ABSTRACT
OBJECTIVE: Mucopolysaccharidosis type IIIA (MPSIIIA) caused by recessive SGSH variants results in sulfamidase deficiency, leading to neurocognitive decline and death. No disease-modifying therapy is available. The AAVance gene therapy trial investigates AAVrh.10 overexpressing human sulfamidase (LYS-SAF302) delivered by intracerebral injection in children with MPSIIIA. Post-treatment MRI monitoring revealed lesions around injection sites. Investigations were initiated in one patient to determine the cause. METHODS: Clinical and MRI details were reviewed. Stereotactic needle biopsies of a lesion were performed; blood and CSF were sampled. All samples were used for viral studies. Immunohistochemistry, electron microscopy, and transcriptome analysis were performed on brain tissue of the patient and various controls. RESULTS: MRI revealed focal lesions around injection sites with onset from 3 months after therapy, progression until 7 months post therapy with subsequent stabilization and some regression. The patient had transient slight neurological signs and is following near-normal development. No evidence of viral or immunological/inflammatory cause was found. Immunohistochemistry showed immature oligodendrocytes and astrocytes, oligodendrocyte apoptosis, strong intracellular and extracellular sulfamidase expression and hardly detectable intracellular or extracellular heparan sulfate. No activation of the unfolded protein response was found. INTERPRETATION: Results suggest that intracerebral gene therapy with local sulfamidase overexpression leads to dysfunction of transduced cells close to injection sites, with extracellular spilling of lysosomal enzymes. This alters extracellular matrix composition, depletes heparan sulfate, impairs astrocyte and oligodendrocyte function, and causes cystic white matter degeneration at the site of highest gene expression. The AAVance trial results will reveal the potential benefit-risk ratio of this therapy.
Subject(s)
Brain , Mucopolysaccharidosis III , Child , Humans , Brain/pathology , Genetic Therapy/methods , Mucopolysaccharidosis III/genetics , Mucopolysaccharidosis III/therapy , Mucopolysaccharidosis III/pathology , Immunohistochemistry , Heparitin Sulfate/metabolism , Heparitin Sulfate/therapeutic useABSTRACT
Acid-ß-glucosidase (GCase, EC3.2.1.45), the lysosomal enzyme which hydrolyzes the simple glycosphingolipid, glucosylceramide (GlcCer), is encoded by the GBA1 gene. Biallelic mutations in GBA1 cause the human inherited metabolic disorder, Gaucher disease (GD), in which GlcCer accumulates, while heterozygous GBA1 mutations are the highest genetic risk factor for Parkinson's disease (PD). Recombinant GCase (e.g., Cerezyme® ) is produced for use in enzyme replacement therapy for GD and is largely successful in relieving disease symptoms, except for the neurological symptoms observed in a subset of patients. As a first step toward developing an alternative to the recombinant human enzymes used to treat GD, we applied the PROSS stability-design algorithm to generate GCase variants with enhanced stability. One of the designs, containing 55 mutations compared to wild-type human GCase, exhibits improved secretion and thermal stability. Furthermore, the design has higher enzymatic activity than the clinically used human enzyme when incorporated into an AAV vector, resulting in a larger decrease in the accumulation of lipid substrates in cultured cells. Based on stability-design calculations, we also developed a machine learning-based approach to distinguish benign from deleterious (i.e., disease-causing) GBA1 mutations. This approach gave remarkably accurate predictions of the enzymatic activity of single-nucleotide polymorphisms in the GBA1 gene that are not currently associated with GD or PD. This latter approach could be applied to other diseases to determine risk factors in patients carrying rare mutations.
