ABSTRACT
Protease inhibitors (PIs) remain an important component of antiretroviral therapy for the treatment of HIV-1 infection due to their high genetic barrier to resistance development. Nevertheless, the two most commonly prescribed HIV PIs, atazanavir and darunavir, still require co-administration with a pharmacokinetic boosting agent to maintain sufficient drug plasma levels which can lead to undesirable drug-drug interactions. Herein, we describe GS-9770, a novel investigational non-peptidomimetic HIV PI with unboosted once-daily oral dosing potential due to improvements in its metabolic stability and its pharmacokinetic properties in preclinical animal species. This compound demonstrates potent inhibitory activity and high on-target selectivity for recombinant HIV-1 protease versus other aspartic proteases tested. In cell culture, GS-9770 inhibits Gag polyprotein cleavage and shows nanomolar anti-HIV-1 potency in primary human cells permissive to HIV-1 infection and against a broad range of HIV subtypes. GS-9770 demonstrates an improved resistance profile against a panel of patient-derived HIV-1 isolates with resistance to atazanavir and darunavir. In resistance selection experiments, GS-9770 prevented the emergence of breakthrough HIV-1 variants at all fixed drug concentrations tested and required multiple protease substitutions to enable outgrowth of virus exposed to escalating concentrations of GS-9770. This compound also remained fully active against viruses resistant to drugs from other antiviral classes and showed no in vitro antagonism when combined pairwise with drugs from other antiretroviral classes. Collectively, these preclinical data identify GS-9770 as a potent, non-peptidomimetic once-daily oral HIV PI with potential to overcome the persistent requirement for pharmacological boosting with this class of antiretroviral agents.
Subject(s)
HIV Infections , HIV Protease Inhibitors , HIV-1 , Humans , HIV Protease Inhibitors/pharmacology , HIV Protease Inhibitors/therapeutic use , Darunavir/pharmacology , Darunavir/therapeutic use , Atazanavir Sulfate/pharmacology , Atazanavir Sulfate/therapeutic use , Drug Resistance, Viral , HIV-1/genetics , Anti-Retroviral Agents/therapeutic use , HIV Infections/drug therapy , HIV Protease/genetics , HIV Protease/metabolismABSTRACT
Delivery of pharmacologically active nucleoside triphosphate analogs to sites of viral infection is challenging. In prior work we identified a 2'-C-methyl-1'-cyano-7-deaza-adenosine C-nucleotide analog with desirable selectivity and potency for the treatment of hepatitis C virus (HCV) infection. However, the prodrug selected for clinical development, GS-6620, required a high dose for meaningful efficacy and had unacceptable variability due to poor oral absorption as a result of suboptimal solubility, intestinal metabolism, and efflux transport. While obtaining clinical proof of concept for the nucleotide analog, a more effective prodrug strategy would be necessary for clinical utility. Here, we report an alternative prodrug of the same nucleoside analog identified to address liabilities of GS-6620. A phosphoramidate prodrug containing the nonproteinogenic amino acid methylalanine, an isopropyl ester and phenol in the (S) conformation at phosphorous, GS2, was found to have improved solubility, intestinal stability, and hepatic activation. GS2 is a more selective substrate for hepatically expressed carboxyl esterase 1 (CES1) and is resistant to hydrolysis by more widely expressed hydrolases, including cathepsin A (CatA) and CES2. Unlike GS-6620, GS2 was not cleaved by intestinally expressed CES2 and, as a result, was stable in intestinal extracts. Levels of liver triphosphate following oral administration of GS2 in animals were higher than those of GS-6620, even when administered under optimal conditions for GS-6620 absorption. Combined, these properties suggest that GS2 will have better oral absorption in the clinic when administered in a solid dosage form and the potential to extend the clinical proof of concept obtained with GS-6620.
