Indoximod is an orally available Indoleamine 2,3-dioxigenase inhibitor. It shows higher potency in reversing IDO-mediated T cell suppression. Indoximod improves the efficacy of multiple chemotherapeutics agents and some immunological checkpoints mediators in Phase I/II clinical studies for metastatic breast cancer, metastatic melanoma, non-small cell lung cancer, primary malignant brain tumors, metastatic pancreatic cancer, as well as metastatic prostate cancer.

UM171 is a potent agonist of human hematopoietic stem cell renewal, independently of AhR suppression. UM171 act differently than other small molecule stimulators of hematopoiesis, such as the aryl hydrocarbon receptor (AhR) antagonist StemRegenin 1 (SR1). Addition of UM171 to cultures containing SR1 and cytokines further enhances the ex vivo expansion of normal HSCs, including CD34+ cells.

I-BET-762 (GSK 525762) is a small molecule benzodiazepine, by 'mimicking' acetylated histones interferes with the recognition of acetylated histones by BET family of bromodomains (BRD2, BRD3, and BRD4), which disrupts chromatin remodeling and gene expression. Prevention of the expression of certain growth-promoting genes may lead to an inhibition of tumour cell growth. GlaxoSmithKline is developing GSK 525762 for the oral treatment of solid tumours and haematological malignancies.

G749 is a Fms-like tyrosine receptor kinase 3 (FLT3) inhibitor and a promising next-generation drug candidate for the treatment of relapsed and refractory acute myeloid leukemia (AML) patients with various FLT3-ITD/FLT3-TKD mutants that shows the ability to overcome drug resistance. It demonstrated potent and sustained inhibition of the FLT3 wild type and mutants including FLT3-ITD, FLT3-D835Y, FLT3-ITD/N676D, and FLT3-ITD/F691L in cellular assays. G749 retained its inhibitory potency in various drug-resistance milieus such as patient plasma, FLT3 ligand surge, and stromal protection. It also displayed potent antileukemic activity in bone marrow blasts from AML patients regardless of FLT3 mutation status, including those with little or only minor responses to AC220 or PKC412. Oral administration of G749 yielded complete tumor regression and increased life span in animal models.

OTS-167 is a maternal embryonic leucine zipper kinase (MELK) inhibitor which demonstrated antitumor properties in laboratory tests. It is being developed as an anti-cancer drug. The compound has been shown to suppress the growth of breast, lung, pancreatic and prostate cancer cells that express high levels of the MELK protein. OTS167 reached phase II clinical trials in patients with AML, ALL, advanced MDSs, advanced MPNs, or advanced CML and phase I in patients with breast cancer.

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.

CPI-0610 is a small molecule inhibitor of the Bromodomain and Extra-Terminal (BET) family of proteins, with potential antineoplastic activity. Upon administration, the BET inhibitor CPI-0610 binds to the acetylated lysine recognition motifs on the bromodomain of BET proteins, thereby preventing the interaction between the BET proteins and acetylated histone peptides. This disrupts chromatin remodeling and gene expression. Prevention of the expression of certain growth-promoting genes may lead to an inhibition of tumor cell growth. CPI-0610 is currently being evaluated in three Phase 1 clinical trials in the U.S.

Amgen is developing AMG-900, an orally active, small molecule aurora kinase A, B and C inhibitor for the treatment of solid tumours and haematological malignancies. In tumor cells, AMG-900 inhibited autophosphorylation of aurora-A and -B as well as phosphorylation of histone H3 on Ser(10), a proximal substrate of aurora-B. The predominant cellular response of tumor cells to AMG-900 treatment was aborted cell division without a prolonged mitotic arrest, which ultimately resulted in cell death. AMG-900 inhibited the proliferation of 26 tumor cell lines, including cell lines resistant to the antimitotic drug paclitaxel and to other aurora kinase inhibitors (AZD1152, MK-0457, and PHA-739358), at low nanomolar concentrations. Furthermore, AMG-900 was active in an AZD1152-resistant HCT116 variant cell line that harbors an aurora-B mutation (W221L). Oral administration of AMG-900 blocked the phosphorylation of histone H3 in a dose-dependent manner and significantly inhibited the growth of HCT116 tumor xenografts. Importantly, AMG-900 was broadly active in multiple xenograft models, including 3 multidrug-resistant xenograft models, representing 5 tumor types. AMG-900 has entered clinical evaluation in adult patients with advanced cancers and has the potential to treat tumors refractory to anticancer drugs such as the taxanes.

BVD-523 potently and selectively inhibits ERK1 and ERK2 kinases in a reversible, ATP-competitive fashion. Consistent with its mechanism of action, BVD-523 inhibits signal transduction, cell proliferation, and cell survival, most potently in cell lines bearing mutations that activate MAPK pathway signaling. Similarly, single-agent BVD-523 inhibits tumor growth in vivo in BRAF-mutant melanoma and colorectal xenografts as well as in KRAS-mutant colorectal and pancreatic models. BioMed Valley Discoveries is developing ulixertinib, a potent and selective small molecule inhibitor of ERK 1 and 2 kinases, as an oral treatment for cancers harbouring mutations in the MAPK signaling pathway. Phase I/II development of the drug for advanced cancers including, acute myeloid leukaemia and myelodysplastic syndromes is underway in the US. A phase I trial is underway in the US for pancreatic cancer.

BI-2536, an inhibitor of Polo-like kinase 1 (Plk-1) was being investigated by Boehringer Ingelheim as a possible treatment for cancer. BI-2536 inhibits Plk1 enzyme activity at low nanomolar concentrations. The compound potently causes a mitotic arrest and induces apoptosis in human cancer cell lines of diverse tissue origin and oncogenome signature. BI-2536 inhibits growth of human tumor xenografts in nude mice and induces regression of large tumors with well-tolerated intravenous dose regimens. In treated tumors, cells arrest in prometaphase, accumulate phosphohistone H3, and contain aberrant mitotic spindles. This mitotic arrest is followed by a surge in apoptosis, detectable by immunohistochemistry and noninvasive optical and magnetic resonance imaging. For addressing the therapeutic potential of Plk1 inhibition, BI-2536 has progressed into clinical studies in patients with locally advanced or metastatic cancers. It underwent phase II clinical studies for the treatment of breast cancer; non-small cell lung cancer; pancreatic cancer; prostate cancer; small cell lung cancer, but these studies were discontinued later.