Subject(s)
Cellulases , Gaucher Disease , Parkinson Disease , Humans , Gaucher Disease/drug therapy , Gaucher Disease/genetics , Parkinson Disease/genetics , Heterozygote , Mutation , Cellulases/geneticsABSTRACT
GM1 gangliosidosis is a rare, inherited neurodegenerative disorder caused by mutations in the GLB1 gene, which encodes the lysosomal hydrolase acid ß-galactosidase (ß-gal). ß-gal deficiency leads to toxic accumulation of GM1 ganglioside, predominantly in the central nervous system (CNS), resulting in progressive neurodegeneration. LYS-GM101 is an AAVrh.10-based gene therapy vector carrying the human GLB1 cDNA. The efficacy of intra-cerebrospinal fluid injection of LYS-GM101 analogs was demonstrated in GM1 mouse and cat models with widespread diffusion of ß-gal and correction of GM1 ganglioside accumulation in the CNS without observable adverse effects. Clinical dose selection was performed, based on a good-laboratory-practice study, in nonhuman primates (NHPs) using the clinical LYS-GM101 vector. A broadly distributed increase of ß-gal activity was observed in NHP brain 3 months after intra-cisterna magna injection of LYS-GM101 at 1.0 × 1012 vg/mL CSF and 4.0 × 1012 vg/mL CSF, with 20% and 60% increases compared with vehicle-treated animals, respectively. Histopathologic examination revealed asymptomatic adverse changes in the sensory pathways of the spinal cord and dorsal root ganglia in both sexes and at both doses. Taken as a whole, these pre-clinical data support the initiation of a clinical study with LYS-GM101 for the treatment of GM1 gangliosidosis.
ABSTRACT
Fragile X syndrome (FXS) is the most frequent form of familial intellectual disability. FXS results from the lack of the RNA-binding protein FMRP and is associated with the deregulation of signaling pathways downstream of mGluRI receptors and upstream of mRNA translation. We previously found that diacylglycerol kinase kappa (DGKk), a main mRNA target of FMRP in cortical neurons and a master regulator of lipid signaling, is downregulated in the absence of FMRP in the brain of Fmr1-KO mouse model. Here we show that adeno-associated viral vector delivery of a modified and FMRP-independent form of DGKk corrects abnormal cerebral diacylglycerol/phosphatidic acid homeostasis and FXS-relevant behavioral phenotypes in the Fmr1-KO mouse. Our data suggest that DGKk is an important factor in FXS pathogenesis and provide preclinical proof of concept that its replacement could be a viable therapeutic strategy in FXS.
Subject(s)
Fragile X Syndrome , Animals , Diacylglycerol Kinase/genetics , Diacylglycerol Kinase/metabolism , Disease Models, Animal , Fragile X Mental Retardation Protein/genetics , Fragile X Mental Retardation Protein/metabolism , Fragile X Syndrome/genetics , Fragile X Syndrome/metabolism , Fragile X Syndrome/therapy , Mice , Mice, KnockoutABSTRACT
Ciliary neurotrophic factor (CNTF) is a neurotrophic cytokine able to induce appetite reduction, weight loss and antidiabetic effects. However, its susceptibility to neutralizing anti-CNTF antibodies in patients hampered its use for treatment of human obesity and diabetes. In addition, CNTF has a very short plasma half-life, which limits its use as a therapeutic agent. Solutions, directed to prolong its in vivo effects, vary from the implantation of encapsulated secreting cells to identification of more active variants or chemical modification of the protein itself. PEGylation is a widely used modification for shielding proteins from circulating antibodies and for increasing their plasma half-life. Here, we have selected DH-CNTF, a CNTF variant which has a 40-fold higher affinity for the CNTF receptor α accompanied by an increased activity in cellular assays. The PEGylated DH-CNTF retained the biological activity of native protein in vitro and showed a significant improvement of pharmacokinetic parameters. In an acute model of glucose tolerance, the PEG-DH-CNTF was able to reduce the glycemia in diet-induced obese animals, with a performance equaled by a 10-fold higher dose of DH-CNTF. In addition, the PEGylated DH-CNTF analog demonstrated a more potent weight loss effect than the unmodified protein, opening to the use of CNTF as weight reducing agent with treatment regimens that can better meet patient compliance thanks to reduced dosing schedules.