Subject(s)
Antiviral Agents/therapeutic use , Hepacivirus/pathogenicity , Nucleotides/therapeutic use , Prodrugs/therapeutic use , Triazines/therapeutic use , Adenosine/analogs & derivatives , Administration, Oral , Alanine , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/pharmacokinetics , Caco-2 Cells , Cells, Cultured , Dogs , Hepacivirus/drug effects , Hepatitis C/virology , Humans , Male , Nucleotides/administration & dosage , Nucleotides/pharmacokinetics , Prodrugs/administration & dosage , Prodrugs/pharmacokinetics , Rats , Triazines/administration & dosage , Triazines/pharmacokinetics , Virus Replication/drug effectsABSTRACT
A series of 2'-fluorinated C-nucleosides were prepared and tested for anti-HCV activity. Among them, the triphosphate of 2'-fluoro-2'-C-methyl adenosine C-nucleoside (15) was a potent and selective inhibitor of the NS5B polymerase and maintained activity against the S282T resistance mutant. A number of phosphoramidate prodrugs were then prepared and evaluated leading to the identification of the 1-aminocyclobutane-1-carboxylic acid isopropyl ester variant (53) with favorable pharmacokinetic properties including efficient liver delivery in animals.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Nucleosides/chemistry , Nucleosides/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Amides/chemistry , Amides/pharmacokinetics , Amides/pharmacology , Animals , Antiviral Agents/pharmacokinetics , Caco-2 Cells , Cell Line , Cricetinae , Drug Discovery , Drug Resistance, Viral , Halogenation , Hepacivirus/genetics , Hepacivirus/physiology , Hepatitis C/drug therapy , Humans , Methylation , Molecular Docking Simulation , Nucleosides/pharmacokinetics , Phosphoric Acids/chemistry , Phosphoric Acids/pharmacokinetics , Phosphoric Acids/pharmacology , Point Mutation , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Prodrugs/pharmacology , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effectsABSTRACT
Ribose modified 1'-C-cyano pyrimidine nucleosides were synthesized. A silver triflate mediated Vorbrüggen reaction was used to generate the nucleoside scaffold and follow-up chemistry provided specific ribose modified analogs. Nucleosides and phosphoramidate prodrugs were tested for their anti-HCV activity.
Subject(s)
DNA-Directed RNA Polymerases/antagonists & inhibitors , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Hepacivirus/enzymology , Pyrimidine Nucleosides/chemical synthesis , Pyrimidine Nucleosides/pharmacology , Chemistry Techniques, Synthetic , Enzyme Inhibitors/chemistry , Pyrimidine Nucleosides/chemistryABSTRACT
Nucleotide analog inhibitors have shown clinical success in the treatment of hepatitis C virus (HCV) infection, despite an incomplete mechanistic understanding of NS5B, the viral RNA-dependent RNA polymerase. Here we study the details of HCV RNA replication by determining crystal structures of stalled polymerase ternary complexes with enzymes, RNA templates, RNA primers, incoming nucleotides, and catalytic metal ions during both primed initiation and elongation of RNA synthesis. Our analysis revealed that highly conserved active-site residues in NS5B position the primer for in-line attack on the incoming nucleotide. A ß loop and a C-terminal membrane-anchoring linker occlude the active-site cavity in the apo state, retract in the primed initiation assembly to enforce replication of the HCV genome from the 3' terminus, and vacate the active-site cavity during elongation. We investigated the incorporation of nucleotide analog inhibitors, including the clinically active metabolite formed by sofosbuvir, to elucidate key molecular interactions in the active site.
Subject(s)
Hepacivirus/physiology , RNA, Viral/biosynthesis , RNA-Dependent RNA Polymerase/chemistry , Ribonucleotides/chemistry , Viral Nonstructural Proteins/chemistry , Virus Replication , Amino Acid Sequence , Catalytic Domain , Conserved Sequence , Crystallography, X-Ray , Hepacivirus/enzymology , Hepacivirus/genetics , Molecular Sequence Data , Protein Structure, Secondary , Sofosbuvir , Uridine Monophosphate/analogs & derivatives , Uridine Monophosphate/chemistryABSTRACT
The first synthesis of 1'-C-CN, 2'-F, 2'-C-Me pyrimidines is described. Anti-HCV activity was assessed and compared to the 1'-C-CN, 2'-C-Me as well as the 2'-F, 2'-C-Me pyrimidines. A phosphoramidate prodrug of the cytidine derivative showed activity in the low micromolar range against HCV replicons.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Pyrimidine Nucleosides/chemistry , Pyrimidine Nucleosides/pharmacology , Amides/chemistry , Amides/pharmacology , Cell Line , Halogenation , Hepacivirus/enzymology , Hepatitis C/drug therapy , Hepatitis C/virology , Humans , Methylation , Phosphoric Acids/chemistry , Phosphoric Acids/pharmacology , Prodrugs/chemistry , Prodrugs/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Replicon/drug effectsABSTRACT
The first synthesis of 1'-cyano-2'-C-methyl pyrimidine nucleosides is described. Anti-HCV activity of these nucleosides and their nucleotide phosphoramidate prodrugs was assessed and compared to the 1'-unsubstituted counterparts and to the related 1'-cyano-2'-C-methyl C-nucleoside parent of GS-6620.
