2.1 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 DAKLINZA [see Warnings and Precautions (5.1)].

NS5A Resistance Testing in HCV Genotype 1a-Infected Patients with Cirrhosis: Consider screening for the presence of NS5A polymorphisms at amino acid positions M28, Q30, L31, and Y93 in patients with cirrhosis who are infected with HCV genotype 1a prior to the initiation of treatment with DAKLINZA and sofosbuvir with or without ribavirin [see Microbiology (12.4), Table 11].

2.2 Recommended Dosage

The recommended dosage of DAKLINZA is 60 mg, taken orally, once daily, with or without food [see Clinical Pharmacology (12.3)].

Table 1 provides the recommended DAKLINZA-containing treatment regimens and duration based on HCV genotype and patient population. The optimal duration of DAKLINZA and sofosbuvir with or without ribavirin has not been established for HCV genotype 3 patients with cirrhosis or for HCV genotype 1 patients with Child-Pugh C cirrhosis [see Clinical Studies (14.2, 14.4)].

For patients with HCV/HIV-1 coinfection, follow the dosage recommendations in Table 1 [see Clinical Studies (14)]. Refer to Drug Interactions (7) for dosage recommendations for concomitant HIV-1 antiviral drugs.

For specific dosage recommendations for sofosbuvir, refer to the prescribing information.

For HCV genotype 1 or 3 patients with Child-Pugh B or C cirrhosis or post-transplantation patients, the starting dose of ribavirin is 600 mg once daily, increasing up to 1000 mg daily as tolerated. The starting dose and on-treatment dose of ribavirin can be decreased based on hemoglobin and creatinine clearance.

For HCV genotype 3 patients with compensated cirrhosis (Child-Pugh A), the recommended dosing of ribavirin is based on weight (1000 mg for patients weighing less than 75 kg and 1200 mg for those weighing at least 75 kg administered orally in two divided doses with food).

2.3 Dosage Modification Due to Drug Interactions

Refer to the drug interactions and contraindications sections for other drugs before coadministration with DAKLINZA.

Dosage reduction of DAKLINZA for adverse reactions is not recommended.

2.4 Discontinuation of Therapy

If sofosbuvir is permanently discontinued in a patient receiving DAKLINZA with sofosbuvir, then DAKLINZA should also be discontinued.

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 DAKLINZA. In patients with serologic evidence of HBV infection, monitor for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV treatment with DAKLINZA and during post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated.

5.2 Risk of Adverse Reactions or Loss of Virologic Response Due to Drug Interactions

The concomitant use of DAKLINZA and other drugs may result in known or potentially significant drug interactions, some of which may lead to [see Contraindications (4) and Drug Interactions (7)]:

•

loss of therapeutic effect of DAKLINZA and possible development of resistance,

•

dosage adjustments of concomitant medications or DAKLINZA,

•

possible clinically significant adverse reactions from greater exposures of concomitant drugs or DAKLINZA.

See Table 3 for drugs contraindicated with DAKLINZA due to loss of efficacy and possible development of resistance [see Contraindications (4)]. See Table 7 for steps to prevent or manage other possible and known significant drug interactions [see Drug Interactions (7)]. Consider the potential for drug interactions before and during DAKLINZA therapy, review concomitant medications during DAKLINZA therapy, and monitor for the adverse reactions associated with the concomitant drugs.

5.3 Serious Symptomatic Bradycardia When Coadministered with Sofosbuvir and Amiodarone

Postmarketing cases of symptomatic bradycardia and cases requiring pacemaker intervention have been reported when amiodarone was coadministered with a sofosbuvir-containing regimen. A fatal cardiac arrest was reported in a patient receiving a sofosbuvir-containing regimen (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 bradycardia effect is unknown.

Coadministration of amiodarone with DAKLINZA in combination with sofosbuvir is not recommended. For patients taking amiodarone who have no alternative treatment options and who will be coadministered DAKLINZA and sofosbuvir:

•

Counsel patients about the risk of serious symptomatic bradycardia.

•

Cardiac monitoring in an inpatient 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 in combination with DAKLINZA who need to start amiodarone therapy due to no other alternative treatment options should undergo similar cardiac monitoring as outlined above.

Due to amiodarone’s long elimination half-life, patients discontinuing amiodarone just prior to starting sofosbuvir in combination with DAKLINZA 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 pain, confusion, or memory problems [see Adverse Reactions (6.2) and Drug Interactions (7.3), Table 7].

