Zepatier

Dosage Forms And Strengths

ZEPATIER is available as a beige-colored, oval-shaped, film-coated tablet debossed with “770” on one side and plain on the other. Each tablet contains 50 mg elbasvir and 100 mg grazoprevir.

Storage And Handling

Each ZEPATIER tablet contains 50 mg elbasvir and 100 mg grazoprevir, is beige, oval-shaped, film-coated, debossed with “770” on one side and plain on the other. The tablets are packaged into a carton (NDC 0006-3074-02) containing two (2) 14-count child-resistant dose packs for a total of 28 tablets.

Store ZEPATIER in the original blister package until use to protect from moisture.

Store ZEPATIER at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (between 59°F to 86°F).

Manufactured by: MSD International GmbH, Ballydine, Clonmel, Ireland. Revised: Nov 2017

ZEPATIER^® is indicated for the treatment of chronic hepatitis C virus (HCV) genotype 1 or 4 infection in adults.

ZEPATIER is indicated for use with ribavirin in certain patient populations.

Testing Prior To The Initiation Of Therapy

Testing For HBV Infection

Test all patients for evidence of current or prior HBV infection by measuring hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) before initiating HCV treatment with ZEPATIER.

NS5A Resistance Testing In HCV Genotype 1a-Infected Patients

Testing patients with HCV genotype 1a infection for the presence of virus with NS5A resistance-associated polymorphisms is recommended prior to initiation of treatment with ZEPATIER to determine dosage regimen and duration , Table 1. In subjects receiving ZEPATIER for 12 weeks, sustained virologic response (SVR12) rates were lower in genotype 1a-infected patients with one or more baseline NS5A resistance-associated polymorphisms at amino acid positions 28, 30, 31, or 93 , Table 11.

Hepatic Laboratory Testing

Obtain hepatic laboratory testing prior to and during treatment with ZEPATIER.

Recommended Dosage In Adults

ZEPATIER is a two-drug, fixed-dose combination product containing 50 mg of elbasvir and 100 mg of grazoprevir in a single tablet. The recommended dosage of ZEPATIER is one tablet taken orally once daily with or without food. ZEPATIER is used in combination with ribavirin in certain patient populations (see Table 1). When administered with ZEPATIER, the recommended dosage of ribavirin in patients without renal impairment is weight-based administered in two divided doses with food. For further information on ribavirin dosing and dosage modifications, refer to the ribavirin prescribing information.

Treatment Regimen And Duration Of Therapy

Relapse rates are affected by baseline host and viral factors and differ between treatment regimens and durations for certain subgroups.

Table 1 below provides the recommended ZEPATIER treatment regimen and duration based on the patient population and genotype in HCV mono-infected and HCV/HIV-1 co-infected patients with or without cirrhosis and with or without renal impairment including patients receiving hemodialysis.

Table 1: Recommended Dosage Regimens and Durations for ZEPATIER for Treatment of HCV Genotype 1 or 4 in Patients with or without Cirrhosis

Renal Impairment

No dosage adjustment of ZEPATIER is recommended in patients with any degree of renal impairment including patients on hemodialysis. Administer ZEPATIER with or without ribavirin according to the recommendations in Table 1. Refer to the ribavirin tablet prescribing information for the correct ribavirin dosage for patients with CrCl less than or equal to 50 mL per minute.

Hepatic Impairment

No dosage adjustment of ZEPATIER is recommended in patients with mild hepatic impairment (Child-Pugh A). ZEPATIER is contraindicated in patients with moderate or severe hepatic impairment (Child-Pugh B or C).

• ZEPATIER is contraindicated in patients with moderate or severe hepatic impairment (Child-Pugh B or C) due to the expected significantly increased grazoprevir plasma concentration and the increased risk of alanine aminotransferase (ALT) elevations.
• ZEPATIER is contraindicated with inhibitors of organic anion transporting polypeptides 1B1/3 (OATP1B1/3) that are known or expected to significantly increase grazoprevir plasma concentrations, strong inducers of cytochrome P450 3A (CYP3A), and efavirenz.
• If ZEPATIER is administered with ribavirin, the contraindications to ribavirin also apply to this combination regimen. Refer to the ribavirin prescribing information for a list of contraindications for ribavirin.

Table 2 lists drugs that are contraindicated with ZEPATIER.

Table 2: Drugs that are Contraindicated with ZEPATIER

WARNINGS

Included as part of the "PRECAUTIONS" Section

PRECAUTIONS

Risk Of Hepatitis B Virus Reactivation In Patients Coinfected With HCV And HBV

Hepatitis B virus (HBV) reactivation has been reported in HCV/HBV coinfected patients who were undergoing or had completed treatment with HCV direct acting antivirals, and who were not receiving HBV antiviral therapy. Some cases have resulted in fulminant hepatitis, hepatic failure and death. Cases have been reported in patients who are HBsAg positive and also in patients with serologic evidence of resolved HBV infection (i.e., HBsAg negative and anti-HBc positive). HBV reactivation has also been reported in patients receiving certain immunosuppressant or chemotherapeutic agents; the risk of HBV reactivation associated with treatment with HCV direct-acting antivirals may be increased in these patients.

