Clinical Trials in Adult Subjects

The safety assessment of ledipasvir and sofosbuvir was based on pooled data from three randomized, open-label Phase 3 clinical trials (ION-3, ION-1, and ION-2) of subjects with genotype 1 HCV with compensated liver disease (with and without cirrhosis) including 215, 539, and 326 subjects who received ledipasvir and sofosbuvir tablets (90 mg/400 mg) once daily by mouth for 8, 12, and 24 weeks, respectively [see Clinical Studies (14)].

The proportion of subjects who permanently discontinued treatment due to adverse events was 0%, less than 1%, and 1% for subjects receiving ledipasvir and sofosbuvir for 8, 12, and 24 weeks, respectively.

The most common adverse reactions (at least 10%) were fatigue and headache in subjects treated with 8, 12, or 24 weeks of ledipasvir and sofosbuvir.

Table 4 lists adverse reactions (adverse events assessed as causally related by the investigator, all grades) observed in at least 5% of subjects receiving 8, 12, or 24 weeks of treatment with ledipasvir and sofosbuvir in clinical trials. The majority of adverse reactions presented in Table 4 occurred at severity of grade 1. The side-by-side tabulation is to simplify presentation; direct comparison across trials should not be made due to differing trial designs.

The safety assessment of ledipasvir and sofosbuvir was also based on pooled data from three open-label trials (Study 1119, ION-4, and ELECTRON-2) in 118 subjects with chronic HCV genotype 4, 5, or 6 infection with compensated liver disease (with or without cirrhosis) [see Clinical Studies (14.3)]. The subjects received ledipasvir and sofosbuvir tablets (90 mg/400 mg) once daily by mouth for 12 weeks. The safety profile in subjects with chronic HCV genotype 4, 5, or 6 infection with compensated liver disease was similar to that observed in subjects with chronic HCV genotype 1 infection with compensated liver disease. The most common adverse reactions occurring in at least 10% of subjects were asthenia (18%), headache (14%), and fatigue (10%).

Adverse Reactions in Subjects with Cirrhosis

The safety assessment of ledipasvir and sofosbuvir with or without ribavirin was based on a randomized, double-blind and placebo-controlled trial in treatment-experienced genotype 1 subjects with compensated cirrhosis and was compared to placebo in the SIRIUS trial. Subjects were randomized to receive 24 weeks of ledipasvir and sofosbuvir tablets (90 mg/400 mg) once daily by mouth without ribavirin or 12 weeks of placebo followed by 12 weeks of ledipasvir and sofosbuvir tablets (90 mg/400 mg) once daily by mouth + ribavirin [see Clinical Studies (14.2)]. Table 5 presents the adverse reactions, as defined above, that occurred with at least 5% greater frequency in subjects treated with 24 weeks of ledipasvir and sofosbuvir or 12 weeks of ledipasvir and sofosbuvir + ribavirin, compared to those reported for 12 weeks of placebo. The majority of the adverse reactions presented in Table 5 were Grade 1 or 2 in severity.

Adverse Reactions in Subjects Coinfected with HIV-1

The safety assessment of ledipasvir and sofosbuvir was based on an open-label clinical trial in 335 genotype 1 or 4 subjects with HCV/HIV-1 coinfection who were on stable antiretroviral therapy in Study ION-4 [see Clinical Studies (14.4)]. The safety profile in HCV/HIV-1 coinfected subjects was similar to that observed in HCV mono-infected subjects. The most common adverse reactions occurring in at least 10% of subjects were headache (20%) and fatigue (17%).

Adverse Reactions in Liver Transplant Recipients and/or Subjects with Decompensated Cirrhosis

The safety assessment of ledipasvir and sofosbuvir with ribavirin in liver transplant recipients and/or those who had decompensated liver disease was based on pooled data from two Phase 2 open-label clinical trials including 336 subjects who received ledipasvir and sofosbuvir tablets (90 mg/400 mg) plus ribavirin for 12 weeks. Subjects with Child-Pugh-Turcotte (CPT) scores greater than 12 were excluded from the trials [see Clinical Studies (14.5)].

The adverse events observed were consistent with the expected clinical sequelae of liver transplantation and/or decompensated liver disease, or the known safety profile of ledipasvir and sofosbuvir and/or ribavirin.

Decreases in hemoglobin to less than 10 g/dL and 8.5 g/dL during treatment were observed in 38% and 13% of subjects treated with ledipasvir and sofosbuvir plus ribavirin for 12 weeks, respectively. Ribavirin was permanently discontinued in 11% of subjects treated with ledipasvir and sofosbuvir plus ribavirin for 12 weeks.

