Entinostat (MS-275) is an orally active, highly selective, small-molecule histone deacetylase inhibitor (HDACi) derived from benzamide. Entinostat preferentially inhibited HDAC1 versus HDAC3 and had no inhibitory activity toward HDAC8. The time to maximum plasma concentration (tmax) of entinostat ranged from 0.5 to 60h (median of 2h). Elimination of the drug was bi-exponential, with a terminal half-life of 30-80h. Entinostat is a well-tolerated that demonstrates promising therapeutic potential in both solid and hematologic malignancies. Its efficacy does not appear directly dose-related, and as such, more relevant biomarkers are needed to adequately assess its activity.

Tipifarnib is an oral farnesyltransferase (FTase) inhibitor which was developed by Janssen (J&J). Upon administration, tipifarnib inhibits FTase and thus suppresses the activity of downstream effectors. The drug reached phase III of clinical trials for such diseases as pancreatic cancer (terminated), colorectal cancer (terminated) and acute myeloid leukemia (in elderly patients).

AR-42, also known as (S)-HDAC-42, is a phenylbutyrate-based histone deacetylase (HDAC) inhibitor. HDACs are enzymes that determine acetylation status of histones, thereby affecting chromatin structure and regulating the expression and activity of numerous proteins involved in both cancer initiation and cancer progression. AR-42 possesses antitumor activity at multiple cellular levels. It is currently in Phase I/Ib trials for hematological malignancies and solid tumors.

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.

Phorbol 12-myristate 13-acetate (PMA) also commonly known as 12-O-Tetradecanoylphorbol-13-acetate (TPA) is a phorbol ester that is commonly used to activate phospholipid-dependent protein kinase (protein kinase C). PMA/ TPA possesses potential antineoplastic effects and was studied in phase II clinical trials together with dexamethasone in patients with relapsed or refractory acute myeloid leukemia. In addition, PMA/ TPA participated in phase I trial for treating patients with hematologic cancer or bone marrow disorder that has not responded to previous treatment. Nevertheless, both clinical trials were terminated. Besides, PMA/ TPA was studied in patients with solid tumors, which had depressed white blood cell and neutrophil counts because of prior treatment with cytotoxic cancer chemotherapeutic drugs. It was shown, that the drug increased the low white blood cell and neutrophil counts toward the normal range.

JNJ-28312141 is an orally active colony-stimulating factor-1 receptor and FMS-related receptor tyrosine kinase-3 inhibitor. In preclinical models, JNJ-28312141 caused regression of ITD-FLT3–dependent MV-4-11 AML xenografts. The drug also suppressed the growth of H460 non-small cell lung adenocarcinoma xenografts and inhibited osteoclastogenesis and osteolysis in a rat model of metastatic bone disease.

The compound StemRegenin 1 (SR1) is a selective, cell-permeable, small molecule that promotes the self-renewal of human hematopoietic stem cells in culture. SR1 is an antagonist of the aryl hydrocarbon receptor. SR1 is the first small molecule that promotes robust expansion/self-renewal of human CD34 peripheral blood and cord blood hematopoietic stem cells (HSCs). The culture of HSCs with SR1 led to a 50-fold increase in cells expressing CD34 and a 17-fold increase in cells that retain the ability to engraft immunodeficient mice. SR1 can be potentially used for ex vivo expansion of normal HSCs or leukemic stem/progenitor cells

ORY-1001 (known as RG 6016) is a Lysine Specific Demethylase 1 (LSD1, also known as KDM1A) inhibitor (IC50 <20nM) with high selectivity against related FAD dependent aminoxidases (MAO-A/B, IL4I1, KDM1B >100uM, SMOX 7uM). LSD1 is a histone eraser enzyme that removes methyl groups, specifically mono and demethylated H3K4 and H3K9, and by doing so regulates the expression of many genes important in the onset and progression of diseases such as cancer and neurodegenerative disorders. ORY-1001 is a lead drug candidate of Oryzon Genomics S.A. under development for the treatment of acute myeloid leukemia (AML) – phase I/II and small cell lung cancer (SCLC) – phase I. Oryzon has made significant progress with ORY-1001 over the past years.

A-674563 is a potent, orally available Akt1 inhibitor with an IC50 value of 11nM. Also displays activity against PKA and CDK2 with IC50 values of 16nM and 46nM respectively. A-674563 dose-dependently inhibited survival and proliferation of U937 AML cells and six lines of human AML progenitor cells, yet sparing human peripheral blood mononuclear leukocytes (PBMCs). A-674563 activated caspase-3/9 and apoptosis in the AML cells. intraperitoneal injection of A-674563 at well-tolerated doses suppressed U937 leukemic xenograft tumor growth in nude mice, whiling significantly improving the animal survival. A-674563 exerts potent anti-leukemic activity in vitro and in vivo, possibly via concurrent targeting Akt and SphK1 signalings. A-674563 also exerts potent anti-melanoma activity, involving Akt-dependent and Akt-independent mechanisms.

NVP-ADW742 is a novel small weight molecular inhibitor of insulin-like growth factor-1 receptor (IGF-IR), which is investigated for treatment of different types of cancers.