Sofosbuvir

12.1 Mechanism of Action VOSEVI is a fixed-dose combination of sofosbuvir, velpatasvir, and voxilaprevir which are DAA agents against the hepatitis C virus [see Microbiology (12.4) ].

1 INDICATIONS AND USAGE VOSEVI is indicated for the treatment of adult patients with chronic hepatitis C virus (HCV) infection without cirrhosis or with compensated cirrhosis (Child-Pugh A) who have [see Dosage and Administration (2.2) and Clinical Studies (14) ]: genotype 1, 2, 3, 4, 5, or 6 infection and have previously been treated with an HCV regimen containing an NS5A inhibitor. genotype 1a or 3 infection and have previously been treated with an HCV regimen containing sofosbuvir without an NS5A inhibitor. Additional benefit of VOSEVI over sofosbuvir/velpatasvir was not shown in adults with genotype 1b, 2, 4, 5, or 6 infection previously treated with sofosbuvir without an NS5A inhibitor. VOSEVI is a fixed-dose combination of sofosbuvir, a hepatitis C virus (HCV) nucleotide analog NS5B polymerase inhibitor, velpatasvir, an HCV NS5A inhibitor, and voxilaprevir, an HCV NS3/4A protease inhibitor, and is indicated for the treatment of adult patients with chronic HCV infection without cirrhosis or with compensated cirrhosis (Child-Pugh A) who have ( 1 , 2.2 , 14 ): genotype 1, 2, 3, 4, 5, or 6 infection and have previously been treated with an HCV regimen containing an NS5A inhibitor. genotype 1a or 3 infection and have previously been treated with an HCV regimen containing sofosbuvir without an NS5A inhibitor. Additional benefit of VOSEVI over sofosbuvir/velpatasvir was not shown in adults with genotype 1b, 2, 4, 5, or 6 infection previously treated with sofosbuvir without an NS5A inhibitor.

2 DOSAGE AND ADMINISTRATION Testing: Prior to initiating VOSEVI, test all patients for HBV infection by measuring HBsAg and anti-HBc. ( 2.1 ) Recommended dosage: One tablet (400 mg of sofosbuvir, 100 mg of velpatasvir, and 100 mg of voxilaprevir) taken orally once daily with food. ( 2.2 ) See recommended treatment regimen and duration in table below ( 2.2 ): Genotype Patients Previously Treated with an HCV Regimen Containing: VOSEVI Duration 1, 2, 3, 4, 5, or 6 An NS5A inhibitor In clinical trials, prior NS5A inhibitor experience included daclatasvir, elbasvir, ledipasvir, ombitasvir, or velpatasvir. 12 weeks 1a or 3 Sofosbuvir without an NS5A inhibitor In clinical trials, prior treatment experience included sofosbuvir with or without any of the following: peginterferon alfa/ribavirin, ribavirin, HCV NS3/4A protease inhibitor (boceprevir, simeprevir, or telaprevir). 12 weeks For patients with renal impairment including end stage renal disease on dialysis, follow the dosage recommendations in the table above. ( 2.3 ) VOSEVI is not recommended in patients with moderate or severe hepatic impairment (Child-Pugh B or C). ( 2.4 , 5.2 ) 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 VOSEVI [see Warnings and Precautions (5.1) ]. 2.2 Recommended Dosage The recommended dosage of VOSEVI is one tablet, taken orally, once daily with food [see Clinical Pharmacology (12.3) ]. One tablet of VOSEVI contains 400 mg of sofosbuvir, 100 mg of velpatasvir, and 100 mg of voxilaprevir. Table 1 shows the recommended treatment regimen and duration based on patient population. Table 1 Recommended Treatment Regimen and Duration in Adults Without Cirrhosis or With Compensated Cirrhosis (Child-Pugh A) Genotype Patients Previously Treated with an HCV Regimen Containing: VOSEVI Duration 1, 2, 3, 4, 5, or 6 An NS5A inhibitor In clinical trials, prior NS5A inhibitor experience included daclatasvir, elbasvir, ledipasvir, ombitasvir, or velpatasvir. 12 weeks 1a or 3 Sofosbuvir without an NS5A inhibitor In clinical trials, prior treatment experience included sofosbuvir with or without any of the following: peginterferon alfa/ribavirin, ribavirin, HCV NS3/4A protease inhibitor (boceprevir, simeprevir, or telaprevir). 12 weeks 2.3 Renal Impairment No dosage adjustment of VOSEVI is recommended in patients with any degree of renal impairment including patients on dialysis [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ]. 2.4 Moderate or Severe Hepatic Impairment VOSEVI is not recommended in patients with moderate or severe hepatic impairment (Child-Pugh B or C) due to higher exposures of voxilaprevir in these patients [see Warnings and Precautions (5.2) , Use in Specific Populations (8.7) , and Clinical Pharmacology (12.3) ].