Subject(s)
Ciliary Neurotrophic Factor , Obesity , Animals , Ciliary Neurotrophic Factor/pharmacology , Diet , Humans , Mice , Mice, Obese , Obesity/drug therapy , Obesity/etiology , Polyethylene Glycols/pharmacology , Proteins , Receptor, Ciliary Neurotrophic Factor/metabolism , Weight LossABSTRACT
Patients with mucopolysaccharidosis type IIIA (MPS IIIA) lack the lysosomal enzyme sulfamidase (SGSH), which is responsible for the degradation of heparan sulfate (HS). Build-up of undegraded HS results in severe progressive neurodegeneration for which there is currently no treatment. The ability of the vector adeno-associated virus (AAV)rh.10-CAG-SGSH (LYS-SAF302) to correct disease pathology was evaluated in a mouse model for MPS IIIA. LYS-SAF302 was administered to 5-week-old MPS IIIA mice at three different doses (8.6E+08, 4.1E+10, and 9.0E+10 vector genomes [vg]/animal) injected into the caudate putamen/striatum and thalamus. LYS-SAF302 was able to dose-dependently correct or significantly reduce HS storage, secondary accumulation of GM2 and GM3 gangliosides, ubiquitin-reactive axonal spheroid lesions, lysosomal expansion, and neuroinflammation at 12 weeks and 25 weeks post-dosing. To study SGSH distribution in the brain of large animals, LYS-SAF302 was injected into the subcortical white matter of dogs (1.0E+12 or 2.0E+12 vg/animal) and cynomolgus monkeys (7.2E+11 vg/animal). Increases of SGSH enzyme activity of at least 20% above endogenous levels were detected in 78% (dogs 4 weeks after injection) and 97% (monkeys 6 weeks after injection) of the total brain volume. Taken together, these data validate intraparenchymal AAV administration as a promising method to achieve widespread enzyme distribution and correction of disease pathology in MPS IIIA.
ABSTRACT
BACKGROUND: Pridopidine, in development for Huntington's disease, may modulate aberrant l-dopa-induced effects including l-dopa-induced dyskinesia (LID). OBJECTIVE: This study investigated whether pridopidine could reduce LID in the MPTP macaque model of Parkinson's disease and characterized the observed behavioral effects in terms of receptor occupancy. METHODS: The pharmacokinetic profile and effects of pridopidine (15-30 mg/kg) on parkinsonism, dyskinesia, and quality of on-time, in combination with l-dopa, were assessed in MPTP macaques with LID. Pridopidine receptor occupancy was estimated using known in vitro binding affinities to σ1 and dopamine D2 receptors, in vivo PET imaging, and pharmacokinetic profiling across different species. RESULTS: Pridopidine produced a dose-dependent reduction in dyskinesia (up to 71%, 30 mg/kg) and decreased the duration of on-time with disabling dyskinesia evoked by l-dopa by 37% (20 mg/kg) and 60% (30 mg/kg). Pridopidine did not compromise the anti-parkinsonian benefit of l-dopa. Plasma exposures following the ineffective dose (15 mg/kg) were associated with full σ1 occupancy (>80%), suggesting that σ1 engagement alone is unlikely to account for the antidyskinetic benefits of pridopidine. Exposures following effective doses (20-30 mg/kg), while providing full σ1 occupancy, provide only modest dopamine D2 occupancy (<40%). However, effective pridopidine doses clearly engage a range of receptors (including adrenergic-α2C , dopamine-D3 , and serotoninergic-5-HT1A sites) to a higher degree than D2 and might contribute to the antidyskinetic actions. CONCLUSIONS: In MPTP macaques, pridopidine produced a significant decrease in LID without compromising the antiparkinsonian benefit of l-dopa. Although the actions of pridopidine were associated with full σ1 occupancy, effective exposures are more likely associated with occupancy of additional, non-sigma receptors. This complex pharmacology may underlie the effectiveness of pridopidine against LID. © 2018 International Parkinson and Movement Disorder Society.