HBV reactivation is characterized as an abrupt increase in HBV replication manifesting as a rapid increase in serum HBV DNA level. In patients with resolved HBV infection reappearance of HBsAg can occur. Reactivation of HBV replication may be accompanied by hepatitis, i.e., increases in aminotransferase levels and, in severe cases, increases in bilirubin levels, liver failure, and death can occur.

Test all patients for evidence of current or prior HBV infection by measuring HBsAg and anti-HBc before initiating HCV treatment with ZEPATIER. In patients with serologic evidence of HBV infection, monitor for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV treatment with ZEPATIER and during post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated.

Increased Risk Of ALT Elevations

During clinical trials with ZEPATIER with or without ribavirin, 1% of subjects experienced elevations of ALT from normal levels to greater than 5 times the upper limit of normal (ULN), generally at or after treatment week 8. ALT elevations were typically asymptomatic and most resolved with ongoing or completion of therapy. Higher rates of late ALT elevations occurred in the following subpopulations: female sex (2% [10/608]), Asian race (2% [4/164]), and age 65 years or older (2% [3/177]).

Hepatic laboratory testing should be performed prior to therapy, at treatment week 8, and as clinically indicated. For patients receiving 16 weeks of therapy, additional hepatic laboratory testing should be performed at treatment week 12.

• Patients should be instructed to consult their healthcare professional without delay if they have onset of fatigue, weakness, lack of appetite, nausea and vomiting, jaundice, or discolored feces.
• Consider discontinuing ZEPATIER if ALT levels remain persistently greater than 10 times the ULN.
• Discontinue ZEPATIER if ALT elevation is accompanied by signs or symptoms of liver inflammation or increasing conjugated bilirubin, alkaline phosphatase, or International Normalized Ratio (INR).

Risks Associated With Ribavirin Combination Treatment

If ZEPATIER is administered with ribavirin, the warnings and precautions for ribavirin, including the pregnancy avoidance warning, also apply to this combination regimen. Refer to the ribavirin prescribing information for a full list of warnings and precautions for ribavirin.

Risk Of Adverse Reactions Or Reduced Therapeutic Effect Due To Drug Interactions

The concomitant use of ZEPATIER and certain drugs may result in known or potentially significant drug interactions, some of which may lead to:

• Possible clinically significant adverse reactions from greater exposure of concomitant drugs or components of ZEPATIER.
• Significant decrease of elbasvir and grazoprevir plasma concentrations which may lead to reduced therapeutic effect of ZEPATIER and possible development of resistance.

See Tables 2 and 6 for steps to prevent or manage these known or potentially significant drug interactions, including dosing recommendations.

Patient Counseling Information

Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).

For patients receiving ZEPATIER with ribavirin, advise patients to read the FDA-approved patient labeling (Medication Guide) for ribavirin.

Risk Of Hepatitis B Virus Reactivation In Patients Coinfected With HCV And HBV

Inform patients that HBV reactivation can occur in patients coinfected with HBV during or after treatment of HCV infection. Advise patients to tell their healthcare provider if they have a history of hepatitis B virus infection.

Risk Of ALT Elevations

Inform patients to watch for early warning signs of liver inflammation, such as fatigue, weakness, lack of appetite, nausea and vomiting, as well as later signs such as jaundice and discolored feces, and to consult their healthcare professional without delay if such symptoms occur.

Pregnancy

Advise patients taking ZEPATIER with ribavirin to avoid pregnancy during treatment and within 6 months of stopping ribavirin and to notify their healthcare provider immediately in the event of a pregnancy.

Drug Interactions

Inform patients that ZEPATIER may interact with some drugs; therefore, advise patients to report the use of any prescription, non-prescription medication, or herbal products to their healthcare provider.

Storage

Advise patients to store ZEPATIER in the original package until use to protect from moisture.

Administration

Advise patients to take ZEPATIER every day at the regularly scheduled time with or without food. Inform patients that it is important not to miss or skip doses and to take ZEPATIER for the duration that is recommended by the healthcare provider.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Carcinogenesis And Mutagenesis

Elbasvir and grazoprevir were not genotoxic in a battery of in vitro or in vivo assays, including microbial mutagenesis, chromosomal aberration in Chinese Hamster Ovary cells, and in in vivo rat micronucleus assays.

Carcinogenicity studies with elbasvir or grazoprevir have not been conducted.

If ZEPATIER is administered in a regimen containing ribavirin, the information for ribavirin on carcinogenesis and mutagenesis also applies to this combination regimen. Refer to the ribavirin prescribing information for information on carcinogenesis and mutagenesis.

Impairment Of Fertility

No effects on mating, female or male fertility, or early embryonic development were observed in rats at up to the highest dose tested. Systemic exposures (AUC) to elbasvir and grazoprevir were approximately 8 and 114 times, respectively, the exposure in humans at the recommended human dose.

If ZEPATIER is administered with ribavirin, the information for ribavirin on impairment of fertility also applies to this combination regimen. Refer to the ribavirin prescribing information for information on impairment of fertility.

