SOVALDI (sofosbuvir) is a nucleotide analog inhibitor of HCV NS5B polymerase. The IUPAC name for sofosbuvir is ( S )-isopropyl 2-(( S )-(((2 R ,3 R ,4 R ,5 R )-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2 H )-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)-(phenoxy)phosphorylamino)propanoate. It has a molecular formula of C 22 H 29 FN 3 O 9 P and a molecular weight of 529.45. It has the following structural formula: Sofosbuvir is a white to off-white crystalline solid with a solubility of ≥ 2 mg/mL across the pH range of 2–7.7 at 37 °C and is slightly soluble in water. SOVALDI tablets, 200 mg or 400 mg, are for oral administration. Each tablet contains 200 mg or 400 mg of sofosbuvir. The tablets include the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, mannitol, and microcrystalline cellulose. The tablets are film-coated with a coating material containing the following inactive ingredients: polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide, and yellow iron oxide. SOVALDI pellets, 150 mg or 200 mg, are for oral administration, supplied as white to off-white pellets in unit-dose packets. Each unit-dose packet contains 150 mg or 200 mg of sofosbuvir. The pellets include the following inactive ingredients: amino methacrylate copolymer, colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl cellulose, hypromellose, lactose monohydrate, microcrystalline cellulose, polyethylene glycol, silicon dioxide, sodium lauryl sulfate, sodium stearyl fumarate, stearic acid, and talc. Chemical Structure

SOVALDI is a hepatitis C virus (HCV) nucleotide analog NS5B polymerase inhibitor indicated for the treatment of: Adult patients with genotype 1, 2, 3 or 4 chronic HCV infection without cirrhosis or with compensated cirrhosis as a component of a combination antiviral treatment regimen. Pediatric patients 3 years of age and older with genotype 2 or 3 chronic HCV infection without cirrhosis or with compensated cirrhosis in combination with ribavirin. Adult Patients: SOVALDI is indicated for the treatment of adult patients with chronic hepatitis C virus (HCV) infection as a component of a combination antiviral treatment regimen : genotype 1 or 4 infection without cirrhosis or with compensated cirrhosis for use in combination with pegylated interferon and ribavirin genotype 2 or 3 infection without cirrhosis or with compensated cirrhosis for use in combination with ribavirin. Pediatric Patients: SOVALDI is indicated for the treatment of chronic HCV genotype 2 or 3 infection in pediatric patients 3 years of age and older without cirrhosis or with compensated cirrhosis for use in combination with ribavirin .

SOVALDI is available as tablets or pellets for oral use. Each dosage form is available in two dose strengths. 400 mg Tablets: 400 mg sofosbuvir: yellow, capsule-shaped, film-coated tablet debossed with "GSI" on one side and "7977" on the other side. 200 mg Tablets: 200 mg sofosbuvir: yellow, oval-shaped, film-coated tablet debossed with "GSI" on one side and "200" on the other side. 200 mg Pellets: 200 mg sofosbuvir: white to off-white pellets in unit-dose packets. 150 mg Pellets: 150 mg sofosbuvir: white to off-white pellets in unit-dose packets. Tablets: 400 mg and 200 mg of sofosbuvir. Oral Pellets: 200 mg and 150 mg of sofosbuvir.

Testing Prior to the Initiation of Therapy: Test all patients for HBV infection by measuring HBsAg and anti-HBc. Recommended dosage in adults: One 400 mg tablet taken once daily with or without food. Recommended dosage in pediatric patients 3 years of age and older: Recommended dosage of SOVALDI in pediatric patients 3 years of age and older with genotype 2 or 3 HCV using SOVALDI tablets or oral pellets is based on weight. Refer to Table 3 of the full prescribing information for specific dosing guidelines based on body weight. HCV/HIV-1 coinfection: For adult and pediatric patients with HCV/HIV-1 coinfection, follow the dosage recommendations in the tables below, respectively. Recommended adult treatment regimen and duration: Adult Patient Population Regimen and Duration Genotype 1 or 4 Treatment-naïve without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + peginterferon alfa + ribavirin 12 weeks Genotype 2 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 12 weeks Genotype 3 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 24 weeks SOVALDI in combination with ribavirin for 24 weeks can be considered for adult patients with genotype 1 infection who are interferon ineligible. Should be used in combination with ribavirin for treatment of HCV in adult patients with hepatocellular carcinoma awaiting liver transplantation for up to 48 weeks or until liver transplantation, whichever occurs first. Recommended treatment regimen and duration for pediatric patients 3 years of age and older: Pediatric Patient Population 3 Years of Age and Older Regimen and Duration Genotype 2 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 12 weeks Genotype 3 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 24 weeks A dosage recommendation cannot be made for patients with severe renal impairment or end stage renal disease. Instructions for Use should be followed for preparation and administration of SOVALDI oral pellets