Less Common Adverse Reactions Reported in Clinical Trials (less than 5%): The following adverse reactions occurred in less than 5% of subjects receiving ledipasvir and sofosbuvir tablets (90 mg/400 mg) in any one trial. These events have been included because of their seriousness or assessment of potential causal relationship.

Psychiatric disorders: depression (including in subjects with pre-existing history of psychiatric illness).

Depression (particularly in subjects with pre-existing history of psychiatric illness) occurred in subjects receiving sofosbuvir containing regimens. Suicidal ideation and suicide have occurred in less than 1% of subjects treated with sofosbuvir in combination with ribavirin or pegylated interferon/ribavirin in other clinical trials.

Laboratory Abnormalities

Adverse Reactions in Adults with Severe Renal Impairment, Including those on Dialysis

In an open-label trial (Trial 0154) in which adults with HCV with compensated liver disease (with or without cirrhosis) and severe renal impairment received ledipasvir and sofosbuvir tablets (90 mg/400 mg) for 12 weeks (N=18), the most common adverse reaction was fatigue (17%) [see Clinical Studies (14.6)].

In an open-label clinical trial, Trial 4063, a total of 95 adults with HCV with compensated liver disease (with or without cirrhosis) and ESRD requiring dialysis received ledipasvir and sofosbuvir tablets (90 mg/400 mg) for 8 (n=45), 12 (n=31), or 24 (n=19) weeks. The most common adverse reactions were insomnia and headache (each reported in 4% of subjects overall) [see Clinical Studies (14.6)].

Adverse Reactions in Pediatric Subjects 3 Years of Age and Older

The safety assessment of ledipasvir and sofosbuvir tablets (90 mg/400 mg), ledipasvir and sofosbuvir (HARVONI) tablets (45 mg/200 mg), or ledipasvir and sofosbuvir (HARVONI) oral pellets in pediatric subjects 3 years of age and older is based on data from a Phase 2, open-label clinical trial (Study 1116). In total, 226 subjects were enrolled, which included 223 subjects without cirrhosis or with compensated cirrhosis who were treated with ledipasvir and sofosbuvir for 12 weeks; one genotype 1 treatment-experienced subject with cirrhosis who was treated with ledipasvir and sofosbuvir for 24 weeks; and two genotype 3 subjects who were treated with ledipasvir and sofosbuvir + ribavirin for 24 weeks. The adverse reactions observed were consistent with those observed in clinical studies of ledipasvir and sofosbuvir tablets (90 mg/400 mg) in adults. Limited safety data are available in pediatric subjects receiving ledipasvir and sofosbuvir for 24 weeks. No Grade 3 or 4 adverse reactions or discontinuation due to an adverse reaction was observed in those pediatric subjects receiving ledipasvir and sofosbuvir for 24 weeks [see Clinical Studies (14.7)].

Cardiac Disorders

Serious symptomatic bradycardia has been reported in patients taking amiodarone who initiate treatment with ledipasvir and sofosbuvir [see Warnings and Precautions (5.2), Drug Interactions (7.2)].

Skin and Subcutaneous Tissue Disorders

Skin rashes, sometimes with blisters or angioedema-like swelling
Angioedema

Risk Summary

If ledipasvir and sofosbuvir 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 ledipasvir and sofosbuvir pose a risk to pregnancy outcomes. In animal reproduction studies, no evidence of adverse developmental outcomes was observed with ledipasvir or sofosbuvir at exposures greater than those in humans at the recommended human dose (RHD) [see Data]. During organogenesis in the rat and rabbit, systemic exposures (AUC) to ledipasvir were approximately 4 (rats) and 2 (rabbits) times the exposure in humans at the RHD, while exposures to the predominant circulating metabolite of sofosbuvir (GS-331007) were ≥3 (rats) and 7 (rabbits) times the exposure in humans at the RHD. In rat pre/postnatal development studies, maternal systemic exposures (AUC) to ledipasvir and GS-331007 were approximately 5 and 7 times, respectively, the exposure 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

Risk Summary

It is not known whether ledipasvir, sofosbuvir, or their metabolites are present in human breast milk, affect human milk production or have effects on the breastfed infant. When administered to lactating rats, ledipasvir was detected in the plasma of nursing pups likely due to the presence of ledipasvir in milk, without clear effects on nursing pups [see Data]. The predominant circulating metabolite of sofosbuvir (GS-331007) was the primary component observed in the milk of lactating rats, without effect on nursing pups.

