ZEPATIER is a fixed-dose combination tablet containing elbasvir and grazoprevir for oral administration. Elbasvir is an HCV NS5A inhibitor, and grazoprevir is an HCV NS3/4A protease inhibitor. Each tablet contains 50 mg elbasvir and 100 mg grazoprevir. The tablets include the following inactive ingredients: colloidal silicon dioxide, copovidone, croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate, mannitol, microcrystalline cellulose, sodium chloride, sodium lauryl sulfate, and vitamin E polyethylene glycol succinate. The tablets are film-coated with a coating material containing the following inactive ingredients: carnauba wax, ferrosoferric oxide, hypromellose, iron oxide red, iron oxide yellow, lactose monohydrate, titanium dioxide, and triacetin. Elbasvir: The IUPAC name for elbasvir is Dimethyl N , N' -([(6 S )-6-phenylindolo[1,2- c ][1,3]benzoxazine-3,10-diyl]bis{1 H -imidazole-5,2-diyl-(2 S )-pyrrolidine-2,1-diyl[(2 S )-3-methyl-1-oxobutane-1,2-diyl]})dicarbamate. It has a molecular formula of C 49 H 55 N 9 O 7 and a molecular weight of 882.02. It has the following structural formula: Elbasvir is practically insoluble in water (less than 0.1 mg per mL) and very slightly soluble in ethanol (0.2 mg per mL), but is very soluble in ethyl acetate and acetone. Chemical Structure Grazoprevir: The IUPAC name for grazoprevir is (1a R ,5 S ,8 S ,10 R ,22a R )- N -[(1 R ,2 S )-1-[(Cyclopropylsulfonamido)carbonyl]-2-ethenylcyclopropyl]-14-methoxy-5-(2-methylpropan-2-yl)-3,6-dioxo-1,1a,3,4,5,6,9,10,18,19,20,21,22,22a-tetradecahydro-8 H -7,10-methanocyclopropa[18,19][1,10,3,6]dioxadiazacyclononadecino[11,12- b ]quinoxaline-8-carboxamide. It has a molecular formula of C 38 H 50 N 6 O 9 S and a molecular weight of 766.90. It has the following structural formula: Grazoprevir is practically insoluble in water (less than 0.1 mg per mL) but is freely soluble in ethanol and some organic solvents (e.g., acetone, tetrahydrofuran and N,N-dimethylformamide). Chemical Structure

ZEPATIER ® is indicated for the treatment of chronic hepatitis C virus (HCV) genotype 1 or 4 infection in adult and pediatric patients 12 years of age and older or weighing at least 30 kg. ZEPATIER is indicated for use with ribavirin in certain patient populations . ZEPATIER is a fixed-dose combination product containing elbasvir, a hepatitis C virus (HCV) NS5A inhibitor, and grazoprevir, an HCV NS3/4A protease inhibitor, and is indicated for treatment of chronic HCV genotype 1 or 4 infection in adult and pediatric patients 12 years of age and older or weighing at least 30 kg. ZEPATIER is indicated for use with ribavirin in certain patient populations.

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. Tablets: 50 mg elbasvir and 100 mg grazoprevir

Testing Prior to Initiation of Therapy: Test all patients for HBV infection by measuring HBsAg and anti-HBc. Genotype 1a: Testing for the presence of virus with NS5A resistance-associated polymorphisms is recommended. Obtain hepatic laboratory testing. Recommended dosage in adult and pediatric patients 12 years of age and older or weighing at least 30 kg: One tablet taken orally once daily with or without food. Dosage Regimens and Durations for ZEPATIER in Patients with Genotype 1 or 4 HCV with or without Cirrhosis Patient Population Treatment Duration Genotype 1a: Treatment-naïve or PegIFN/RBV-experienced Peginterferon alfa + ribavirin. without baseline NS5A polymorphisms Polymorphisms at amino acid positions 28, 30, 31, or 93. ZEPATIER 12 weeks Genotype 1a: Treatment-naïve or PegIFN/RBV-experienced with baseline NS5A polymorphisms ZEPATIER + ribavirin 16 weeks Genotype 1b: Treatment-naïve or PegIFN/RBV-experienced ZEPATIER 12 weeks Genotype 1a or 1b: PegIFN/RBV/PI-experienced Peginterferon alfa + ribavirin + HCV NS3/4A protease inhibitor. ZEPATIER + ribavirin 12 weeks Genotype 4: Treatment-naïve ZEPATIER 12 weeks Genotype 4: PegIFN/RBV-experienced ZEPATIER + ribavirin 16 weeks HCV/HIV-1 co-infection: Follow the dosage recommendations in the table above. Renal Impairment, including hemodialysis: No dosage adjustment of ZEPATIER is recommended. Refer to ribavirin prescribing information for ribavirin dosing and dosage modifications