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 SOVALDI

Recommended Dosage in Adults The recommended dosage of SOVALDI is one 400 mg tablet, taken orally, once daily with or without food . Administer SOVALDI in combination with ribavirin or in combination with pegylated interferon and ribavirin for the treatment of HCV. The recommended treatment regimen and duration for SOVALDI combination therapy is provided in Table 1. For patients with HCV/HIV-1 coinfection, follow the dosage recommendations in Table 1. Refer to Drug Interactions for dosage recommendations for concomitant HIV-1 antiviral drugs. Table 1 Recommended Treatment Regimen and Duration in Adult Patients with Genotype 1, 2, 3, or 4 HCV Patient Population Treatment Regimen and Duration Genotype 1 or 4 Treatment-naïve without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + peginterferon alfa See peginterferon alfa prescribing information for dosage recommendation for patients with genotype 1 or 4 HCV. + ribavirin Dosage of ribavirin is weight-based (<75 kg = 1000 mg and ≥75 kg = 1200 mg). The daily dosage of ribavirin is administered orally in two divided doses with food. Patients with renal impairment (CrCl ≤50 mL/min) require ribavirin dosage reduction; refer to ribavirin tablet prescribing information. 12 weeks Genotype 2 Treatment-naïve and treatment-experienced Treatment-experienced patients have failed an interferon-based regimen with or without ribavirin. without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 12 weeks Genotype 3 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 24 weeks Patients with Genotype 1 HCV Who are Ineligible to Receive an Interferon-Based Regimen SOVALDI in combination with ribavirin for 24 weeks can be considered as a therapeutic option for patients with genotype 1 infection who are ineligible to receive an interferon-based regimen . Treatment decision should be guided by an assessment of the potential benefits and risks for the individual patient. Patients with Hepatocellular Carcinoma Awaiting Liver Transplantation Administer SOVALDI in combination with ribavirin for up to 48 weeks or until the time of liver transplantation, whichever occurs first, to prevent post-transplant HCV reinfection