Use In Specific Populations

Pregnancy

Risk Summary

No adequate human data are available to establish whether or not ZEPATIER poses a risk to pregnancy outcomes. In animal reproduction studies, no evidence of adverse developmental outcomes was observed with the components of ZEPATIER (elbasvir or grazoprevir) at exposures greater than those in humans at the recommended human dose (RHD). During organogenesis in the rat and rabbit, systemic exposures (AUC) were approximately 10 and 18 times (for elbasvir) and 117 and 41 times (for grazoprevir), respectively, the exposure in humans at the RHD. In rat pre/postnatal developmental studies, maternal systemic exposures (AUC) to elbasvir and grazoprevir were approximately 10 and 78 times, respectively, the exposure in humans at the RHD.

The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

If ZEPATIER is administered with ribavirin, the combination regimen is contraindicated in pregnant women and in men whose female partners are pregnant. Refer to the ribavirin prescribing information for more information on use in pregnancy.

Data

Animal Data

Elbasvir: Elbasvir was administered orally at up to 1000 mg/kg/day to pregnant rats and rabbits on gestation days 6 to 20 and 7 to 20, respectively, and also to rats on gestation day 6 to lactation/postpartum day 20. No effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at up to the highest dose tested. Systemic exposures (AUC) to elbasvir were approximately 10 (rats) and 18 (rabbits) times the exposure in humans at the RHD. In both species, elbasvir has been shown to cross the placenta, with fetal plasma concentrations of up to 0.8% (rabbits) and 2.2% (rats) that of maternal concentrations observed on gestation day 20.

Grazoprevir: Grazoprevir was administered to pregnant rats (oral doses up to 400 mg/kg/day) and rabbits (intravenous doses up to 100 mg/kg/day) on gestation days 6 to 20 and 7 to 20, respectively, and also to rats (oral doses up to 400 mg/kg/day) on gestation day 6 to lactation/post-partum day 20. No effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at up to the highest dose tested. Systemic exposures (AUC) to grazoprevir were ≥78 (rats) and 41 (rabbits) times the exposure in humans at the RHD. In both species, grazoprevir has been shown to cross the placenta, with fetal plasma concentrations of up to 7% (rabbits) and 89% (rats) that of maternal concentrations observed on gestation day 20.

Lactation

Risk Summary

It is not known whether ZEPATIER is present in human breast milk, affects human milk production, or has effects on the breastfed infant. When administered to lactating rats, the components of ZEPATIER (elbasvir and grazoprevir) were present in milk, without effects on growth and development observed in nursing pups.

The developmental and health benefits of breastfeeding should be considered along with the motherfs clinical need for ZEPATIER and any potential adverse effects on the breastfed child from ZEPATIER or from the underlying maternal condition.

If ZEPATIER is administered with ribavirin, the information for ribavirin with regard to nursing mothers also applies to this combination regimen. Refer to the ribavirin prescribing information for information on use during lactation.

Data

Elbasvir:

No effects of elbasvir on growth and postnatal development were observed in nursing pups at up to the highest dose tested. Maternal systemic exposure (AUC) to elbasvir was approximately 10 times the exposure in humans at the RHD. Elbasvir was excreted into the milk of lactating rats following oral administration (1000 mg/kg/day) from gestation day 6 to lactation day 14, with milk concentrations approximately 4 times that of maternal plasma concentrations observed 2 hours post-dose on lactation day 14.

Grazoprevir:

No effects of grazoprevir on growth and postnatal development were observed in nursing pups at up to the highest dose tested. Maternal systemic exposure (AUC) to grazoprevir was approximately 78 times the exposure in humans at the RHD. Grazoprevir was excreted into the milk of lactating rats following oral administration (up to 400 mg/kg/day) from gestation day 6 to lactation day 14, with milk concentrations of 54 and 87% that of maternal plasma concentrations observed 2 and 8 hours post-dose, respectively, on lactation day 14.

Females And Males Of Reproductive Potential

If ZEPATIER is administered with ribavirin, the information for ribavirin with regard to pregnancy testing, contraception, and infertility also applies to this combination regimen. Refer to ribavirin prescribing information for additional information.

Pediatric Use

Safety and efficacy in pediatric patients have not been established in pediatric patients less than 18 years of age.

Geriatric Use

Clinical trials of ZEPATIER with or without ribavirin included 187 subjects aged 65 years and over. Higher elbasvir and grazoprevir plasma concentrations were observed in subjects aged 65 years and over. A higher rate of late ALT elevations was observed in subjects aged 65 years and over in clinical trials. However, no dosage adjustment of ZEPATIER is recommended in geriatric patients.

Gender

Higher elbasvir and grazoprevir plasma concentrations were observed in females compared to males. Females experienced a higher rate of late ALT elevations in clinical trials. However, no dose adjustment of ZEPATIER is recommended based on gender.

Race

Higher elbasvir and grazoprevir plasma concentrations were observed in Asians compared to Caucasians. Asians experienced a higher rate of late ALT elevations in clinical trials. However, no dose adjustment of ZEPATIER is recommended based on race/ethnicity.