The development and health benefits of breastfeeding should be considered along with the mother's clinical need for ledipasvir and sofosbuvir and any potential adverse effects on the breastfed child from ledipasvir and sofosbuvir or from the underlying maternal condition.

If ledipasvir and sofosbuvir is administered with ribavirin, the nursing mother's information for ribavirin also applies to this combination regimen. Refer to the ribavirin prescribing information for more information on use during lactation.

Data

Cardiac Electrophysiology

Thorough QT studies have been conducted for ledipasvir and sofosbuvir.

The effect of ledipasvir 120 mg twice daily (2.67 times the maximum recommended dosage) for 10 days on QTc interval was evaluated in a randomized, multiple-dose, placebo-, and active-controlled (moxifloxacin 400 mg) three-period crossover thorough QT trial in 59 healthy subjects. At the dose of 120 mg twice daily (2.67 times the maximum recommended dosage), ledipasvir does not prolong QTc interval to any clinically relevant extent.

The effect of sofosbuvir 400 mg (maximum recommended dosage) and 1200 mg (three times the maximum recommended dosage) on QTc interval was evaluated in a randomized, single-dose, placebo-, and active-controlled (moxifloxacin 400 mg) four-period crossover thorough QT trial in 59 healthy subjects. At a dose three times the maximum recommended dose, sofosbuvir does not prolong QTc to any clinically relevant extent.

Absorption

The pharmacokinetic properties of ledipasvir, sofosbuvir, and the predominant circulating metabolite GS-331007 have been evaluated in healthy adult subjects and in subjects with chronic hepatitis C. Following oral administration of ledipasvir and sofosbuvir tablets (90 mg/400 mg), ledipasvir median peak concentrations were observed 4 to 4.5 hours post-dose. Sofosbuvir was absorbed quickly and the peak median plasma concentration was observed ~0.8 to 1 hour post-dose. Median peak plasma concentration of GS-331007 was observed between 3.5 to 4 hours post-dose.

Based on the population pharmacokinetic analysis in HCV-infected subjects, geometric mean steady-state AUC0–24 for ledipasvir (N=2113), sofosbuvir (N=1542), and GS-331007 (N=2113) were 7290, 1320, and 12,000 ng∙hr/mL, respectively. Steady-state Cmax for ledipasvir, sofosbuvir, and GS-331007 were 323, 618, and 707 ng/mL, respectively. Sofosbuvir and GS-331007 AUC0–24 and Cmax were similar in healthy adult subjects and subjects with HCV infection. Relative to healthy subjects (N=191), ledipasvir AUC0–24 and Cmax were 24% lower and 32% lower, respectively, in HCV-infected subjects.

Effect of Food

Relative to fasting conditions, the administration of a single dose of ledipasvir and sofosbuvir tablets (90 mg/400 mg) with a moderate fat (~600 kcal, 25% to 30% fat) or high fat (~1000 kcal, 50% fat) meal increased sofosbuvir AUC0–inf by approximately 2-fold, but did not significantly affect sofosbuvir Cmax. The exposures of GS-331007 and ledipasvir were not altered in the presence of either meal type. The response rates in Phase 3 trials were similar in HCV-infected subjects who received ledipasvir and sofosbuvir tablets (90 mg/400 mg) with food or without food. Ledipasvir and sofosbuvir can be administered without regard to food.

Distribution

Ledipasvir is greater than 99.8% bound to human plasma proteins. After a single 90 mg dose of [14C]-ledipasvir in healthy subjects, the blood to plasma ratio of 14C-radioactivity ranged between 0.51 and 0.66.

Sofosbuvir is approximately 61–65% bound to human plasma proteins and the binding is independent of drug concentration over the range of 1 microgram/mL to 20 microgram/mL. Protein binding of GS-331007 was minimal in human plasma. After a single 400 mg dose of [14C]-sofosbuvir in healthy subjects, the blood to plasma ratio of 14C-radioactivity was approximately 0.7.

Metabolism

In vitro, no detectable metabolism of ledipasvir was observed by human CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Evidence of slow oxidative metabolism via an unknown mechanism has been observed. Following a single dose of 90 mg [14C]-ledipasvir, systemic exposure was almost exclusively to the parent drug (greater than 98%). Unchanged ledipasvir is the major species present in feces.

