HCV NS3/4A protease (Ki = 0.36 nM); HCV replication (EC50 = 7.8 nM); SARS-CoV-2 M^pro (IC50 = 9.6±2.3 μM); SARS-CoV-2 RdRp (IC50 = 5.5±0.2 μM)

Simeprevir has a medium inhibitory concentration (IC50) of less than 13 nM for all HCV NS3/4A enzymes tested, demonstrating strong inhibition on NS3/4A protease of genotypes 1a, 1b, 2, 4, 5, and 6. In contrast, genotype 3 has an IC50 of 37 nM. Also inhibiting the bilirubin transporters OATP1B1 and MRP2 in vitro is simeprevir. When compared to MRP2 (IC50 of about 10,000 nM), which is primarily a conjugated bilirubin transporter, it is a more potent inhibitor of OATP1B1 (IC50=720 nM), which is primarily responsible for transporting unconjugated bilirubin1].

Simeprevir has a rather lengthy in vivo absorption phase; it takes 4-6 hours for the maximum concentration (Cmax) to be reached. 99.9% of it is firmly attached to plasma proteins, primarily albumin. Following a single oral administration, the absolute bioavailability is 44%. Rats with a liver to blood ratio of 29:1 have a well-distributed liver. In preclinical studies, the ratio of liver to plasma concentration is 39 for humans, which is extremely high. With a ratio of 128 in the small intestine, the tissue/plasma AUC ratios are the highest. Plasma concentrations are higher than the EC99 at 8 hours and around the EC50 at 24 hours after dosing, while tissue simeprevir concentrations reach their peak values within 4 hours after dosing.Liver simeprevir concentrations can stay above the EC99 for up to 31 hours after dosing. When simeprevir is given with food, its AUC24h increases by 61%–69%. Thus, it is recommended to take simeprevir with food. Simeprevir is a P-glycoprotein substrate and inhibitor as well. Simeprevir is excreted by the biliary system after being metabolized by CYP3A4. It also inhibits cytochrome 3A4 in the gut, but not CYP3A4 in the liver[1].

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Pharmacology [1]
Absorption[1]
Simeprevir has a relatively long absorption phase, reaching maximum concentration (Cmax) after 4–6 hours. After multiple doses for 5 days, Cmax and area under the plasma concentration-time curve (AUC) after 24 hours (AUC24h) increased more than dose proportionally between 75 mg and 200 mg once daily, suggesting saturation of first-pass metabolism and/or efflux transporters. The AUC 24h for the 200 mg once daily dose group was approximately 10 times higher than that for the 100 mg once daily dose. Steady-state is reached after 7 days of once daily dosing. Exposure to simeprevir in HCV-uninfected subjects with Child–Pugh B and C cirrhosis was 2.4-fold and 5.2-fold higher, respectively, than in HCV uninfected subjects with normal liver function. Plasma Cmax and AUC24h of simeprevir were similar during coadministration of simeprevir with PEG-IFN-α and RBV compared with administration of simeprevir alone. In HCV-infected subjects, the mean steady-state plasma concentration was 1,936 ng/mL, more than 200-fold higher than the EC50 value determined in previous in vitro studies. While plasma exposure dropped to around the EC50 at 24 hours postdosing, the liver concentration remained above the replicon 99% effective concentration (EC99) for up to 31 hours postdosing, thus suggesting the feasibility of once-daily dosing. Moreover, in a Phase I study, it was shown that simeprevir exposure was higher in healthy Japanese volunteers than in Caucasian volunteers. In Phase III trials, mean plasma simeprevir exposure in Asian subjects (n=14) was 3.4-fold higher than in the general population of this trial. The AUC24h of simeprevir was increased by 61%–69% when administered with food; simeprevir should therefore be taken with food. Finally, simeprevir is a substrate and inhibitor of P-glycoprotein.21

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Distribution[1]
Simeprevir is extensively (99.9%) bound to plasma proteins, mainly to albumin. The absolute bioavailability was 44% after a single oral administration. Transport into human hepatocytes is thought to be mediated by OATP1B1/3. In rats, a liver to blood ratio of 29:1 was found, which would mean good distribution to the liver. For humans, in preclinical studies, the liver to plasma concentration ratio was high (ratio of 39). The highest tissue/plasma AUC ratios were observed in the small intestine (ratio of 128). While tissue simeprevir concentrations reached peak values within 4 hours postdosing, simeprevir concentrations in liver remained above the EC99 for up to 31 hours postdosing, and plasma concentrations were higher than the EC99 at 8 hours and around the EC50 at 24 hours postdosing.

