RESUMO
A new strategy of peptide half-life extension has been evaluated. We investigated libraries of a small and very stable protein scaffold called Nanofitin, capable of high affinity for protein targets. We have identified Nanofitins targeting Human and mouse Serum Albumin, which could significantly improve the pharmacokinetics of an active associated peptide, mobilizing the patient's own albumin without external source. To demonstrate the impact of this approach on half-life extension, a genetic fusion of an Exenatide peptide with an Albumin Binding Nanofitin (ABNF) was performed. Specific activity of Exenatide-ABNF was measured and unaffected by the fusion. In vivo mice results provided convincing data (t½ of 8 min for Exenatide peptide compared to 20 h for Exenatide-ABNF) with sustained pharmacological activity over 3 days. This study constitutes a proof-of-concept of in vivo half-life extension of a biologic using an ABNF. Besides, the absence of cysteine in the Nanofitin scaffold, which is therefore devoid of structuring disulfide bonds, allows manufacturing in microbial cost effective systems.
Assuntos
Produtos Biológicos , Peptídeos , Albuminas , Animais , Exenatida , Meia-Vida , Camundongos , Peptídeos/químicaRESUMO
Natalizumab (NZM), a humanized monoclonal IgG4 antibody to α4 integrins, is used to treat patients with relapsing-remitting multiple sclerosis (MS)1,2, but in about 6% of the cases persistent neutralizing anti-drug antibodies (ADAs) are induced leading to therapy discontinuation3,4. To understand the basis of the ADA response and the mechanism of ADA-mediated neutralization, we performed an in-depth analysis of the B and T cell responses in two patients. By characterizing a large panel of NZM-specific monoclonal antibodies, we found that, in both patients, the response was polyclonal and targeted different epitopes of the NZM idiotype. The neutralizing activity was acquired through somatic mutations and correlated with a slow dissociation rate, a finding that was supported by structural data. Interestingly, in both patients, the analysis of the CD4+ T cell response, combined with mass spectrometry-based peptidomics, revealed a single immunodominant T cell epitope spanning the FR2-CDR2 region of the NZM light chain. Moreover, a CDR2-modified version of NZM was not recognized by T cells, while retaining binding to α4 integrins. Collectively, our integrated analysis identifies the basis of T-B collaboration that leads to ADA-mediated therapeutic resistance and delineates an approach to design novel deimmunized antibodies for autoimmune disease and cancer treatment.
Assuntos
Anticorpos Neutralizantes/administração & dosagem , Epitopos de Linfócito T/imunologia , Esclerose Múltipla/tratamento farmacológico , Natalizumab/administração & dosagem , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Neutralizantes/química , Formação de Anticorpos/efeitos dos fármacos , Formação de Anticorpos/imunologia , Linfócitos B/efeitos dos fármacos , Humanos , Imunoglobulina G/química , Imunoglobulina G/imunologia , Integrina alfa4/antagonistas & inibidores , Integrina alfa4/imunologia , Esclerose Múltipla/imunologia , Esclerose Múltipla/patologia , Conformação Proteica/efeitos dos fármacos , Linfócitos T/química , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologiaRESUMO
The therapeutic antibodies and their by-products (antibody fragments, conjugated, etc.) establish one of the most dynamic biopharmaceutical market segments today. Due to their intrinsic properties of specificity towards their target, towards their flexible affinity and due to their stability, antibodies became therapeutic agents of the very first choice. One of the challenges of this sector is to create antibodies of very good quality, more and more quickly, while having less and less consequent development costs in fine.
TITLE: Développabilité. ABSTRACT: Les anticorps thérapeutiques et leurs dérivés (fragments d'anticorps, conjugués, etc.) constituent aujourd'hui l'un des segments du marché biopharmaceutique les plus dynamiques. De par leurs propriétés intrinsèques de spécificité vis-à-vis de leur cible, de leur affinité modulable et de par leur stabilité, les anticorps sont devenus des agents thérapeutiques de tout premier choix. Un des challenges de ce secteur est de créer des anticorps de très bonne qualité, de plus en plus rapidement, tout en ayant des coûts de développement de moins en moins conséquents in fine.