5.4 Risks Associated with Ribavirin Combination Treatment

If DAKLINZA and sofosbuvir are administered with ribavirin, the warnings and precautions for ribavirin, in particular the pregnancy avoidance warning, apply to this combination regimen. Refer to the ribavirin prescribing information for a full list of the warnings and precautions for ribavirin.

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.

Approximately 2400 subjects with chronic HCV infection have been treated with the recommended dose of DAKLINZA in combination with other anti-HCV drugs in clinical trials. Six hundred seventy-nine subjects have received a DAKLINZA and sofosbuvir-based regimen. Safety experience from three clinical trials of DAKLINZA and sofosbuvir with or without ribavirin is presented.

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of DAKLINZA. Because these reactions 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.

Cardiac Disorders: Serious symptomatic bradycardia has been reported in patients taking amiodarone who initiate treatment with a sofosbuvir-containing regimen [see Warnings and Precautions (5.3) and Drug Interactions (7.3)].

7.1 Potential for Other Drugs to Affect DAKLINZA

Daclatasvir is a substrate of CYP3A. Therefore, moderate or strong inducers of CYP3A may decrease the plasma levels and therapeutic effect of daclatasvir [see Dosage and Administration (2.3), Contraindications (4), and Table 7]. Strong inhibitors of CYP3A (eg, clarithromycin, itraconazole, ketoconazole, ritonavir) may increase the plasma levels of daclatasvir [see Dosage and Administration (2.3) and Table 7].

7.2 Potential for DAKLINZA to Affect Other Drugs

Daclatasvir is an inhibitor of P-glycoprotein transporter (P-gp), organic anion transporting polypeptide (OATP) 1B1 and 1B3, and breast cancer resistance protein (BCRP). Administration of DAKLINZA may increase systemic exposure to medicinal products that are substrates of P-gp, OATP 1B1 or 1B3, or BCRP, which could increase or prolong their therapeutic effect or adverse reactions (see Table 7).

7.3 Established and Other 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.

Refer to the prescribing information for other agents in the regimen for drug interaction information. The most conservative recommendation should be followed.

Please also refer to Section 4 (Contraindications) and Section 12.3 (Pharmacokinetics) for complete information on all drug interactions.

Table 7 provides clinical recommendations for established or potentially significant drug interactions between DAKLINZA and other drugs [see Contraindications (4)]. Clinically relevant increase in concentration is indicated as “↑” and clinically relevant decrease as “↓” for drug interaction data [see Clinical Pharmacology (12.3)].

7.4 Drugs without Clinically Significant Interactions with DAKLINZA

Please see Section 12.3 (Pharmacokinetics) for information regarding anticipated interactions that are not clinically relevant.

Based on the results of drug interaction trials [see Clinical Pharmacology (12.3)], no clinically relevant changes in exposure were observed for cyclosporine, darunavir (with ritonavir), dolutegravir, escitalopram, ethinyl estradiol/norgestimate, lopinavir (with ritonavir), methadone, midazolam, tacrolimus, or tenofovir with concomitant use of daclatasvir. No clinically relevant changes in daclatasvir exposure were observed with cyclosporine, darunavir (with ritonavir), dolutegravir, escitalopram, famotidine, lopinavir (with ritonavir), omeprazole, sofosbuvir, tacrolimus, or tenofovir. No dosage adjustment for daclatasvir is necessary with darunavir/cobicistat or moderate CYP3A inhibitors, including atazanavir (unboosted), fosamprenavir, ciprofloxacin, diltiazem, erythromycin, fluconazole, or verapamil.

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

If DAKLINZA and sofosbuvir are 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.

8.4 Pediatric Use

Safety and effectiveness of DAKLINZA in pediatric patients younger than 18 years of age have not been established.

8.5 Geriatric Use

Of 1184 subjects treated with the recommended dose of DAKLINZA in ten clinical trials, 7% of subjects were 65 years of age or older. Safety was similar across older and younger subjects and there were no safety findings unique to subjects 65 years and older. SVR12 rates were comparable among older and younger subjects. No dosage adjustment of DAKLINZA is required for elderly patients [see Clinical Pharmacology (12.3)].

8.6 Renal Impairment

No dosage adjustment of DAKLINZA is required for patients with any degree of renal impairment [see Clinical Pharmacology (12.3)]. Refer also to the sofosbuvir and ribavirin prescribing information for information regarding use in patients with renal impairment.

