RESUMO
In a lead optimization effort towards NS5B NNI inhibitors, two multi-step parallel libraries were designed and successfully synthesized. Through this effort we discovered compound 9B, which achieved rigorous and delicate balance of inhibition across the common genotypes and mutants with <10 nM potency. In addition, the bicyclic compounds 9B exhibited improved FASSIF solubility over the tetracyclic compound MK-8876. This strategic approach demonstrated that, even within limited reaction scope, multi-step parallel libraries could provide access to more complex chemical space. This expedient access facilitates diverse, purpose-driven optimization of SAR and physicochemical properties.
Assuntos
Antivirais/farmacologia , Benzofuranos/farmacologia , Inibidores Enzimáticos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/síntese química , Antivirais/farmacocinética , Benzofuranos/síntese química , Benzofuranos/farmacocinética , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Hepacivirus/enzimologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ratos Wistar , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/farmacocinética , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-AtividadeRESUMO
Hepatitis C virus (HCV) NS5B polymerase is a prime target for the development of direct-acting antiviral drugs for the treatment of chronic HCV infection. Several novel and potent HCV NS5B non-nucleoside inhibitors with unique tetracyclic bezonfuran-based structures were prepared and evaluated. Similar to clinical developmental compound MK-8876, N-linked (compounds 1 and 2) and C-linked (compounds 3 and 4) tetracyclic structures maintained broad spectrum anti-replicon potency profiles and demonstrated moderate to excellent oral bioavailability and pharmacokinetic parameters across the three preclinical animal species. To better understand the importance of tetracyclic structures related to pan genotypic potency profiles especially against clinically relevant GT1a variants, the teracycles with different ring size were prepared and in vitro evaluations suggested compounds with six number ring have better overall potency profiles.
Assuntos
Antivirais/farmacologia , Benzofuranos/farmacologia , Desenho de Fármacos , Proteínas não Estruturais Virais/antagonistas & inibidores , Antivirais/síntese química , Antivirais/química , Benzofuranos/síntese química , Benzofuranos/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
Elbasvir is an investigational NS5A inhibitor with in vitro activity against multiple HCV genotypes. Antiviral activity of elbasvir was measured in replicons derived from wild-type or resistant variants of genotypes 1a, 1b, and 3. The barrier to resistance was assessed by the number of resistant colonies selected by exposure to various elbasvir concentrations. In a phase 1b dose-escalating study, virologic responses were determined in 48 noncirrhotic adult men with chronic genotype 1 or 3 infections randomized to placebo or elbasvir from 5 to 50 mg (genotype 1) or 10 to 100 mg (genotype 3) once daily for 5 days. The NS5A gene was sequenced from plasma specimens obtained before, during, and after treatment. Elbasvir suppressed the emergence of resistance-associated variants (RAVs) in vitro in a dose-dependent manner. Variants selected by exposure to high elbasvir concentrations typically encoded multiple amino acid substitutions (most commonly involving loci 30, 31, and 93), conferring high-level elbasvir resistance. In the monotherapy study, patients with genotype 1b had greater reductions in HCV RNA levels than patients with genotype 1a at all elbasvir doses; responses in patients with genotype 3 were generally less pronounced than for genotype 1, particularly at lower elbasvir doses. M28T, Q30R, L31V, and Y93H in genotype 1a, L31V and Y93H in genotype 1b, and A30K, L31F, and Y93H in genotype 3 were the predominant RAVs selected by elbasvir monotherapy. Virologic findings in patients were consistent with the preclinical observations. NS5A-RAVs emerged most often at amino acid positions 28, 30, 31, and 93 in both the laboratory and clinical trial. (The MK-8742 P002 trial has been registered at ClinicalTrials.gov under identifier NCT01532973.).