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Metabolism[1]
Simeprevir, like telaprevir and to a lesser extent boceprevir, is metabolized by CYP3A4. It can therefore be the subject of drug–drug interactions with moderate or strong inhibitors and inducers of CYP3A enzymes, with significant increases or decreases in exposure to simeprevir. Unlike boceprevir and telaprevir, simeprevir is an inhibitor of gut cytochrome 3A4 but not hepatic CYP3A4. The effect of a low dose (600 mg) of a potent CYP3A inducer, rifampicin, on the pharmacokinetics of simeprevir was evaluated and showed that the combination of rifampicin and simeprevir resulted in a 48% decrease in AUC24h while Cmax was increased by 31%. Although simeprevir exposure in subjects with moderate hepatic impairment was higher than in healthy subjects, no dose adjustments are required in patients with moderate hepatic impairment.

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Excretion[1]
Simeprevir is eliminated by biliary excretion. After a single dose of 200 mg of simeprevir, approximately 91% of total radioactivity was recovered in feces and less than 1% in urine, indicating that simeprevir is eliminated from the body via biliary excretion and renal excretion is irrelevant. The elimination half-life in HCV-infected patients was 41 hours, which is almost 3–4 times longer than that in HCV-uninfected individuals. The pharmacokinetic parameters of simeprevir were also not influenced by renal function and no dose adjustments are necessary in patients with mild, moderate, or severe renal impairment. Safety and efficacy, however, have not been studied in patients with end-stage renal disease or on hemodialysis.

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Pharmacodynamics[1]
There was no clear pharmacokinetic/pharmacodynamic relationship between simeprevir exposure and antiviral activity with simeprevir doses of 75 mg once daily (QD) or above. Within the range of exposures to simeprevir in Phase III trials, no clear exposure–response relationships for efficacy (rapid virologic response [RVR], SVR, viral breakthrough [VBT] or relapse) were observed. During clinical trials with simeprevir, higher exposures to simeprevir have been associated with increased frequency of adverse reactions, including rash and photosensitivity.

Using a fluorescence resonance energy transfer cleavage assay with the RetS1 peptide substrate, derived from the genotype 1a NS4A-4B junction, and bacterially expressed full-length NS3 protease domain, supplemented with an NS4A peptide, the in vitro inhibitory activity of simeprevir against NS3/4A is ascertained. In summary, RetS1 substrate is added to NS3/4A after it has been preincubated for 10 minutes in the presence of TMC435350. Fluorescence is then continuously monitored for 20 minutes (excitation wavelength: 355 nm; emission wavelength: 500 nm). Substratum cleavage is reported as a percentage of cleavage observed in the vehicle control.

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Biochemical protease assays.[2]
Protease activity for HCV genotype 1 to 6 NS3 proteins was monitored in a continuous FRET-based assay. The assay buffer contained 25 μM NS4A peptide, 50 mM Tris-HCl (pH 7.5), 15% glycerol (vol/vol), 0.6 mM lauryldimethylamine N-oxide, and 10 mM dithiothreitol. This buffer was prepared fresh daily by addition of NS4A peptide and dithiothreitol to a mixture of the other components that was stored at 4°C. The final assay conditions also included 0.5 μM FRET substrate, variable concentrations of NS3/4A and ITMN-8187 as specified, and up to 5% dimethyl sulfoxide (DMSO) (from addition of inhibitor or mock treatment). Assays were conducted at room temperature in black 96-well plates, and fluorescence data were collected using a SpectraMax M5 or SpectraMax EM plate readers (Molecular Devices, Sunnyvale, CA) with excitation and emission wavelengths set to 490 and 520 nm, respectively. The half-maximal inhibitory concentrations (IC50s) for NS3/4A inhibition by ITMN-8187 were determined using NS3-initiated reactions (without preincubation of enzyme and inhibitor). The final 1× assay concentrations of NS3 were 0.05 nM for all genotypic variants tested except 1a and 3a (0.1 nM and 0.4 nM, respectively). Assay wells were prepared by adding and mixing 170 μl of 1× assay buffer, 10 μl of the 20× ITMN-8187 in DMSO (or DMSO blank), 10 μl of 20× substrate, and 10 μl of a 20× NS3/4A stock in the specified order. Data acquisition for 1 h was initiated immediately after NS3/4A addition and mixing. Reaction rates were calculated from progress curve slopes over the first 30 min. Dose-response curves (rate versus log10 concentration of ITMN-8187) were fit to a 4-parameter logistic function to extract IC50s.