Renal Impairment

No dosage adjustment of ZEPATIER is recommended in patients with any degree of renal impairment including patients receiving hemodialysis. Administer ZEPATIER with or without ribavirin according to recommendations in Table 1. Refer to the prescribing information for ribavirin tablets for renal dosage adjustment of ribavirin in patients with CrCl less than or equal to 50 mL per minute.

Hepatic Impairment

No dosage adjustment of ZEPATIER is recommended in patients with mild hepatic impairment (Child-Pugh A). ZEPATIER is contraindicated in patients with moderate hepatic impairment (Child-Pugh B) due to the lack of clinical safety and efficacy experience in HCV-infected Child-Pugh B patients, and in patients with severe hepatic impairment (Child-Pugh C) due to a 12-fold increase in grazoprevir exposure in non-HCV infected Child-Pugh C subjects.

The safety and efficacy of ZEPATIER have not been established in patients awaiting liver transplant or in liver transplant recipients.

SIDE EFFECTS

The following adverse reaction is described below and elsewhere in the labeling:

• Increased Risk of ALT Elevations.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

If ZEPATIER is administered with ribavirin, refer to the prescribing information for ribavirin for a description of ribavirin-associated adverse reactions.

The safety of ZEPATIER was assessed based on 2 placebo-controlled trials and 7 uncontrolled Phase 2 and 3 clinical trials in approximately 1700 subjects with chronic hepatitis C virus infection with compensated liver disease (with or without cirrhosis).

Adverse Reactions With ZEPATIER In Treatment-Naive Subjects

C-EDGE TN was a Phase 3 randomized, double-blind, placebo-controlled trial in 421 treatmentnaive (TN) subjects with HCV infection who received ZEPATIER or placebo one tablet once daily for 12 weeks. Adverse reactions (all intensity) occurring in C-EDGE TN in at least 5% of subjects treated with ZEPATIER for 12 weeks are presented in Table 3. In subjects treated with ZEPATIER who reported an adverse reaction, 73% had adverse reactions of mild severity. The type and severity of adverse reactions in subjects with compensated cirrhosis were comparable to those seen in subjects without cirrhosis. No subjects treated with ZEPATIER or placebo had serious adverse reactions. The proportion of subjects treated with ZEPATIER or placebo who permanently discontinued treatment due to adverse reactions was 1% in each group.

Table 3: Adverse Reactions (All Intensity) Reported in ≥5% of Treatment-Naive Subjects with HCV Treated with ZEPATIER for 12 Weeks in C-EDGE TN

C-EDGE COINFECTION was a Phase 3 open-label trial in 218 treatment-naive HCV/HIV co-infected subjects who received ZEPATIER one tablet once daily for 12 weeks. Adverse reactions (all intensity) reported in C-EDGE COINFECTION in at least 5% of subjects treated with ZEPATIER for 12 weeks were fatigue (7%), headache (7%), nausea (5%), insomnia (5%), and diarrhea (5%). No subjects reported serious adverse reactions or discontinued treatment due to adverse reactions. No subjects switched their antiretroviral therapy regimen due to loss of plasma HIV-1 RNA suppression. Median increase in CD4+ T-cell counts of 31 cells per mm³ was observed at the end of 12 weeks of treatment.

Adverse Reactions With ZEPATIER With Or Without Ribavirin In Treatment-Experienced Subjects

C-EDGE TE was a Phase 3 randomized, open-label trial in treatment-experienced (TE) subjects. Adverse reactions of moderate or severe intensity reported in C-EDGE TE in at least 2% of subjects treated with ZEPATIER one tablet once daily for 12 weeks or ZEPATIER one tablet once daily with ribavirin for 16 weeks are presented in Table 4. No subjects treated with ZEPATIER without ribavirin for 12 weeks reported serious adverse reactions or discontinued treatment due to adverse reactions. The proportion of subjects treated with ZEPATIER with ribavirin for 16 weeks with serious adverse reactions was 1%. The proportion of subjects treated with ZEPATIER with ribavirin for 16 weeks who permanently discontinued treatment due to adverse reactions was 3%. The type and severity of adverse reactions in subjects with cirrhosis were comparable to those seen in subjects without cirrhosis.

Table 4: Adverse Reactions (Moderate or Severe Intensity) Reported in ≥2% of PegIFN/RBV-Experienced Subjects with HCV Treated with ZEPATIER for 12 Weeks or ZEPATIER + Ribavirin for 16 Weeks in C-EDGE TE

The type and severity of adverse reactions with ZEPATIER with or without ribavirin in 10 treatment-experienced subjects with HCV/HIV co-infection were comparable to those reported in subjects without HIV co-infection. Median increase in CD4+ T-cell counts of 32 cells/mm³ was observed at the end of 12 weeks of treatment with ZEPATIER alone. In subjects treated with ZEPATIER with ribavirin for 16 weeks, CD4+ T-cell counts decreased a median of 135 cells per mm³ at the end of treatment. No subjects switched their antiretroviral therapy regimen due to loss of plasma HIV-1 RNA suppression. No subject experienced an AIDS-related opportunistic infection.