Assuntos
Anticorpos Monoclonais , Desenvolvimento de Medicamentos , Indústria Farmacêutica , Imunoconjugados , Fragmentos de Imunoglobulinas , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/uso terapêutico , Medicamentos Biossimilares/síntese química , Medicamentos Biossimilares/química , Medicamentos Biossimilares/uso terapêutico , Desenvolvimento de Medicamentos/economia , Desenvolvimento de Medicamentos/métodos , Desenvolvimento de Medicamentos/normas , Indústria Farmacêutica/economia , Indústria Farmacêutica/métodos , Indústria Farmacêutica/normas , Humanos , Imunoconjugados/química , Imunoconjugados/metabolismo , Imunoconjugados/uso terapêutico , Fragmentos de Imunoglobulinas/biossíntese , Fragmentos de Imunoglobulinas/química , Fragmentos de Imunoglobulinas/uso terapêuticoRESUMO
Therapeutic antibodies generation has to be faster with less development costs. This requires combination of in silico predictions associated with cutting edge screening and characterization technologies. Here, non-exhaustive examples illustrate this simultaneity need.
TITLE: Exemples d'études de développabilité apportant un éclairage à la prise de décision. ABSTRACT: De nos jours, la génération d'anticorps thérapeutiques doit être plus rapide avec des coûts de développement moins importants. Pour cela, des prédictions in silico sont associées à des technologies de criblage et de caractérisation de pointe. Les exemples choisis ici sont non-exhaustifs mais illustrent ce besoin de travailler en parallèle.
Assuntos
Anticorpos Monoclonais , Simulação por Computador , Tomada de Decisões , Desenho de Fármacos , Desenvolvimento de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/economia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Monoclonais/uso terapêutico , Desenvolvimento de Medicamentos/economia , Desenvolvimento de Medicamentos/métodos , Desenvolvimento de Medicamentos/organização & administração , Desenvolvimento de Medicamentos/normas , Avaliação Pré-Clínica de Medicamentos/métodos , Avaliação Pré-Clínica de Medicamentos/normas , Indústria Farmacêutica/economia , Indústria Farmacêutica/métodos , Indústria Farmacêutica/normas , Ensaios de Triagem em Larga Escala/economia , Ensaios de Triagem em Larga Escala/métodos , Ensaios de Triagem em Larga Escala/normas , HumanosRESUMO
Various important biological pathways are modulated by TGFß isoforms; as such they are potential targets for therapeutic intervention. Fresolimumab, also known as GC1008, is a pan-TGFß neutralizing antibody that has been tested clinically for several indications including an ongoing trial for focal segmental glomerulosclerosis. The structure of the antigen-binding fragment of fresolimumab (GC1008 Fab) in complex with TGFß3 has been reported previously, but the structural capacity of fresolimumab to accommodate tight interactions with TGFß1 and TGFß2 was insufficiently understood. We report the crystal structure of the single-chain variable fragment of fresolimumab (GC1008 scFv) in complex with target TGFß1 to a resolution of 3.00 Å and the crystal structure of GC1008 Fab in complex with TGFß2 to 2.83 Å. The structures provide further insight into the details of TGFß recognition by fresolimumab, give a clear indication of the determinants of fresolimumab pan-specificity and provide potential starting points for the development of isoform-specific antibodies using a fresolimumab scaffold.
Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos/imunologia , Reações Antígeno-Anticorpo/imunologia , Fator de Crescimento Transformador beta/química , Fator de Crescimento Transformador beta/imunologia , Anticorpos Monoclonais Humanizados , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Cristalografia por Raios X , Humanos , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Modelos Moleculares , Conformação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/imunologia , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/imunologiaRESUMO
An aminoquinazoline series targeting the essential bacterial enzyme GlmU (uridyltransferase) were previously reported (Biochem. J.2012, 446, 405). In this study, we further explored SAR through a combination of traditional medicinal chemistry and structure-based drug design, resulting in a novel scaffold (benzamide) with selectivity against protein kinases. Virtual screening identified fragments that could be fused into the core scaffold, exploiting additional binding interactions and thus improving potency. These efforts resulted in a hybrid compound with target potency increased by a 1000-fold, while maintaining selectivity against selected protein kinases and an improved level of solubility and protein binding. Despite these significant improvements no significant antibacterial activity was yet observed within this class.
Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Proteínas de Escherichia coli/antagonistas & inibidores , Escherichia coli/enzimologia , Haemophilus influenzae/enzimologia , Complexos Multienzimáticos/antagonistas & inibidores , Quinazolinas/química , Quinazolinas/farmacologia , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Parede Celular/efeitos dos fármacos , Parede Celular/enzimologia , Desenho de Fármacos , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/metabolismo , Infecções por Haemophilus/tratamento farmacológico , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Complexos Multienzimáticos/metabolismoRESUMO
In Escherichia coli, penicillin-binding protein 3 (PBP3), also known as FtsI, is a central component of the divisome, catalyzing cross-linking of the cell wall peptidoglycan during cell division. PBP3 is mainly periplasmic, with a 23 residues cytoplasmic tail and a single transmembrane helix. We have solved the crystal structure of a soluble form of PBP3 (PBP3(57-577)) at 2.5 Å revealing the two modules of high molecular weight class B PBPs, a carboxy terminal module exhibiting transpeptidase activity and an amino terminal module of unknown function. To gain additional insight, the PBP3 Val88-Ser165 subdomain (PBP3(88-165)), for which the electron density is poorly defined in the PBP3 crystal, was produced and its structure solved by SAD phasing at 2.1 Å. The structure shows a three dimensional domain swapping with a ß-strand of one molecule inserted between two strands of the paired molecule, suggesting a possible role in PBP3(57-577) dimerization.
Assuntos
Proteínas de Escherichia coli/química , Escherichia coli , Proteínas de Ligação às Penicilinas/química , Peptidoglicano Glicosiltransferase/química , Domínio Catalítico , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/isolamento & purificação , Proteínas de Escherichia coli/metabolismo , Modelos Moleculares , Proteínas de Ligação às Penicilinas/genética , Proteínas de Ligação às Penicilinas/isolamento & purificação , Proteínas de Ligação às Penicilinas/metabolismo , Peptidoglicano Glicosiltransferase/genética , Peptidoglicano Glicosiltransferase/isolamento & purificação , Peptidoglicano Glicosiltransferase/metabolismo , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização ProteicaRESUMO
Thymidylate kinase (TMK) is an essential enzyme in bacterial DNA synthesis. The deoxythymidine monophosphate (dTMP) substrate binding pocket was targeted in a rational-design, structure-supported effort, yielding a unique series of antibacterial agents showing a novel, induced-fit binding mode. Lead optimization, aided by X-ray crystallography, led to picomolar inhibitors of both Streptococcus pneumoniae and Staphylococcus aureus TMK. MICs < 1 µg/mL were achieved against methicillin-resistant S. aureus (MRSA), S. pneumoniae, and vancomycin-resistant Enterococcus (VRE). Log D adjustments yielded single diastereomers 14 (TK-666) and 46, showing a broad antibacterial spectrum against Gram-positive bacteria and excellent selectivity against the human thymidylate kinase ortholog.