Assuntos
Benzofuranos/farmacologia , Hepacivirus/efeitos dos fármacos , Imidazóis/farmacologia , Adolescente , Adulto , Feminino , Genótipo , Hepacivirus/genética , Humanos , Masculino , Pessoa de Meia-Idade , Replicon/genética , Adulto JovemRESUMO
BACKGROUND: Virologic failure following treatment of hepatitis C virus (HCV) genotype 1 with direct-acting antiviral agents is often accompanied by the emergence of resistant variants. MK-5172 is an investigational once-daily protease inhibitor. We analyzed variants in treatment-naive noncirrhotic patients with virologic failure on MK-5172 (100-800 mg/day) plus pegylated interferon alfa/ribavirin (peg-IFN/RBV) during a phase 2 trial. METHODS: Population and selective clonal sequencing were performed at baseline and at virologic failure in the 4 MK-5172 dosing arms. MK-5172 activity was determined using a mutant replicon assay. RESULTS: Six of 266 (2.3%) MK-5172 recipients satisfied prespecified criteria for virologic failure, all with genotype 1a infection. Five patients with virologic failure were in the MK-5172 100-mg arm, including 4 patients with low plasma MK-5172 levels documented during triple therapy. Variants associated with >4-fold loss of potency were detected in 3 of the 4 patients with genotype 1a breakthrough while on MK-5172. The fifth patient had undetectable HCV-RNA levels at the end of triple therapy but subsequently broke through during the peg-IFN/RBV tail 16 weeks after completion of MK-5172. Three patients had D168 variants at virologic failure, including 2 with the D168A variant associated with a 95-fold loss of potency. The sole apparent relapse was actually a genotype 3a reinfection in the MK-5172 200-mg group. CONCLUSIONS: Virologic failure occurred uncommonly (6/266 [2.3%]) in MK-5172/peg-IFN/RBV recipients. The most prevalent treatment-emergent variants were detected at the D168 locus. D168A variants conferring approximately 2-log reduction in MK-5172 susceptibility emerged in 2 of the 4 evaluable patients with genotype 1a breakthrough. Clinical Trials Registration. NCT01353911.
Assuntos
Hepatite C/tratamento farmacológico , Interferons/uso terapêutico , Quinoxalinas/uso terapêutico , Ribavirina/uso terapêutico , Amidas , Carbamatos , Ciclopropanos , Farmacorresistência Viral , Genótipo , Humanos , SulfonamidasRESUMO
HCV NS3/4a protease inhibitors are proven therapeutic agents against chronic hepatitis C virus infection, with boceprevir and telaprevir having recently received regulatory approval as add-on therapy to pegylated interferon/ribavirin for patients harboring genotype 1 infections. Overcoming antiviral resistance, broad genotype coverage, and a convenient dosing regimen are important attributes for future agents to be used in combinations without interferon. In this communication, we report the preclinical profile of MK-5172, a novel P2-P4 quinoxaline macrocyclic NS3/4a protease inhibitor currently in clinical development. The compound demonstrates subnanomolar activity against a broad enzyme panel encompassing major hepatitis C virus (HCV) genotypes as well as variants resistant to earlier protease inhibitors. In replicon selections, MK-5172 exerted high selective pressure, which yielded few resistant colonies. In both rat and dog, MK-5172 demonstrates good plasma and liver exposures, with 24-h liver levels suggestive of once-daily dosing. When administered to HCV-infected chimpanzees harboring chronic gt1a or gt1b infections, MK-5172 suppressed viral load between 4 to 5 logs at a dose of 1 mg/kg of body weight twice daily (b.i.d.) for 7 days. Based on its preclinical profile, MK-5172 is anticipated to be broadly active against multiple HCV genotypes and clinically important resistance variants and highly suited for incorporation into newer all-oral regimens.
Assuntos
Hepacivirus/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Quinoxalinas/farmacologia , Quinoxalinas/farmacocinética , Proteínas não Estruturais Virais/antagonistas & inibidores , Amidas , Animais , Antivirais/farmacologia , Carbamatos , Ciclopropanos , Cães , Farmacorresistência Viral , Genótipo , Hepacivirus/enzimologia , Hepacivirus/genética , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Fígado/efeitos dos fármacos , Pan troglodytes , Quinoxalinas/metabolismo , Ratos , Sulfonamidas , Carga Viral/efeitos dos fármacosRESUMO
A series of macrocyclic compounds containing a cyclic constraint in the P2-P4 linker region have been discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155K, A156T, A156V, and D168V mutant activity while maintaining high rat liver exposure. The effect of the constraint is most dramatic against gt 1b A156 mutants where ~20-fold improvements in potency are achieved by introduction of a variety of ring systems into the P2-P4 linker.
