Sofosbuvir and Velpatasvir

1 INDICATIONS AND USAGE Sofosbuvir and velpatasvir is indicated for the treatment of adults and pediatric patients 3 years of age and older with chronic hepatitis C virus (HCV) genotype 1, 2, 3, 4, 5, or 6 infection [see Dosage and Administration (2.2 , 2.3 , 2.4 ) and Clinical Studies (14) ] : without cirrhosis or with compensated cirrhosis with decompensated cirrhosis for use in combination with ribavirin. Sofosbuvir and velpatasvir is a fixed-dose combination of sofosbuvir, a hepatitis C virus (HCV) nucleotide analog NS5B polymerase inhibitor, and velpatasvir, an HCV NS5A inhibitor, and is indicated for the treatment of adults and pediatric patients 3 years of age and older with chronic HCV genotype 1, 2, 3, 4, 5, or 6 infection ( 1 ): without cirrhosis or with compensated cirrhosis with decompensated cirrhosis for use in combination with ribavirin.

2 DOSAGE AND ADMINISTRATION Testing prior to the initiation of therapy: Test all patients for HBV infection by measuring HBsAg and anti-HBc. ( 2.1 ) See recommended treatment regimen and duration in patients 3 years of age and older with genotypes 1, 2, 3, 4, 5, or 6 HCV in table below: ( 2.2 ) Patient Population Regimen and Duration Treatment-naïve and treatment-experienced In clinical trials, regimens contained peginterferon alfa/ribavirin with or without an HCV NS3/4A protease inhibitor (boceprevir, simeprevir, or telaprevir). , without cirrhosis and with compensated cirrhosis (Child-Pugh A) Sofosbuvir and velpatasvir 12 weeks Treatment-naïve and treatment-experienced , with decompensated cirrhosis (Child-Pugh B and C) Sofosbuvir and velpatasvir + ribavirin 12 weeks Recommended dosage in adults: One tablet (400 mg of sofosbuvir and 100 mg of velpatasvir) taken orally once daily with or without food. ( 2.3 ) Recommended dosage in pediatric patients 3 years and older: Recommended dosage is based on weight. Refer to Table 2 of the full prescribing information for specific dosing guidelines based on body weight. ( 2.4 ) For pediatric patients less than 6 years of age, administer sofosbuvir and velpatasvir (EPCLUSA) oral pellets with food. ( 2.4 ) Instructions for Use should be followed for preparation and administration of sofosbuvir and velpatasvir (EPCLUSA) oral pellets. ( 2.5 ) HCV/HIV-1 coinfection: For patients with HCV/HIV-1 coinfection, follow the dosage recommendations in the table above. ( 2.2 ) For treatment-naïve and treatment-experienced liver transplant recipients without cirrhosis or with compensated cirrhosis (Child-Pugh A), the recommended regimen is sofosbuvir and velpatasvir once daily for 12 weeks. ( 2.2 ) If used in combination with ribavirin, follow the recommendations for ribavirin dosing and dosage modifications. ( 2.3 , 2.4 ) For patients with renal impairment including end stage renal disease on dialysis, follow the dosage recommendations in the table above. ( 2.6 ) 2.1 Testing Prior to the Initiation of Therapy 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 sofosbuvir and velpatasvir [see Warnings and Precautions (5.1) ]. 2.2 Recommended Treatment Regimen and Duration in Patients 3 Years of Age and Older Table 1 shows the recommended treatment regimen and duration based on patient population . For patients with HCV/HIV-1 coinfection follow the dosage recommendations in Table 1. For treatment-naïve and treatment-experienced liver transplant recipients without cirrhosis or with compensated cirrhosis (Child-Pugh A), the recommended regimen is sofosbuvir and velpatasvir once daily for 12 weeks [see Clinical Studies (14.3 and 14.5) ]. Refer to Drug Interactions (7) for dosage recommendations for concomitant drugs. Table 1 Recommended Treatment Regimen and Duration in Patients 3 Years of Age and Older with Genotype 1, 2, 3, 4, 5, or 6 HCV Patient Population Treatment Regimen and Duration Treatment-naïve and treatment-experienced In clinical trials in adults, regimens contained peginterferon alfa/ribavirin with or without an HCV NS3/4A protease inhibitor (boceprevir, simeprevir, or telaprevir). , without cirrhosis and with compensated cirrhosis (Child-Pugh A) Sofosbuvir and velpatasvir 12 weeks Treatment-naïve and treatment-experienced , with decompensated cirrhosis (Child-Pugh B or C) Sofosbuvir and velpatasvir + ribavirin See Dosage and Administration 2.3 and 2.4 for ribavirin dosage recommendations. 12 weeks 2.3 Recommended Dosage in Adults The recommended dosage of sofosbuvir and velpatasvir in adults is one tablet (400 mg sofosbuvir and 100 mg velpatasvir) taken orally once daily with or without food [see Clinical Pharmacology (12.3) ] . When administered with sofosbuvir and velpatasvir, the recommended dosage of ribavirin is based on weight (administered with f…