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Cytochrome P450 (CYP) inhibition and induction assays.[2]
The drug-drug interaction potential of ITMN-8187 was investigated through in vitro evaluation of CYP inhibition to estimate IC50 and the potential of time-dependent inhibition of CYP enzymes (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A) in human liver microsomes (XenoTech Inc., see Supplemental Methods). Briefly, compounds were incubated with human liver microsomes, CYP probe substrates, and NADP-oxidase (NADPH). The reaction was terminated by protein precipitation with the addition of acetonitrile. After centrifugation, the supernatant was analyzed via LC-MS/MS to quantify the extent of specific metabolite formation for the probe substrate of each CYP enzyme. The potential for ITMN-8187 to induce CYP enzymes activities (CYP1A2, CYP2B6, and CYP3A4) was investigated in fresh human hepatocytes using selective probe substrate.

Huh7-Luc cells are plated in a 384-well plate at a density of 2,500 cells/well using Dulbecco's modified Eagles medium supplemented with 10% fetal calf serum. The cells are then cultured with serially diluted simeprevir (TMC435350) at various concentrations, with a final DMSO concentration of 0.5% in the absence of G418. Following a 72-hour incubation period, a ViewLux reader is used to measure the luciferase signal after Steady Lite reagent is added to the medium in a 1:1 ratio.

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HCV replicon assays.[2]
Huh7 luc/neo ET cells and pFK I389luc-ubi-neo/NS3-3′/ET HCV replicons were licensed from Reblikon GMBH. The stable HCV replicon (pFK I389luc-ubineo/NS3-3′/ET) expresses a firefly luciferase-ubiquitin-neomycin phosphotransferase fusion protein. Expression of the NS3/5B HCV polyprotein containing three cell culture-adaptive mutations (E1202G, T1280I, K1846T) was driven by the encephalomyocarditis virus internal ribosomal entry site. The HCV genotype 1a subgenomic replicon generated at InterMune represents a 1b-to-1a chimera near the N terminus of NS3 distal to the compound binding site. Huh7 cells containing subgenomic HCV replicons were cultured at 37°C in 5% CO2 in DMEM containing 10% heat-inactivated FBS, 2 mM l-glutamine, 1% nonessential amino acids, 50 IU/ml penicillin, 50 μg/ml streptomycin solution, and 0.5 mg/ml G418. HCV replicon-containing Huh7 cells were plated at a density of 5 × 103 cells/well in 96-well tissue culture plates containing 100 μl DMEM with G418. Approximately 24 h later, the medium was removed and replaced with 90 μl DMEM lacking G418. ITMN-8187 or test compounds were serially diluted 3-fold in DMSO in two duplicate rows for each determination of the half-maximal effective concentration (EC50). The serially diluted compound solutions were diluted 10-fold in DMEM lacking serum and G418; 10 μl of these compound solutions in medium were added to duplicate tissue culture plates. The final volume was 100 μl with a DMSO concentration of 1%. Plates were incubated at 37°C for approximately 48 h. At 48 h, a microscopic visual examination of the tissue culture plates was conducted to assess compound solubility. Medium was removed from one of the two duplicate plates, and luciferase activity was measured using the Bright-Glo luciferase assay to determine EC50s. The ATPlite assay kit was used to determine ATP levels of cells and medium in the second plate for determination of half-maximal cytotoxic concentrations (CC50s). Both Bright-Glo and ATPlite assay kits were used according to the manufacturers' instructions. Test compound potency levels against R155K, A156T, and D168V HCV 1b mutant replicons were similarly determined. To assess the effect of concentration in serum on compound potency, the above-described assay was carried out in the presence of 40% FBS. The effect of serum is expressed as fold shift relative to 10% FBS reference conditions.