Sofosbuvir is extensively metabolized in the liver to form the pharmacologically active nucleoside analog triphosphate GS-461203. The metabolic activation pathway involves sequential hydrolysis of the carboxyl ester moiety catalyzed by human cathepsin A (CatA) or carboxylesterase 1 (CES1) and phosphoramidate cleavage by histidine triad nucleotide-binding protein 1 (HINT1) followed by phosphorylation by the pyrimidine nucleotide biosynthesis pathway. Dephosphorylation results in the formation of nucleoside metabolite GS-331007 that cannot be efficiently rephosphorylated and lacks anti-HCV activity in vitro. After a single 400 mg oral dose of [14C]-sofosbuvir, GS-331007 accounted for approximately greater than 90% of total systemic exposure.

Elimination

Following a single 90 mg oral dose of [14C]-ledipasvir, mean total recovery of the [14C]-radioactivity in feces and urine was approximately 87%, with most of the radioactive dose recovered from feces (approximately 86%). Unchanged ledipasvir excreted in feces accounted for a mean of 70% of the administered dose and the oxidative metabolite M19 accounted for 2.2% of the dose. These data indicate that biliary excretion of unchanged ledipasvir is a major route of elimination, with renal excretion being a minor pathway (approximately 1%). The median terminal half-life of ledipasvir following administration of ledipasvir and sofosbuvir tablets (90 mg/400 mg) was 47 hours.

Following a single 400 mg oral dose of [14C]-sofosbuvir, mean total recovery of the dose was greater than 92%, consisting of approximately 80%, 14%, and 2.5% recovered in urine, feces, and expired air, respectively. The majority of the sofosbuvir dose recovered in urine was GS-331007 (78%) while 3.5% was recovered as sofosbuvir. These data indicate that renal clearance is the major elimination pathway for GS-331007. The median terminal half-lives of sofosbuvir and GS-331007 following administration of ledipasvir and sofosbuvir tablets (90 mg/400 mg) were 0.5 and 27 hours, respectively.

Specific Populations

Drug Interaction Studies

Ledipasvir and sofosbuvir are substrates of drug transporters P-gp and BCRP while GS-331007 is not. P-gp inducers (e.g., rifampin or St. John's wort) may decrease ledipasvir and sofosbuvir plasma concentrations, leading to reduced therapeutic effect of ledipasvir and sofosbuvir, and the use with P-gp inducers is not recommended with ledipasvir and sofosbuvir [see Warnings and Precautions (5.3)]. Coadministration with drugs that inhibit P-gp and/or BCRP may increase ledipasvir and sofosbuvir plasma concentrations without increasing GS-331007 plasma concentration; ledipasvir and sofosbuvir may be coadministered with P-gp and/or BCRP inhibitors. Neither ledipasvir nor sofosbuvir is a substrate for hepatic uptake transporters OCT1, OATP1B1, or OATP1B3. GS-331007 is not a substrate for renal transporters, including organic anion transporter OAT1 or OAT3, or organic cation transporter OCT2.

Ledipasvir is subject to slow oxidative metabolism via an unknown mechanism. In vitro, no detectable metabolism of ledipasvir by CYP enzymes has been observed. Biliary excretion of unchanged ledipasvir is a major route of elimination. Sofosbuvir is not a substrate for CYP and UGT1A1 enzymes. Clinically significant drug interactions with ledipasvir and sofosbuvir mediated by CYP or UGT1A1 enzymes are not expected.

The effects of coadministered drugs on the exposure of ledipasvir, sofosbuvir, and GS-331007 are shown in Table 8 [see Drug Interactions (7)].

No effect on the pharmacokinetic parameters of ledipasvir, sofosbuvir, and GS-331007 was observed with raltegravir and the combination of abacavir and lamivudine; emtricitabine, rilpivirine, and tenofovir disoproxil fumarate; or dolutegravir, emtricitabine, and tenofovir disoproxil fumarate.

Ledipasvir is an inhibitor of drug transporter P-gp and breast cancer resistance protein (BCRP) and may increase intestinal absorption of coadministered substrates for these transporters. Ledipasvir is an inhibitor of transporters OATP1B1, OATP1B3, and BSEP only at concentrations exceeding those achieved in clinic. Ledipasvir is not an inhibitor of transporters MRP2, MRP4, OCT2, OAT1, OAT3, MATE1, and OCT1. The drug-drug interaction potential of ledipasvir is primarily limited to the intestinal inhibition of P-gp and BCRP. Clinically relevant transporter inhibition by ledipasvir in the systemic circulation is not expected due to its high protein binding. Sofosbuvir and GS-331007 are not inhibitors of drug transporters P-gp, BCRP, MRP2, BSEP, OATP1B1, OATP1B3, and OCT1, and GS-331007 is not an inhibitor of OAT1, OCT2, and MATE1. Ledipasvir, sofosbuvir, and GS-331007 are not inhibitors or inducers of CYP or UGT1A1 enzymes.