5 WARNINGS AND PRECAUTIONS 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. ( 5.1 ) Bradycardia with amiodarone coadministration: Serious symptomatic bradycardia may occur in patients taking amiodarone, particularly in patients also receiving beta blockers, or those with underlying cardiac comorbidities and/or advanced liver disease. Coadministration of amiodarone with sofosbuvir and velpatasvir is not recommended. In patients without alternative viable treatment options, cardiac monitoring is recommended. ( 5.2 , 7.3 ) 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 immunosuppressants 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 sofosbuvir and velpatasvir. In patients with serologic evidence of HBV infection, monitor for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV treatment with sofosbuvir and velpatasvir and during post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated. 5.2 Serious Symptomatic Bradycardia When Coadministered with Amiodarone Postmarketing cases of symptomatic bradycardia and cases requiring pacemaker intervention have been reported when amiodarone is coadministered with a sofosbuvir-containing regimen. A fatal cardiac arrest was reported in a patient taking amiodarone who was coadministered a sofosbuvir-containing regimen (HARVONI ® [ledipasvir/sofosbuvir]). Bradycardia has generally occurred within hours to days, but cases have been observed up to 2 weeks after initiating HCV treatment. Patients also taking beta blockers, or those with underlying cardiac comorbidities and/or advanced liver disease may be at increased risk for symptomatic bradycardia with coadministration of amiodarone. Bradycardia generally resolved after discontinuation of HCV treatment. The mechanism for this effect is unknown. Coadministration of amiodarone with sofosbuvir and velpatasvir is not recommended. For patients taking amiodarone who have no other alternative viable treatment options and who will be coadministered sofosbuvir and velpatasvir: Counsel patients about the risk of symptomatic bradycardia. Cardiac monitoring in an in-patient setting for the first 48 hours of coadministration is recommended, after which outpatient or self-monitoring of the heart rate should occur on a daily basis through at least the first 2 weeks of treatment. Patients who are taking sofosbuvir and velpatasvir who need to start amiodarone therapy due to no other alternat…

4 CONTRAINDICATIONS Sofosbuvir and velpatasvir and ribavirin combination regimen is contraindicated in patients for whom ribavirin is contraindicated. Refer to the ribavirin prescribing information for a list of contraindications for ribavirin [see Dosage and Administration (2.2 , 2.3 , 2.4) ]. Sofosbuvir and velpatasvir and ribavirin combination regimen is contraindicated in patients for whom ribavirin is contraindicated. ( 4 )