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

Recommended Dosage in Adult and Pediatric Patients 12 Years of Age and Older or Weighing at Least 30 kg 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 . 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 Patient Population Treatment Duration Genotype 1a: Treatment-naïve or PegIFN/RBV-experienced Patients who have failed treatment with peginterferon alfa (PegIFN) + ribavirin (RBV). without baseline NS5A polymorphisms NS5A resistance-associated polymorphisms at amino acid positions 28, 30, 31, or 93. See section 2.1 Testing prior to the initiation of therapy, subsection NS5A resistance testing in HCV genotype 1a-infected patients. ZEPATIER 12 weeks Genotype 1a: Treatment-naïve or PegIFN/RBV-experienced with baseline NS5A polymorphisms ZEPATIER + RBV For patients with CrCl greater than 50 mL per minute, the recommended dosage of ribavirin is weight-based (less than 66 kg = 800 mg per day, 66 to 80 kg = 1000 mg per day, 81 to 105 kg = 1200 mg per day, greater than 105 kg = 1400 mg per day) administered in two divided doses with food. For patients with CrCl less than or equal to 50 mL per minute, including patients receiving hemodialysis, refer to the ribavirin tablet prescribing information for the correct ribavirin dosage. In pediatric patients, the dosing for ribavirin is weight-based in two divided doses. Refer to the ribavirin tablet prescribing information for the correct ribavirin dosage regimen. 16 weeks Genotype 1b: Treatment-naïve or PegIFN/RBV-experienced ZEPATIER 12 weeks Genotype 1a The optimal ZEPATIER-based treatment regimen and duration of therapy for PegIFN/RBV/PI-experienced genotype 1a-infected patients with one or more baseline NS5A resistance-associated polymorphisms at positions 28, 30, 31, and 93 has not been established. or 1b: PegIFN/RBV/PI-experienced Patients who have failed treatment with PegIFN + RBV + HCV NS3/4A protease inhibitor (PI): boceprevir, simeprevir, or telaprevir. ZEPATIER + RBV 12 weeks Genotype 4: Treatment-Naïve ZEPATIER 12 weeks Genotype 4: PegIFN/RBV-experienced ZEPATIER + RBV 16 weeks 2.3 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) or those with any history of prior hepatic decompensation .

Risk of Hepatitis B Virus Reactivation: Test all patients for evidence of current or prior HBV infection before initiation of HCV treatment. Monitor HCV/HBV coinfected patients for HBV reactivation and hepatitis flare during HCV treatment and post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated. ALT Elevations: Perform hepatic laboratory testing prior to therapy, at treatment week 8, and as clinically indicated. For patients receiving 16 weeks of therapy, perform additional hepatic laboratory testing at treatment week 12. For ALT elevations on ZEPATIER, follow recommendations in full prescribing information. Risk of Hepatic Decompensation/Failure in Patients with Evidence of Advanced Liver Disease: Hepatic decompensation/failure, including fatal outcomes, have been reported mostly in patients with cirrhosis and baseline moderate or severe liver impairment (Child-Pugh B or C) treated with HCV NS3/4A protease inhibitor-containing regimens. Monitor for clinical and laboratory evidence of hepatic decompensation. Discontinue ZEPATIER in patients who develop evidence of hepatic decompensation/failure. Risk Associated with Ribavirin Combination Treatment: If ZEPATIER is administered with ribavirin, the warnings and precautions for ribavirin also apply. 5.1 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)

Risk of Hepatic Decompensation/Failure in Patients with Evidence of Advanced Liver Disease Postmarketing cases of hepatic decompensation/failure, including those with fatal outcomes, have been reported in patients treated with HCV NS3/4A protease inhibitor-containing regimens, including ZEPATIER. Reported cases occurred in patients treated with HCV NS3/4A protease inhibitor-containing regimens with baseline cirrhosis with and without moderate or severe liver impairment (Child-Pugh B or C) as well as some patients without cirrhosis. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hepatic laboratory testing should be performed in all patients . In patients with compensated cirrhosis (Child-Pugh A) or evidence of advanced liver disease, such as portal hypertension, more frequent hepatic laboratory testing may be warranted; and patients should be monitored for signs and symptoms of hepatic decompensation such as the presence of jaundice, ascites, hepatic encephalopathy, and variceal hemorrhage. Discontinue ZEPATIER in patients who develop evidence of hepatic decompensation/failure. ZEPATIER is contraindicated in patients with moderate to severe hepatic impairment (Child-Pugh B or C) or those with any history of prior hepatic decompensation

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 .