Subject(s)
Antiparkinson Agents/adverse effects , Dyskinesia, Drug-Induced/drug therapy , Levodopa/adverse effects , MPTP Poisoning/drug therapy , Movement/drug effects , Parkinsonian Disorders/drug therapy , Piperidines/pharmacology , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine , Animals , Brain/diagnostic imaging , Brain/metabolism , Dyskinesia, Drug-Induced/etiology , Macaca fascicularis , Parkinsonian Disorders/chemically induced , Positron-Emission Tomography , Receptor, Muscarinic M2/metabolism , Receptor, Serotonin, 5-HT1A/metabolism , Receptor, Serotonin, 5-HT2A/metabolism , Receptors, Adrenergic, alpha-2/metabolism , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Receptors, Histamine H3/metabolism , Receptors, sigma/metabolism , Sigma-1 ReceptorABSTRACT
Multiple sclerosis (MS) is a chronic, progressive, disabling disorder characterized by immune-mediated demyelination, inflammation, and neurodegenerative tissue damage in the central nervous system (CNS), associated with frequent exacerbations and remissions of neurologic symptoms and eventual permanent neurologic disability. While there are several MS therapies that are successful in reducing MS relapses, none have been effective in treating all patients. The specific response of an individual patient to any one of the MS therapies remains largely unpredictable, and physicians and patients are forced to use a trial and error approach when deciding on treatment regimens. A priori markers to predict the optimal benefit-to-risk profile of an individual MS patient would greatly facilitate the decision-making process, thereby helping the patient receive the most optimal treatment early on in the disease process. Pharmacogenomic methods evaluate how a person's genetic and genomic makeup affects their response to therapeutics. This review focuses on how pharmacogenomics studies are being used to identify biologically relevant differences in MS treatments and provide characterization of the predictive clinical response patterns. As pharmacogenomics research is dependent on the availability of longitudinal clinical research, studies concerning glatiramer acetate and the interferon beta products which have the majority of published long term data to date are described in detail. These studies have provided considerable insight in the prognostic markers associated with MS disease and potential predictive markers of safety and beneficial response.
Subject(s)
Biomedical Research/trends , Multiple Sclerosis/drug therapy , Multiple Sclerosis/genetics , Pharmacogenetics/trends , Pharmacogenomic Testing/trends , Precision Medicine/trends , Evidence-Based Medicine/trends , Humans , Treatment OutcomeABSTRACT
Laquinimod is an oral drug currently being evaluated for the treatment of relapsing, remitting, and primary progressive multiple sclerosis and Huntington's disease. Laquinimod exerts beneficial activities on both the peripheral immune system and the CNS with distinctive changes in CNS resident cell populations, especially astrocytes and microglia. Analysis of genome-wide expression data revealed activation of the aryl hydrocarbon receptor (AhR) pathway in laquinimod-treated mice. The AhR pathway modulates the differentiation and function of several cell populations, many of which play an important role in neuroinflammation. We therefore tested the consequences of AhR activation in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) using AhR knockout mice. We demonstrate that the pronounced effect of laquinimod on clinical score, CNS inflammation, and demyelination in EAE was abolished in AhR-/- mice. Furthermore, using bone marrow chimeras we show that deletion of AhR in the immune system fully abrogates, whereas deletion within the CNS partially abrogates the effect of laquinimod in EAE. These data strongly support the idea that AhR is necessary for the efficacy of laquinimod in EAE and that laquinimod may represent a first-in-class drug targeting AhR for the treatment of multiple sclerosis and other neurodegenerative diseases.