7 DRUG INTERACTIONS P-gp inducers and/or moderate to strong CYP inducers (e.g., rifampin, St. John's wort, carbamazepine): May decrease concentrations of sofosbuvir and/or velpatasvir. Use of sofosbuvir and velpatasvir with P-gp inducers and/or moderate to strong CYP inducers is not recommended. ( 5.3 , 7 ) Consult the full prescribing information prior to use for potential drug interactions. ( 5.2 , 5.3 , 7 ) 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. ( 7.3 ) 7.1 Potential for Other Drugs to Affect Sofosbuvir and Velpatasvir Sofosbuvir and velpatasvir are substrates of drug transporters P-gp and BCRP while GS-331007 (the predominant circulating metabolite of sofosbuvir) is not. In vitro, slow metabolic turnover of velpatasvir by CYP2B6, CYP2C8, and CYP3A4 was observed. Drugs that are inducers of P-gp and/or moderate to strong inducers of CYP2B6, CYP2C8, or CYP3A4 (e.g., rifampin, St. John's wort, carbamazepine) may decrease plasma concentrations of sofosbuvir and/or velpatasvir, leading to reduced therapeutic effect of sofosbuvir and velpatasvir. The use of these agents with sofosbuvir and velpatasvir is not recommended [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3) ] . Sofosbuvir and velpatasvir may be coadministered with P-gp, BCRP, and CYP inhibitors. 7.2 Potential for Sofosbuvir and Velpatasvir to Affect Other Drugs Velpatasvir is an inhibitor of drug transporters P-gp, breast cancer resistance protein (BCRP), OATP1B1, OATP1B3, and OATP2B1. Coadministration of sofosbuvir and velpatasvir with drugs that are substrates of these transporters may increase the exposure of such drugs. 7.3 Established and Potentially Significant Drug Interactions 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 cytochrome P450 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 4 provides a listing of established or potentially clinically significant drug interactions. The drug interactions described are based on studies conducted with either sofosbuvir and velpatasvir tablets (400 mg/100 mg), or sofosbuvir and velpatasvir as individual agents, or are predicted drug interactions that may occur with sofosbuvir and velpatasvir [see Warnings and Precautions (5.2 , 5.3) and Clinical Pharmacology (12.3) ] . Table 4 Potentially Significant Drug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Studies or Predicted Interaction This table is not all inclusive. Concomitant Drug Class: Drug Name Effect on Concentration ↓ = decrease, ↑ = increase. Clinical Effect/Recommendation DF = disoproxil fumarate. Acid Reducing Agents: ↓ velpatasvir Velpatasvir solubility decreases as pH increases. Drugs that increase gastric pH are expected to decrease concentration of velpatasvir. Antacids (e.g., aluminum and magnesium hydroxide) Separate antacid and sofosbuvir and velpatasvir administration by 4 hours. H 2 -rece…

8.1 Pregnancy Risk Summary If sofosbuvir and velpatasvir 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 ribavirin-associated risks of use during pregnancy. No adequate human data are available to establish whether or not sofosbuvir and velpatasvir pose a risk to pregnancy outcomes. In animal reproduction studies, no evidence of adverse developmental outcomes was observed with sofosbuvir or velpatasvir at exposures greater than those in humans at the recommended human dose (RHD) [see Data ] . During organogenesis in the mouse, rat, and rabbit, systemic exposures (AUC) to velpatasvir were approximately 31 (mice), 6 (rats), and 0.4 (rabbits) times the exposure in humans at the RHD, while exposures to the predominant circulating metabolite of sofosbuvir (GS-331007) were approximately 4 (rats) and 10 (rabbits) times the exposure in humans at the RHD. In rat pre/postnatal development studies, maternal systemic exposures (AUC) to velpatasvir and GS-331007 were approximately 5 times the exposures of each component 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. Data Sofosbuvir: Sofosbuvir was administered orally to pregnant rats (up to 500 mg/kg/day) and rabbits (up to 300 mg/kg/day) on gestation days 6 to 18 and 6 to 19, respectively, and also to rats (oral doses up to 500 mg/kg/day) on gestation day 6 to lactation/post-partum day 20. No significant effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at the highest doses tested. The systemic exposures (AUC) of the predominant circulating metabolite of sofosbuvir (GS-331007) during gestation were approximately 4 (rats) and 10 (rabbits) times the exposure in humans at the RHD. Velpatasvir: Velpatasvir was administered orally to pregnant mice (up to 1000 mg/kg/day), rats (up to 200 mg/kg/day), and rabbits (up to 300 mg/kg/day) on gestation days 6 to 15, 6 to 17, and 7 to 20, respectively, and also to rats (oral doses up to 200 mg/kg) on gestation day 6 to lactation/post-partum day 20. No significant effects on embryo-fetal (mice, rats, and rabbits) or pre/postnatal (rats) development were observed at the highest doses tested. The systemic exposures (AUC) of velpatasvir during gestation were approximately 31 (mice), 6 (rats), and 0.4 (rabbits) times the exposure in humans at the RHD.