C-SALVAGE was a Phase 2 open-label trial in 79 PegIFN/RBV/PI-experienced subjects. Adverse reactions of moderate or severe intensity reported in C-SALVAGE in at least 2% of subjects treated with ZEPATIER once daily with ribavirin for 12 weeks were fatigue (3%) and insomnia (3%). No subjects reported serious adverse reactions or discontinued treatment due to adverse reactions.

Adverse Reactions With ZEPATIER In Subjects With Severe Renal Impairment Including Subjects On Hemodialysis

The safety of elbasvir and grazoprevir in comparison to placebo in subjects with severe renal impairment (Stage 4 or Stage 5 chronic kidney disease, including subjects on hemodialysis) and chronic hepatitis C virus infection with compensated liver disease (with or without cirrhosis) was assessed in 235 subjects (C-SURFER). The adverse reactions (all intensity) occurring in at least 5% of subjects treated with ZEPATIER for 12 weeks are presented in Table 5. In subjects treated with ZEPATIER who reported an adverse reaction, 76% had adverse reactions of mild severity. The proportion of subjects treated with ZEPATIER or placebo with serious adverse reactions was less than 1% in each treatment arm, and less than 1% and 3% of subjects, respectively, permanently discontinued treatment due to adverse reactions in each treatment arm.

Table 5: Adverse Reactions (All Intensity) Reported in ≥5% of Treatment-Naive or PegIFN/RBV-Experienced Subjects with Stage 4 or 5 Chronic Kidney Disease and HCV Treated with ZEPATIER for 12 Weeks in C-SURFER

Laboratory Abnormalities In Subjects Receiving ZEPATIER With Or Without Ribavirin

Serum ALT Elevations

During clinical trials with ZEPATIER with or without ribavirin, regardless of treatment duration, 1% (12/1599) of subjects experienced elevations of ALT from normal levels to greater than 5 times the ULN, generally at or after treatment week 8 (mean onset time 10 weeks, range 6-12 weeks). These late ALT elevations were typically asymptomatic. Most late ALT elevations resolved with ongoing therapy with ZEPATIER or after completion of therapy. The frequency of late ALT elevations was higher in subjects with higher grazoprevir plasma concentrations. The incidence of late ALT elevations was not affected by treatment duration. Cirrhosis was not a risk factor for late ALT elevations.

Serum Bilirubin Elevations

During clinical trials with ZEPATIER with or without ribavirin, regardless of treatment duration, elevations in bilirubin at greater than 2.5 times ULN were observed in 6% of subjects receiving ZEPATIER with ribavirin compared to less than 1% in those receiving ZEPATIER alone. These bilirubin increases were predominately indirect and generally observed in association with ribavirin co-administration. Bilirubin elevations were typically not associated with serum ALT elevations.

Decreased Hemoglobin

During clinical trials with ZEPATIER with or without ribavirin, the mean change from baseline in hemoglobin levels in subjects treated with ZEPATIER for 12 weeks was –0.3 g per dL and with ZEPATIER with ribavirin for 16 weeks was approximately.2.2 g per dL. Hemoglobin declined during the first 8 weeks of treatment, remained low during the remainder of treatment, and normalized to baseline levels during follow-up. Less than 1% of subjects treated with ZEPATIER with ribavirin had hemoglobin levels decrease to less than 8.5 g per dL during treatment. No subjects treated with ZEPATIER alone had a hemoglobin level less than 8.5 g per dL.

DRUG INTERACTIONS

Potential For Drug Interactions

Grazoprevir is a substrate of OATP1B1/3 transporters. Co-administration of ZEPATIER with OATP1B1/3 inhibitors that are known or expected to significantly increase grazoprevir plasma concentrations is contraindicated , and Table 2.

Elbasvir and grazoprevir are substrates of CYP3A and P-gp, but the role of intestinal P-gp in the absorption of elbasvir and grazoprevir appears to be minimal. Co-administration of moderate or strong inducers of CYP3A with ZEPATIER may decrease elbasvir and grazoprevir plasma concentrations, leading to reduced therapeutic effect of ZEPATIER. Co-administration of ZEPATIER with strong CYP3A inducers or efavirenz is contraindicated , and Table 2. Co-administration of ZEPATIER with moderate CYP3A inducers is not recommended , and Table 6. Co-administration of ZEPATIER with strong CYP3A inhibitors may increase elbasvir and grazoprevir concentrations. Co-administration of ZEPATIER with certain strong CYP3A inhibitors is not recommended , and Table 6.

Fluctuations in INR values may occur in patients receiving warfarin concomitantly with HCV treatment, including treatment with ZEPATIER. Frequent monitoring of INR values is recommended during treatment and post-treatment follow-up.

Established And Other Potentially Significant Drug Interactions

If dose adjustments of concomitant medications are made due to treatment with ZEPATIER, doses should be readjusted after administration of ZEPATIER is completed.

Table 6 provides a listing of established or potentially clinically significant drug interactions. The drug interactions described are based on studies conducted with either ZEPATIER, the components of ZEPATIER (elbasvir [EBR] and grazoprevir [GZR]) as individual agents, or are predicted drug interactions that may occur with ZEPATIER.