8.7 Hepatic Impairment

Based on a hepatic impairment study in non–HCV-infected subjects, no dosage adjustment of DAKLINZA is required for patients with mild (Child-Pugh A), moderate (Child-Pugh B), or severe (Child-Pugh C) hepatic impairment [see Clinical Pharmacology (12.3)].

12.1 Mechanism of Action

Daclatasvir is a direct-acting antiviral agent (DAA) against the hepatitis C virus [see Microbiology (12.4)].

12.2 Pharmacodynamics

12.3 Pharmacokinetics

The pharmacokinetic properties of daclatasvir were evaluated in healthy adult subjects and in subjects with chronic HCV. Administration of daclatasvir tablets in HCV-infected subjects resulted in approximately dose-proportional increases in Cmax, AUC, and Cmin up to 60 mg once daily. Steady state is anticipated after approximately 4 days of once-daily daclatasvir administration. Exposure of daclatasvir was similar between healthy and HCV-infected subjects. Population pharmacokinetic estimates for daclatasvir 60 mg once daily in chronic HCV-infected subjects are shown in Table 8.

12.4 Microbiology

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

14.1 Description of Clinical Trials

The efficacy of DAKLINZA in combination with sofosbuvir and with or without ribavirin was evaluated in three phase 3 clinical trials, as summarized in Table 12 [see Clinical Studies (14.2, 14.3, 14.4)]. HCV RNA levels were measured during these clinical trials using the COBAS® TaqMan® HCV test (version 2.0), for use with the High Pure System. The assay had a lower limit of quantification (LLOQ) of 25 IU per mL. Sustained virologic response was the primary endpoint and was defined as HCV RNA below the LLOQ at post-treatment week 12 (SVR12).

14.2 Clinical Trials in HCV Genotype 3 (ALLY-3)

ALLY-3 was an open-label trial that included 152 subjects with chronic HCV genotype 3 infection and compensated liver disease who were treatment naive (n=101) or treatment experienced (n=51). Most treatment-experienced subjects had failed prior treatment with peginterferon/ribavirin, but 7 subjects had been treated previously with a sofosbuvir regimen and 2 subjects with a regimen containing an investigational agent. Previous exposure to NS5A inhibitors was prohibited. Subjects received DAKLINZA 60 mg plus sofosbuvir 400 mg once daily for 12 weeks and were monitored for 24 weeks post treatment.

The 152 treated subjects in ALLY-3 had a median age of 55 years (range, 24-73); 59% of the subjects were male; 90% were white, 5% were Asian, and 4% were black. Most subjects (76%) had baseline HCV RNA levels greater than or equal to 800,000 IU per mL; 21% of the subjects had compensated cirrhosis, and 40% had the IL28B rs12979860 CC genotype.

SVR12 and outcomes in subjects without SVR12 in ALLY-3 are shown by patient population in Table 13. SVR12 rates were comparable regardless of HCV treatment history, age, gender, IL28B allele status, or baseline HCV RNA level. For SVR outcomes related to baseline NS5A amino acid polymorphisms, see Microbiology (12.4).

14.3 Clinical Trials in HCV/HIV Coinfected Subjects (ALLY-2)

ALLY-2 was an open-label trial that included 153 subjects with chronic hepatitis C and HIV coinfection who received DAKLINZA and sofosbuvir for 12 weeks. Subjects with HCV genotype 1, 2, 3, 4, 5, or 6 infection were eligible to enroll. Subjects were HCV treatment-naive (n=101) or HCV treatment-experienced (n=52). Prior exposure to NS5A inhibitors was prohibited. The dose of DAKLINZA was 60 mg once daily (dose-adjusted for concomitant antiretroviral use) and the dose of sofosbuvir was 400 mg once daily [see Drug Interactions (7.3)].

The 153 treated subjects had a median age of 53 years (range, 24-71); 88% of subjects were male; 63% were white, 33% were black, and 1% were Asian. Sixty-eight percent of subjects had HCV genotype 1a, 15% had HCV genotype 1b, 8% had genotype 2, 7% had genotype 3, and 2% had genotype 4. Most subjects (80%) had baseline HCV RNA levels greater than or equal to 800,000 IU per mL; 16% of the subjects had compensated cirrhosis, and 73% had IL28B rs12979860 non-CC genotype. Concomitant HIV therapy included PI-based regimens (darunavir + ritonavir, atazanavir + ritonavir, or lopinavir/ritonavir) for 46% of subjects, NNRTI-based regimens (efavirenz, nevirapine, or rilpivirine) for 26%, integrase-based regimens (raltegravir or dolutegravir) for 26%, and nucleoside-only regimens (abacavir + emtricitabine + zidovudine) for 1%. Two patients were not receiving treatment for HIV.