Assuntos
Proteínas de Transporte/antagonistas & inibidores , Hepacivirus/enzimologia , Compostos Macrocíclicos/química , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Sítios de Ligação , Proteínas de Transporte/metabolismo , Domínio Catalítico , Ciclização , Genótipo , Meia-Vida , Hepacivirus/genética , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Fígado/metabolismo , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacocinética , Simulação de Acoplamento Molecular , Mutação , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacocinética , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
A series of macrocyclic compounds containing 2-substituted-quinoline moieties have been discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155K mutant activity while maintaining the high rat liver exposure. Cyclization of the 2-substituted quinoline substituent led to a series of tricyclic P2 compounds which also display superb gt3a potency.
Assuntos
Proteínas de Transporte/antagonistas & inibidores , Hepacivirus/enzimologia , Compostos Macrocíclicos/química , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Proteínas de Transporte/metabolismo , Ciclização , Genótipo , Meia-Vida , Hepacivirus/genética , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Fígado/metabolismo , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacocinética , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacocinética , Quinolinas/química , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
Efforts to develop novel, interferon-sparing therapies for treatment of chronic hepatitis C (HCV) infection are contingent on the ability of combination therapies consisting of direct antiviral inhibitors to achieve a sustained virologic response. This work demonstrates a proof of concept that coadministration of the nucleoside analogue MK-0608 with the protease inhibitor MK-7009, both of which produced robust viral load declines as monotherapy, to an HCV-infected chimpanzee can achieve a cure of infection.
Assuntos
Antivirais/administração & dosagem , Hepacivirus/efeitos dos fármacos , Hepatite C Crônica/tratamento farmacológico , Indóis/administração & dosagem , Pan troglodytes/virologia , Tubercidina/análogos & derivados , Carga Viral/efeitos dos fármacos , Animais , Antivirais/farmacologia , Antivirais/uso terapêutico , Ciclopropanos , Relação Dose-Resposta a Droga , Esquema de Medicação , Quimioterapia Combinada , Hepacivirus/enzimologia , Hepacivirus/fisiologia , Hepatite C Crônica/virologia , Indóis/farmacologia , Indóis/uso terapêutico , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Prolina/análogos & derivados , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico , Sulfonamidas , Resultado do Tratamento , Tubercidina/administração & dosagem , Tubercidina/farmacologia , Tubercidina/uso terapêutico , Proteínas não Estruturais Virais/antagonistas & inibidoresRESUMO
The administration of hepatitis C virus (HCV) NS3/4A protease inhibitors to patients with chronic HCV infections has demonstrated that they have dramatic antiviral effects and that compounds acting via this mechanism are likely to form a key component of future anti-HCV therapy. We report here on the preclinical profile of MK-7009, an inhibitor of genotype 1a and 1b proteases at subnanomolar concentrations with modestly shifted potency against genotype 2a and 2b proteases at low nanomolar concentrations. Potent activity was also observed in a cell-based HCV replicon assay in the presence of added human serum (50%). In multiple species evaluated in preclinical studies, the MK-7009 concentrations in the liver were maintained at a significant multiple of the cell-based replicon 50% effective concentration over 12 to 24 h following the administration of moderate oral doses (5 to 10 mg per kg of body weight). MK-7009 also had excellent selectivity against both a range of human proteases and a broad panel of pharmacologically relevant ion channels, receptors, and enzymes. On the basis of this favorable profile, MK-7009 was selected for clinical development and is currently being evaluated in controlled clinical trials with both healthy volunteers and HCV-infected patients.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Indóis/farmacologia , Inibidores de Proteases/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/farmacocinética , Área Sob a Curva , Linhagem Celular , Ciclopropanos , Cães , Genótipo , Meia-Vida , Hepacivirus/enzimologia , Hepacivirus/genética , Humanos , Indóis/farmacocinética , Interferon alfa-2 , Interferon-alfa/farmacologia , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Macaca mulatta , Pan troglodytes , Prolina/análogos & derivados , Inibidores de Proteases/farmacocinética , Ratos , Proteínas Recombinantes , Replicon , Especificidade por Substrato , Sulfonamidas , Proteínas não Estruturais Virais/genéticaRESUMO
The potential of hepatitis C virus (HCV) to develop antiviral resistance renders phenotypic analysis of viral relapse or breakthrough sequences essential to the clinical evaluation of HCV antivirals. This work describes a transient assay in which clinical NS3/4A sequences are co-expressed in Huh-7 cells with a reporter whose activity is an easily quantifiable measure of protease activity. The utility of the assay was demonstrated in potency evaluations of a novel protease inhibitor against panels of NS3/4A sequences spanning genotypes 1-3. The compound was potent against genotype 1a and 1b protease sequences with sub-nanomolar to low nanomolar EC(50)s, slightly diminished in potency against genotype 2b sequences, but poorly active against genotype 3a sequences. Diverse sequences of the same HCV genotype, however, varied in response to the inhibitor as much as 30-fold, with susceptibility differences not easily attributed to specific amino acid polymorphisms. The results demonstrate the versatility of a novel phenotype assay in the evaluation of a promising new class of NS3/4A inhibitor. The results highlight further the complexity in correlating susceptibility differences with specific sequence polymorphisms, and underscore the value in direct phenotyping of clinical sequences for compound sensitivity. The assay will be useful for monitoring changes in susceptibility due to emergence of resistant virus during clinical studies of protease inhibitors.
