Barasertib (AZD1152) is a dihydrogen phosphate prodrug of a pyrazoloquinazoline Aurora kinase inhibitor [AZD1152–hydroxyquinazoline pyrazol anilide (HQPA)] and is converted rapidly to the active AZD1152-HQPA in plasma. AstraZeneca was developing the aurora kinase inhibitor, barasertib (AZD 1152) as a therapeutic for cancer. AZD1152-HQPA is a highly potent and selective inhibitor of Aurora B (Ki, 0.36nmol/L) compared with Aurora A (Ki, 1,369nmol/L) and has a high specificity versus a panel of 50 other kinases. Consistent with inhibition of Aurora B kinase, addition of AZD1152-HQPA to tumour cells in vitro induces chromosome misalignment, prevents cell division, and consequently reduces cell viability and induces apoptosis. Barasertib (AZD1152) potently inhibited the growth of human colon, lung, and haematologic tumour xenografts (mean tumour growth inhibition range, 55% to ≥100%; P < 0.05) in immunodeficient mice. Detailed pharmacodynamic analysis in colorectal SW620 tumour-bearing athymic rats treated i.v. with Barasertib (AZD1152) revealed a temporal sequence of phenotypic events in tumours: transient suppression of histone H3 phosphorylation followed by accumulation of 4N DNA in cells (2.4-fold higher compared with controls) and then an increased proportion of polyploid cells (>4N DNA, 2.3-fold higher compared with controls). Histologic analysis showed aberrant cell division that was concurrent with an increase in apoptosis in AZD1152-treated tumours. Bone marrow analyses revealed transient myelosuppression with the drug that was fully reversible following cessation of Barasertib (AZD1152) treatment. Barasertib (AZD1152) was in phase III for the treatment of Acute myeloid leukaemia, but later these studies were discontinued.

Tetrandrine, isolated from the root of Stephania tetrandra S Moore, is a traditional Chinese clinical agent for silicosis, autoimmune disorders, inflammatory pulmonary diseases, cardiovascular diseases and hypertension. Tetrandrine is a potent MDR-reversing agent and is an ABCB1/ABCC1 inhibitor. Tetrandrine (CBT-1) is being developed by CBA Pharma, as an adjunctive therapy to chemotherapy in various cancer types with multiple drug resistance (MDR), including acute myelogenous leukemia , Breast, Non-Hodgkin’s Lymphoma, Hodgkin’s disease, Non-Small Cell Lung Cancer, Multiple Myeloma, Gallbladder, Pancreatic, Gastrointestinal Tract, Small Cell Lung Cancer, Bladder, Head & Neck, and Sarcoma.

Cridanimod (Virexxa) is a small-molecule immunomodulator and interferon inducer, which, in preliminary studies, has been shown to increase progesterone receptor expression in endometrial tissue. Restoration of progesterone receptor expression may re-sensitize endometrial tumor tissue to progestin therapy in previously unresponsive tumors. Cridanimod was originally developed by Polysan and Pharmsynthez and licensed to Xenetic Biosciences. Virexxa is currently being studied in an ongoing Phase 2 multi-national study in conjunction with progestin therapy for the treatment of endometrial cancer in women with the recurrent or persistent disease who have failed progestin monotherapy.

Stibogluconic acid (Sodium stibogluconate) is the pentavalent antimonial compound used to treat leishmaniasis and is only available for administration by injection. Sodium stibogluconate is sold in the UK as Pentostam (manufactured by GlaxoSmithKline). Sodium stibogluconate was granted orphan drug designation for the treatment of cutaneous leishmaniasis by the US FDA in January 2007. It is available in the United States only through the Centers for Disease Control. Sodium stibogluconate is indicated for the treatment of various types of a protozoal infection called leishmaniasis, which may result from sandfly bites in tropical and temperate parts of the world. It is also investigated for use/treatment in cancer. The mode of action of sodium stibogluconate is not clearly understood. In vitro exposure of amastigotes to 500 mg pentavalent antimony/ml results in a greater than 50% decrease in parasite DNA, RNA protein and purine nucleoside triphosphate levels. It has been postulated that the reduction in ATP (adenosine triphosphate) and GTP (guanosine triphosphate) synthesis contributes to decreased macromolecular synthesis. Sodium stibogluconate was shown to specifically inhibit type I DNA topoisomerase from Leishmania donovani through the inhibition of the unwinding and cleavage of the supercoiled plasmid pBR322, and to stabilize topoisomerase and DNA covalent complexes but not calf-thymus topoisomerase I and Escherichia coli DNA gyrase. Sodium stibogluconate is also a potent inhibitor of PTPases Src homology PTPase1 (SHP-1), SHP-2, and PTP1B but not the dual-specificity phosphatase mitogen-activated protein kinase phosphatase 1. Sodium stibogluconate combined with IFN-alpha-2b (IFN-α) inhibited solid tumor cell line growth in vitro, in vivo it was well tolerated and augmented cellular immune parameters.

Bisantrene was classed as an anthracycline chemotherapeutic agent. It inhibits replication, kills tumor cells in clonogenic assays, and intercalates with DNA, where it inhibits both DNA and RNA synthesis. Bisantrene preferentially binds to A-T rich regions of DNA, where it effects changes to supercoiling and initiates strand breaks in association with DNA-associated proteins. This results from the inhibition of the enzyme topoisomerase II, which relaxes DNA coiling during replication and transcription. Toxicity studies in dogs and monkeys revealed that leukopenia, anorexia, diarrhea injection site necrosis, enterocolitis, muscle degeneration, and pulmonary edema were observed with high doses. Bisantrene was found to have less associated cardiotoxicity than other anthracenes. The existing data for bisantrene clearly demonstrated activity in acute myeloid leukemia, and in other indications including lymphoma, refractory breast cancer, and ovarian cancer.