograft tumor models. AbbVie is developing veliparib for the treatment of cancers. Clinical trials are underway worldwide, investigating veliparib primarily as part of a combination therapy in oncology indications such as brain, colorectal, melanoma, ovarian, prostate and pancreatic cancers.

Ombrabulin is an experimental drug candidate discovered by Ajinomoto and further developed by Sanofi-Aventis for cancer treatment. Ombrabulin is a synthetic water-soluble analog of combretastatin A4, derived from the South African willow bush (Combretum caffrum), with potential vascular-disrupting and antineoplastic activities. Ombrabulin binds to the colchicine binding site of endothelial cell tubulin, inhibiting tubulin polymerization and inducing mitotic arrest and apoptosis in endothelial cells. As apoptotic endothelial cells detach from their substrate, tumor blood vessels collapse; the acute disruption of tumor blood flow may result in tumor necrosis. Ombrabulin has been used in trials studying the treatment of Sarcoma, Neoplasms, Solid Tumor, Neoplasms, Malignant, and Advanced Solid Tumors, among others. In January 2013, Sanofi said it discontinued development of Ombrabulin after disappointing results from phase III clinical trials.

Ganetespib (formerly called STA-9090) is a novel, injectable resorcinolic triazolone small molecule inhibitor of Hsp90, developed by Synta Pharmaceuticals. Ganetespib inhibits the growth of many tumor types in vitro and in vivo including AML, ALL, CML, NHL, neuroblastoma, Ewing sarcoma, rhabdoid cancer, rhabdomyosarcoma, melanoma, and carcinomas of the breast, lung, prostate, bladder and colon7-10,14-27. Ganetespib has being studied in multiple adult oncology indications. The 50% inhibitory concentrations (IC50) for Ganetespib against malignant mast cell lines are 10-50 times lower than that for 17-AAG, indicating that triazolone class of HSP90 inhibitors likely exhibits greater potency than geldanamycin based inhibitors. Ganetespib inhibits MG63 cell lines with IC50 of 43 nM. Ganetespib binds to the ATP-binding domain at the N-terminus of Hsp90 and serves as a potent Hsp90 inhibitor by causing degradation of multiple oncogenic Hsp90 client proteins including HER2/neu, mutated EGFR, Akt, c-Kit, IGF-1R, PDGFRα, Jak1, Jak2, STAT3, STAT5, HIF-1α, CDC2 and c-Met as well as Wilms' tumor 1. Ganetespib, at low nanomolar concentrations, potently arrests cell proliferation and induces apoptosis in a wide variety of human cancer cell lines, including many receptor tyrosine kinase inhibitor- and tanespimycin-resistant cell lines. Ganetespib exhibits potent cytotoxicity in a range of solid and hematologic tumor cell lines, including those that express mutated kinases that confer resistance to small-molecule tyrosine kinase inhibitors. Ganetespib has been studied in 5 completed Synta-sponsored clinical trials (Studies 9090-02, 9090-03, 9090-04, 9090-05, and 9090-07) and 3 completed Synta-sponsored studies in normal healthy volunteers (9090-12, 9090-13, and 9090-15). Ganetespib is currently being studied in 6 Synta-sponsored clinical trials. Studies include: one Phase 1 study, three Phase 2 studies, one Phase 2b study, and one Phase 3 study. Ganetespib is also being studied in 24 Investigator Sponsored Trials (ISTs)