Subject(s)
Encephalomyelitis, Autoimmune, Experimental/etiology , Encephalomyelitis, Autoimmune, Experimental/metabolism , Quinolones/pharmacology , Receptors, Aryl Hydrocarbon/agonists , Receptors, Aryl Hydrocarbon/metabolism , Animals , Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP1A1/metabolism , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Gene Deletion , Gene Expression , Gene Expression Profiling , Gene Expression Regulation/drug effects , Hepatocytes/metabolism , Humans , Immune System/immunology , Immune System/metabolism , Mice , Mice, Knockout , Receptors, Aryl Hydrocarbon/genetics , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , TranscriptomeABSTRACT
Pridopidine has demonstrated improvement in Huntington Disease (HD) motor symptoms as measured by secondary endpoints in clinical trials. Originally described as a dopamine stabilizer, this mechanism is insufficient to explain the clinical and preclinical effects of pridopidine. This study therefore explored pridopidine's potential mechanisms of action. The effect of pridopidine versus sham treatment on genome-wide expression profiling in the rat striatum was analysed and compared to the pathological expression profile in Q175 knock-in (Q175 KI) vs Q25 WT mouse models. A broad, unbiased pathway analysis was conducted, followed by testing the enrichment of relevant pathways. Pridopidine upregulated the BDNF pathway (P = 1.73E-10), and its effect on BDNF secretion was sigma 1 receptor (S1R) dependent. Many of the same genes were independently found to be downregulated in Q175 KI mice compared to WT (5.2e-7 < P < 0.04). In addition, pridopidine treatment upregulated the glucocorticoid receptor (GR) response, D1R-associated genes and the AKT/PI3K pathway (P = 1E-10, P = 0.001, P = 0.004, respectively). Pridopidine upregulates expression of BDNF, D1R, GR and AKT/PI3K pathways, known to promote neuronal plasticity and survival, as well as reported to demonstrate therapeutic benefit in HD animal models. Activation of S1R, necessary for its effect on the BDNF pathway, represents a core component of the mode of action of pridopidine. Since the newly identified pathways are downregulated in neurodegenerative diseases, including HD, these findings suggest that pridopidine may exert neuroprotective effects beyond its role in alleviating some symptoms of HD.
Subject(s)
Brain-Derived Neurotrophic Factor/biosynthesis , Corpus Striatum/metabolism , Huntington Disease/drug therapy , Neuroprotective Agents/administration & dosage , Piperidines/administration & dosage , Animals , Brain-Derived Neurotrophic Factor/genetics , Corpus Striatum/drug effects , Corpus Striatum/pathology , Disease Models, Animal , Gene Expression Regulation/genetics , Genome , Humans , Huntington Disease/genetics , Huntington Disease/pathology , Mice , Neuroprotective Agents/metabolism , Rats , Receptors, Dopamine D5/biosynthesis , Receptors, Dopamine D5/genetics , Receptors, Glucocorticoid/biosynthesis , Receptors, Glucocorticoid/genetics , Signal Transduction/drug effectsABSTRACT
The identification of a new series of P. falciparum growth inhibitors is described. Starting from a series of known human class I HDAC inhibitors a SAR exploration based on growth inhibitory activity in parasite and human cells-based assays led to the identification of compounds with submicromolar inhibition of P. falciparum growth (EC50 < 500 nM) and good selectivity over the activity of human HDAC in cells (up to >50-fold). Inhibition of parasital HDACs as the mechanism of action of this new class of selective growth inhibitors is supported by hyperacetylation studies.
ABSTRACT
Neuromedin U (NMU) is an endogenous peptide implicated in the regulation of feeding, energy homeostasis, and glycemic control, which is being considered for the therapy of obesity and diabetes. A key liability of NMU as a therapeutic is its very short half-life in vivo. We show here that conjugation of NMU to human serum albumin (HSA) yields a compound with long circulatory half-life, which maintains full potency at both the peripheral and central NMU receptors. Initial attempts to conjugate NMU via the prevalent strategy of reacting a maleimide derivative of the peptide with the free thiol of Cys34 of HSA met with limited success, because the resulting conjugate was unstable in vivo. Use of a haloacetyl derivative of the peptide led instead to the formation of a metabolically stable conjugate. HSA-NMU displayed long-lasting, potent anorectic, and glucose-normalizing activity. When compared side by side with a previously described PEG conjugate, HSA-NMU proved superior on a molar basis. Collectively, our results reinforce the notion that NMU-based therapeutics are promising candidates for the treatment of obesity and diabetes.