Co-administration of ZEPATIER with moderate CYP3A inducers is not recommended as they may decrease the plasma concentration of ZEPATIER. Co-administration of ZEPATIER with certain strong CYP3A inhibitors is not recommended as they may increase the plasma concentration of ZEPATIER. Clearance of HCV infection with direct-acting antivirals may lead to changes in hepatic function, which may impact safe and effective use of concomitant medications. Frequent monitoring of relevant laboratory parameters (INR or blood glucose) and dose adjustments of certain concomitant medications may be necessary. Consult the full prescribing information prior to and during treatment for potential drug interactions. ( 4 , 5.5 , 7 , 12.3 ) 7.1 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 . 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 . Co-administration of ZEPATIER with moderate CYP3A inducers is not recommended . 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

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. Clearance of HCV infection with direct-acting antivirals may lead to changes in hepatic function, which may impact the safe and effective use of concomitant medications. For example, altered blood glucose control resulting in serious symptomatic hypoglycemia has been reported in diabetic patients in postmarketing case reports and published epidemiological studies. Management of hypoglycemia in these cases required either discontinuation or dose modification of concomitant medications used for diabetes treatment. Frequent monitoring of relevant laboratory parameters (e.g., International Normalized Ratio [INR] in patients taking warfarin, blood glucose levels in diabetic patients) or drug concentrations of concomitant medications such as CYP450 substrates with a narrow therapeutic index (e.g., certain immunosuppressants) is recommended to ensure safe and effective use. Dose adjustments of concomitant medications may be necessary. 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 This table is not all inclusive. Concomitant Drug Class: Drug Name Effect on Concentration ↓ = decrease, ↑ = increase Clinical Comment Antibiotics : Nafcillin ↓ EBR ↓ GZR Co-administration of ZEPATIER with nafcillin may lead to reduced therapeutic effect of ZEPATIER. Co-administration is not recommended. Antifungals: oral Ketoconazole These interactions have been studied in healthy adults. ↑ EBR ↑ GZR Co-administration of oral ketoconazole is not recommended. Endothelin Antagonists: Bosentan ↓ EBR ↓ GZR Co-administration of ZEPATIER with bosentan may lead to reduced therapeutic effect of ZEPATIER. Co-administration is not recommended. Immunosuppressants: Tacrolimus ↑ tacrolimus Frequent monitoring of tacrolimus whole blood concentrations, changes in renal function, and tacrolimus-associated adverse events upon the initiation of co-administration is recommended. HIV Medications: Etravirine ↓ EBR ↓ GZR Co-administration of ZEPATIER with etravirine may lead to reduced therapeutic effect of ZEPATIER. Co-administration is not recommended. Elvitegravir/ cobicistat/ emtricitabine/ tenofovir (disoproxil fumarate or alafenamide) ↑ EBR ↑ GZR Co-administration of cobicistat-containing regimens is not recommended. HMG-CoA Reductase Inhibitors See Drug Interactions for a list of HMG Co-A reductase inhibitors without clinically relevant interactions with ZEPATIER. : Atorvastatin ↑ atorvastatin The dose of atorvastatin should not exceed a daily dose of 20 mg when co-administered with ZEPATIER. Rosuvastatin ↑ rosuvastatin The dose of rosuvastatin should not exceed a daily dose of 10 mg when co-administered with ZEPATIER. Fluvastatin Lovastatin Simvastatin ↑ fluvastatin ↑ lovastatin ↑ simvastatin Statin-associated adverse events such as myopathy should be closely monitored. The lowest necessary dose should be used when co-administered with ZEPATIER. Wakefulness-Promoting Agents: Modafinil ↓ EBR ↓ GZR Co-administration of ZEPATIER with modafinil may lead to reduced therapeutic effect of ZEPATIER. Co-administration is not recommended

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.