Subject(s)
Antiviral Agents/pharmacology , Enzyme Inhibitors/pharmacology , Hepacivirus/drug effects , Hepacivirus/enzymology , Nucleosides/pharmacology , Pyrimidine Nucleosides/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Microbial Sensitivity Tests , Molecular Conformation , Nucleosides/chemical synthesis , Nucleosides/chemistry , Pyrimidine Nucleosides/chemical synthesis , Pyrimidine Nucleosides/chemistry , RNA-Dependent RNA Polymerase/metabolism , Structure-Activity Relationship , Viral Nonstructural Proteins/metabolismABSTRACT
The anti-hepatitis C virus nucleotide prodrug GS-6620 employs a double-prodrug approach, with l-alanine-isopropyl ester and phenol moieties attached to the 5'-phosphate that release the nucleoside monophosphate in hepatocytes and a 3'-isobutyryl ester added to improve permeability and oral bioavailability. Consistent with the stability found in intestinal homogenates, following oral administration, intact prodrug levels in blood plasma were the highest in dogs, followed by monkeys, and then were the lowest in hamsters. In contrast, liver levels of the triphosphate metabolite at the equivalent surface area-adjusted doses were highest in hamsters, followed by in dogs and monkeys. Studies in isolated primary hepatocytes suggest that relatively poor oral absorption in hamsters and monkeys was compensated for by relatively efficient hepatocyte activation. As intestinal absorption was found to be critical to the effectiveness of GS-6620 in nonclinical species, stomach pH, formulation, and food effect studies were completed in dogs. Consistent with in vitro absorption studies in Caco-2 cells, the absorption of GS-6620 was found to be complex and highly dependent on concentration. Higher rates of metabolism were observed at lower concentrations that were unable to saturate intestinal efflux transporters. In first-in-human clinical trials, the oral administration of GS-6620 resulted in poor plasma exposure relative to that observed in dogs and in large pharmacokinetic and pharmacodynamic variabilities. While a double-prodrug approach, including a 3'-isobutyryl ester, provided higher intrinsic intestinal permeability, this substitution appeared to be a metabolic liability, resulting in extensive intestinal metabolism and relatively poor oral absorption in humans.
Subject(s)
Antiviral Agents/pharmacokinetics , Prodrugs/pharmacokinetics , Administration, Oral , Animals , Antiviral Agents/pharmacology , Caco-2 Cells , Cell Line , Cricetinae , Dogs , Hepacivirus/drug effects , Humans , Macaca fascicularis , Male , Mesocricetus , Prodrugs/pharmacologyABSTRACT
As a class, nucleotide inhibitors (NIs) of the hepatitis C virus (HCV) nonstructural protein 5B (NS5B) RNA-dependent RNA polymerase offer advantages over other direct-acting antivirals, including properties, such as pangenotype activity, a high barrier to resistance, and reduced potential for drug-drug interactions. We studied the in vitro pharmacology of a novel C-nucleoside adenosine analog monophosphate prodrug, GS-6620. It was found to be a potent and selective HCV inhibitor against HCV replicons of genotypes 1 to 6 and against an infectious genotype 2a virus (50% effective concentration [EC50], 0.048 to 0.68 µM). GS-6620 showed limited activities against other viruses, maintaining only some of its activity against the closely related bovine viral diarrhea virus (EC50, 1.5 µM). The active 5'-triphosphate metabolite of GS-6620 is a chain terminator of viral RNA synthesis and a competitive inhibitor of NS5B-catalyzed ATP incorporation, with Ki/Km values of 0.23 and 0.18 for HCV NS5B genotypes 1b and 2a, respectively. With its unique dual substitutions of 1'-CN and 2'-C-Me on the ribose ring, the active triphosphate metabolite was found to have enhanced selectivity for the HCV NS5B polymerase over host RNA polymerases. GS-6620 demonstrated a high barrier to resistance in vitro. Prolonged passaging resulted in the selection of the S282T mutation in NS5B that was found to be resistant in both cellular and enzymatic assays (>30-fold). Consistent with its in vitro profile, GS-6620 exhibited the potential for potent anti-HCV activity in a proof-of-concept clinical trial, but its utility was limited by the requirement of high dose levels and pharmacokinetic and pharmacodynamic variability.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Nucleosides/chemistry , Nucleosides/pharmacology , Prodrugs/pharmacology , Virus Replication/drug effects , Antiviral Agents/adverse effects , Cell Line, Tumor , Cell Survival , Hep G2 Cells , Humans , Nucleosides/adverse effects , Prodrugs/adverse effects , Prodrugs/chemistry , Viral Nonstructural Proteins/antagonists & inhibitorsABSTRACT