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 (5.3) ]. The most common adverse reactions (incidence greater than or equal to 10%, all grades) observed with treatment with VOSEVI for 12 weeks were headache, fatigue, diarrhea, and nausea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Gilead Sciences, Inc. at 1-800-GILEAD-5 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. Adverse Reactions in HCV-Infected Subjects without Cirrhosis or with Compensated Cirrhosis The adverse reactions data for VOSEVI were derived from two Phase 3 clinical trials (POLARIS-1 and POLARIS-4) that evaluated a total of 445 subjects infected with genotype 1, 2, 3, 4, 5, or 6 HCV, without cirrhosis or with compensated cirrhosis (Child-Pugh A), who received VOSEVI for 12 weeks. VOSEVI was studied in placebo- and active-controlled (sofosbuvir/velpatasvir) trials [see Clinical Studies (14.1 and 14.2) ]. The proportion of subjects who permanently discontinued treatment due to adverse events was 0.2% for subjects who received VOSEVI for 12 weeks. The most common adverse reactions (adverse events assessed as causally related by the investigator and at least 10%) were headache, fatigue, diarrhea, and nausea in subjects treated with VOSEVI for 12 weeks. Table 2 lists adverse reactions (adverse events assessed as causally related by the investigator, all grades) observed in at least 5% of subjects receiving 12 weeks of treatment with VOSEVI in the Phase 3 clinical trials. The side-by-side tabulation is to simplify presentation; direct comparison across trials should not be made due to differing trial designs. Table 2 Adverse Reactions (All Grades) Reported in ≥5% of Subjects With HCV Without Cirrhosis or With Compensated Cirrhosis Receiving VOSEVI in POLARIS-1 and POLARIS-4 POLARIS-1 POLARIS-4 VOSEVI 12 weeks (N=263) Placebo 12 weeks (N=152) VOSEVI 12 weeks (N=182) SOF/VEL 12 weeks (N=151) Headache 21% 14% 23% 23% Fatigue 17% 15% 19% 23% Diarrhea 13% 9% 14% 3% Nausea 13% 7% 10% 3% Asthenia 6% 4% 4% 6% Insomnia 6% 3% 3% 1% In POLARIS-1, of the subjects receiving VOSEVI who experienced adverse reactions, 99% were mild or moderate (Grade 1 or 2) in severity. In POLARIS-4, of the subjects receiving VOSEVI who experienced adverse reactions, all the reported adverse reactions were mild or moderate (Grade 1 or 2) in severity. Less Common Adverse Reactions Reported in Clinical Trials The following adverse reactions occurred in less than 5% of subjects without cirrhosis or with compensated cirrhosis treated with VOSEVI for 12 weeks and are included because of a potential causal relationship. Rash: In the POLARIS-1 and POLARIS-4 trials, rash occurred in less than 1% and 2% of subjects treated with VOSEVI, respectively. Rash was reported in 1% of subjects treated with placebo in POLARIS-1 and was not reported by any subject taking sofosbuvir/velpatasvir in POLARIS-4. No serious adverse reactions of rash occurred, and all rashes were mild or moderate in severity. Depression: In the POLARIS-1 and POLARIS-4 trials, depressed mood occurred in less than 1% and 1% of subjects treated with VOSEVI, respectively. Depressed mood was not reported by any subject taking placebo in POLARIS-1 and was reported in 1% of subjects treated with sofosbuvir/velpatasvir in POLARIS-4. No serious adverse reactions of depressed mood occurred and all events were mild or moderate in severity. Laboratory Abnormalities Lipase Elevations: Isolated, asymptomatic lipase elevations of greater than 3×ULN were observed in POLARIS-1 in 2% of subjects treated with VOSEVI and 3% of subjects treated with placebo, and in POLARIS-4 in 2% of subjects treated with VOSEVI and less than 1% of subjects treated with sofosbuvir/velpatasvir. Creatine Kinase: Isolated, asymptomatic creatine kinase elevations greater than or equal to 10×ULN were reported in POLARIS-1 in 1% of subjects treated with VOSEVI and 1% of subjects treated with placebo, and in POLARIS-4 in less than 1% of subjects treated with VOSEVI and no subjects treated with sofosbuvir/velpatasvir. Total bilirubin: Increases in total bilirubin less than or equal to 1.5×ULN were observed in subjects treated with VOSEVI due to inhibition of OATP1B1 and OATP1B3 by voxilaprevir: 4% and 6% of subjects without cirrhosis in POLARIS-1 and POLARIS-4, respectively; and 7% and 13% of subjects with compensated cirrhosis in POLARIS-1 and POLARIS-4, respectively. No subjects experienced jaundice and total bilirubin levels decreased after completing VOSEVI treatment. 6.2 Postmarketing Experience The follo