The effects of ledipasvir or sofosbuvir on the exposure of coadministered drugs are shown in Table 9 [see Drug Interactions (7)].

No effect on the pharmacokinetic parameters of the following coadministered drugs was observed with ledipasvir or sofosbuvir: abacavir, cyclosporine, darunavir/ritonavir, dolutegravir, efavirenz, emtricitabine, lamivudine, methadone, or rilpivirine.

Mechanism of Action

Ledipasvir is an inhibitor of the HCV NS5A protein, which is required for viral replication. Resistance selection in cell culture and cross-resistance studies indicate ledipasvir targets NS5A as its mode of action.

Sofosbuvir is an inhibitor of the HCV NS5B RNA-dependent RNA polymerase, which is required for viral replication. Sofosbuvir is a nucleotide prodrug that undergoes intracellular metabolism to form the pharmacologically active uridine analog triphosphate (GS-461203), which can be incorporated into HCV RNA by the NS5B polymerase and acts as a chain terminator. In a biochemical assay, GS-461203 inhibited the polymerase activity of the recombinant NS5B from HCV genotypes 1b and 4a with IC50 values of 3.3 and 2.7 microM, respectively. GS-461203 is neither an inhibitor of human DNA and RNA polymerases nor an inhibitor of mitochondrial RNA polymerase.

Antiviral Activity

In HCV replicon assays, the EC50 values of ledipasvir against full-length replicons from genotypes 1a and 1b were 0.031 nM and 0.004 nM, respectively. The median EC50 values of ledipasvir against chimeric replicons encoding NS5A sequences from clinical isolates from treatment-naïve HCV-infected subjects were 0.02 nM for genotype 1a (range 0.007–1.0 nM; N=23) and 0.006 nM for genotype 1b (range 0.002–1.0 nM; N=34). Ledipasvir had median EC50 values ranging between 0.002 nM to 0.16 nM against 11 genotype 4 subtypes (4a, 4d, 4n, 4r, 4o, 4c, 4f, 4k, 4l, 4m, and 4t). The median EC50 value for subtype 4b was 199.6 nM (range 0.66–1799 nM; N=3); the two 4b isolates with EC50 values greater than 100 nM had NS5A resistance-associated polymorphisms L30S+M31M+P58S+Y93H. The median EC50 value of ledipasvir was 0.03 nM against genotype 5a isolates (range 0.008–0.081 nM; N=35). For genotype 6, the EC50 values for ledipasvir varied by subtype. Subtypes 6a and 6h had median EC50 values of 0.55 and 0.17 nM, respectively. For subtypes 6e, 6l, 6n, 6q, 6k, and 6m, the median EC50 values ranged from 60.6 nM to 430.1 nM.

In HCV replicon assays, the EC50 values of sofosbuvir against full-length replicons from genotypes 1a, 1b, and 4a, and chimeric 1b replicons encoding NS5B from genotypes 5a or 6a ranged from 14–110 nM. The median EC50 value of sofosbuvir against chimeric replicons encoding NS5B sequences from clinical isolates was 62 nM for genotype 1a (range 29–128 nM; N=67) and 102 nM for genotype 1b (range 45–170 nM; N=29). In replication competent virus assays, the EC50 value of sofosbuvir against genotype 1a was 30 nM. Evaluation of sofosbuvir in combination with ledipasvir showed no antagonistic effect in reducing HCV RNA levels in replicon cells.

Resistance

Persistence of Resistance-Associated Substitutions

No data are available on the persistence of ledipasvir or sofosbuvir resistance-associated substitutions. NS5A resistance-associated substitutions for other NS5A inhibitors have been found to persist for >1 year in some patients. The long-term clinical impact of the emergence or persistence of virus containing ledipasvir or sofosbuvir resistance-associated substitutions is unknown.