Subject(s)
Anti-Obesity Agents/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Neuropeptides/chemical synthesis , Neuropeptides/pharmacology , Polyethylene Glycols/pharmacology , Serum Albumin/chemical synthesis , Animals , Anti-Obesity Agents/pharmacokinetics , Anti-Obesity Agents/pharmacology , Blood Glucose , Cell Line , Drug Evaluation, Preclinical , Humans , Hypoglycemic Agents/pharmacokinetics , Hypoglycemic Agents/pharmacology , Male , Mice , Mice, Inbred C57BL , Neuropeptides/pharmacokinetics , Polyethylene Glycols/pharmacokinetics , Receptors, Neurotransmitter/agonists , Serum Albumin/pharmacokinetics , Serum Albumin/pharmacology , Serum Albumin, Human , Weight Loss/drug effectsABSTRACT
Neuromedin U (NMU) is an endogenous peptide, whose role in the regulation of feeding and energy homeostasis is well documented. Two NMU receptors have been identified: NMUR1, expressed primarily in the periphery, and NMUR2, expressed predominantly in the brain. We recently demonstrated that acute peripheral administration of NMU exerts potent but acute anorectic activity and can improve glucose homeostasis, with both actions mediated by NMUR1. Here, we describe the development of a metabolically stable analog of NMU, based on derivatization of the native peptide with high molecular weight poly(ethylene) glycol (PEG) ('PEGylation'). PEG size, site of attachment, and conjugation chemistry were optimized, to yield an analog which displays robust and long-lasting anorectic activity and significant glucose-lowering activity in vivo. Studies in NMU receptor-deficient mice showed that PEG-NMU displays an expanded pharmacological profile, with the ability to engage NMUR2 in addition to NMUR1. In light of these data, PEGylated derivatives of NMU represent promising candidates for the treatment of obesity and diabetes.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Neuropeptides/pharmacology , Obesity/drug therapy , Polyethylene Glycols/chemistry , Receptors, Neurotransmitter/agonists , Animals , Dose-Response Relationship, Drug , Glucose Tolerance Test , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neuropeptides/administration & dosage , Neuropeptides/chemical synthesis , Polyethylene Glycols/administration & dosage , Polyethylene Glycols/chemical synthesis , Polyethylene Glycols/pharmacology , Receptors, Neurotransmitter/deficiency , Structure-Activity RelationshipABSTRACT
Infections caused by hepatitis C virus (HCV) are a significant world health problem for which novel therapies are in urgent demand. The polymerase of HCV is responsible for the replication of viral genome and has been a prime target for drug discovery efforts. Here, we report on the further development of tetracyclic indole inhibitors, binding to an allosteric site on the thumb domain. Structure-activity relationship (SAR) studies around an indolo-benzoxazocine scaffold led to the identification of compound 33 (MK-3281), an inhibitor with good potency in the HCV subgenomic replication assay and attractive molecular properties suitable for a clinical candidate. The compound caused a consistent decrease in viremia in vivo using the chimeric mouse model of HCV infection.
Subject(s)
Antiviral Agents/chemical synthesis , Hepacivirus/drug effects , Indoles/chemical synthesis , Oxazocines/chemical synthesis , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Animals , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Biological Availability , Cell Line, Tumor , Crystallography, X-Ray , Dogs , Hepacivirus/enzymology , Hepacivirus/physiology , Humans , Indoles/pharmacokinetics , Indoles/pharmacology , Macaca mulatta , Mice , Mice, SCID , Mice, Transgenic , Models, Molecular , Molecular Structure , Oxazocines/pharmacokinetics , Oxazocines/pharmacology , Rats , Rats, Sprague-Dawley , Stereoisomerism , Structure-Activity Relationship , Viremia/drug therapy , Viremia/virology , Virus Replication/drug effectsABSTRACT
The purpose of this study was to investigate the in vivo absorption enhancement of a nucleoside (phosphoramidate prodrug of 2'-methyl-cytidine) anti-viral agent of proven efficacy by means of intestinal permeation enhancers. Natural nucleosides are hydrophilic molecules that do not rapidly penetrate cell membranes by diffusion and their absorption relies on specialized transporters. Therefore, the oral absorption of nucleoside prodrugs and the target organ concentration of the biologically active nucleotide can be limited due to poor permeation across the intestinal epithelium. In the present study, the specificity, concentration dependence, and effect of four classes of absorption promoters, i.e. fatty acids, steroidal detergents, mucoadhesive polymers, and secretory transport inhibitors, were evaluated in a rat in vivo model. Sodium caprate and alpha-tocopheryl-polyethyleneglycol-1000-succinate (TPGS) showed a significant effect in increasing liver concentration of nucleotide (5-fold). These results suggested that both excipients might be suited in a controlled release matrix for the synchronous release of the drug and absorption promoter directly to the site of absorption and highlights that the effect is strictly dependent on the absorption promoter dose. The feasibility of such a formulation approach in humans was evaluated with the aim of developing a solid dosage form for the peroral delivery of nucleosides and showed that these excipients do provide a potential valuable tool in pre-clinical efficacy studies to drive discovery programs forward.