Assuntos
Hepacivirus/genética , Hepacivirus/isolamento & purificação , Hepatite C/sangue , Inibidores de Proteases/sangue , Proteínas não Estruturais Virais/análise , Genótipo , Humanos , Inibidores de Proteases/isolamento & purificação , Proteínas não Estruturais Virais/genéticaRESUMO
Studies directed at developing a broadly acting non-nucleoside inhibitor of HCV NS5B led to the discovery of a novel structural class of 5-aryl benzofurans that simultaneously interact with both the palmâ I and palmâ II binding regions. An initial candidate was potent inâ vitro against HCV GT1a and GT1b replicons, and induced multi-log reductions in HCV viral load when orally dosed to chronic GT1 infected chimpanzees. However, inâ vitro potency losses against clinically relevant GT1a variants prompted a further effort to develop compounds with sustained potency across a broader array of HCV genotypes and mutants. Ultimately, a biology and medicinal chemistry collaboration led to the discovery of the development candidate MK-8876. MK-8876 demonstrated a pan-genotypic potency profile and maintained potency against clinically relevant mutants. It demonstrated moderate bioavailability in rats and dogs, but showed low plasma clearance characteristics consistent with once-daily dosing. Herein we describe the efforts which led to the discovery of MK-8876, which advanced into Phaseâ 1 monotherapy studies for evaluation and characterization as a component of an all-oral direct-acting drug regimen for the treatment of chronic HCV infection.
Assuntos
Antivirais/química , Antivirais/uso terapêutico , Benzofuranos/química , Benzofuranos/uso terapêutico , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Benzofuranos/farmacocinética , Benzofuranos/farmacologia , Cães , Hepacivirus/fisiologia , Humanos , Simulação de Acoplamento Molecular , Pan troglodytes , Ratos , Proteínas não Estruturais Virais/metabolismoRESUMO
HCV diversity suggests that evaluation of HCV inhibitors for broad genotypic efficacy is warranted. The replicon system enables cell-culture compound efficacy evaluation against an active replication complex, and a functional replicon dependent upon a genotype 2b polymerase would augment existing cell-culture efficacy studies that are presently limited to genotype 1a, 1b, and 2a replicons. We made a chimeric Neo(r) 1b:2b replicon where genotype 2b NS5B was inserted into a genotype 1b NS3-5A background and transfected replicon RNA to generate Neo(r) cell lines. All cell lines contained novel substitutions within NS5B which were subsequently engineered into the parental 1b:2b replicon and shown to enhance replication to various degrees. A single NS5B M31I substitution enhanced replication to levels sufficiently robust to quantify sensitivity to HCV inhibitors in a transient replication assay. The M31I 1b:2b replicon was similarly sensitive to an active-site nucleoside inhibitor of NS5B as genotype 1b replicons, but was insensitive to two non-nucleoside inhibitors which were otherwise efficacious against the genotype 1b replicons. This work describes a novel HCV replicon sustained by a genotype 2b polymerase that is sufficiently robust for quantifiable analysis in a transient replication assay, and demonstrates its utility in characterizing anti-HCV compounds for cross-genotypic efficacy.