Sprague-Dawley (SD) rats and cynomolgus monkeys
3 mg/kg
Oral administration

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In vivo preclinical studies.[2]
Pharmacokinetic properties of ITMN-8187 and simpeprevir were evaluated in Sprague-Dawley (SD) rats, beagle dogs, and cynomolgus monkeys. Procedures were performed under protocols approved by the Institutional Animal Care and Use Committee of the test facility. The animals were fasted overnight and through 4 h after administration of ITMN-8187. SD rats, beagle dogs, and cynomolgus monkeys (three males per species per dosing route) were administered with ITMN-8187 at 3 mg/kg by oral gavage or 0.5 mg/kg by intravenous (i.v.) bolus injection. The formulations used in the i.v. and oral studies were 0.5-mg/ml and 0.6-mg/ml solutions, respectively, in DMSO-solutol-saline (2/2/96, vol/vol/vol). For each species, blood samples were collected at 0.25, 0.5, 1, 2, 4, 8, 12, and 24 h after both i.v. and oral administration. Blood samples were also collected at 5 min after dosing from i.v. studies in all three species. Blood samples were collected in tubes containing tripotassium EDTA (K3EDTA), processed for plasma by centrifugation at 5°C, and stored at −20°C until analysis was performed. In addition, following oral administration of ITMN-8187 at 3 mg/kg, liver tissues were collected from rats and monkeys at predefined time points, rinsed in phosphate-buffered saline, dried, and stored in vials at −80°C until analysis. Drug concentration from each plasma or liver tissue sample at each time point was individually quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Pharmacokinetic analysis of the concentration in plasma-time profiles was performed using Phoenix/WinNonlin version 6.3.

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HCV chimeric mouse model.[2]
Chimeric mice were created by transplanting human hepatocytes into immunodeficient transgenic mice carrying Alb-uPA. The immunodeficient homozygous Alb-uPA mice carrying chimeric mouse/human livers with serum were then infected with virus from patients with HCV infection; the inoculum varied by HCV genotype or mutations. The HCV chimeric mouse model used in these studies was provided by Phoenix Bio. Briefly, male uPA+/+-SCID mice 2 to 4 weeks of age were transplanted with human hepatocytes with an estimated replacement index of ≥70%, based on human albumin measurements (>9 mg/ml). After transplantation, the mice were infected at 10 to 14 weeks with HCV genotypes 1a or 1b by inoculation with HCV-positive patient serum. HCV infection in the chimeric mice was confirmed by the presence of serum HCV RNA measurements by real-time PCR (RT-PCR; lower limit of quantification, 4 × 104 copies/ml). uPA+/+-SCID mice confirmed to be infected with HCV genotypes 1a or 1b were dosed for 4 days with vehicle (2% Solutol) or ITMN-8187 at 30 mg/kg once daily by oral gavage. The vehicle and ITMN-8187 dosing solutions were formulated fresh daily. Serum was collected from individual mice on day 0 before treatment with vehicle or ITMN-8187 began (baseline), at 6 and 12 h postdose with vehicle or ITMN-8187 on day 1, and then once daily on days 2 to 4 for measurement of HCV RNA concentration. Data are expressed as the average HCV RNA concentration (copies/milliliter) per experimental group (n = 4); statistical differences (P < 0.05) between the vehicle-treated control mice and ITMN-8187-treated groups were analyzed using the Student t test.

Absorption, Distribution and Excretion
The mean absolute bioavailability of simeprevir following a single oral 150 mg dose of simeprevir capsule in fed conditions is 62%. Maximum plasma concentrations (Cmax) are typically achieved between 4 to 6 hours following the oral administration.
Simeprevir is predominantly eliminated through biliary excretion. In a radioactivity study, 91% of radiolabeled drug was detected in the feces and less than 1% was detected in the urine. From the recovered drug in the feces, the unchanged form of simeprevir accounted for 31% of the total administered dose.
The volume of distribution for simeprevir has yet to be determined. In animal studies, simeprevir is extensively distributed to gut and liver (liver:blood ratio of 29:1 in rat) tissues.
The clearance of simeprevir has yet to be determined.
Simeprevir is extensively bound to plasma proteins (greater than 99.9%), primarily to albumin and, to a lesser extent, alfa 1-acid glycoprotein. Plasma protein binding is not meaningfully altered in patients with renal or hepatic impairment.
Administration of simeprevir with food to healthy subjects increased the relative bioavailability (AUC) by 61% and 69% after a high-fat, high-caloric (928 kcal) and normal-caloric (533 kcal) breakfast, respectively, and delayed the absorption by 1 hour and 1.5 hours, respectively. Due to increased bioavailability, Olysio should be administered with food. The type of food does not affect exposure to simeprevir.
Elimination of simeprevir occurs via biliary excretion. Renal clearance plays an insignificant role in its elimination. Following a single oral administration of 200 mg (14)C-simeprevir to healthy subjects, on average 91% of the total radioactivity was recovered in feces. Less than 1% of the administered dose was recovered in urine. Unchanged simeprevir in feces accounted for on average 31% of the administered dose.
In animals, simeprevir is extensively distributed to gut and liver (liver:blood ratio of 29:1 in rat) tissues. In vitro data and physiologically-based pharmacokinetic modeling and simulations indicate that hepatic uptake in humans is mediated by OATP1B1/3.
For more Absorption, Distribution and Excretion (Complete) data for Simeprevir (10 total), please visit the HSDB record page.