Table 6: Potentially Significant Drug Interactions: Alteration in Dose May Be Recommended Based on Results from Drug Interaction Studies or Predicted Interactions*

Drugs Without Clinically Significant Interactions With ZEPATIER

The interaction between the components of ZEPATIER (elbasvir or grazoprevir) or ZEPATIER and the following drugs were evaluated in clinical studies, and no dose adjustments are needed when ZEPATIER is used with the following drugs individually: acid reducing agents (proton pump inhibitors, H2 blockers, antacids), buprenorphine/naloxone, digoxin, dolutegravir, methadone, mycophenolate mofetil, oral contraceptive pills, phosphate binders, pitavastatin, pravastatin, prednisone, raltegravir, ribavirin, rilpivirine, tenofovir disoproxil fumarate, and sofosbuvir.

No clinically relevant drug-drug interaction is expected when ZEPATIER is co-administered with abacavir, emtricitabine, entecavir, and lamivudine.

Risk Summary

No adequate human data are available to establish whether or not ZEPATIER poses a risk to pregnancy outcomes. In animal reproduction studies, no evidence of adverse developmental outcomes was observed with the components of ZEPATIER (elbasvir or grazoprevir) at exposures greater than those in humans at the recommended human dose (RHD). During organogenesis in the rat and rabbit, systemic exposures (AUC) were approximately 10 and 18 times (for elbasvir) and 117 and 41 times (for grazoprevir), respectively, the exposure in humans at the RHD. In rat pre/postnatal developmental studies, maternal systemic exposures (AUC) to elbasvir and grazoprevir were approximately 10 and 78 times, respectively, the exposure in humans at the RHD.

The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

If ZEPATIER is administered with ribavirin, the combination regimen is contraindicated in pregnant women and in men whose female partners are pregnant. Refer to the ribavirin prescribing information for more information on use in pregnancy.

Data

Animal Data

Elbasvir: Elbasvir was administered orally at up to 1000 mg/kg/day to pregnant rats and rabbits on gestation days 6 to 20 and 7 to 20, respectively, and also to rats on gestation day 6 to lactation/postpartum day 20. No effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at up to the highest dose tested. Systemic exposures (AUC) to elbasvir were approximately 10 (rats) and 18 (rabbits) times the exposure in humans at the RHD. In both species, elbasvir has been shown to cross the placenta, with fetal plasma concentrations of up to 0.8% (rabbits) and 2.2% (rats) that of maternal concentrations observed on gestation day 20.

Grazoprevir: Grazoprevir was administered to pregnant rats (oral doses up to 400 mg/kg/day) and rabbits (intravenous doses up to 100 mg/kg/day) on gestation days 6 to 20 and 7 to 20, respectively, and also to rats (oral doses up to 400 mg/kg/day) on gestation day 6 to lactation/post-partum day 20. No effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at up to the highest dose tested. Systemic exposures (AUC) to grazoprevir were ≥78 (rats) and 41 (rabbits) times the exposure in humans at the RHD. In both species, grazoprevir has been shown to cross the placenta, with fetal plasma concentrations of up to 7% (rabbits) and 89% (rats) that of maternal concentrations observed on gestation day 20.

The following adverse reaction is described below and elsewhere in the labeling:

• Increased Risk of ALT Elevations.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

If ZEPATIER is administered with ribavirin, refer to the prescribing information for ribavirin for a description of ribavirin-associated adverse reactions.

The safety of ZEPATIER was assessed based on 2 placebo-controlled trials and 7 uncontrolled Phase 2 and 3 clinical trials in approximately 1700 subjects with chronic hepatitis C virus infection with compensated liver disease (with or without cirrhosis).

Adverse Reactions With ZEPATIER In Treatment-Naive Subjects

C-EDGE TN was a Phase 3 randomized, double-blind, placebo-controlled trial in 421 treatmentnaive (TN) subjects with HCV infection who received ZEPATIER or placebo one tablet once daily for 12 weeks. Adverse reactions (all intensity) occurring in C-EDGE TN in at least 5% of subjects treated with ZEPATIER for 12 weeks are presented in Table 3. In subjects treated with ZEPATIER who reported an adverse reaction, 73% had adverse reactions of mild severity. The type and severity of adverse reactions in subjects with compensated cirrhosis were comparable to those seen in subjects without cirrhosis. No subjects treated with ZEPATIER or placebo had serious adverse reactions. The proportion of subjects treated with ZEPATIER or placebo who permanently discontinued treatment due to adverse reactions was 1% in each group.

Table 3: Adverse Reactions (All Intensity) Reported in ≥5% of Treatment-Naive Subjects with HCV Treated with ZEPATIER for 12 Weeks in C-EDGE TN

C-EDGE COINFECTION was a Phase 3 open-label trial in 218 treatment-naive HCV/HIV co-infected subjects who received ZEPATIER one tablet once daily for 12 weeks. Adverse reactions (all intensity) reported in C-EDGE COINFECTION in at least 5% of subjects treated with ZEPATIER for 12 weeks were fatigue (7%), headache (7%), nausea (5%), insomnia (5%), and diarrhea (5%). No subjects reported serious adverse reactions or discontinued treatment due to adverse reactions. No subjects switched their antiretroviral therapy regimen due to loss of plasma HIV-1 RNA suppression. Median increase in CD4+ T-cell counts of 31 cells per mm³ was observed at the end of 12 weeks of treatment.

