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.

Alvocidib (also known as Flavopiridol or HMR-1275) is a flavonoid alkaloid CDK9 kinase inhibitor under clinical development for the treatment of acute myeloid leukemia, by Tolero Pharmaceuticals, Inc. As a broad spectrum CDK inhibitor, Alvocidib can inhibit cell cycle progression in either G1 or G2 and induces G1 arrest in either MCF-7 or MDA-MB-468 cells by inhibition of the CDK4 or CDK2 kinase activity. Alvocidib exhibits potent cytotoxicity against a wide variety of tumor cell lines (LNCAP, HCT116, A2780, K562, PC3, and Mia PaCa-2) with IC50 values ranging from 16 nM for LNCAP to 130 nM for K562. Administration of Alvocidib at 7.5 mg/kg for 7 days displays slight antitumor activity against P388 murine leukemia, and active against the human A2780 ovarian carcinoma implanted sc in nude mice). Alvocidib treatment at 1-2.5 mg/kg for 10 days significantly suppresses collagen-induced arthritis in mice in a dose-dependent manner, by inhibiting synovial hyperplasia and joint destruction, whereas serum concentrations of anti-collagen type II (CII) Abs and proliferative responses to CII are maintained. Tolero Pharmaceuticals Inc. announced that the FDA has granted orphan drug designation for Alvocidib, its cyclin-dependent kinase small molecule inhibitor, for the treatment of patients with acute myeloid leukemia.

Filgotinib (GLPG0634) is a highly selective JAK1 inhibitor. GLPG0634 is a promising drug candidate for the future treatment of autoimmune and inflammatory disorders. It is in phase III clinical trials (initiated mid-2016) for the treatment of rheumatoid arthritis, Crohn's disease and ulcerative colitis. Most common adverse events observed were infections, gastrointestinal disorders and nervous system disorders.

AZD-3759 is an oral inhibitor of both wild-type and mutant EGFR with IC50 values in nanomolar range. The drug was discovered by AstraZeneca for the treatment of non-small-cell lung cancer with CNS metastases. AZD-3759 can penetrate the blood-brain barrier and was confirmed to be effective in vitro with NSCLC cell lines as well as in mouse model of brain metastases. AZD-3759 is currently in Phase 1 clinical trial.

Seletalisib (UCB-5857) is a potent, ATP-competitive, and selective phosphoinositide 3-kinase (PI3K) delta inhibitor. Findings from cellular assays of adaptive immunity demonstrated that seletalisib blocks human T-cell production of several cytokines from activated T-cells. Additionally, seletalisib inhibited B-cell proliferation and cytokine release. In human whole blood assays, seletalisib inhibited CD69 expression upon B-cell activation and anti-IgE-mediated basophil degranulation. Seletalisib safety, tolerability and pharmacokinetic/pharmacodynamic profiles support its continued clinical development in immune-inflammatory diseases. UCB Pharma is developing Seletalisib for the treatment of immune and inflammatory diseases including Activated PI3K delta Syndrome (APDS), Sjogren's syndrome and psoriasis.

TAK-063 is a highly potent, selective, and orally active phosphodiesterase 10A (PDE10A) inhibitor with IC50 of 0.30 nM; >15000-fold selectivity over other PDEs. TAK-063 is currently being evaluated in clinical trials for the treatment of schizophrenia. Phosphodiesterase 10A (PDE10A) is a cAMP/cGMP phosphodiesterase highly expressed in medium spiny neurons (MSNs) in the striatum. TAK-063 represents a promising drug for the treatment of schizophrenia with potential for superior safety and tolerability profiles.

GSK-461364 is a potent, selective, reversible, ATP-competitive inhibitor of Plk1. GSK-461364 broadly inhibits cancer cell proliferation with differential survival outcome. GSK-461364 blocks cells in G2 and M phases of the cell cycle and causes M-phase caspase-3/caspase-7 activation. GSK-461364 is efficacious in xenograft tumor models. GlaxoSmithKline is developing GSK-461364 for the treatment of solid tumours and non-Hodgkin's lymphoma.

LY3023414, an investigational drug, is a small molecule that that demonstrates activity against PI3K, mTOR, and DNA-PK in tumor cells, thereby inducing cell-cycle effects and inhibiting cancer cell viability. As shown in vitro LY3023414 inhibits the ability of PI3K and mTOR to phosphorylate substrates in the PI3K/mTOR pathway, one of the most frequently mutated pathways in cancer, leading to cancer progression and resistance to existing treatments. Downstream target inhibition by LY3023414 occurs rapidly via an intermittent “on/off” mechanism that may enhance the drug's clinical tolerability, which may in turn allow LY3023414 to overcome some of the toxicities associated with PI3K/mTOR inhibitors and potentially reduce the emergence of feedback mechanisms leading to resistance. The physicochemical and absorption properties of LY3023414 are favorable, as evidenced by the molecule's high solubility across a wide pH range and high oral bioavailability. On the basis of these findings, LY3023414 is currently being evaluated in clinical trials in patients with advanced cancer such as metastatic prostate cancer and non-small cell lung cancer in combination with other chemotherapeutic agents and in endometrial cancer as a monotherapy.

Sepantronium bromide (YM155) is a selective survivin suppressant that exhibits potent antitumor activities by inducing apoptosis and autophagy in various types of cancer. Sepantronium bromide inhibited the growth of various human cancer cell lines in vitro with GI50 values in the low nM range. Sepantronium bromide blocked the growth of 119 human cancer cell lines, with the greatest inhibition in lines derived from non-Hodgkin's lymphoma, hormone-refractory prostate cancer, ovarian cancer, sarcoma, non-small-cell lung cancer, breast cancer, leukemia, and melanoma, with an average GI50 of 15 nM. Sepantronium bromide inhibited the growth of tumor cell lines regardless of their p53 status and demonstrated significant antitumor activity in 5 mice xenograft models. It also caused tumor regressions in vivo, possibly by its effects in reducing intratumoral survivin expression levels and increasing apoptosis. Sepantronium Bromide had been in phase II clinical trials by Astellas for the treatment of prostate cancer, melanoma, non-Hodgkin's lymphoma, breast cancer, diffuse large B cell lymphoma, non-small cell lung cancer (NSCLC) and other solid tumors. This compound had also been in clinical trials by National Cancer Institute (NCI) for the treatment of solid tumors (phase I) and advanced non-small cell lung cancer (NSCLC) (phase II). However, all these researches about this compound for all indications were discontinued.

AT7519M or AT7519, a small molecule inhibitor of cyclin-dependent kinases 1, 2, 4, 5, and 9, participated in phase II clinical trials in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). As a result, in CLL, some patients had tumor reductions, but the objective response rate (ORR) was low. In MCL, activity was noted with ORR of 27%. In addition, AT7519M was studied in patients with previously treated multiple myeloma, to understand whether the drug alone or in combination with bortezomib were effective treatments. Recent experiments also have shown that AT7519 is a promising drug for the treatment of high-risk neuroblastoma patients with MYCN amplification. It is known, that MYCN-dependent neuroblastomas have low cure rates with current multimodal treatment.