Assuntos
Hepacivirus/genética , RNA Polimerase Dependente de RNA/genética , Replicon , Proteínas não Estruturais Virais/genética , Adenosina/análogos & derivados , Adenosina/farmacologia , Linhagem Celular , Hepacivirus/fisiologia , Humanos , Modelos Moleculares , RNA Polimerase Dependente de RNA/antagonistas & inibidores , RNA Polimerase Dependente de RNA/química , Ribonucleosídeo Difosfato Redutase/farmacologia , Especificidade da Espécie , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/química , Replicação ViralRESUMO
BACKGROUND: Vaniprevir is a potent macrocyclic hepatitis C virus (HCV) nonstructural protein 3/4A protease inhibitor. This phase III study evaluated the safety and efficacy of vaniprevir in combination with peginterferon alfa-2b and ribavirin (PR) for 24 weeks compared with PR alone for 48 weeks in treatment-naive Japanese patients with HCV genotype 1 infection. METHODS: Treatment-naive Japanese patients with HCV genotype 1 infection were randomly assigned to receive vaniprevir (300 mg twice daily) plus PR for 12 weeks then PR alone for 12 weeks, vaniprevir (300 mg twice daily) plus PR for 24 weeks, or PR alone for 48 weeks. The primary end point was sustained virologic response 24 weeks after completion of treatment (SVR24). RESULTS: In total, 294 patients were randomly assigned to receive treatment. Most patients had HCV genotype 1b infection (98 %, 288 of 294 patients). SVR24 was achieved in 83.7, 84.5, and 55.1 % of the patients in the vaniprevir 12-week, vaniprevir 24-week, and control arms, respectively. The difference in SVR24 rates between each vaniprevir arm and the control arm was statistically significant (p < 0.001 for both). Relapse was commoner in the control arm (29.5 %) than in the vaniprevir arms (8.6 % and 10.5 % for the 12-week and 24-week arms, respectively). Commonly reported adverse events were generally similar across treatment arms, with the exception of an increase in the incidence of gastrointestinal adverse events such as nausea, diarrhea, and vomiting in patients receiving vaniprevir. These events were considered manageable. CONCLUSION: Vaniprevir is a valuable addition to the therapeutic options available to Japanese patients with HCV genotype 1 infection who are eligible for interferon-based treatment. CLINICALTRIALS. GOV IDENTIFIER: NCT01370642.
Assuntos
Antivirais/uso terapêutico , Hepacivirus/genética , Hepatite C Crônica/tratamento farmacológico , Indóis/administração & dosagem , Adulto , Idoso , Antivirais/administração & dosagem , Antivirais/efeitos adversos , Ciclopropanos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Genótipo , Hepacivirus/isolamento & purificação , Hepatite C Crônica/virologia , Humanos , Interferon alfa-2 , Interferon-alfa/administração & dosagem , Isoindóis , Japão , Lactamas Macrocíclicas , Leucina/análogos & derivados , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis/administração & dosagem , Prolina/análogos & derivados , Proteínas Recombinantes/administração & dosagem , Recidiva , Ribavirina/administração & dosagem , Sulfonamidas , Resultado do Tratamento , Adulto JovemRESUMO
UNLABELLED: In the phase III registration studies conducted in Japan, Japanese HCV gt1 patients administered vaniprevir 300 mg twice daily plus pegylated interferon/ribavirin for 12 or 24 weeks achieved SVR24 rates of 83.7-84.5% among treatment-naïve patients, and 92.0-96.2% and 61.9% among breakthrough/relapsers or null-responders to prior interferon based therapy. As evidenced by direct sequencing, patients who did not achieve SVR24 principally failed due to treatment-emerging mutations at D168 or in a few cases R155. In this work, additional sequence analysis was conducted to address whether there were baseline polymorphisms associated with failure, evaluate the persistence of resistant virus among treatment failures, and assess for evidence of second site co-evolution with R155 or D168 mutations. To accomplish this, clonal sequencing (up to 40 clones per sample) was conducted on baseline, failure, and follow-up samples from all 38 patients among the vaniprevir treatment arms who met virologic failure criteria (37 gt1b, 1 gt1a, herein referred to as virologic failures) and baseline samples from 41 vaniprevir-treated SVR24 patients (all gt1b) selected among the three studies. SVR24 and virologic failure patients showed similar distributions of baseline polymorphisms previously associated with failure to one or more protease inhibitors. Furthermore, there was no evidence for baseline polymorphisms or a genetic signature across the NS3 protease domain specific to virologic failure patients, and which distinguishes them from baseline SVR24 sequences beyond a chance distribution. 24 of 32 virologic failures for whom baseline, failure, and follow-up samples were available showed reduced prevalence of the resistant virus first observed at the time of failure during the protocol-defined follow-up period of 24 weeks. Finally, pairwise analysis using either alignment or phylogenetic based methodologies provided no evidence for second site evolution with either the R155 or D168 mutations attributed to failure. This work supports and extends earlier findings based upon direct sequencing that attributed virologic failure to vaniprevir in the Phase III studies solely to the emergence of R155 or D168 mutations, with no apparent influence by other residues within the NS3 protease domain on treatment outcome. CLINICALTRIALS. GOVIDENTIFIERS: NCT01370642, NCT01405937, NCT01405560.