Assuntos
Antibacterianos/farmacologia , Benzoatos/farmacologia , Enterococcus/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Núcleosídeo-Fosfato Quinase/antagonistas & inibidores , Staphylococcus aureus/efeitos dos fármacos , Streptococcus pneumoniae/efeitos dos fármacos , Timina/análogos & derivados , Resistência a Vancomicina/efeitos dos fármacos , Antibacterianos/síntese química , Benzoatos/síntese química , Domínio Catalítico , Cristalografia por Raios X , Humanos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Núcleosídeo-Fosfato Quinase/metabolismo , Relação Estrutura-Atividade , Timina/síntese química , Timina/farmacologiaRESUMO
There is an urgent need for new antibacterials that pinpoint novel targets and thereby avoid existing resistance mechanisms. We have created novel synthetic antibacterials through structure-based drug design that specifically target bacterial thymidylate kinase (TMK), a nucleotide kinase essential in the DNA synthesis pathway. A high-resolution structure shows compound TK-666 binding partly in the thymidine monophosphate substrate site, but also forming new induced-fit interactions that give picomolar affinity. TK-666 has potent, broad-spectrum Gram-positive microbiological activity (including activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus), bactericidal action with rapid killing kinetics, excellent target selectivity over the human ortholog, and low resistance rates. We demonstrate in vivo efficacy against S. aureus in a murine infected-thigh model. This work presents the first validation of TMK as a compelling antibacterial target and provides a rationale for pursuing novel clinical candidates for treating Gram-positive infections through TMK.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/enzimologia , Núcleosídeo-Fosfato Quinase/antagonistas & inibidores , Enterococcus/efeitos dos fármacos , Enterococcus/enzimologia , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Humanos , Modelos Moleculares , Núcleosídeo-Fosfato Quinase/metabolismo , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologiaRESUMO
A novel class of heat shock protein 90 (Hsp90) inhibitors was developed after a low throughput screen (LTS) of a focused library containing approximately 21K compounds selected by virtual screening. The initial [1-{3-H-imidazo[4-5-c]pyridin-2-yl}-3,4-dihydro-2H-pyrido[2,1-a]isoindole-6-one] (1) compound showed moderate activity (IC(50) = 7.6 µM on Hsp82, the yeast homologue of Hsp90). A high-resolution X-ray structure shows that compound 1 binds into an "induced" hydrophobic pocket, 10-15 Å away from the ATP/resorcinol binding site. Iterative cycles of structure-based drug design (SBDD) and chemical synthesis led to the design and preparation of analogues with improved affinity. These optimized molecules make productive interactions within the ATP binding site as reported by other Hsp90 inhibitors. This resulted in compound 8, which is a highly potent inhibitor in biochemical and cellular assays (K(d) = 0.35 nM on Hsp90; IC(50) = 30 nM on SKBr3 mammary carcinoma cells) and in an in vivo leukemia model.
Assuntos
Antineoplásicos/síntese química , Fluorenos/síntese química , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Compostos Heterocíclicos com 3 Anéis/síntese química , Imidazóis/síntese química , Piridinas/síntese química , Trifosfato de Adenosina/química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Fluorenos/química , Fluorenos/farmacologia , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Imidazóis/química , Imidazóis/farmacologia , Leucemia/tratamento farmacológico , Camundongos , Modelos Moleculares , Ligação Proteica , Piridinas/química , Piridinas/farmacologia , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Angiogenesis, a critical driver of tumor development, is controlled by interconnected signaling pathways. Vascular endothelial growth factor receptor (VEGFR) 2 and tyrosine kinase with immunoglobulin and epidermal growth factor homology domain 2 play crucial roles in the biology of normal and tumor vasculature. Regorafenib (BAY 73-4506), a novel oral multikinase inhibitor, potently inhibits these endothelial cell kinases in biochemical and cellular kinase phosphorylation assays. Furthermore, regorafenib inhibits additional angiogenic kinases (VEGFR1/3, platelet-derived growth factor receptor-ß and fibroblast growth factor receptor 1) and the mutant oncogenic kinases KIT, RET and B-RAF. The antiangiogenic effect of regorafenib was demonstrated in vivo by dynamic contrast-enhanced magnetic resonance imaging. Regorafenib administered once orally at 10 mg/kg significantly decreased the extravasation of Gadomer in the vasculature of rat GS9L glioblastoma tumor xenografts. In a daily (qd)×4 dosing study, the pharmacodynamic effects persisted for 48 hr after the last dosing and correlated with tumor growth inhibition (TGI). A significant reduction in tumor microvessel area was observed in a human colorectal xenograft after qd×5 dosing at 10 and 30 mg/kg. Regorafenib exhibited potent dose-dependent TGI in various preclinical human xenograft models in mice, with tumor shrinkages observed in breast MDA-MB-231 and renal 786-O carcinoma models. Pharmacodynamic analyses of the breast model revealed strong reduction in staining of proliferation marker Ki-67 and phosphorylated extracellular regulated kinases 1/2. These data demonstrate that regorafenib is a well-tolerated, orally active multikinase inhibitor with a distinct target profile that may have therapeutic benefit in human malignancies.
Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , Compostos de Fenilureia/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Piridinas/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Feminino , Imageamento por Ressonância Magnética , Camundongos , Camundongos Nus , Fosforilação , Ratos , Ratos Endogâmicos F344RESUMO
Novel anthranilamides were surprisingly found to exert additional activity on B-RAF. Corresponding thiophene, pyrazole, and thiazole core analogs were prepared as VEGFR-2 inhibitors with c-KIT, and B-RAF activity. Compounds in the phenyl, thiophene, and thiazole series are in vivo active.