Effect of Baseline HCV Polymorphisms on Treatment Response

Cross Resistance

Based on resistance patterns observed in cell culture replicon studies and HCV-infected subjects, cross-resistance between ledipasvir and other NS5A inhibitors is expected. Both sofosbuvir and ledipasvir were fully active against substitutions associated with resistance to other classes of direct-acting antivirals with different mechanisms of action, such as NS5B non-nucleoside inhibitors and NS3 protease inhibitors. The efficacy of ledipasvir/sofosbuvir has not been established in patients who have previously failed treatment with other regimens that include an NS5A inhibitor.

Carcinogenesis and Mutagenesis

Impairment of Fertility

Treatment-Naïve Adults without Cirrhosis ─ ION-3 (Study 0108)

ION-3 was a randomized, open-label trial in treatment-naïve non-cirrhotic subjects with genotype 1 HCV. Subjects were randomized in a 1:1:1 ratio to one of the following three treatment groups and stratified by HCV genotype (1a vs 1b): ledipasvir and sofosbuvir tablets (90 mg/400 mg) for 8 weeks, ledipasvir and sofosbuvir tablets (90 mg/400 mg) for 12 weeks, or ledipasvir and sofosbuvir tablets (90 mg/400 mg) + ribavirin for 8 weeks.

Demographics and baseline characteristics were balanced across the treatment groups. Of the 647 treated subjects, the median age was 55 years (range: 20 to 75); 58% of the subjects were male; 78% were White; 19% were Black; 6% were Hispanic or Latino; mean body mass index was 28 kg/m2 (range: 18 to 56 kg/m2); 81% had baseline HCV RNA levels greater than or equal to 800,000 IU per mL; 80% had genotype 1a HCV infection; 73% had non-C/C IL28B alleles (CT or TT).

Table 11 presents the SVR12 for the ledipasvir and sofosbuvir treatment groups in the ION-3 trial after 8 and 12 weeks of ledipasvir and sofosbuvir treatment. Ribavirin was not shown to increase the SVR12 observed with ledipasvir and sofosbuvir. Therefore, the ledipasvir and sofosbuvir + ribavirin arm is not presented in Table 11.

The treatment difference between the 8-week treatment of ledipasvir and sofosbuvir and 12-week treatment of ledipasvir and sofosbuvir was –2.3% (97.5% confidence interval –7.2% to 2.5%). Among subjects with a baseline HCV RNA less than 6 million IU per mL, the SVR12 was 97% (119/123) with 8-week treatment of ledipasvir and sofosbuvir and 96% (126/131) with 12-week treatment of ledipasvir and sofosbuvir.

Relapse rates by baseline viral load are presented in Table 12.

Treatment-Naïve Adults with or without Cirrhosis ─ ION-1 (Study 0102)

ION-1 was a randomized, open-label trial that evaluated 12 and 24 weeks of treatment with ledipasvir and sofosbuvir tablets (90 mg/400 mg) with or without ribavirin in 865 treatment-naïve subjects with genotype 1 HCV including those with cirrhosis. Subjects were randomized in a 1:1:1:1 ratio to receive ledipasvir and sofosbuvir for 12 weeks, ledipasvir and sofosbuvir + ribavirin for 12 weeks, ledipasvir and sofosbuvir for 24 weeks, or ledipasvir and sofosbuvir + ribavirin for 24 weeks. Randomization was stratified by the presence or absence of cirrhosis and HCV genotype (1a vs 1b).

Demographics and baseline characteristics were balanced across the treatment groups. Of the 865 treated subjects, the median age was 54 years (range: 18 to 80); 59% of the subjects were male; 85% were White; 12% were Black; 12% were Hispanic or Latino; mean body mass index was 27 kg/m2 (range: 18 to 48 kg/m2); 79% had baseline HCV RNA levels greater than or equal to 800,000 IU per mL; 67% had genotype 1a HCV infection; 70% had non-C/C IL28B alleles (CT or TT); and 16% had cirrhosis.

Table 13 presents the SVR12 for the treatment group of ledipasvir and sofosbuvir for 12 weeks in the ION-1 trial. Ribavirin was not shown to increase SVR12 observed with ledipasvir and sofosbuvir. Therefore, the ledipasvir and sofosbuvir + ribavirin arm is not presented in Table 13.

SVR12 for selected subgroups are presented in Table 14.