Assuntos
Antivirais/uso terapêutico , Evolução Molecular , Genótipo , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Hepatite C/virologia , Indóis/uso terapêutico , Substituição de Aminoácidos , Antivirais/farmacologia , Códon , Ciclopropanos , Farmacorresistência Viral , Quimioterapia Combinada , Hepacivirus/classificação , Humanos , Indóis/farmacologia , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Mutação , Filogenia , Prolina/análogos & derivados , Análise de Sequência de DNA , Sulfonamidas , Falha de Tratamento , Resultado do TratamentoRESUMO
With the goal of identifying inhibitors of hepatitis C virus (HCV) NS3/4a protease that are potent against a wide range of genotypes and clinically relevant mutant viruses, several subseries of macrocycles were investigated based on observations made during the discovery of MK-5172. Quinazolinone-containing macrocycles were identified as promising leads, and optimization for superior cross-genotype and mutant enzyme potency as well as rat liver and plasma concentrations following oral dosing, led to the development of MK-2748. Additional investigation of a series of bis-macrocycles containing a fused 18- and 15-membered ring system were also optimized for the same properties, leading to the discovery of MK-6325. Both compounds display the broad genotype and mutant potency necessary for clinical development as next-generation HCV NS3/4a protease inhibitors.
Assuntos
Antivirais/farmacologia , Hepacivirus/enzimologia , Compostos Macrocíclicos/farmacologia , Quinazolinonas/farmacologia , Sulfonas/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacocinética , Cristalografia por Raios X , Descoberta de Drogas , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Hepatite C/virologia , Humanos , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacocinética , Modelos Moleculares , Mutação , Quinazolinonas/química , Quinazolinonas/farmacocinética , Ratos , Sulfonas/farmacocinética , Proteínas não Estruturais Virais/genéticaRESUMO
The NS5A protein plays a critical role in the replication of HCV and has been the focus of numerous research efforts over the past few years. NS5A inhibitors have shown impressive in vitro potency profiles in HCV replicon assays, making them attractive components for inclusion in all oral combination regimens. Early work in the NS5A arena led to the discovery of our first clinical candidate, MK-4882 [2-((S)-pyrrolidin-2-yl)-5-(2-(4-(5-((S)-pyrrolidin-2-yl)-1H-imidazol-2-yl)phenyl)benzofuran-5-yl)-1H-imidazole]. While preclinical proof-of-concept studies in HCV-infected chimpanzees harboring chronic genotypeâ 1 infections resulted in significant decreases in viral load after both single- and multiple-dose treatments, viral breakthrough proved to be a concern, thus necessitating the development of compounds with increased potency against a number of genotypes and NS5A resistance mutations. Modification of the MK-4882 core scaffold by introduction of a cyclic constraint afforded a series of tetracyclic inhibitors, which showed improved virologic profiles. Herein we describe the research efforts that led to the discovery of MK-8742, a tetracyclic indole-based NS5A inhibitor, which is currently in phaseâ 2b clinical trials as part of an all-oral, interferon-free regimen for the treatment of HCV infection.