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Metabolism / Metabolites
Simeprevir undergoes hepatic metabolism. The primary metabolic pathway involves CYP3A system-mediated oxidation. Involvement of CYP2C8 and CYP2C19 cannot be excluded.
Following a single oral administration of 200 mg (1.3 times the recommended dosage) (14)C-simeprevir to healthy subjects, the majority of the radioactivity in plasma (mean: 83%) was accounted for by unchanged drug and a small part of the radioactivity in plasma was related to metabolites (none being major metabolites). Metabolites identified in feces were formed via oxidation at the macrocyclic moiety or aromatic moiety or both and by O-demethylation followed by oxidation.
Simeprevir is metabolized in the liver. In vitro experiments with human liver microsomes indicated that simeprevir primarily undergoes oxidative metabolism by the hepatic CYP3A system. Involvement of CYP2C8 and CYP2C19 cannot be excluded. Co-administration of Olysio with moderate or strong inhibitors of CYP3A may significantly increase the plasma exposure of simeprevir, and co-administration with moderate or strong inducers of CYP3A may significantly reduce the plasma exposure of simeprevir.
The in vitro metabolism of 14C-TMC435 was investigated in hepatocytes and liver microsomes of mouse, rat, rabbit, monkey and human. The metabolic activity reported in vitro from animals and man was low. Phase II conjugation pathways of Phase I metabolites were formed in hepatocytes. Parent TMC435 was found in much greater levels than any metabolite in vitro. More than 20 metabolites were identified. The metabolic Phase I route of highest importance were O-demethylation of unchanged drug (particularly in animals), oxidation of unchanged drug and oxidized metabolites (particularly in monkey and man) and glucuronidation was the major Phase II of oxidized metabolites (less in human). Only one human metabolite identified in vitro not seen in rat or dog was M22 (oxidized unchanged drug) but this metabolite was identified in rat (feces). In vivo data reveals that the main moiety present in plasma of rat, dog and man was parent TMC435. The major metabolites reported in vivo in plasma from animals and human were M18 and M21. O-desmethyl-TMC435 M21 was the only common circulating metabolite found in rat dog and human plasma (M21: 8% of the mean TMC435 plasma and only small traces in dogs), while M18 was common to plasma of rats and dogs but with respect to the parent compound they appeared with low concentrations (M18: between 28.9% and 12.5% in rats, with only small traces in dogs). Only traces of metabolites M18, M21 and M8 formed by O-demethylation and oxidation at the aromatic moiety were reported in dog plasma. M21 represents less than 10% of unchanged drug and also total radioactivity therefore systemic exposure to M21 was not assessed in the safety evaluation studies. M21 did not appear to accumulate in man. In bile from rats, moderately high levels of parent compound were reported (0.11 to 17.2%). TMC435 metabolites in this matrix were formed mainly by hydroxylation and O-demethylation and also by glucuronidation.
The most important metabolic route TMC435 in rat and dog was O-demethylation of the parent drug to M18 (12.8%- 6.4% male-female rats; 18.8% dogs). In rats other metabolites were formed by oxidation of M18 and oxidation of unchanged drug. In dogs, further oxidation of M18 to M14 and M8, and of the unchanged drug to M21, M16 and M11 were also reported as minor routes. The human metabolism profile suggests that TMC435 is mainly metabolized by two main routes, (1) oxidation of unchanged drug, either at the macrocyclic moiety (M27, M21 and M22), or at the aromatic moiety (M26 and M16), or both (M23, M24, M25 and M11) and (2) the O-demethylation of unchanged drug to M18, followed by oxidation on the macrocyclic moiety to M14 and by oxidation on the aromatic moiety to M5, appears to be the secondary metabolic pathway in man. M21 and M22 were the most important metabolites in human faeces. Other relevant metabolites (1% of the dose) were M11, M16, M27 and M18. All metabolites detected in human feces were detected in vitro and/or in vivo in rat and/or dog feces. The main CYP enzymes involved in TMC435 metabolism were CYP3A enzymes although in vitro data suggests the involvement of CYP2C8 and CYP2C19.

