In vitro studies in human liver microsomes showed that sofosbuvir was an efficient substrate for Cathepsin A (Cat A) and carboxyl esterase 1 (CES1). There were no indications of metabolism via urdine diphosphate glucuronosyltransferases (UGTs) or flavin-containing monooxygenase (FMO). Sofosbuvir was cleaved by CatA and CES1 and subsequent activation steps included amino acid removal by histidine triad nucleotide-binding protein 1 (HINT1) and phosphorylation by uridine monophosphate-cytidine monophosphate (UMP-CMP) kinase and nucleoside diphosphate (NDP) kinase. In vitro data indicated that Cat A preferentially hydrolysed sofosbuvir (the S-diastereomer) while CES1 did not exhibit stereoselectivity. This would be consistent with studies using GS-9851 showing a less efficient metabolism to the triphosphate in the hepatically-derived cell line containing the Clone A replicon and shown to exhibit low CES 1 activity, but high Cat A activity compared with primary human hepatocytes. Following incubation of hepatocytes from rat, dog, monkey and human GS-9851 was converted to the triphosphate GS-461203 in all species, most efficiently in human. Sofosbuvir was also readily converted to the triphosphate in dog liver after oral doses and was the dominant metabolite at all time points assessed with a long half-life of approx. 18 hours. The active metabolite GS-461203 could not be detected in monkey. Further while GS-461203 was detected in rat liver, it could not be measured in liver from mouse.
Sofosbuvir is extensively metabolized in the liver to form the pharmacologically active nucleoside analog triphosphate GS-461203. The metabolic activation pathway involves sequential hydrolysis of the carboxyl ester moiety catalyzed by human cathepsin A (CatA) or carboxylesterase 1 (CES1) and phosphoramidate cleavage by histidine triad nucleotide-binding protein 1 (HINT1) followed by phosphorylation by the pyrimidine nucleotide biosynthesis pathway. Dephosphorylation results in the formation of nucleoside metabolite GS-331007 that cannot be efficiently rephosphorylated and lacks anti-HCV activity in vitro.
GS-331007 and GS-566500 were detected in all species with GS-331007 being the major drug related material in all species and all matrices. In plasma, urine and feces of all species administered sofosbuvir the primary metabolite detected was GS-331007 accounting for >80% of total exposure. In rat liver and plasma GS-566500 was also detected. The metabolite profile was overall comparable between non-pregnant, pregnant and postpartum rats and in milk of postpartum rats with GS-331007 and 2 sulfate conjugates of GS-331007 being the major metabolites.
In dog following a single oral dose of 20 mg/kg of sofosbuvir three metabolites in plasma were identified, GS-331007, GS-566500 and M4 (proposed glucuronidation product of GS-606965), accounting for 93.4%, 1.6% and 0.5%, respectively of total plasma AUC. Parent compound amounted to 4.5%. In dog (and mouse) the majority of a radioactive dose was recovered in urine within 8 to 12 hours.
IDENTIFICATION AND USE: Sofosbuvir is a white to off-white crystalline solid. Sofosbuvir is a direct-acting antiviral agent (pan-genotypic polymerase inhibitor) against the hepatitis C virus. It is used in conjunction with other antiviral agents for the treatment of chronic hepatitis C virus (HCV) genotype 1, 2, 3, or 4 infections in adults, including those with hepatocellular carcinoma awaiting liver transplantation and those with human immunodeficiency virus (HIV) co-infection. Sofosbuvir must be used as part of a multiple-drug regimen and should not be used alone for the treatment of chronic HCV infection. HUMAN EXPOSURE AND TOXICITY: The highest documented dose of sofosbuvir was a single supratherapeutic dose of sofosbuvir 1200 mg administered to 59 healthy subjects. There were no untoward effects observed at this dose level, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups. Sofosbuvir did not induce chromosome aberration using human peripheral blood lymphocytes. ANIMAL STUDIES: Single dose toxicity study was performed with GS-9851/PSI-7851 (the diastereomeric mixture) in rats. No mortality, clinical signs, body weight changes, macroscopic pathology, or organ weight changes for liver and kidney up to a highest dose of 1,800 mg/kg. Sofosbuvir or GS-9851, a 1:1 diastereomeric mixture of sofosbuvir and its stereoisomer, were evaluated in repeat-dose oral toxicity studies up to 13 weeks in mice, 26 weeks in rats, and 39 weeks in dogs. The primary target organs identified were the cardiovascular, hepatobiliary, gastrointestinal (GI) and hematopoietic (erythroid) systems. In the 7-day toxicity studies with GS-9851 doses of 2000 mg/kg/day in the rat and 1500 mg/kg/day in the dog resulted (but were not limited to) in increased mucus secretions in the stomach, glycogen depletion, and increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin, with associated histopathologic liver findings in dogs; and heart adverse effects in rats (e.g., multifocal cardiac myofiber degeneration) and dogs (e.g., increased QT/QTc intervals). Findings in the liver and heart were not observed in long-term studies with GS-9851 or sofosbuvir. In chronic toxicity studies in rats (26 weeks) and dogs (39 weeks), effects included (but were not limited to) GI-related clinical signs (e.g., soft feces and emesis) and a decrease (e.g., approximately 10%) in mean red cell indices that were observed mainly in the high-dose group of dogs. Sofosbuvir had no effects on embryo-fetal viability or on fertility when evaluated in rats. No teratogenic effects were observed in rat and rabbit developmental toxicity studies with sofosbuvir. It had no adverse effects on behavior, reproduction, or development of the offspring in the rat pre- and post-natal development study. At the highest dose tested, exposure to the predominant circulating metabolite GS-331007 was at least 8-fold the exposure in humans at the recommended clinical dose. Fertility was normal in the offspring of rats exposed daily from before birth (in utero) through lactation day 20 at daily GS-331007 exposures (AUC) of approximately 12-fold higher than human exposures at the recommended clinical dose. Two-year carcinogenicity studies in mice and rats were conducted with sofosbuvir. Mice were administered doses of up to 200 mg/kg/day in males and 600 mg/kg/day in females, while rats were administered doses of up to 750 mg/kg/day in males and females. No increase in the incidence of drug-related neoplasms were observed at the highest doses tested in mice and rats, resulting in AUC exposure to the predominant circulating metabolite GS-331007 of approximately 7- and 30-fold (in mice) and 13- and 17-fold (in rats), in males and females respectively, the exposure in humans at the recommended clinical dose. Sofosbuvir was not genotoxic in a battery of in vitro or in vivo assays, including bacterial mutagenicity, and in vivo mouse micronucleus assays.