Assuntos
Antivirais/química , Benzofuranos/química , Inibidores Enzimáticos/química , Hepacivirus/enzimologia , Imidazóis/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/síntese química , Antivirais/farmacocinética , Benzofuranos/síntese química , Benzofuranos/farmacocinética , Cães , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Meia-Vida , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Imidazóis/síntese química , Imidazóis/farmacocinética , Indóis/química , Mutação , Pan troglodytes , Ligação Proteica , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismoRESUMO
A new class of HCV NS3/4a protease inhibitors containing a P2 to P4 macrocyclic constraint was designed using a molecular modeling-derived strategy. Building on the profile of previous clinical compounds and exploring the P2 and linker regions of the series allowed for optimization of broad genotype and mutant enzyme potency, cellular activity, and rat liver exposure following oral dosing. These studies led to the identification of clinical candidate 15 (MK-5172), which is active against genotype 1-3 NS3/4a and clinically relevant mutant enzymes and has good plasma exposure and excellent liver exposure in multiple species.
RESUMO
The discovery of MK-1220 is reported along with the development of a series of HCV NS3/4A protease inhibitors containing a P2 to P4 macrocyclic constraint with improved preclinical pharmacokinetics. Optimization of the P2 heterocycle substitution pattern as well as the P3 amino acid led to compounds with greatly improved plasma exposure following oral dosing in both rats and dogs while maintaining excellent enzyme potency and cellular activity. These studies led to the identification of MK-1220.
RESUMO
A new class of HCV NS3/4a protease inhibitors which contain a P2 to P4 macrocyclic constraint was designed using a molecular-modeling derived strategy. Exploration of the P2 heterocyclic region, the P2 to P4 linker, and the P1 side chain of this class of compounds via a modular synthetic strategy allowed for the optimization of enzyme potency, cellular activity, and rat liver exposure following oral dosing. These studies led to the identification of clinical candidate 35b (vaniprevir, MK-7009), which is active against both the genotype 1 and genotype 2 NS3/4a protease enzymes and has good plasma exposure and excellent liver exposure in multiple species.
Assuntos
Hepacivirus/enzimologia , Indóis/farmacologia , Inibidores de Serina Proteinase/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Área Sob a Curva , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/metabolismo , Ciclopropanos , Cães , Descoberta de Drogas , Avaliação Pré-Clínica de Medicamentos , Indóis/química , Indóis/farmacocinética , Concentração Inibidora 50 , Peptídeos e Proteínas de Sinalização Intracelular , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Fígado/metabolismo , Macaca mulatta , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacocinética , Compostos Macrocíclicos/farmacologia , Taxa de Depuração Metabólica , Modelos Químicos , Estrutura Molecular , Pan troglodytes , Prolina/análogos & derivados , Ratos , Inibidores de Serina Proteinase/química , Inibidores de Serina Proteinase/farmacocinética , Relação Estrutura-Atividade , Sulfonamidas , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/metabolismoRESUMO
Hepatitis C virus (HCV) exists in six major genotypes. Compared with the 1b enzyme, genotype 2b HCV polymerase exhibits a more than 100-fold reduction in sensitivity to the indole-N-acetamide class of non-nucleoside inhibitors. These compounds have been shown to bind in a pocket occupied by helix A of the mobile Lambda1 loop in the apoenzyme. The three-dimensional structure of the HCV polymerase from genotype 2b was determined to 1.9-A resolution and compared with the genotype 1b enzyme. This structural analysis suggests that genotypic variants result in a different shape of the inhibitor binding site. Mutants of the inhibitor binding pocket were generated in a 1b enzyme and evaluated for their binding affinity and sensitivity to inhibition by indole-N-acetamides. Most of the point mutants showed little variation in activity and IC(50), with the exception of 15- and 7-fold increases in IC(50) for Leu392Ile and Val494Ala mutants (1b-->2b), respectively. Furthermore, a 1b replicon with 20-fold resistance to this class of inhibitors was selected and shown to contain the Leu392Ile mutation. Chimeric enzymes, where the 2b fingertip Lambda1 loop, pocket or both replaced the corresponding regions of the 1b enzyme, were also generated. The fingertip chimera retained 1b-like inhibitor binding affinity, whereas the other two chimeric constructs and the 2b enzyme displayed between 50- and 100-fold reduction in binding affinity. Together, these data suggest that differences in the amino acid composition and shape of the indole-N-acetamide binding pocket are responsible for the resistance of the 2b polymerase to this class of inhibitors.