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Biological Half-Life
The elimination half-life of simeprevir following 200mg dose administration is about 41 hours in HCV-positive patients and 10 to 13 hours in individuals without HCV infection.
The half-life was variable among species accounting to 4.0 hr in rats, 3.7 hr in rabbits and dogs and 5 to 6 hr in Rhesus and Cynomolgus monkeys.
The terminal elimination half-life of simeprevir was 10 to 13 hours in hepatitis C virus (HCV)-uninfected subjects and 41 hours in HCV-infected subjects receiving 200 mg (1.3 times the recommended dosage) of simeprevir.

Toxicity Summary
IDENTIFICATION AND USE: Simeprevir is a white to almost white powder. Simeprevir is used in conjunction with peginterferon alfa and ribavirin for the treatment of chronic hepatitis C virus (HCV) genotype 1 infection in adults with compensated liver disease (including cirrhosis) who are treatment-naive (previously untreated) or in whom prior treatment with interferon and ribavirin failed (including those with prior null response, prior partial response, or prior relapse). Simeprevir must be used in conjunction with peginterferon alfa (peginterferon alfa-2a or peginterferon alfa-2b) and ribavirin and should not be used alone for the treatment of chronic HCV infection. HUMAN EXPOSURE AND TOXICITY: Very few data are available on the effects of overdose to simeprevir. Simeprevir was generally well tolerated when given as single doses up to 600 mg or once daily doses up to 400 mg for 5 days in healthy adult subjects, and as 200 mg once daily for 4 weeks in adult patients with HCV. ANIMAL STUDIES: Simeprevir was well tolerated after single doses up to 500 mg/kg in mice, 1000 mg/kg in rats, 160 mg/kg in dogs and 300 mg/kg in monkeys. There were no adverse effects of simeprevir on vital functions (cardiac, respiratory and central nervous system) in animal studies. Repeat dose oral toxicity studies with simeprevir were conducted in mice (up to 3 months), rats (up to 6 months), dogs (up to 9 months), and monkeys (up to 28 days). Gastrointestinal effects were observed in all species. A higher incidence of soft, mucoid or pale feces was seen in mice, rats and/or dogs. The presence of swelling/vacuolization of apical enterocytes in the duodenum and jejunum was noted in mice, rats and dogs. The compound formulation caused abnormal stomach contents and/or abdominal distention, in mice and rats, as a result of delayed gastric emptying. Liver effects were observed in mice, rats and dogs. These findings were often accompanied by increases in bilirubin, and liver enzymes in plasma. In a mouse embryofetal study at doses up to 1000 mg/kg, simeprevir resulted in early and late in utero fetal losses and early maternal deaths at an exposure approximately 6 times higher than the mean AUC in humans at the recommended 150 mg daily dose. Significantly decreased fetal weights and an increase in fetal skeletal variations were seen at exposures approximately 4 times higher than the mean AUC in humans at the recommended daily dose. In a rat pre- and postnatal study, maternal animals were exposed to simeprevir during gestation and lactation at doses up to 1000 mg/kg/day. In pregnant rats, simeprevir resulted in early deaths at 1000 mg/kg/day corresponding to exposures similar to the mean AUC in humans at the recommended 150 mg once daily dose. Significant reduction in body weight gain was seen at an exposure 0.7 times the mean AUC in humans at the recommended 150 mg once daily dose. The developing rat offspring exhibited significantly decreased body weight and negative effects on physical growth (delay and small size) and development (decreased motor activity) following simeprevir exposure in utero (via maternal dosing) and during lactation (via maternal milk to nursing pups) at a maternal exposure similar to the mean AUC in humans at the recommended 150 mg once daily dose. Subsequent survival, behavior and reproductive capacity were not affected. In a rat fertility study at doses up to 500 mg/kg/day, 3 male rats treated with simeprevir (2/24 rats at 50 mg/kg/day and 1/24 rats at 500 mg/kg/day) showed no motile sperm, small testes and epididymides, and resulted in infertility in 2 out of 3 of the male rats at approximately 0.2 times the mean AUC in humans. Simeprevir was not genotoxic in a series of in vitro and in vivo tests including the Ames test, the mammalian forward mutation assay in mouse lymphoma cells or the in vivo mammalian micronucleus test.