Hepatitis C virus (HCV) infection presents an unmet medical need requiring more effective treatment options. Nucleoside inhibitors (NI) of HCV polymerase (NS5B) have demonstrated pan-genotypic activity and durable antiviral response in the clinic, and they are likely to become a key component of future treatment regimens. NI candidates that have entered clinical development thus far have all been N-nucleoside derivatives. Herein, we report the discovery of a C-nucleoside class of NS5B inhibitors. Exploration of adenosine analogs in this class identified 1'-cyano-2'-C-methyl 4-aza-7,9-dideaza adenosine as a potent and selective inhibitor of NS5B. A monophosphate prodrug approach afforded a series of compounds showing submicromolar activity in HCV replicon assays. Further pharmacokinetic optimization for sufficient oral absorption and liver triphosphate loading led to identification of a clinical development candidate GS-6620. In a phase I clinical study, the potential for potent activity was demonstrated but with high intra- and interpatient pharmacokinetic and pharmacodynamic variability.
Subject(s)
Antiviral Agents/therapeutic use , Enzyme Inhibitors/therapeutic use , Hepacivirus/enzymology , Hepatitis C/drug therapy , Nucleosides/pharmacology , Organophosphorus Compounds/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Dogs , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Hepatitis C/enzymology , Hepatitis C/virology , Humans , Nucleosides/chemistry , Organophosphorus Compounds/chemistry , Rats , Viral LoadABSTRACT
Ribonucleoside analogues have potential utility as anti-viral, -parasitic, -bacterial and -cancer agents. However, their clinical applications have been limited by off target effects. Development of antiviral ribonucleosides for treatment of hepatitis C virus (HCV) infection has been hampered by appearance of toxicity during clinical trials that evaded detection during preclinical studies. It is well established that the human mitochondrial DNA polymerase is an off target for deoxyribonucleoside reverse transcriptase inhibitors. Here we test the hypothesis that triphosphorylated metabolites of therapeutic ribonucleoside analogues are substrates for cellular RNA polymerases. We have used ribonucleoside analogues with activity against HCV as model compounds for therapeutic ribonucleosides. We have included ribonucleoside analogues containing 2'-C-methyl, 4'-methyl and 4'-azido substituents that are non-obligate chain terminators of the HCV RNA polymerase. We show that all of the anti-HCV ribonucleoside analogues are substrates for human mitochondrial RNA polymerase (POLRMT) and eukaryotic core RNA polymerase II (Pol II) in vitro. Unexpectedly, analogues containing 2'-C-methyl, 4'-methyl and 4'-azido substituents were inhibitors of POLRMT and Pol II. Importantly, the proofreading activity of TFIIS was capable of excising these analogues from Pol II transcripts. Evaluation of transcription in cells confirmed sensitivity of POLRMT to antiviral ribonucleosides, while Pol II remained predominantly refractory. We introduce a parameter termed the mitovir (mitochondrial dysfunction caused by antiviral ribonucleoside) score that can be readily obtained during preclinical studies that quantifies the mitochondrial toxicity potential of compounds. We suggest the possibility that patients exhibiting adverse effects during clinical trials may be more susceptible to damage by nucleoside analogs because of defects in mitochondrial or nuclear transcription. The paradigm reported here should facilitate development of ribonucleosides with a lower potential for toxicity.