7 DRUG INTERACTIONS P-gp inducers and/or moderate to strong CYP inducers (e.g., St. John's wort, carbamazepine): May decrease concentrations of sofosbuvir, velpatasvir, and/or voxilaprevir. Use of VOSEVI with P-gp inducers and/or moderate to strong CYP inducers is not recommended. ( 5.4 , 7 ) Consult the full prescribing information prior to use for potential drug interactions. ( 4 , 5.3 , 5.4 , 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 VOSEVI Sofosbuvir, velpatasvir, and voxilaprevir are substrates of drug transporters P-gp and BCRP while GS-331007 (predominant circulating metabolite of sofosbuvir) is not. Voxilaprevir is also a substrate of OATP1B1 and OATP1B3. In vitro, slow metabolic turnover of velpatasvir by CYP2B6, CYP2C8, and CYP3A4 and of voxilaprevir by CYP1A2, CYP2C8, and primarily CYP3A4 was observed. Drugs that are inducers of P-gp and/or moderate to strong inducers of CYP2B6, CYP2C8, or CYP3A4 (e.g., St. John's wort, carbamazepine) may significantly decrease plasma concentrations of sofosbuvir, velpatasvir, and/or voxilaprevir leading to reduced therapeutic effect of VOSEVI. The use of these agents with VOSEVI is not recommended [see Warnings and Precautions (5.4) and Clinical Pharmacology (12.3) ]. VOSEVI may be coadministered with P-gp, BCRP, and CYP inhibitors. The use of OATP inhibitors which may substantially increase exposure of voxilaprevir (e.g., cyclosporine) with VOSEVI is not recommended [see Clinical Pharmacology (12.3) ]. 7.2 Potential for VOSEVI to Affect Other Drugs Velpatasvir and voxilaprevir are inhibitors of drug transporters P-gp, BCRP, OATP1B1, and OATP1B3. Velpatasvir is also an inhibitor of OATP2B1. Coadministration of VOSEVI with drugs that are substrates of these transporters may alter the exposure of such drugs. Coadministration of VOSEVI with BCRP substrates (e.g., methotrexate, mitoxantrone, imatinib, irinotecan, lapatinib, rosuvastatin, sulfasalazine, topotecan) is not recommended [see Clinical Pharmacology (12.3) ]. 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 3 provides a listing of established or potentially clinically significant drug interactions. The drug interactions described are based on studies conducted with either VOSEVI, the components of VOSEVI (sofosbuvir, velpatasvir, and/or voxilaprevir), or are predicted drug interactions that may occur with VOSEVI [see Contraindications (4) , Warnings and Precautions (5.3 , 5.4) , and Clinical Pharmacology (12.3) ]. Table 3 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 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 VOSEVI administration by 4 hours. H 2 -receptor antagonists (e.g., famotidine) These interactions have been studied in healthy adults. H 2 -receptor antagonists may be administered simultaneously with or staggered from VOSEVI at a dose that does not exceed doses comparable with famotidine 40 mg twice daily. Proton-pump inhibitors (e.g., omeprazole) Omeprazole 20 mg can be administered with VOSEVI. Use with other proton pump-inhibitors has not been studied. Antiarrhythmics: amiodarone Effect on amiodarone, sofosbuvir, velpatasvir, and voxilaprevir concentrations unknown Coadministration of amiodarone with VOSEVI may result in serious symptomatic bradycardia. The mechanism of this effec