Previously-Treated Adults with or without Cirrhosis ─ ION-2 (Study 0109)

ION-2 was a randomized, open-label trial that evaluated 12 and 24 weeks of treatment with ledipasvir and sofosbuvir tablets (90 mg/400 mg) with or without ribavirin in genotype 1 HCV-infected subjects with or without cirrhosis who failed prior therapy with an interferon-based regimen, including regimens containing an HCV protease inhibitor. Subjects were randomized in a 1:1:1:1 ratio to receive ledipasvir and sofosbuvir for 12 weeks, ledipasvir and sofosbuvir + ribavirin for 12 weeks, ledipasvir and sofosbuvir for 24 weeks, or ledipasvir and sofosbuvir + ribavirin for 24 weeks. Randomization was stratified by the presence or absence of cirrhosis, HCV genotype (1a vs 1b) and response to prior HCV therapy (relapse/breakthrough vs nonresponse).

Demographics and baseline characteristics were balanced across the treatment groups. Of the 440 treated subjects, the median age was 57 years (range: 24 to 75); 65% of the subjects were male; 81% were White; 18% were Black; 9% were Hispanic or Latino; mean body mass index was 28 kg/m2 (range: 19 to 50 kg/m2); 89% had baseline HCV RNA levels greater than or equal to 800,000 IU per mL; 79% had genotype 1a HCV infection; 88% had non-C/C IL28B alleles (CT or TT); and 20% had cirrhosis. Forty-seven percent (47%) of the subjects failed a prior therapy of pegylated interferon and ribavirin. Among these subjects, 49% were relapse/breakthrough and 51% were non-responder. Fifty-three percent (53%) of the subjects failed a prior therapy of pegylated interferon and ribavirin with an HCV protease inhibitor. Among these subjects, 62% were relapse/breakthrough and 38% were non-responder.

Table 15 presents the SVR12 for the ledipasvir and sofosbuvir treatment groups in the ION-2 trial. Ribavirin was not shown to increase SVR12 observed with ledipasvir and sofosbuvir. Therefore, the ledipasvir and sofosbuvir + ribavirin arms are not presented in Table 15.

Among the subjects with available SVR12 and SVR24 data (206/218), all subjects who achieved SVR12 in the ION-2 study also achieved SVR24.

SVR12 and relapse rates for selected subgroups are presented in Tables 16 and 17.

Previously-Treated Adults with Cirrhosis ─ SIRIUS (Study 0121)

SIRIUS was a randomized, double-blind and placebo-controlled trial that evaluated the efficacy of ledipasvir and sofosbuvir tablets (90 mg/400 mg) + ribavirin for 12 weeks or ledipasvir and sofosbuvir tablets (90 mg/400 mg) without ribavirin for 24 weeks in genotype 1 HCV-infected subjects with compensated cirrhosis who failed prior therapy with a Peg-IFN + ribavirin regimen followed by a subsequent Peg-IFN + ribavirin + an HCV protease inhibitor regimen. Subjects were randomized in a 1:1 ratio to receive placebo for 12 weeks followed by ledipasvir and sofosbuvir + ribavirin for 12 weeks or ledipasvir and sofosbuvir for 24 weeks. Randomization was stratified by HCV genotype (1a vs 1b) and response to prior HCV therapy (never achieved HCV RNA less than LLOQ vs achieved HCV RNA less than LLOQ).

Demographics and baseline characteristics were balanced across the treatment groups. Of the 155 randomized subjects, the median age was 56 years (range: 23 to 77); 74% of the subjects were male; 97% were White; mean body mass index was 27 kg/m2 (range: 19 to 47 kg/m2); 63% had genotype 1a HCV infection; 94% had non-C/C IL28B alleles (CT or TT). One subject discontinued therapy while on placebo, and was not included in the efficacy analysis.

The SVR12 was 96% (74/77) and 97% (75/77) in subjects treated with ledipasvir and sofosbuvir + ribavirin for 12 weeks and ledipasvir and sofosbuvir for 24 weeks without ribavirin, respectively. All 5 subjects who did not achieve SVR12 relapsed.

Genotype 4

In two open-label studies (Study 1119 and ION-4), ledipasvir and sofosbuvir tablets (90 mg/400 mg) were administered for 12 weeks to treatment-naïve and previously-treated adult subjects with genotype 4 HCV infection. Study 1119 enrolled 44 treatment-naïve or previously-treated subjects with genotype 4 HCV, with or without cirrhosis. ION-4 enrolled 4 treatment-naïve and 4 previously-treated subjects with genotype 4 HCV infection who were coinfected with HIV-1, none of whom had cirrhosis.

In Study 1119, the overall SVR12 rate was 93% (41/44). SVR12 was similar based upon prior HCV treatment history and cirrhosis status. In ION-4, all 8 subjects achieved SVR12.