Subject(s)
Antiviral Agents/pharmacology , Cell Nucleus/metabolism , DNA-Directed RNA Polymerases/metabolism , Hepacivirus/metabolism , Mitochondria/metabolism , RNA Polymerase II/metabolism , Ribonucleosides/pharmacology , Transcription, Genetic/drug effects , Animals , Antiviral Agents/adverse effects , Cattle , Cell Line , Hepatitis C/drug therapy , Hepatitis C/enzymology , RNA, Viral/biosynthesis , Ribonucleosides/adverse effectsABSTRACT
A series of 2'-C-methyl branched purine and pyrimidine C-nucleosides were prepared. Their anti-HCV activity and pharmacological properties were profiled, and compared with known 2'-C-Me N-nucleoside counterparts. In particular, 2'-C-Me 4-aza-7,9-dideazaadenosine C-nucleoside (2) was found to have potent and selective anti-HCV activity in vitro as well as a favorable pharmacokinetic profile and in vivo potential for enhanced potency over the corresponding N-nucleoside.
Subject(s)
Antiviral Agents/chemical synthesis , Aza Compounds/chemical synthesis , Hepacivirus/drug effects , Purine Nucleosides/chemical synthesis , Pyrimidine Nucleosides/chemical synthesis , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Animals , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Aza Compounds/pharmacokinetics , Aza Compounds/pharmacology , Cell Line , Cricetinae , Dogs , Hepacivirus/enzymology , Hepacivirus/growth & development , Hepatocytes/drug effects , Hepatocytes/virology , Humans , Injections, Intravenous , Primary Cell Culture , Purine Nucleosides/pharmacokinetics , Purine Nucleosides/pharmacology , Pyrimidine Nucleosides/pharmacokinetics , Pyrimidine Nucleosides/pharmacology , RNA-Dependent RNA Polymerase/metabolism , Rats , Viral Nonstructural Proteins/metabolismABSTRACT
A series of 1'-substituted analogs of 4-aza-7,9-dideazaadenosine C-nucleoside were prepared and evaluated for the potential as antiviral agents. These compounds showed a broad range of inhibitory activity against various RNA viruses. In particular, the whole cell potency against HCV when R=CN was attributed to inhibition of HCV NS5B polymerase and intracellular concentration of the corresponding nucleoside triphosphate.
Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Nucleosides/chemical synthesis , Nucleosides/pharmacology , Adenosine/chemical synthesis , Adenosine/chemistry , Adenosine/pharmacology , Antiviral Agents/chemistry , Aza Compounds/chemical synthesis , Aza Compounds/chemistry , Aza Compounds/pharmacology , Humans , Molecular Structure , Nucleosides/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/drug effectsABSTRACT
The discovery of GS-9451 is reported. Modification of the P3 cap and P2 quinoline with a series of solubilizing groups led to the identification of potent HCV NS3 protease inhibitors with greatly improved pharmacokinetic properties in rats, dogs and monkeys.
Subject(s)
Antiviral Agents/chemical synthesis , Carboxylic Acids/chemical synthesis , Hepacivirus/drug effects , Quinolines/chemical synthesis , Serine Proteinase Inhibitors/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Biological Availability , Caco-2 Cells , Carboxylic Acids/pharmacokinetics , Carboxylic Acids/pharmacology , Crystallography, X-Ray , Dogs , Hepacivirus/chemistry , Hepacivirus/enzymology , Hepatitis C/drug therapy , Hepatitis C/virology , Humans , Macaca fascicularis , Models, Molecular , Quinolines/pharmacokinetics , Quinolines/pharmacology , Rats , Serine Proteinase Inhibitors/pharmacokinetics , Serine Proteinase Inhibitors/pharmacology , Structure-Activity Relationship , Viral Nonstructural Proteins/chemistryABSTRACT
A potent and novel class of phosphinic acid derived product-like inhibitors of the HCV NS3/4A protease was discovered previously. Modification of the phosphinic acid and quinoline heterocycle led to GS-9256 with potent cell-based activity and favorable pharmacokinetic parameters. Based on these attributes, GS-9256 was advanced to human clinical trial as a treatment for chronic infection with genotype 1 HCV.