Subject(s)
Cytidine/analogs & derivatives , Intestinal Absorption/drug effects , Intestinal Absorption/physiology , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Animals , Caco-2 Cells , Cytidine/chemistry , Cytidine/pharmacokinetics , Drug Synergism , Humans , Male , Mice , Mice, Knockout , Rats , Rats, Sprague-DawleyABSTRACT
5-Aryl-2-(trifluoroacetyl)thiophenes were identified as a new series of class II HDAC inhibitors (HDACi). Further development of this new series led to compounds such as 6h, a potent inhibitor of HDAC4 and HDAC6 (HDAC4 WT IC(50) = 310 nM, HDAC6 IC(50) = 70 nM) that displays 40-fold selectivity over HDAC1 and improved stability in HCT116 cancer cells (t(1/2) = 11 h). Compounds 6h and 2 show inhibition of alpha-tubulin deacetylation in HCT116 cells at 1 microM concentration and antiproliferation effects only at concentrations where inhibition of histone H3 deacetylation is observed.
Subject(s)
Antineoplastic Agents/chemical synthesis , Histone Deacetylase 2/antagonists & inhibitors , Repressor Proteins/antagonists & inhibitors , Thiophenes/chemical synthesis , Acetylation , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Histone Deacetylase 1/antagonists & inhibitors , Histone Deacetylase 6 , Histone Deacetylases/metabolism , Histones/metabolism , Humans , Isoenzymes/antagonists & inhibitors , Structure-Activity Relationship , Thiophenes/chemistry , Thiophenes/pharmacology , Tubulin/metabolismABSTRACT
The application of a phosphoramidate prodrug approach to 2'-C-methylcytidine (NM107), the first nucleoside inhibitor of the hepatitis C virus (HCV) NS5B polymerase, is reported. 2'-C-Methylcytidine, as its valyl ester prodrug (NM283), was efficacious in reducing the viral load in patients infected with HCV. Several of the phosphoramidates prepared demonstrated a 10- to 200-fold superior potency with respect to the parent nucleoside in the cell-based replicon assay. This is due to higher levels of 2'-C-methylcytidine triphosphate in the cells. These prodrugs are efficiently activated and converted to the triphosphate in hepatocytes of several species. Our SAR studies ultimately led to compounds that gave high levels of NTP in hamster and rat liver after subcutaneous dosing and that were devoid of the toxic phenol moiety usually found in ProTides.