Recommended Dosage in Pediatric Patients 3 Years of Age and Older with Genotype 2 or 3 HCV The recommended treatment regimen, duration, and recommended dosage for SOVALDI combination therapy is provided in Table 2 and Table 3. Table 4 provides the weight-based dosage of ribavirin when used in combination with SOVALDI for pediatric patients. For patients with HCV/HIV-1 coinfection, follow the dosage recommendations in Table 3 and Table 4. Refer to Drug Interactions for dosage recommendations for concomitant HIV-1 antiviral drugs. In pediatric patients with hepatocellular carcinoma awaiting liver transplantation, administer SOVALDI in combination with ribavirin for up to 48 weeks or until the time of liver transplantation, whichever occurs first, to prevent post-transplant HCV reinfection . Table 2 Recommended Treatment Regimen and Duration in Pediatric Patients 3 Years and Older with Genotype 2 or 3 HCV Patient Population Treatment Regimen and Duration Genotype 2 Treatment-naïve and treatment-experienced Treatment-experienced patients have failed an interferon based regimen with or without ribavirin. without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin See Table 4 for weight-based ribavirin dosing recommendations. 12 weeks Genotype 3 Treatment-naïve and treatment-experienced without cirrhosis or with compensated cirrhosis (Child-Pugh A) SOVALDI + ribavirin 24 weeks The recommended dosage of SOVALDI in pediatric patients 3 years and older with genotype 2 or 3 HCV using SOVALDI tablets or oral pellets (with or without food) is based on weight (Table 3), and is to be taken orally once daily in combination with ribavirin . SOVALDI pellets can be taken by pediatric patients who cannot swallow the tablet formulation . Table 3 Dosing for Pediatric Patients 3 Years and Older Using SOVALDI Tablets or Oral Pellets Body Weight (kg) Dosing of SOVALDI Tablets or Oral Pellets SOVALDI Daily Dose at least 35 one 400 mg tablet once daily or two 200 mg tablets once daily or two 200 mg packets of pellets once daily 400 mg per day 17 to less than 35 one 200 mg tablet once daily or one 200 mg packet of pellets once daily 200 mg per day less than 17 one 150 mg packet of pellets once daily 150 mg per day Table 4 Recommended Dosing for Ribavirin in Combination Therapy with SOVALDI for Pediatric Patients 3 Years and Older Body Weight (kg) Oral Ribavirin Daily Dosage The daily dosage of ribavirin is weight-based and is administered orally in two divided doses with food. less than 47 15 mg per kg per day (divided dose AM and PM) 47–49 600 mg per day (1 × 200 mg AM, 2 × 200 mg PM) 50–65 800 mg per day (2 × 200 mg AM, 2 × 200 mg PM) 66–80 1000 mg per day (2 × 200 mg AM, 3 × 200 mg PM) greater than 80 1200 mg per day (3 × 200 mg AM, 3 × 200 mg PM) 2.4 Preparation and Administration of Oral Pellets See the SOVALDI oral pellets full Instructions for Use for details on the preparation and administration of SOVALDI pellets. Do not chew SOVALDI pellets. If SOVALDI pellets are administered with food, sprinkle the pellets on one or more spoonfuls of non-acidic soft food at or below room temperature. Examples of non-acidic foods include pudding, chocolate syrup, mashed potato, and ice cream. Take SOVALDI pellets within 30 minutes of gently mixing with food and swallow the entire contents without chewing to avoid a bitter aftertaste

Dosage Modification Dosage reduction of SOVALDI is not recommended. If a patient has a serious adverse reaction potentially related to peginterferon alfa and/or ribavirin, the peginterferon alfa and/or ribavirin dosage should be reduced or discontinued, if appropriate, until the adverse reaction abates or decreases in severity. Refer to the peginterferon alfa and ribavirin prescribing information for additional information about how to reduce and/or discontinue the peginterferon alfa and/or ribavirin dosage

Discontinuation of Dosing If the other agents used in combination with SOVALDI are permanently discontinued, SOVALDI should also be discontinued

Severe Renal Impairment and End Stage Renal Disease No dosage recommendation can be given for patients with severe renal impairment (estimated Glomerular Filtration Rate [eGFR] less than 30 mL/min/1.73m 2 ) or with end stage renal disease (ESRD) due to higher exposures (up to 20-fold) of the predominant sofosbuvir metabolite .

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. Bradycardia with amiodarone coadministration: Serious symptomatic bradycardia may occur in patients taking amiodarone with a sofosbuvir-containing regimen, particularly in patients also receiving beta blockers, or those with underlying cardiac comorbidities and/or advanced liver disease. Coadministration of amiodarone with SOVALDI is not recommended. In patients without alternative, viable treatment options, cardiac monitoring is recommended. ( 5.2 , 6.2 , 7.1 ) 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 SOVALDI. In patients with serologic evidence of HBV infection, monitor for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV treatment with SOVALDI and during post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated

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 SOVALDI is not recommended. For patients taking amiodarone who have no other alternative, viable treatment options and who will be coadministered SOVALDI: Counsel patients about the risk of serious 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 SOVALDI who need to start amiodarone therapy due to no other alternative, viable treatment options should undergo similar cardiac monitoring as outlined above. Due to amiodarone's long half-life, patients discontinuing amiodarone just prior to starting SOVALDI should also undergo similar cardiac monitoring as outlined above. Patients who develop signs or symptoms of bradycardia should seek medical evaluation immediately. Symptoms may include near-fainting or fainting, dizziness or lightheadedness, malaise, weakness, excessive tiredness, shortness of breath, chest pains, confusion or memory problems