Adverse Reactions With ZEPATIER With Or Without Ribavirin In Treatment-Experienced Subjects

C-EDGE TE was a Phase 3 randomized, open-label trial in treatment-experienced (TE) subjects. Adverse reactions of moderate or severe intensity reported in C-EDGE TE in at least 2% of subjects treated with ZEPATIER one tablet once daily for 12 weeks or ZEPATIER one tablet once daily with ribavirin for 16 weeks are presented in Table 4. No subjects treated with ZEPATIER without ribavirin for 12 weeks reported serious adverse reactions or discontinued treatment due to adverse reactions. The proportion of subjects treated with ZEPATIER with ribavirin for 16 weeks with serious adverse reactions was 1%. The proportion of subjects treated with ZEPATIER with ribavirin for 16 weeks who permanently discontinued treatment due to adverse reactions was 3%. The type and severity of adverse reactions in subjects with cirrhosis were comparable to those seen in subjects without cirrhosis.

Table 4: Adverse Reactions (Moderate or Severe Intensity) Reported in ≥2% of PegIFN/RBV-Experienced Subjects with HCV Treated with ZEPATIER for 12 Weeks or ZEPATIER + Ribavirin for 16 Weeks in C-EDGE TE

The type and severity of adverse reactions with ZEPATIER with or without ribavirin in 10 treatment-experienced subjects with HCV/HIV co-infection were comparable to those reported in subjects without HIV co-infection. Median increase in CD4+ T-cell counts of 32 cells/mm³ was observed at the end of 12 weeks of treatment with ZEPATIER alone. In subjects treated with ZEPATIER with ribavirin for 16 weeks, CD4+ T-cell counts decreased a median of 135 cells per mm³ at the end of treatment. No subjects switched their antiretroviral therapy regimen due to loss of plasma HIV-1 RNA suppression. No subject experienced an AIDS-related opportunistic infection.

C-SALVAGE was a Phase 2 open-label trial in 79 PegIFN/RBV/PI-experienced subjects. Adverse reactions of moderate or severe intensity reported in C-SALVAGE in at least 2% of subjects treated with ZEPATIER once daily with ribavirin for 12 weeks were fatigue (3%) and insomnia (3%). No subjects reported serious adverse reactions or discontinued treatment due to adverse reactions.

Adverse Reactions With ZEPATIER In Subjects With Severe Renal Impairment Including Subjects On Hemodialysis

The safety of elbasvir and grazoprevir in comparison to placebo in subjects with severe renal impairment (Stage 4 or Stage 5 chronic kidney disease, including subjects on hemodialysis) and chronic hepatitis C virus infection with compensated liver disease (with or without cirrhosis) was assessed in 235 subjects (C-SURFER). The adverse reactions (all intensity) occurring in at least 5% of subjects treated with ZEPATIER for 12 weeks are presented in Table 5. In subjects treated with ZEPATIER who reported an adverse reaction, 76% had adverse reactions of mild severity. The proportion of subjects treated with ZEPATIER or placebo with serious adverse reactions was less than 1% in each treatment arm, and less than 1% and 3% of subjects, respectively, permanently discontinued treatment due to adverse reactions in each treatment arm.

Table 5: Adverse Reactions (All Intensity) Reported in ≥5% of Treatment-Naive or PegIFN/RBV-Experienced Subjects with Stage 4 or 5 Chronic Kidney Disease and HCV Treated with ZEPATIER for 12 Weeks in C-SURFER

Laboratory Abnormalities In Subjects Receiving ZEPATIER With Or Without Ribavirin

Serum ALT Elevations

During clinical trials with ZEPATIER with or without ribavirin, regardless of treatment duration, 1% (12/1599) of subjects experienced elevations of ALT from normal levels to greater than 5 times the ULN, generally at or after treatment week 8 (mean onset time 10 weeks, range 6-12 weeks). These late ALT elevations were typically asymptomatic. Most late ALT elevations resolved with ongoing therapy with ZEPATIER or after completion of therapy. The frequency of late ALT elevations was higher in subjects with higher grazoprevir plasma concentrations. The incidence of late ALT elevations was not affected by treatment duration. Cirrhosis was not a risk factor for late ALT elevations.

Serum Bilirubin Elevations

During clinical trials with ZEPATIER with or without ribavirin, regardless of treatment duration, elevations in bilirubin at greater than 2.5 times ULN were observed in 6% of subjects receiving ZEPATIER with ribavirin compared to less than 1% in those receiving ZEPATIER alone. These bilirubin increases were predominately indirect and generally observed in association with ribavirin co-administration. Bilirubin elevations were typically not associated with serum ALT elevations.