Subject(s)
Amides/metabolism , Amides/therapeutic use , Antiviral Agents/metabolism , Cytidine/analogs & derivatives , Hepatitis C/drug therapy , Phosphoric Acids/metabolism , Phosphoric Acids/therapeutic use , Prodrugs/metabolism , Prodrugs/therapeutic use , Amides/pharmacology , Amides/toxicity , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Antiviral Agents/toxicity , Cell Line , Cytidine/metabolism , Cytidine/pharmacology , Cytidine/therapeutic use , Cytidine/toxicity , Hepacivirus/drug effects , Hepacivirus/physiology , Hepatocytes/drug effects , Hepatocytes/metabolism , Hepatocytes/virology , Humans , Phosphoric Acids/pharmacology , Phosphoric Acids/toxicity , Polyphosphates/metabolism , Prodrugs/pharmacology , Prodrugs/toxicity , Structure-Activity Relationship , Virus Replication/drug effectsABSTRACT
The currently approved treatment for hepatitis C virus infections is a combination of Ribavirin and pegylated Interferon. It leads to a sustained virologic response in approximately only half of the patients treated. For this reason there is an urgent need of new therapeutic agents. 2'-C-Methylcytidine is the first nucleoside inhibitor of the HCV NS5B polymerase that was efficacious in reducing the viral load in patients infected with HCV. The application of a monophosphate prodrug approach based on unprecedented cyclic phosphoramidates is reported. Our SAR studies led to compounds that are efficiently converted to the active triphosphate in human hepatocytes.
Subject(s)
Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Cytidine/analogs & derivatives , Hepacivirus/drug effects , Hepatitis C/drug therapy , Prodrugs/pharmacology , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/chemistry , Cricetinae , Cytidine/administration & dosage , Cytidine/chemistry , Cytidine/metabolism , Cytidine/pharmacology , Drug Stability , Hepatocytes/virology , Humans , Prodrugs/administration & dosage , Prodrugs/chemistry , Prodrugs/metabolism , Structure-Activity RelationshipABSTRACT
A variety of new prodrugs of 2'-methyl cytidine based on acyloxy ethylamino phosphoramidates have been synthesized and tested in vitro and in vivo for their biological activity. Compared with the parent drug a 10- to 20-fold increase in formation of nucleotide triphosphate in rat and human hepatocytes could be achieved.
Subject(s)
Amides/chemical synthesis , Cytidine/analogs & derivatives , Cytidine/chemical synthesis , Phosphoric Acids/chemical synthesis , Prodrugs/chemical synthesis , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Amides/pharmacology , Animals , Cells, Cultured , Cytidine/pharmacology , Dogs , Drug Evaluation, Preclinical/methods , Hepacivirus/drug effects , Hepacivirus/enzymology , Hepatocytes/drug effects , Hepatocytes/enzymology , Hepatocytes/virology , Humans , Phosphoric Acids/pharmacology , Prodrugs/pharmacology , RNA-Dependent RNA Polymerase/metabolism , Rabbits , Rats , Viral Nonstructural Proteins/metabolismABSTRACT
Human HIV integrase inhibitors are a novel class of antiretroviral drugs that act by blocking incorporation of the proviral DNA into the host cell genome, a crucial step in the life cycle of HIV. In the present work, quantitative methods for prediction of human pharmacokinetics were used to guide the selection of development candidates from a series of dihydroxypyrimidine and N-methylpyrimidinone carboxamide inhibitors of HIV integrase, which are cleared mainly by O-glucuronidation. The pharmacokinetics of 10 drugs from this series was determined in several preclinical species, including rats, dogs, rhesus monkeys, and rabbits, and the in vitro turnover, plasma protein binding, and blood/plasma partition ratio were studied using preparations from both preclinical species and humans. Two clearance prediction methods, based on physiologically based scaling or allometric scaling normalized for differences in microsomal turnover, were used to extrapolate human clearance. For three clinical candidates, including the novel AIDS drug raltegravir (MK-0518, Isentress), oral drug exposure was predicted and compared with that observed in healthy human volunteers. Both scaling methods gave a reasonable correspondence between predicted and observed oral exposure. Prediction errors for the physiologically based method were less than 1.7-fold for two drugs, including raltegravir, and less than 3.5-fold for one drug. The exposures predicted using normalized allometric scaling were within 1.1- to 1.5-fold of observed values for all three compounds. The accuracy of prediction by normalized allometric scaling was similar when using data from either four preclinical species or from rats and dogs only. The prediction methods used may be applicable to other drugs cleared predominantly by glucuronidation.