Assuntos
Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Humanos , Camundongos , Inibidores de Proteínas Quinases/uso terapêutico , Relação Estrutura-AtividadeRESUMO
Since the molecular revolution of the 1980s, knowledge of the aetiology of cancer has increased considerably, which has led to the discovery and development of targeted therapies tailored to inhibit cancer-specific pathways. The introduction and refinement of rapid, high-throughput screening technologies over the past decade has greatly facilitated this targeted discovery and development process. Here, we describe the discovery and continuing development of sorafenib (previously known as BAY 43-9006), the first oral multikinase inhibitor that targets Raf and affects tumour signalling and the tumour vasculature. The discovery cycle of sorafenib (Nexavar; Bayer Pharmaceuticals) - from initial screening for a lead compound to FDA approval for the treatment of advanced renal cell carcinoma in December 2005 - was completed in just 11 years, with approval being received approximately 5 years after the initiation of the first Phase I trial.
Assuntos
Antineoplásicos/uso terapêutico , Benzenossulfonatos/uso terapêutico , Desenho de Fármacos , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Piridinas/uso terapêutico , Animais , Benzenossulfonatos/farmacologia , Carcinoma de Células Renais/tratamento farmacológico , Ensaios Clínicos como Assunto , Técnicas de Química Combinatória , Humanos , Neoplasias Renais/tratamento farmacológico , Niacinamida/análogos & derivados , Compostos de Fenilureia , Piridinas/farmacologia , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Sorafenibe , Quinases raf/antagonistas & inibidoresRESUMO
The RAS-RAF-MEK-ERK signaling pathway (ERK pathway) plays a key role in tumorigenesis and cancer progression. Mutations of RAS or B-RAF lead to a constitutive activation of the ERK pathway, which ultimately results in increased cell division, and cell survival. This review article focuses on the recent literature related to ERK pathway inhibitors, with a particular emphasis on RAF kinase inhibitors. Preclinical and clinical data for the RAF kinase inhibitor sorafenib (BAY 43-9006 tosylate), that was recently approved in the US for the treatment of advanced renal cell carcinoma, are also outlined.
Assuntos
Antineoplásicos , Inibidores Enzimáticos , Neoplasias/tratamento farmacológico , Quinases raf/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Humanos , Estrutura Molecular , Neoplasias/enzimologiaRESUMO
4,5-Disubstituted cis-pyrrolidinones were investigated as inhibitors of type II 17beta-hydroxysteroid dehydrogenase (17beta-HSD). Early structure-activity relationship patterns for this class of compounds are discussed.
Assuntos
17-Hidroxiesteroide Desidrogenases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Pirrolidinonas/farmacologia , 17-Hidroxiesteroide Desidrogenases/metabolismo , Inibidores Enzimáticos/química , Humanos , Pirrolidinonas/química , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
We studied the cytological and biochemical properties of the FtsA protein of Streptococcus pneumoniae. FtsA is a widespread bacterial cell division protein that belongs to the actin superfamily. In Escherichia coli and Bacillus subtilis, FtsA localizes to the septal ring after FtsZ, but its exact role in septation is not known. In S. pneumoniae, we found that, during exponential growth, the protein localizes to the nascent septa, at the equatorial zones of the dividing cells, where an average of 2200 FtsA molecules per cell are present. Likewise, FtsZ was found to localize with the same pattern and to be present at an average of 3000 molecules per cell. Consistent with the colocalization, FtsA was found to interact with FtsZ and with itself. Purified FtsA is able to bind several nucleotides, the affinity being highest for adenosine triphosphate (ATP), and lower for other triphosphates and diphosphates. The protein polymerizes in vitro, in a nucleotide-dependent manner, forming long corkscrew-like helixes, composed of 2 + 2 paired protofilaments. No nucleotide hydrolytic activity was detected. Consistent with the absence of an ATPase activity, the polymers are highly stable and not dynamic. These results suggest that the FtsA protein could also polymerize in vivo and the polymers participate in septation.