Genotype 5

In the open-label 1119 trial, ledipasvir and sofosbuvir tablets (90 mg/400 mg) were administered for 12 weeks to 41 treatment-naïve or previously treated adult subjects with genotype 5 HCV infection, with or without cirrhosis. The overall SVR12 was 93% (38/41). SVR12 was similar based upon prior HCV treatment history and cirrhosis status.

Genotype 6

In the open-label ELECTRON-2 trial, ledipasvir and sofosbuvir tablets (90 mg/400 mg) were administered for 12 weeks to 25 treatment-naïve or previously treated adult subjects with genotype 6 HCV infection, with or without cirrhosis. The overall SVR12 was 96% (24/25). SVR12 was similar based upon prior HCV treatment history and cirrhosis status. The single subject who relapsed discontinued study treatment early (at approximately Week 8).

Subjects 12 Years to <18 Years of Age: Ledipasvir and sofosbuvir was evaluated in 100 subjects 12 years to <18 years of age with HCV genotype 1 infection. Demographics and baseline characteristics were balanced across treatment-naïve and treatment-experienced subjects (patients had failed an interferon based regimen with or without ribavirin). The median age was 15 years (range: 12 to 17); 63% of the subjects were female; 91% were White, 7% were Black, and 2% were Asian; 13% were Hispanic/Latino; mean body mass index was 23 kg/m2 (range: 13.1 to 36.6 kg/m2); mean weight was 61 kg (range 33 to 126 kg); 55% had baseline HCV RNA levels greater than or equal to 800,000 IU/mL; 81% had genotype 1a HCV infection. One subject (treatment-naïve) had known compensated cirrhosis. The majority of subjects (84%) had been infected through vertical transmission.

The SVR12 rate was 98% overall (98% [78/80] in treatment-naïve subjects and 100% [20/20] in treatment-experienced subjects). No subject experienced on-treatment virologic failure or relapse. Two subjects were lost to follow-up.

Subjects 6 Years to <12 Years of Age: Ledipasvir and sofosbuvir was evaluated in 90 subjects 6 years to <12 years of age with HCV genotype 1 or 4 infection. Among these subjects, 72 (80%) were treatment-naïve and 18 (20%) were treatment-experienced. Eighty-nine of the subjects (87 with genotype 1 HCV infection and 2 with genotype 4 HCV infection) were treated with ledipasvir and sofosbuvir for 12 weeks, 1 subject with genotype 1 HCV infection was treated with ledipasvir and sofosbuvir for 24 weeks. The median age was 9 years (range: 6 to 11); 59% of the subjects were male; 79% were White, 8% were Black, and 6% were Asian; 10% were Hispanic/Latino; mean body mass index was 18 kg/m2 (range: 13 to 31kg/m2); mean weight was 33 kg (range 18 to 76 kg); 59% had baseline HCV RNA levels greater than or equal to 800,000 IU/mL; 86% had genotype 1a HCV infection; 2 subjects (1 treatment-naïve, 1 treatment-experienced) had known compensated cirrhosis. The majority of subjects (97%) had been infected through vertical transmission.

The SVR12 rate was 99% (86/87) in subjects with genotype 1 HCV infection, and 100% (2/2) in subjects with genotype 4 HCV infection. The one genotype 1 subject treated with ledipasvir and sofosbuvir for 24 weeks also achieved SVR12. The one subject (genotype 1) who did not achieve SVR12 and relapsed had been treated with ledipasvir and sofosbuvir for 12 weeks.

Subjects 3 Years to <6 Years of Age: Ledipasvir and sofosbuvir was evaluated in 34 subjects 3 years to <6 years of age with HCV genotype 1 (N = 33) or genotype 4 (N = 1) infection. All of the subjects were treatment-naïve and treated with ledipasvir and sofosbuvir for 12 weeks. The median age was 5 years (range: 3 to 5); 71% of the subjects were female; 79% were White, 3% were Black, and 6% were Asian; 18% were Hispanic/Latino; mean body mass index was 17 kg/m2 (range: 13 to 25 kg/m2); mean weight was 19 kg (range 11 to 34 kg); 56% had baseline HCV RNA levels greater than or equal to 800,000 IU/mL; 82% had genotype 1a HCV infection; no subjects had known cirrhosis. All subjects (100%) had been infected through vertical transmission.

The SVR12 rate was 97% (32/33) in subjects with genotype 1 HCV infection, and the one subject with genotype 4 HCV infection also achieved SVR12. One subject prematurely discontinued study treatment due to an adverse event.