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Interactions
In vitro, simeprevir is a substrate and inhibitor of P-glycoprotein (P-gp) transport. Concomitant use of simeprevir with drugs that are P-gp substrates may result in increased concentrations of such drugs.
Pharmacokinetic interaction with cyclosporine (increased cyclosporine concentrations). Cyclosporine dosage adjustments are not needed when used concomitantly with simeprevir; routine monitoring of cyclosporine concentrations is recommended.
Concomitant use of simvastatin (single 40-mg dose) and simeprevir (150 mg once daily for 10 days) resulted in a 1.5-fold increase in simvastatin AUC due to inhibition of OATP1B1 and/or CYP3A4 by simeprevir. If simvastatin is used concomitantly with simeprevir, dosage of simvastatin should be titrated carefully and the lowest necessary dosage of simvastatin used; the patient should be monitored for safety.
Concomitant use of a rosuvastatin (single 10 mg dose) and simeprevir (150 mg once daily for 7 days) resulted in a 2.8-fold increase in rosuvastatin AUC due to inhibition of OATP1B1 by simeprevir. If rosuvastatin is used concomitantly with simeprevir, dosage of rosuvastatin should be initiated at 5 mg once daily and should not exceed 10 mg once daily.
For more Interactions (Complete) data for Simeprevir (38 total), please visit the HSDB record page.

[1]. Simeprevir for the treatment of hepatitis C virus infection. Pharmgenomics Pers Med. 2014; 7: 241–249.

[2]. Preclinical Characterization and Human Microdose Pharmacokinetics of ITMN-8187, a Nonmacrocyclic Inhibitor of the Hepatitis C Virus NS3 Protease. Antimicrob Agents Chemother . 2016 Dec 27;61(1):e01569-16.

Therapeutic Uses
Antiviral Agents; Protease Inhibitors
Olysio is a hepatitis C virus (HCV) NS3/4A protease inhibitor indicated for the treatment of chronic hepatitis C (CHC) genotype 1 infection as a component of a combination antiviral treatment regimen. /Included in US product label/
Olysio monotherapy is not recommended.
Olysio combination with peginterferon alfa and ribavirin: screening patients with hepatitis C virus (HCV) genotype 1a infection for the presence of virus with the NS3 Q80K polymorphism is strongly recommended and alternative therapy should be considered if HCV genotype 1a with Q80K is detected.
Olysio is not recommended in patients who have previously failed therapy with a treatment regimen that included Olysio or other hepatitis C virus (HCV) protease inhibitors.

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Drug Warnings
Simeprevir contains a sulfonamide moiety. In clinical trials of simeprevir, an increased incidence of rash or photosensitivity was not observed in the 16 patients who had a history of sulfa allergy. However, data are insufficient to exclude an association between sulfa allergy and the frequency or severity of adverse reactions reported with simeprevir.
During the 12 weeks of treatment with Olysio, dyspnea was reported in 12% of Olysio-treated subjects compared to 8% of placebo-treated subjects (all grades; pooled Phase 3 trials). All dyspnea events reported in Olysio-treated subjects were of mild or moderate severity (Grade 1 or 2). There were no Grade 3 or 4 dyspnea events reported and no subjects discontinued treatment with Olysio due to dyspnea. Sixty-one percent (61%) of dyspnea events occurred in the first 4 weeks of treatment with Olysio.
Adverse effects reported in more than 20% of patients receiving simeprevir in conjunction with peginterferon alfa and ribavirin in clinical trials and occurring with an incidence at least 3% higher than that reported in patients receiving placebo in conjunction with peginterferon alfa and ribavirin include rash (including photosensitivity), pruritus, and nausea.
Rash has been reported in patients receiving simeprevir in conjunction with peginterferon alfa and ribavirin. Rash occurred most frequently during the first 4 weeks of treatment, but can occur at any time during the course of treatment. Rash generally was mild or moderate in severity, but severe rash and rash requiring discontinuance of the drug have been reported. Patients with mild to moderate rash should be monitored for possible progression (e.g., development of oral lesions, conjunctivitis, systemic symptoms). If rash becomes severe, simeprevir should be discontinued. Patients should be monitored until rash resolves.
For more Drug Warnings (Complete) data for Simeprevir (12 total), please visit the HSDB record page.

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Pharmacodynamics
Simeprevir is a direct-acting antiviral agent and inhibitor for HCV NS3/4A protease, which is an important enzyme required for viral replication. Unlike [DB08873] and [DB05521], simeprevir is a competitive, reversible, macrocyclic, noncovalent inhibitor. The macromolecular cyclic portion of the molecule improves the affnity and selectivity characteristics, which allows rapid association and slow dissociation to the protein target through noncovalent binding.