Subject(s)
Carrier Proteins/antagonists & inhibitors , Drug Discovery , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Hepacivirus/drug effects , Peptides, Cyclic/chemistry , Phosphinic Acids/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Dogs , Enzyme Inhibitors/chemical synthesis , Hepacivirus/enzymology , Humans , Inhibitory Concentration 50 , Intracellular Signaling Peptides and Proteins , Molecular Structure , Peptides, Cyclic/chemical synthesis , Peptides, Cyclic/pharmacology , Phosphinic Acids/chemical synthesis , Phosphinic Acids/pharmacology , SwineABSTRACT
A potent and novel class of product-like inhibitors of the HCV NS3 protease was discovered by employing a phosphinic acid as a carboxylate isostere. The replicon activity and pharmacokinetic profile of this series of compounds was optimized by exploring the substitution of the phosphinic acid, as well as conformationally constraining these compounds through macrocyclization. The syntheses and preliminary biological evaluation of these phosphinic acids is described.
Subject(s)
Hepacivirus/drug effects , Hepacivirus/enzymology , Phosphinic Acids/chemical synthesis , Phosphinic Acids/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Cyclization , Humans , Inhibitory Concentration 50 , Molecular Structure , Phosphinic Acids/chemistryABSTRACT
Further structure-activity relationships of a novel series of fungal efflux pump inhibitors with respect to potentiation of the activity of fluconazole against strains of C. albicans and C. glabrata over-expressing ABC-type efflux pumps are systematically explored. Rat protein binding and pharmacokinetics of selected analogues are reported.
Subject(s)
Antifungal Agents/pharmacology , Membrane Transport Proteins/drug effects , Piperazines/chemistry , Quinazolinones/pharmacology , Serum/chemistry , Animals , Antifungal Agents/blood , Antifungal Agents/chemistry , Antifungal Agents/pharmacokinetics , Candida albicans/drug effects , Hepatocytes/metabolism , Male , Membrane Transport Proteins/metabolism , Molecular Structure , Piperazine , Quinazolinones/blood , Quinazolinones/pharmacokinetics , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
The design, synthesis, and IMPDH inhibitory activity of a series of phosphonic acid-containing analogues of mycophenolic acid are described.
Subject(s)
Enzyme Inhibitors/pharmacology , IMP Dehydrogenase/antagonists & inhibitors , Mycophenolic Acid/pharmacology , Organophosphonates/chemistry , Drug Evaluation, Preclinical , Enzyme Activation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Molecular Structure , Mycophenolic Acid/chemical synthesis , Mycophenolic Acid/chemistry , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The discovery of a series of quinazolinone-based fungal efflux pump inhibitors by high-throughput screening for potentiation of fluconazole in C. albicans is described. Attempts to improve the aqueous solubility of screening hits led to the discovery of an analog with greatly improved physical properties and activity against clinically-relevant Candida spp.
Subject(s)
ATP-Binding Cassette Transporters/antagonists & inhibitors , Antifungal Agents/chemical synthesis , Candida/drug effects , Fungal Proteins/antagonists & inhibitors , Membrane Transport Modulators , Membrane Transport Proteins/antagonists & inhibitors , Piperazines/chemical synthesis , Quinazolines/chemical synthesis , Antifungal Agents/pharmacology , Candida/enzymology , Drug Resistance, Fungal , Drug Synergism , Fluconazole/chemistry , Fluconazole/pharmacology , Humans , In Vitro Techniques , Models, Molecular , Piperazines/chemistry , Piperazines/pharmacology , Quinazolines/chemistry , Quinazolines/pharmacology , Solubility , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Structure-activity relationships of a novel series of fungal efflux pump inhibitors with respect to potentiation of the activity of fluconazole against strains of Candida albicans and Candida glabrata over-expressing ABC-type efflux pumps are systematically explored.