A placebo-controlled, double-blind, randomized study of recombinant thrombomodulin (ART-123) to prevent oxaliplatin-induced peripheral neuropathy.

PURPOSE: The purpose of this clinical study was to be the first to explore whether ART-123, a recombinant human soluble thrombomodulin, prevents oxaliplatin-induced peripheral neuropathy (OIPN). METHODS: This randomized, phase IIa trial enrolled stage II/III colon cancer patients who received adjuvant mFOLFOX6 chemotherapy. Participants were randomly allocated to 3 arms in a double-blind manner: placebo (placebo: days 1-3); 1-day ART (ART-123: day 1, placebo: days 2-3); and 3-day ART (ART-123: days 1-3). ART-123 (380 U/kg/day) or placebo was infused intravenously before each 2-week cycle of mFOLFOX6. OIPN was assessed with the Functional Assessment of Cancer Therapy/Gynecological Oncology Group-Neurotoxicity-12 (FACT/GOG-Ntx-12) score by participants and the NCI Common Terminology Criteria for Adverse Events (NCI-CTCAE) by investigators. RESULTS: Seventy-nine participants (placebo n = 28, 1-day ART n = 27, 3-day ART n = 24) received study drugs. The least-squares mean FACT/GOG-Ntx-12 scores at cycle 12 from the mixed effect model for repeated measures were 28.9 with placebo, 36.3 with 1-day ART (vs. placebo: 7.3 [95% CI 1.9 to12.8, p = 0.009]), and 32.3 with 3-day ART (vs. placebo: 3.4 [95% CI -.1 to 9.0, p = 0.222]). The cumulative incidence of NCI-CTCAE grade ≥ 2 sensory neuropathy at cycle 12 was 64.3% with placebo, 40.7% with 1-day ART (vs. placebo: -23.5 [95% CI -48.4 to 4.0], p = 0.108), and 45.8% with 3-day ART (vs. placebo: -18.5 [95% CI -44.2 to 9.4], p = 0.264). Common adverse events were consistent with those reported with mFOLFOX6; no severe bleeding adverse events occurred. CONCLUSION: ART-123 showed a potential preventive effect against OIPN with good tolerability. A larger study with 1-day ART is warranted. NCT02792842, registration date: June 8, 2016.

Thrombomodulin alfa prevents oxaliplatin-induced neuropathic symptoms through activation of thrombin-activatable fibrinolysis inhibitor and protein C without affecting anti-tumor activity.

Oxaliplatin, a platinum-based chemotherapeutic agent, is widely used to treat colorectal cancer, but it induces peripheral neuropathy as a serious dose-limiting side effect. Recently, thrombomodulin alfa, a recombinant human soluble thrombomodulin, was reported to prevent oxaliplatin-induced peripheral neuropathy in a clinical phase 2 study. Here we conducted preclinical pharmacology studies. Rats were given oxaliplatin (6 mg/kg) intravenously to induce mechanical hyperalgesia associated with peripheral neuropathy. Single intravenous administration of thrombomodulin alfa (0.1, 0.3, 1 mg/kg) dose dependently prevented the development of oxaliplatin-induced mechanical hyperalgesia, with no sex difference in the efficacy. The preventative effect of thrombomodulin alfa on mechanical hyperalgesia was attenuated by antithrombin or carboxypeptidase inhibitor. In addition, carboxypeptidase B, a homolog of activated thrombin-activatable fibrinolysis inhibitor (TAFI) and human-derived activated protein C, prevented mechanical hyperalgesia, whereas antithrombin or other anti-coagulants did not. These results suggest that thrombomodulin alfa prevents sensory symptoms of oxaliplatin-induced peripheral neuropathy through the activation of TAFI and protein C by modulating thrombin activity, but the effects are independent of an anticoagulant effect. On the other hand, thrombomodulin alfa did not affect the anti-cancer activity of oxaliplatin on human colon cancer cell lines or mice transplanted with HCT116 cells. These results indicate that thrombomodulin alfa prevents sensory symptoms of oxaliplatin-induced peripheral neuropathy without affecting the anti-tumor activity of oxaliplatin. Therefore, thrombomodulin alfa is a promising drug to prevent the symptoms of oxaliplatin-induced peripheral neuropathy.

MK-1775, a small molecule Wee1 inhibitor, enhances anti-tumor efficacy of various DNA-damaging agents, including 5-fluorouracil.

MK-1775 is a potent and selective small molecule Wee1 inhibitor. Previously we have shown that it abrogated DNA damaged checkpoints induced by gemcitabine, carboplatin, and cisplatin and enhanced the anti-tumor efficacy of these agents selectively in p53-deficient tumor cells. MK-1775 is currently in Phase I clinical trial in combination with these anti-cancer drugs. In this study, the effects of MK-1775 on 5-fluorouracil (5-FU) and other DNA-damaging agents with different modes of action were determined. MK-1775 enhanced the cytotoxic effects of 5-FU in p53-deficient human colon cancer cells. MK-1775 inhibited CDC2 Y15 phosphorylation in cells, abrogated DNA damaged checkpoints induced by 5-FU treatment, and caused premature entry of mitosis determined by induction of Histone H3 phosphorylation. Enhancement by MK-1775 was specific for p53-deficient cells since this compound did not sensitize p53-wild type human colon cancer cells to 5-FU in vitro. In vivo, MK-1775 potentiated the anti-tumor efficacy of 5-FU or its prodrug, capecitabine, at tolerable doses. These enhancements were well correlated with inhibition of CDC2 phosphorylation and induction of Histone H3 phosphorylation in tumors. In addition, MK-1775 also potentiated the cytotoxic effects of pemetrexed, doxorubicin, camptothecin, and mitomycin C in vitro. These studies support the rationale for testing the combination of MK-1775 with various DNA-damaging agents in cancer patients.