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Simeprevir (TMC435, Olysio™), a second-generation hepatitis C virus (HCV) protease inhibitor, has been recently approved for the treatment of genotype 1 chronic hepatitis C in combination with pegylated interferon and ribavirin. This molecule has very different characteristics from first-generation protease inhibitors. Results from trials show that simeprevir is highly effective and safe, with few adverse events. We discuss the specific features of this new treatment option for HCV infection, in terms of in vitro data, pharmacological data, and clinical trials. We also discuss the impact of Q80K polymorphism at baseline. Studies evaluating interferon-free regimens with simeprevir are ongoing. Future combinations of two or more direct-acting antiviral agents, targeting different viral enzymes and with synergistic antiviral effects, will be approved, allowing treatment of pan-genotypic HCV with optimized sustained virologic responses. Simeprevir will undoubtedly be part of future treatment strategies.[1]

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The current paradigm for the treatment of chronic hepatitis C virus (HCV) infection involves combinations of agents that act directly on steps of the HCV life cycle. Here we report the preclinical characteristics of ITMN-8187, a nonmacrocyclic inhibitor of the NS3/4A HCV protease. X-ray crystallographic studies of ITMN-8187 and simeprevir binding to NS3/4A protease demonstrated good agreement between structures. Low nanomolar biochemical potency was maintained against NS3/4A derived from HCV genotypes 1, 2b, 4, 5, and 6. In cell-based potency assays, half-maximal reduction of genotype 1a and 1b HCV replicon RNA was afforded by 11 and 4 nM doses of ITMN-8187, respectively. Combinations of ITMN-8187 with other directly acting antiviral agents in vitro displayed additive antiviral efficacy. A 30-mg/kg of body weight dose of ITMN-8187 administered for 4 days yielded significant viral load reductions through day 5 in a chimeric mouse model of HCV. A 3-mg/kg oral dose administered to rats, dogs, or monkeys yielded concentrations in plasma 16 h after dosing that exceeded the half-maximal effective concentration of ITMN-8187. Human microdose pharmacokinetics showed low intersubject variability and prolonged oral absorption with first-order elimination kinetics compatible with once-daily dosing. These preclinical characteristics compare favorably with those of other NS3/4A inhibitors approved for the treatment of chronic HCV infection.[2]

C38H47N5O7S2

749.94

749.291

C, 60.86; H, 6.32; N, 9.34; O, 14.93; S, 8.55

923604-59-5

Simeprevir sodium;1241946-89-3;Simeprevir-13C,d3

24873435

White to off-white solid powder

1.4±0.1 g/cm3

1.653

4.99

2

10

8

52

1490

5

S(C1([H])C([H])([H])C1([H])[H])(N([H])C([C@@]12C([H])([H])[C@@]1([H])C([H])=C([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])N(C([H])([H])[H])C([C@]1([H])C([H])([H])[C@@]([H])(C([H])([H])[C@@]1([H])C(N2[H])=O)OC1=C([H])C(C2=NC(C([H])(C([H])([H])[H])C([H])([H])[H])=C([H])S2)=NC2C(C([H])([H])[H])=C(C([H])=C([H])C1=2)OC([H])([H])[H])=O)=O)(=O)=O |t:21|

JTZZSQYMACOLNN-VDWJNHBNSA-N

InChI=1S/C38H47N5O7S2/c1-21(2)30-20-51-35(40-30)29-18-32(26-13-14-31(49-5)22(3)33(26)39-29)50-24-16-27-28(17-24)36(45)43(4)15-9-7-6-8-10-23-19-38(23,41-34(27)44)37(46)42-52(47,48)25-11-12-25/h8,10,13-14,18,20-21,23-25,27-28H,6-7,9,11-12,15-17,19H2,1-5H3,(H,41,44)(H,42,46)/b10-8-/t23-,24-,27-,28-,38-/m1/s1

(1R,4R,6S,7Z,15R,17R)-N-cyclopropylsulfonyl-17-[7-methoxy-8-methyl-2-(4-propan-2-yl-1,3-thiazol-2-yl)quinolin-4-yl]oxy-13-methyl-2,14-dioxo-3,13-diazatricyclo[13.3.0.04,6]octadec-7-ene-4-carboxamide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: 2.5 mg/mL (3.33 mM) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 1.43 mg/mL (1.91 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 14.3 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 3: ≥ 1.43 mg/mL (1.91 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 14.3 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)