Assuntos
Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Biopolímeros/metabolismo , Divisão Celular/fisiologia , Streptococcus pneumoniae/citologia , Proteínas de Bactérias/genética , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Deleção de Genes , Genes Essenciais , Magnésio/metabolismo , Mutagênese Insercional , Proteínas Recombinantes/metabolismo , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/metabolismo , Frações Subcelulares/metabolismo , Técnicas do Sistema de Duplo-HíbridoRESUMO
Inhibition of vascular endothelial growth factor receptor (VEGFR) signalling, using either antibodies or small molecule inhibitors of the VEGFR kinase domain, has become a major area of research in oncology. The phthalazine PTK787/ZK222584, first published in the literature in 1998, is one of the most advanced VEGFR inhibitors in the clinic. This paper provides an update on the patenting activity related to the phthalazine class. In addition, newer kinase inhibitor pharmacophores derived from this class (e.g., anthranilamides) will be reviewed.
RESUMO
With two compounds on the market (Gleevec and Iressa), and a number of drug candidates in late-stage clinical trials, small-molecule kinase inhibitors hold great potential as novel therapies for cancer and inflammatory disorders. Inhibitors from the urea class were first reported in 1996 and have emerged as an important compound class for medicinal chemists due to their unique binding mode and kinase inhibition profile. Currently, five members of this class are undergoing clinical trials, BIRB-796 (Boehringer Ingelheim Pharmaceuticals Inc), BAY-43-9006 (Bayer AG/Onyx Pharmaceuticals Inc), CP-547632 (Pfizer Inc), MLN-518 (Millennium Pharmaceuticals Inc) and KRN-951 (Kirin Brewery Co Ltd). This review focuses on the most recent developments in the discovery of urea-based protein kinase inhibitors.
Assuntos
Química Farmacêutica/métodos , Desenho de Fármacos , Inibidores de Proteínas Quinases/síntese química , Ureia/análogos & derivados , Química Farmacêutica/tendências , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Humanos , Estrutura Molecular , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/uso terapêutico , Ureia/química , Ureia/uso terapêuticoRESUMO
The present paper is based on discharges and suspended particulate matter concentrations from a 9-years high-resolution database for the Garonne River (large plain river) covering contrasted hydrologic years, and a 12-months high frequency sampling for the Nivelle River (small mountainous river). Annual SPM fluxes in the Garonne River range from 0.6 x 10(6) t year(-1) (1997) to 3.9 x 10(6) t year(-1) (1996). In contrast, the Nivelle River transported 11 x 10(3) t year(-1) from December 1995 to December 1996. From the long-term observation of the Garonne River an empirical relation between SPM* (discharge-weighted mean annual SPM concentrations) and annual discharge was established. This relation allows estimating annual SPM fluxes for the Garonne River with less than 30% deviation from reference values for the whole range of mean annual discharge observed during the past decade. Specific (=area-normalized) annual SPM fluxes (YSPM) range from 11 to 74 t km(-2) year(-1) for the Garonne River. Comparison of these results with YSPM of the Nivelle River (69 t km(-2) year(-1) in 1996) suggests that interannual hydrological variations may have a greater impact on fluvial SPM transport than basin-specific parameters. By extracting individual SPM concentrations and corresponding discharge values from the database, different sampling frequencies were simulated and resulting SPM fluxes were then compared to reference fluxes derived from the complete database. If a deviation of simulated flux estimates from reference fluxes lower than +/-20% is accepted, the Garonne River (large plain river) must be sampled at least every 3 days (10 samples per month) and the Nivelle River every 7 h (approx. 100 samples per month). For the Garonne River this minimum sampling frequency is valid for all contrasted hydrologic years of the observation period. Below these minimum sampling frequencies, annual SPM flux estimates may greatly differ from reference fluxes (up to 200%) and there is high probability of systematic underestimation. Consequently, annual SPM flux estimates for the Garonne River derived from the empirical relation (SPM*-annual discharge) are likely to be more satisfactory (errors <30%) than estimates based on sampling frequencies lower than the minimum frequency. These findings underline the need of adapted sampling strategies for erosion assessment, reliable chemical (e.g. nutrients and pollutants) mass balances and characterisation of fluvial transport mechanisms in the world's contrasted watersheds.