RESUMO
Chronic hepatitis B (CHB) virus infection afflicts hundreds of millions of people and causes nearly one million deaths annually. The high levels of circulating viral surface antigen (HBsAg) that characterize CHB may lead to T-cell exhaustion, resulting in an impaired antiviral immune response in the host. Agents that suppress HBsAg could help invigorate immunity toward infected hepatocytes and facilitate a functional cure. A series of dihydropyridoisoquinolizinone (DHQ) inhibitors of human poly(A) polymerases PAPD5/7 were reported to suppress HBsAg in vitro. An example from this class, RG7834, briefly entered the clinic. We set out to identify a potent, orally bioavailable, and safe PAPD5/7 inhibitor as a potential component of a functional cure regimen. Our efforts led to the identification of a dihydropyridophthalazinone (DPP) core with improved pharmacokinetic properties. A conformational restriction strategy and optimization of core substitution led to GS-8873, which was projected to provide deep HBsAg suppression with once-daily dosing.
RESUMO
Benzothiazine-substituted tetramic acids were discovered as highly potent non-nucleoside inhibitors of HCV NS5B polymerase. X-ray crystallography studies confirmed the binding mode of these inhibitors with HCV NS5B polymerase. Rational optimization of time dependent inactivation of CYP 3A4 and clearance was accomplished by incorporation of electron-withdrawing groups to the benzothiazine core.
Assuntos
Antivirais/síntese química , Hepacivirus/efeitos dos fármacos , Pirrolidinonas/química , Tiazinas/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacocinética , Sítios de Ligação , Cristalografia por Raios X , Pirrolidinonas/síntese química , Pirrolidinonas/farmacocinética , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
A new series of benzothiazine-substituted quinolinediones were evaluated as inhibitors of HCV polymerase NS5B. SAR studies on this series revealed a methyl sulfonamide group as a high affinity feature. Analogues with this group showed submicromolar potencies in the HCV cell based replicon assay. Pharmacokinetic and toxicology studies were also performed on a selected compound (34) to evaluate in vivo properties of this new class of inhibitors of HCV NS5B polymerase.
Assuntos
Antivirais/química , RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , Inibidores Enzimáticos/química , Hepacivirus/efeitos dos fármacos , Quinolinas/química , Quinolonas/química , Tiazinas/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/síntese química , Antivirais/farmacocinética , Simulação por Computador , Cristalografia por Raios X , RNA Polimerases Dirigidas por DNA/metabolismo , Cães , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Humanos , Quinolinas/síntese química , Quinolinas/farmacocinética , Quinolonas/síntese química , Quinolonas/farmacologia , Ratos , Relação Estrutura-Atividade , Tiazinas/síntese química , Tiazinas/farmacologia , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacosRESUMO
The use of fragments with low binding affinity for their targets as starting points has received much attention recently. Screening of fragment libraries has been the most common method to find attractive starting points. Herein, we describe a unique, alternative approach to generating fragment leads. A binding model was developed and a set of guidelines were then selected to use this model to design fragments, enabling our discovery of a novel fragment with high LE.
Assuntos
Química Farmacêutica , Desenho de Fármacos , Modelos MolecularesRESUMO
Hepatitis C virus (HCV) is a major global public health problem. While the current standard of care, a direct-acting antiviral (DAA) protease inhibitor taken in combination with pegylated interferon and ribavirin, represents a major advancement in recent years, an unmet medical need still exists for treatment modalities that improve upon both efficacy and tolerability. Toward those ends, much effort has continued to focus on the discovery of new DAAs, with the ultimate goal to provide interferon-free combinations. The RNA-dependent RNA polymerase enzyme NS5B represents one such DAA therapeutic target for inhibition that has attracted much interest over the past decade. Herein, we report the discovery and optimization of a novel series of inhibitors of HCV NS5B, through the use of structure-based design applied to a fragment-derived starting point. Issues of potency, pharmacokinetics, and early safety were addressed in order to provide a clinical candidate in fluoropyridone 19.
Assuntos
Antivirais/farmacologia , Inibidores Enzimáticos/farmacologia , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacocinética , Área Sob a Curva , Linhagem Celular Tumoral , Cães , Descoberta de Drogas/métodos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Hepacivirus/efeitos dos fármacos , Hepacivirus/enzimologia , Hepacivirus/fisiologia , Hepatite C/prevenção & controle , Hepatite C/virologia , Interações Hospedeiro-Patógeno/genética , Humanos , Modelos Moleculares , Terapia de Alvo Molecular/métodos , Ligação Proteica , Estrutura Terciária de Proteína , Piridonas/síntese química , Piridonas/farmacocinética , Piridonas/farmacologia , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/metabolismo , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismoRESUMO
An expedient enantioselective synthesis of the Δ(4)-oxocene cores present in (+)-laurencin and (+)-prelaureatin was accomplished in eight steps via a novel one-pot regio- and stereoselective ring cyclization-fragmentation-expansion cascade from the tetrahydrofuran precursors which were prepared by stereocontrolled cyclization from vinylsilanes. This process is highlighted by an intramolecular oxo-carbenoid insertion and a ß-silyl fragmentation sequence.