Risk of Reduced Therapeutic Effect Due to Use with P-gp Inducers Drugs that are P-gp inducers in the intestine (e.g., rifampin, St. John's wort) may significantly decrease sofosbuvir plasma concentrations and may lead to a reduced therapeutic effect of SOVALDI. The use of rifampin and St. John's wort with SOVALDI is not recommended

Risks Associated with Combination Treatment Because SOVALDI is used in combination with other antiviral drugs for treatment of HCV infection, consult the prescribing information for these drugs used in combination with SOVALDI. Warnings and Precautions related to these drugs also apply to their use in SOVALDI combination treatment.

Coadministration of amiodarone with a sofosbuvir-containing regimen may result in serious symptomatic bradycardia. ( 5.2 , 6.2 , 7.1 ) Drugs that are intestinal P-gp inducers (e.g., rifampin, St. John's wort) may alter the concentrations of sofosbuvir. ( 5.3 , 7 , 12.3 ) Consult the full prescribing information prior to use for potential drug-drug interactions. ( 5.2 , 5.3 , 7 , 12.3 ) 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

Potentially Significant Drug Interactions Sofosbuvir is a substrate of drug transporter P-gp and breast cancer resistance protein (BCRP) while the predominant circulating metabolite GS-331007 is not. Drugs that are P-gp inducers in the intestine (e.g., rifampin or St. John's wort) may decrease sofosbuvir plasma concentration, leading to reduced therapeutic effect of SOVALDI, and thus concomitant use with SOVALDI is not recommended . 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. Information on potential drug interactions with SOVALDI is summarized in Table 7. The table is not all-inclusive . Table 7 Potentially Significant Drug Interactions: Alteration in Dosage 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. Clinical Comment Antiarrhythmics: amiodarone Effect on amiodarone and sofosbuvir concentrations unknown Coadministration of amiodarone with a sofosbuvir-containing regimen may result in serious symptomatic bradycardia. The mechanism of this effect is unknown. Coadministration of amiodarone with SOVALDI is not recommended; if coadministration is required, cardiac monitoring is recommended . Anticonvulsants: Carbamazepine phenytoin phenobarbital oxcarbazepine ↓ sofosbuvir ↓ GS-331007 Coadministration of SOVALDI with carbamazepine, phenytoin, phenobarbital or oxcarbazepine is expected to decrease the concentration of sofosbuvir, leading to reduced therapeutic effect of SOVALDI. Coadministration is not recommended. Antimycobacterials: Rifabutin rifampin rifapentine ↓ sofosbuvir ↓ GS-331007 Coadministration of SOVALDI with rifabutin or rifapentine is expected to decrease the concentration of sofosbuvir, leading to reduced therapeutic effect of SOVALDI. Coadministration is not recommended. Coadministration of SOVALDI with rifampin, an intestinal P-gp inducer, is not recommended . Herbal Supplements: St. John's wort (Hypericum perforatum) ↓ sofosbuvir ↓ GS-331007 Coadministration of SOVALDI with St. John's wort, an intestinal P-gp inducer, is not recommended . HIV Protease Inhibitors: tipranavir/ritonavir ↓ sofosbuvir ↓ GS-331007 Coadministration of SOVALDI with tipranavir/ritonavir is expected to decrease the concentration of sofosbuvir, leading to reduced therapeutic effect of SOVALDI. Coadministration is not recommended

Drugs without Clinically Significant Interactions with SOVALDI Based on drug interaction studies conducted with SOVALDI, no clinically significant drug interactions have been either observed or are expected when SOVALDI is combined with the following drugs : cyclosporine, darunavir/ritonavir, efavirenz, emtricitabine, methadone, oral contraceptives, raltegravir, rilpivirine, tacrolimus, or tenofovir disoproxil fumarate.