Decreased Hemoglobin

During clinical trials with ZEPATIER with or without ribavirin, the mean change from baseline in hemoglobin levels in subjects treated with ZEPATIER for 12 weeks was –0.3 g per dL and with ZEPATIER with ribavirin for 16 weeks was approximately.2.2 g per dL. Hemoglobin declined during the first 8 weeks of treatment, remained low during the remainder of treatment, and normalized to baseline levels during follow-up. Less than 1% of subjects treated with ZEPATIER with ribavirin had hemoglobin levels decrease to less than 8.5 g per dL during treatment. No subjects treated with ZEPATIER alone had a hemoglobin level less than 8.5 g per dL.

Human experience of overdose with ZEPATIER is limited. No specific antidote is available for overdose with ZEPATIER. In case of overdose, it is recommended that the patient be monitored for any signs or symptoms of adverse reactions and appropriate symptomatic treatment instituted.

Hemodialysis does not remove elbasvir or grazoprevir since elbasvir and grazoprevir are highly bound to plasma protein.

Cardiac Electrophysiology

Thorough QT studies have been conducted for elbasvir and grazoprevir.

The effect of elbasvir 700 mg on QTc interval was evaluated in a randomized, single-dose, placebo-and active-controlled (moxifloxacin 400 mg) 3-period crossover thorough QT trial in 42 healthy subjects. At a concentration 3 to 4 times the therapeutic concentration, elbasvir does not prolong QTc to any clinically relevant extent.

The effect of grazoprevir 1600 mg (16 times the approved dose) on QTc interval was evaluated in a randomized, single-dose, placebo-and active-controlled (moxifloxacin 400 mg) 3-period crossover thorough QT trial in 41 healthy subjects. At a concentration 40 times the therapeutic concentration, grazoprevir does not prolong QTc to any clinically relevant extent.

The pharmacokinetic properties of elbasvir and grazoprevir have been evaluated in non-HCVinfected adult subjects and in HCV-infected adult subjects. Elbasvir pharmacokinetics were similar in healthy subjects and HCV-infected subjects and were approximately dose-proportional over the range of 5-100 mg once daily. Grazoprevir oral exposures are approximately 2-fold greater in HCV-infected subjects as compared to healthy subjects. Grazoprevir pharmacokinetics increased in a greater than dose-proportional manner over the range of 10-800 mg once daily in HCV-infected subjects. Ribavirin co-administration with ZEPATIER had no clinically relevant impact on plasma AUC and Cmax of elbasvir and grazoprevir compared to administration of ZEPATIER alone. The geometric mean steady-state pharmacokinetic parameter values for elbasvir and grazoprevir in non-cirrhotic HCV-infected subjects are provided in Table 7. Following once daily administration of ZEPATIER to HCV-infected subjects, elbasvir and grazoprevir reached steady state within approximately 6 days.

Table 7: Geometric Mean (90% Confidence Interval) for Elbasvir and Grazoprevir Steady State Pharmacokinetic Parameter Values in Non-Cirrhotic HCV-Infected Subjects Estimated Based on Population Pharmacokinetic Modeling

Absorption

Following administration of ZEPATIER to HCV-infected subjects, elbasvir peak concentrations occur at a median Tmax of 3 hours (range of 3 to 6 hours); grazoprevir peak concentrations occur at a median Tmax of 2 hours (range of 30 minutes to 3 hours). The absolute bioavailability of elbasvir is estimated to be 32%, and grazoprevir is estimated to be 27%.

Effect of Food

Relative to fasting conditions, the administration of a single dose of ZEPATIER with a high-fat (900 kcal, 500 kcal from fat) meal to healthy subjects resulted in decreases in elbasvir AUC0-inf and Cmax of approximately 11% and 15%, respectively, and increases in grazoprevir AUC0-inf and Cmax of approximately 1.5-fold and 2.8-fold, respectively. These differences in elbasvir and grazoprevir exposure are not clinically relevant; therefore, ZEPATIER may be taken without regard to food.

Distribution

Elbasvir and grazoprevir are extensively bound (greater than 99.9% and 98.8%, respectively) to human plasma proteins. Both elbasvir and grazoprevir bind to human serum albumin and α1-acid glycoprotein. Estimated apparent volume of distribution values of elbasvir and grazoprevir are approximately 680 L and 1250 L, respectively, based on population pharmacokinetic modeling.

In preclinical distribution studies, elbasvir distributes into most tissues including the liver; whereas grazoprevir distributes predominantly to the liver likely facilitated by the active transport through the OATP1B1/3 liver uptake transporter.

Elimination

The geometric mean apparent terminal half-life for elbasvir (50 mg) and grazoprevir (100 mg) is approximately 24 and 31 hours, respectively, in HCV-infected subjects.

Metabolism

Elbasvir and grazoprevir are partially eliminated by oxidative metabolism, primarily by CYP3A. No circulating metabolites of either elbasvir or grazoprevir were detected in human plasma.

Excretion

The primary route of elimination of elbasvir and grazoprevir is through feces with almost all (greater than 90%) of radiolabeled dose recovered in feces compared to less than 1% in urine.