Pyrimidino-thiazolyl carbonitriles were prepared that are potent VEGFR-2 (KDR) kinase inhibitors. The modification of lead structures resulted in 3m which exhibited the best overall profile in KDR inhibitory activity, iv/po pharmacokinetics, and reduced hERG affinity.

An azo-dye lead was modified to a novel N-(1,3-thiazol-2-yl)pyridin-2-amine series of KDR kinase inhibitors through the use of rapid analog libraries. This new class has been found to be potent, selective, and of low molecular weight. Molecular modeling has postulated an interesting conformational preference and binding mode for these compounds in the active site of the enzyme.

Small molecule inhibitors of KDR kinase activity have typically possessed poor intrinsic physical properties including low aqueous solubility and high lipophilicity. These features have often conferred limited cell permeability manifested in low levels of cell-based KDR inhibitory activity and oral bioavailability. Thus, the design of inhibitors with appropriate physical properties has played a critical role in the development of clinical candidates. We present a variety of structural modifications that have afforded improvements in physical properties and thereby have addressed suboptimal cellular potency and pharmacokinetics for three unique classes of KDR kinase inhibitors.

3,7-Diarylsubstituted imidazopyridines were designed and developed as a new class of KDR kinase inhibitors. A variety of imidazopyridines were synthesized and potent inhibitors of KDR kinase activity were identified with good aqueous solubility.

A series of N-(1,3-thiazol-2-yl)pyridin-2-amine KDR kinase inhibitors have been developed that possess optimal properties. Compounds have been discovered that exhibit excellent in vivo potency. The particular challenges of overcoming hERG binding activity and QTc increases in vivo in addition to achieving good pharmacokinetics have been acomplished by discovering a unique class of amine substituents. These compounds have a favorable kinase selectivity profile that can be accentuated with appropriate substitution.

We have discovered 3-(5-thien-3-ylpyridin-3-yl)-1H-indoles as potent inhibitors of KDR kinase activity. This communication details the evolution of this novel class from a potent screening lead of vastly different structure with an emphasis on structural modifications that retained activity and provided improvements in key physical properties. The synthesis and in-depth evaluation of these inhibitors are described.

2,4-Disubstituted pyrimidines were synthesized as a novel class of KDR kinase inhibitors. Evaluation of the SAR of the screening lead compound 1 (KDR IC(50)=105 nM, Cell IC(50)=8% inhibition at 500 nM) led to the potent 3,5-dimethylaniline derivative 2d (KDR IC(50)=6 nM, cell IC(50)=19 nM).

Recent investigations have established the feasibility of using exogenously delivered angiogenic growth factors to increase collateral artery development in animal models of myocardial and hindlimb ischemia. Objective: Our aim was to evaluate the ability of a stabilized form of acidic fibroblast growth factor (aFGF-S-117) to stimulate collateralization and arteriogenesis in the rabbit hindlimb following the surgical induction of ischemia by femoral artery extraction. A secondary objective was to examine angiogenic and arteriogenic effects of aFGF-S-117 in the absence of a peripheral blood flow deficit. Methods and results: Five days after femoral artery removal, aFGF-S-117 (1, 3, or 30 mug/kg) was intramuscularly delivered into the hindlimb, three times per week for 2 consecutive weeks. End-point measurements performed on day 20 found that hindlimb reserve blood flow was significantly improved in rabbits that received 3 or 30 mug/kg of aFGF-S-117. with no difference in efficacy between these two doses. These hemodynamic results were supported by angiographic evidence showing enhanced density of collateral vessels in the medial thigh region and histological findings of increased capillary density within the gastrocnemius muscle from rabbits treated with aFGF-S-117. When an efficacious dose of 3 mug/kg of aFGF was administered to sham-operated rabbits with intact femoral arteries, there was no change in any of the blood flow, angiographic or histological parameters measured. Conclusions: These findings demonstrate that a stabilized form of aFGF stimulated the development of functional collateral arteries in the rabbit hindlimb, an effect which was dependent upon removal of the femoral artery. These results suggest that aFGF- S-117 may have therapeutic potential for the treatment of arterial occlusive disorders. (C) 2003 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

1,5-Diarylbenzimidazoles have been identified as potent inhibitors of KDR kinase activity. The series was developed with a goal of finding compounds with optimal drug-like properties. This communication describes structural modifications in the series that enhance solubility, lower protein binding, and provide compounds with excellent potency and pharmacokinetic profiles.

Modifications to the basic side-chain of early lead structures of the indolyl quinolinone class of KDR kinase inhibitors resulted in improved pharmacokinctic and ancillary profiles. Specifically, compounds bearing 5-amido- and 5-sulphonamido-indolyl substituents exhibited lower plasma clearance and weaker binding affinity for the I-Kr potassium channel hERG. (C) 2003 Elsevier Science Ltd. All rights reserved. (C) 2003 Elsevier Ltd. All rights reserved.

We have synthesized and evaluated the activity of 3,6-disubstituted pyrazolo[1,5-a]pyrimidines as a new class of KDR kinase inhibitors. Starting with screening lead 1, potency against isolated KDR was fully optimized with 3-thienyl and 4-methoxyphenyl substituents at the 6- and 3-positions (3g, KDR IC(50)=19 nM), respectively. The synthesis and SAR of these compounds are described.

We have introduced solubilizing functionality to a 3,6-disubstituted pyrazolo[1,5-a]pyrimidine series of KDR kinase inhibitors to improve the physical properties of these compounds. The addition of a basic side-chain to the 6-aryl ring, introduction of 3-pyridyl groups, and most significantly, incorporation of a 4-pyridinonyl substituent at the 6-position of the core are modifications that maintain and often enhance the intrinsic potency of this class of inhibitors. Moreover, the improvements in physical properties result in marked increases in cellular activity and more favorable pharmacokinetics in rats. The synthesis and SAR of these compounds are described.

Inflammatory breast cancer (IBC) is a specific type of breast tumor that generally has a poor prognosis, in spite of recent advances in treatment. In the present study, semiquantitative reverse transcriptase polymerase chain reaction examination of resected specimens showed that angiogenic factors, not lymphangiogenic factors, are overexpressed in IBC tumors, compared with non‐IBC tumors. Immunohistochemical analysis of the specimens revealed a significantly higher population of tumor‐infiltrating (TI) endothelial cells (ECs) or endothelial precursor cells (EPCs) in tumor‐associated stroma of IBC specimens than in non‐IBC specimens. In a previous study, we examined the phenotype of host cells in response to transplanted IBC cells, using an established human IBC xenograft model (WIBC‐9) (Shirakawa et al. , Cancer Res 2001;61:445–51). The data obtained in that study are consistent with the findings of the present study. To explore the therapeutic potential of blocking vascular endothelial growth factor (VEGF) and angiopoietin (Ang) pathways in IBC, established vectors encoding soluble Flt‐1 (sFlt‐1) and soluble Tie2 (sTie2) were injected directly into WIBC‐9. Both vectors produced growth inhibition ratios of WIBC‐9 that were significantly higher than those of a non‐IBC xenograft (MC‐5). Also, both vectors suppressed WIBC‐9 lung metastases. The efficacy correlated with the number of TI ECs/EPCs, which was determined by fluorescence‐activated cell sorting. These ECs/EPCs incorporated acetylated lipoprotein and were integrated within a HUVEC monolayer in vitro culture on day 5. © 2002 Wiley‐Liss, Inc.