MK-5108, a highly selective Aurora-A kinase inhibitor, shows antitumor activity alone and in combination with docetaxel.

Aurora-A kinase is a one of the key regulators during mitosis progression. Aurora-A kinase is a potential target for anticancer therapies because overexpression of Aurora-A, which is frequently observed in some human cancers, results in aberrant mitosis leading to chromosomal instability and possibly tumorigenesis. MK-5108 is a novel small molecule with potent inhibitory activity against Aurora-A kinase. Although most of the Aurora-kinase inhibitors target both Aurora-A and Aurora-B, MK-5108 specifically inhibited Aurora-A kinase in a panel of protein kinase assays. Inhibition of Aurora-A by MK-5108 in cultured cells induced cell cycle arrest at the G(2)-M phase in flow cytometry analysis. The effect was confirmed by the accumulation of cells with expression of phosphorylated Histone H3 and inhibition of Aurora-A autophosphorylation by immunostaining assays. MK-5108 also induced phosphorylated Histone H3 in skin and xenograft tumor tissues in a nude rat xenograft model. MK-5108 inhibited growth of human tumor cell lines in culture and in different xenograft models. Furthermore, the combination of MK-5108 and docetaxel showed enhanced antitumor activities compared with control and docetaxel alone-treated animals without exacerbating the adverse effects of docetaxel. MK-5108 is currently tested in clinical trials and offers a new therapeutic approach to combat human cancers as a single agent or in combination with existing taxane therapies.

Small-molecule inhibition of Wee1 kinase by MK-1775 selectively sensitizes p53-deficient tumor cells to DNA-damaging agents.

Wee1 is a tyrosine kinase that phosphorylates and inactivates CDC2 and is involved in G(2) checkpoint signaling. Because p53 is a key regulator in the G(1) checkpoint, p53-deficient tumors rely only on the G(2) checkpoint after DNA damage. Hence, such tumors are selectively sensitized to DNA-damaging agents by Wee1 inhibition. Here, we report the discovery of a potent and selective small-molecule inhibitor of Wee1 kinase, MK-1775. This compound inhibits phosphorylation of CDC2 at Tyr15 (CDC2Y15), a direct substrate of Wee1 kinase in cells. MK-1775 abrogates G(2) DNA damage checkpoint, leading to apoptosis in combination with DNA-damaging chemotherapeutic agents such as gemcitabine, carboplatin, and cisplatin selectively in p53-deficient cells. In vivo, MK-1775 potentiates tumor growth inhibition by these agents, and cotreatment does not significantly increase toxicity. The enhancement of antitumor effect by MK-1775 was well correlated with inhibition of CDC2Y15 phosphorylation in tumor tissue and skin hair follicles. Our data indicate that Wee1 inhibition provides a new approach for treatment of multiple human malignancies.

Negative regulation of the protein kinase C activator-induced ICAM-1 expression in the human bronchial epithelial cell line NCI-H292 by p44/42 mitogen-activated protein kinase.

The role of p44/42 mitogen-activated protein kinase (MAPK) in the expression of intercellular adhesion molecule-1 (ICAM-1) in NCI-H292 cells, a human bronchial epithelial cell line, was analyzed. Treatment with the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol 13-acetate (TPA) (16.2 nM) or interferon-gamma (IFN-gamma) (100 U/ml) induced phosphorylation of p44/42 MAPK. The MEK inhibitor U0126 (0.1 to 10 microM) enhanced the TPA-induced ICAM-1 expression but not the IFN-gamma-induced one. U0126 also enhanced the ICAM-1 expression induced by two other PKC activators teleocidin (22.5 nM) and aplysiatoxin (14.9 nM). Furthermore, PD98059 (0.5 to 50 microM), another MEK inhibitor, enhanced the TPA-induced ICAM-1 expression as well. The inhibitor of p38 MAPK SB203580 did not affect the TPA-induced ICAM-1 expression. BAY11-7082, an inhibitor of nuclear factor kappaB (NF-kappaB) activation, and MG132, a 26S proteasome inhibitor, reduced the TPA-induced ICAM-1 expression but not the IFN-gamma-induced one. TPA partially decreased the level of IkappaB-alpha and the reduction was further augmented by U0126 in a concentration-dependent manner. These findings suggested that, in NCI-H292 cells, p44/42 MAPK suppresses PKC activator-induced NF-kappaB activation, thus negatively regulating the PKC activator-induced ICAM-1 expression but not the IFN-gamma-induced one.