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Purpose: The extensive involvement of the HER kinases in epithelial cancer suggests that kinase inhibitors targeting this receptor family have the potential for broad spectrum antitumor activity. BMS-690514 potently inhibits all three HER kinases, and the VEGF receptor kinases. This report summarizes data from biochemical and cellular pharmacology studies, as well as antitumor activity of BMS-690514., Experimental Design: The potency and selectivity of BMS-690514 was evaluated by using an extensive array of enzymatic and binding assays, as well as cellular assays that measure proliferation and receptor signaling. Antitumor activity was evaluated by using multiple xenograft models that depend on HER kinase signaling. The antiangiogenic properties of BMS-690514 were assessed in a matrigel plug assay, and effect on tumor blood flow was measured by dynamic contrast-enhanced MRI., Results: BMS-690514 is a potent and selective inhibitor of epidermal growth factor receptor (EGFR), HER2, and HER4, as well as the VEGF receptor kinases. It inhibits proliferation of tumor cells with potency that correlates with inhibition of receptor signaling, and induces apoptosis in lung tumor cells that have an activating mutation in EGFR. Antitumor activity was observed with BMS-690514 at multiple doses that are well tolerated in mice. There was evidence of suppression of tumor angiogenesis and endothelial function by BMS-690514, which may contribute to its efficacy., Conclusions: By combining inhibition of two receptor kinase families, BMS-690524 is a novel targeted agent that disrupts signaling in the tumor and its vasculature., (©2011 AACR.)

Tumor angiogenesis is a complex and tightly regulated network mediated by various proangiogenic factors. The fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) family of growth factors, and associated tyrosine kinase receptors have a major influence in tumor growth and dissemination and may work synergistically to promote angiogenesis. Brivanib alaninate is the orally active prodrug of brivanib, a selective dual inhibitor of FGF and VEGF signaling. Here, we show that brivanib demonstrates antitumor activity in a broad range of xenograft models over multiple dose levels and that brivanib alaninate shows dose-dependent efficacy equivalent to brivanib in L2987 human tumor xenografts. Brivanib alaninate (107 mg/kg) reduced tumor cell proliferation as determined by a 76% reduction in Ki-67 staining and reduced tumor vascular density as determined by a 76% reduction in anti-CD34 endothelial cell staining. Furthermore, Matrigel plug assays in athymic mice showed that brivanib alaninate inhibited angiogenesis driven by VEGF or basic FGF alone, or combined. Dynamic contrast-enhanced magnetic resonance imaging, used to assess the effects of brivanib alaninate on tumor microcirculation, showed a marked decrease in gadopentetate dimeglumine contrast agent uptake at 107 mg/kg dose, with a reduction in area under the plasma concentration-time curve from time 0 to 60 minutes at 24 and 48 hours of 54% and 64%, respectively. These results show that brivanib alaninate is an effective antitumor agent in preclinical models across a range of doses, and that efficacy is accompanied by changes in cellular and vascular activities.

A series of acylurea analogs derived from pyrrolopyridine and aminopyridine scaffolds were identified as potent inhibitors of Met kinase activity. The SAR at various positions of the two kinase scaffolds was investigated. These studies led to the discovery of compounds 3b and 20b, which demonstrated favorable pharmacokinetic properties in mice and significant antitumor activity in a human gastric carcinoma xenograft model.

We report herein a series of substituted N-(1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amines as inhibitors of vascular endothelial growth factor receptor-2 tyrosine kinase. Through structure-activity relationship studies, biochemical potency, pharmacokinetics, and kinase selectivity were optimized to afford BMS-645737 (13), a compound with good preclinical in vivo activity against human tumor xenograft models.

A series of amino acid ester prodrugs of the dual VEGFR-2/FGFR-1 kinase inhibitor 1 (BMS-540215) was prepared in an effort to improve the aqueous solubility and oral bioavailability of the parent compound. These prodrugs were evaluated for their ability to liberate parent drug 1 in in vitro and in vivo systems. The l-alanine prodrug 8 (also known as brivanib alaninate/BMS-582664) was selected as a development candidate and is presently in phase II clinical trials.

An amide library derived from the pyrrolo[2,1-f][1,2,4]triazine scaffold led to the identification of modest inhibitors of Met kinase activity. Introduction of polar side chains at C-6 of the pyrrolotriazine core provided significant improvements in in vitro potency. The amide moiety could be replaced with acylurea and malonamide substituents to give compounds with improved potency in the Met-driven GTL-16 human gastric carcinoma cell line. Acylurea pyrrolotriazines with substitution at C-5 demonstrated single digit nanomolar kinase activity. X-ray crystallography revealed that the C-5 substituted pyrrolotriazines bind to the Met kinase domain in an ATP-competitive manner.

A series of substituted 4-(4-fluoro-1H-indol-5-yloxy)pyrrolo[2,1-f][1,2,4]triazine-based inhibitors of vascular endothelial growth factor receptor-2 kinase is reported. Structure-activity relationship studies revealed that a methyl group at the 5-position and a substituted alkoxy group at the 6-position of the pyrrolo[2,1-f][1,2,4]triazine core gave potent compounds. Biochemical potency, kinase selectivity, and pharmacokinetics of the series were optimized and in vitro safety liabilities were minimized to afford BMS-540215 (12), which demonstrated robust preclinical in vivo activity in human tumor xenograft models. The l-alanine prodrug of 12, BMS-582664 (21), is currently under evaluation in clinical trials for the treatment of solid tumors.

A series of substituted 4-(2,4-difluoro-5-(methoxycarbamoyl)phenylamino)pyrrolo[2,1-f][1,2,4]triazines was identified as potent and selective inhibitors of the tyrosine kinase activity of the growth factor receptors VEGFR-2 (Flk-1, KDR) and FGFR-1. The enzyme kinetics associated with the VEGFR-2 inhibition of compound 50 (K(i) = 52 +/- 3 nM) confirmed that the pyrrolo[2,1-f][1,2,4]triazine analogues are competitive with ATP. Several analogues demonstrated low-nanomolar inhibition of VEGF- and FGF-dependent human umbilical vein endothelial cell (HUVEC) proliferation. Replacement of the C6-ester substituent of the pyrrolo[2,1-f][1,2,4]triazine core with heterocyclic bioisosteres, such as substituted 1,3,5-oxadiazoles, afforded compounds with excellent oral bioavailability in mice (i.e., 50 F(po) = 79%). Significant antitumor efficacy was observed with compounds 44, 49, and 50 against established L2987 human lung carcinoma xenografts implanted in athymic mice. A full account of the synthesis, structure-activity relationships, pharmacology, and pharmacokinetic properties of analogues within the series is presented.

The pyrrolo[2,1-f][1,2,4]triazine nucleus was identified as a novel kinase inhibitor template which effectively mimics the well-known quinazoline kinase inhibitor scaffold. Attachment of a 4-((3-chloro-4-fluorophenyl)amino) substituent to the template provided potent biochemical inhibitors of the tyrosine kinase activity of EGFR, as well as inhibition of cellular proliferation of the human colon tumor cell line DiFi. Attachment of a 4-((3-hydroxy-4-methylphenyl)amino) substituent provided potent inhibitors of VEGFR-2 which also showed effects on the VEGF-dependent proliferation of human umbilical vein endothelial cells. Biological activity was maintained with substitution at positions 5 or 6, but not 7, suggesting that the former positions are promising sites for introducing side chains which modulate physicochemical properties. Preliminary inhibition studies with varying ATP concentrations suggest that, like the quinazoline-based kinase inhibitors, the pyrrolotriazine-based inhibitors bind in the ATP pocket.