In large randomized controlled trials, serum enzymes elevations were uncommon in patients treated with sofosbuvir despite the fact that the patients being treated had chronic liver disease. In most situations, serum aminotransferase levels improved rapidly upon initiating sofosbuvir therapy, and de novo, late elevations of ALT above 3 times the upper limit of normal (ULN) were uncommon and less frequent than with placebo or no therapy. In multiple, large clinical trials sofosbuvir has not been linked to instances of clinically apparent liver injury with jaundice. Because sofosbuvir is always used with other antiviral agents, it is not always possible to separate the relative role of sofosbuvir from other drugs in causing adverse reactions.
Two rare and unusual forms of liver injury of uncertain relationship to sofosbuvir have been described in patients with receiving antiviral therapy for hepatitis C: sudden hepatic decompensation in patients with preexisting cirrhosis and reactivation of hepatitis B in patients with preexisting evidence of HBV infection.
A rare, but striking liver injury associated with sofosbuvir (and perhaps other potent agents active against HCV) is hepatic decompensation occurring in patients with preexisting cirrhosis. In several instances, decompensation occurred within 2 to 6 weeks of starting therapy (Case 1), while in others it occurred late during therapy or in the immediate posttreatment period. The typical pattern of onset was a progressive rise in bilirubin with signs of hepatic failure such as prolongation of the prothrombin time, decrease in serum albumin and appearance of ascites and hepatic encephalopathy. In many (but not all) instances, serum enzyme levels did not change or increased only slightly in comparison to pretreatment values. In all instances, sofosbuvir was being used in combination with other antiviral agents, such as peginterferon, simeprevir, daclatasvir or ledipasvir, and the specific role of sofosbuvir has been difficult to define. The decompensation usually coincided with rapid viral clearance and patients who survived the episode often had a sustained virological response. The cause of this decompensation is not clear, but it may represent a response to HCV viral eradication (on-target effect) rather than toxicity of the administered antiviral agents (off-target effect on the liver). Alternatively, the injury may be coincidental and unrelated to therapy.
A second form of liver injury that can occur with sofosbuvir therapy and perhaps other potent anti-HCV agents is reactivation of hepatitis B. Instances of clinically apparent hepatitis with rises in serum HBV DNA levels have been reported in patients with chronic hepatitis C who were HBsAg positive and had low levels of HBV DNA which were not thought to be the cause of the chronic liver disease (Case 2). Reactivation has also been described in patients who have anti-HBc without HBsAg in serum, a pattern that suggests previous recovery from hepatitis B. HBV reactivation typically arises within 2 to 8 weeks of starting therapy for hepatitis C and it can be clinically manifest with symptoms of acute hepatitis and marked elevations in serum aminotransferase levels and bilirubin. Instances of death from HBV reactivation have been reported with sofosbuvir therapy. The cause of reactivation is unclear, but it may reflect the eradication of HCV replication which has a nonspecific suppressive effect on HBV replication. Alternatively, the change in immune reactivity with sudden clearance of HCV or as a result of a direct activity of the antiviral agents may alter the replicative status of HBV.
Likelihood score: E* (unproven but suspected cause of clinically apparent liver injury in susceptible individuals).
Concomitant use of rifampin, a potent inducer of P-gp in the intestine, and sofosbuvir may cause decreased plasma concentrations of sofosbuvir and GS-331007 and may lead to decreased therapeutic effect of sofosbuvir. Rifampin and sofosbuvir should not be used concomitantly.
Rifabutin is expected to cause decreased plasma concentrations of sofosbuvir and GS-331007, which may lead to decreased therapeutic effect of sofosbuvir. Concomitant use of rifabutin and sofosbuvir is not recommended.