SVR and outcomes in subjects with HCV genotype 1 without SVR12 in ALLY-2 are shown by patient population in Table 14. Available data on subjects with HCV genotype 2, 4, 5, or 6 infection are insufficient to provide recommendations for these genotypes; therefore, these results are not presented in Table 14. SVR12 rates were comparable regardless of antiretroviral therapy, HCV treatment history, age, race, gender, IL28B allele status, HCV genotype 1 subtype, or baseline HCV RNA level. For SVR outcomes related to baseline NS5A amino acid polymorphisms, see Microbiology (12.4).

No subjects switched their antiretroviral therapy regimen due to loss of plasma HIV-1 RNA suppression. There was no change in absolute CD4+ T-cell counts at the end of 12 weeks of treatment.

14.4 Clinical Trials in Subjects with Child-Pugh A, B, or C Cirrhosis or with HCV Recurrence after Liver Transplantation (ALLY-1)

ALLY-1 was an open-label trial of DAKLINZA, sofosbuvir, and ribavirin that included 113 subjects with chronic HCV infection and Child-Pugh A, B, or C cirrhosis (n=60) or HCV recurrence after liver transplantation (n=53). Subjects with HCV genotype 1, 2, 3, 4, 5, or 6 infection were eligible to enroll. Subjects could be HCV treatment-naive or treatment-experienced, although prior exposure to NS5A inhibitors was prohibited. Subjects received DAKLINZA 60 mg once daily, sofosbuvir 400 mg once daily, and ribavirin for 12 weeks and were monitored for 24 weeks post treatment. Subjects received an initial ribavirin dose of 600 mg or less daily with food; the initial and on-treatment dosing of ribavirin was modified based on hemoglobin and creatinine clearance measurements. If tolerated, the ribavirin dose was titrated up to 1000 mg per day. A high proportion of reductions in ribavirin dosing occurred in the trial. By week 6, approximately half of the subjects received 400 mg per day or less of ribavirin. In total, 16 subjects (15%) completed less than 12 weeks and 11 subjects (10%) completed less than 6 weeks of ribavirin therapy, respectively. For the cohort of patients with cirrhosis (Child-Pugh A, B, or C), the median time to discontinuation of ribavirin was 43 days (range, 8-82, n=9). For the post-transplant cohort, the median time to discontinuation of ribavirin was 20 days (range, 3-57, n=7).

The 113 treated subjects in ALLY-1 had a median age of 59 years (range, 19-82); 67% of the subjects were male; 96% were white, 4% were black, and 1% Asian. Most subjects (59%) were treatment-experienced, and most (71%) had baseline HCV RNA levels greater than or equal to 800,000 IU per mL. Fifty-eight percent of subjects had HCV genotype 1a, 19% had HCV genotype 1b, 4% had genotype 2, 15% had genotype 3, 4% had genotype 4, and 1% had genotype 6, 77% had IL28B rs12979860 non-CC genotype. Among the 60 subjects in the cirrhosis cohort, 20% were Child-Pugh A, 53% were Child-Pugh B, and 27% were Child-Pugh C, and 35% had a Baseline Model for End-Stage Liver Disease (MELD) score of 15 or greater. Most (55%) of the 53 subjects in the post-transplant cohort had F3 or F4 fibrosis (based on FibroSURE® results).

SVR12 and outcomes in subjects without SVR12 in ALLY-1 are shown for subjects with HCV genotype 1 by patient population in Table 15. Available data on subjects with HCV genotype 2, 4, 5, or 6 infection are insufficient to provide recommendations; therefore, these results are not presented in Table 15.

SVR12 rates were comparable regardless of age, gender, IL28B allele status, or baseline HCV RNA level. For SVR12 outcomes related to baseline NS5A amino acid polymorphisms, see Microbiology (12.4). No HCV genotype 1 or genotype 3 subjects with Child-Pugh C cirrhosis had baseline resistance-associated NS5A amino acid polymorphisms. SVR12 rates were comparable between genotype 3 (5/6 with Child-Pugh B or C cirrhosis and 10/11 post-liver transplant) and genotype 1 subjects with or without decompensated cirrhosis.