6 ADVERSE REACTIONS The following serious adverse reactions are described below and elsewhere in labeling: Serious Symptomatic Bradycardia When Coadministered with Amiodarone [see Warnings and Precautions (5.2) ]. The most common adverse reactions (incidence greater than or equal to 10%, all grades) observed in adults and pediatric subjects 6 years of age and older with treatment with sofosbuvir and velpatasvir for 12 weeks are headache and fatigue. ( 6.1 ) The most common adverse reactions (incidence greater than or equal to 10%, grade 1 or 2) observed in pediatric subjects less than 6 years of age are vomiting and product use issue (spitting up the drug). ( 6.1 ) The most common adverse reactions (incidence greater than or equal to 10%, all grades) observed with treatment with sofosbuvir and velpatasvir and ribavirin for 12 weeks in adult patients with decompensated cirrhosis are fatigue, anemia, nausea, headache, insomnia, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Asegua Therapeutics at 1-800-445-3235 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 sofosbuvir and velpatasvir is administered with ribavirin, refer to the prescribing information for ribavirin for a description of ribavirin-associated adverse reactions. Clinical Trials in Adult Subjects Adverse Reactions in Subjects without Cirrhosis or with Compensated Cirrhosis The adverse reactions data for sofosbuvir and velpatasvir in patients without cirrhosis or with compensated cirrhosis were derived from three Phase 3 clinical trials (ASTRAL-1, ASTRAL-2, and ASTRAL-3) which evaluated a total of 1035 subjects infected with genotype 1, 2, 3, 4, 5, or 6 HCV, without cirrhosis or with compensated cirrhosis, who received sofosbuvir and velpatasvir tablets (400 mg/100 mg) for 12 weeks. Sofosbuvir and velpatasvir were studied in placebo- and active-controlled trials [see Clinical Studies (14.2) ] . The proportion of subjects who permanently discontinued treatment due to adverse events was 0.2% for subjects who received sofosbuvir and velpatasvir for 12 weeks. The most common adverse reactions (adverse events assessed as causally related by the investigator and at least 10%) were headache and fatigue in subjects treated with sofosbuvir and velpatasvir for 12 weeks. Adverse reactions, all grades, observed in greater than or equal to 5% of subjects receiving 12 weeks of treatment with sofosbuvir and velpatasvir in ASTRAL-1 include headache (22%), fatigue (15%), nausea (9%), asthenia (5%), and insomnia (5%). Of subjects receiving sofosbuvir and velpatasvir who experienced these adverse reactions, 79% had an adverse reaction of mild severity (Grade 1). With the exception of asthenia, each of these adverse reactions occurred at a similar frequency or more frequently in subjects treated with placebo compared to subjects treated with sofosbuvir and velpatasvir (asthenia: 3% versus 5% for the placebo and sofosbuvir and velpatasvir groups, respectively). The adverse reactions observed in subjects treated with sofosbuvir and velpatasvir in ASTRAL-2 and ASTRAL-3 were consistent with those observed in ASTRAL-1. Irritability was also observed in greater than or equal to 5% of subjects treated with sofosbuvir and velpatasvir in ASTRAL-3. Adverse Reactions in Subjects Coinfected with HCV and HIV-1 The safety assessment of sofosbuvir and velpatasvir in subjects with HCV/HIV-1 coinfection was based on an open-label clinical trial (ASTRAL-5) in 106 subjects who were on stable antiretroviral therapy [see Clinical Studies (14.3) ] . The safety profile in HCV/HIV-1 coinfected subjects was similar to that observed in HCV mono-infected subjects. The most common adverse reactions…