When used concomitantly with sofosbuvir, certain anticonvulsants (i.e., carbamazepine, oxcarbazepine, phenobarbital, phenytoin) are expected to decrease plasma concentrations of sofosbuvir and GS-331007, which may lead to decreased therapeutic effect of sofosbuvir. Concomitant use of these anticonvulsants and sofosbuvir is not recommended.
Sofosbuvir is approximately 61-65% bound to human plasma proteins and the binding is independent of drug concentration over the range of 1 ug/mL to 20 ug/mL. Protein binding of GS-331007 was minimal in human plasma. After a single 400 mg dose of (14)C-sofosbuvir in healthy subjects, the blood to plasma ratio of (14)C-radioactivity was approximately 0.7.
The pharmacokinetic properties of sofosbuvir and the predominant circulating metabolite GS-331007 have been evaluated in healthy adult subjects and in subjects with chronic hepatitis C. Following oral administration of SOVALDI, sofosbuvir was absorbed with a peak plasma concentration observed at approximately 0.5-2 hour post-dose, regardless of dose level. Peak plasma concentration of GS-331007 was observed between 2 to 4 hours post-dose. Based on population pharmacokinetic analysis in subjects with genotype 1 to 6 HCV infection who were coadministered ribavirin (with or without pegylated interferon), geometric mean steady state AUC0-24 was 969 ng*hr/mL for sofosbuvir (N=838), and 6790 ng*hr/mL for GS-331007 (N=1695), respectively. Relative to healthy subjects administered sofosbuvir alone (N = 272), the sofosbuvir AUC0-24 was 60% higher; and GS-331007 AUC0-24 was 39% lower, respectively, in HCV-infected subjects. Sofosbuvir and GS-331007 AUCs are near dose proportional over the dose range of 200 mg to 1200 mg.
Following a single 400 mg oral dose of (14)C-sofosbuvir, mean total recovery of the dose was greater than 92%, consisting of approximately 80%, 14%, and 2.5% recovered in urine, feces, and expired air, respectively. The majority of the sofosbuvir dose recovered in urine was GS-331007 (78%) while 3.5% was recovered as sofosbuvir. These data indicate that renal clearance is the major elimination pathway for GS-331007.
Studies in pregnant rats showed that sofosbuvir crossed the placenta. Fetal blood and brain sofosbuvir derived radioactivity was higher than in dams, but fetal liver and kidney had lower levels than corresponding organs in dams. Sofosbuvir-derived radioactivity was also quantifiable in milk from day 2 postpartum rats, but nursing pups did not appear to be extensively exposed to drug-derived radioactivity. Milk to plasma ratios were 0.1 at 1 hour and 0.8 at 24 hours.
来源:Hazardous Substances Data Bank (HSDB)
文献信息
Beta-D-2'-DEOXY-2'-alpha-FLUORO-2'-beta-C-SUBSTITUTED-2-MODIFIED-N6-SUBSTITUTED PURINE NUCLEOTIDES FOR HCV TREATMENT
申请人:Atea Pharmaceuticals, Inc.
公开号:US20160257706A1
公开(公告)日:2016-09-08
A compound of the structure:
or a pharmaceutically acceptable salt or composition thereof for the treatment of a host infected with or exposed to an HCV virus or other disorders more fully described herein.
NUCLEOTIDE HEMI-SULFATE SALT FOR THE TREATMENT OF HEPATITIS C VIRUS
申请人:Atea Pharmaceuticals, Inc.
公开号:US20180215776A1
公开(公告)日:2018-08-02
A hemi-sulfate salt of the structure:
to treat a host infected with hepatitis C, as well as pharmaceutical compositions and dosage forms, including solid dosage forms, thereof.
一种半硫酸盐的结构,用于治疗感染丙型肝炎的宿主,以及包括固体剂型在内的药物组合物和剂型。
Highly active compounds against COVID-19
申请人:Atea Pharmaceuticals, Inc.
公开号:US10874687B1
公开(公告)日:2020-12-29
The present invention is the use of a small group of purine nucleotide phosphoramidate disclosed herein or a pharmaceutically acceptable salt thereof in an effective amount for the treatment or prevention of the novel 2019 coronavirus disease (COVID-19) in a host, for example a human, in need thereof.
β-D-2′-deoxy-2′-α-fluoro-2′-β-C-substituted-2-modified-N6-substituted purine nucleotides for HCV treatment
申请人:Atea Pharmaceuticals, Inc.
公开号:US10000523B2
公开(公告)日:2018-06-19
A compound of the structure:
or a pharmaceutically acceptable salt or composition thereof for the treatment of a host infected with or exposed to an HCV virus or other disorders more fully described herein.
β-D-2′-deoxy-2′-α-fluoro-2′β-C-substituted-2-modified-N6-substituted purine nucleotides for HCV treatment
申请人:Atea Pharmaceuticals, Inc.
公开号:US10005811B2
公开(公告)日:2018-06-26
A compound of the structure:
or a pharmaceutically acceptable salt or composition thereof for the treatment of a host infected with or exposed to an HCV virus or other disorders more fully described herein.