Sovaldi Drug Information

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. When SOVALDI is administered with ribavirin or peginterferon alfa/ribavirin, refer to the respective prescribing information for a description of adverse reactions associated with their use. Adverse Reactions in Adult Subjects The safety assessment of SOVALDI was based on pooled Phase 3 clinical trial data (both controlled and uncontrolled) including: 650 subjects who received SOVALDI + ribavirin (RBV) combination therapy for 12 weeks, 98 subjects who received SOVALDI + ribavirin combination therapy for 16 weeks, 250 subjects who received SOVALDI + ribavirin combination therapy for 24 weeks, 327 subjects who received SOVALDI + peginterferon (Peg-IFN) alfa + ribavirin combination therapy for 12 weeks, 243 subjects who received peginterferon alfa + ribavirin for 24 weeks, and 71 subjects who received placebo (PBO) for 12 weeks . The proportion of subjects who permanently discontinued treatment due to adverse events was 4% for subjects receiving placebo, 1% for subjects receiving SOVALDI + ribavirin for 12 weeks, less than 1% for subjects receiving SOVALDI + ribavirin for 24 weeks, 11% for subjects receiving peginterferon alfa + ribavirin for 24 weeks and 2% for subjects receiving SOVALDI + peginterferon alfa + ribavirin for 12 weeks.

Adverse events observed in at least 15% of subjects in the Phase 3 clinical trials outlined above are provided in Table 5. A side-by-side tabulation is displayed to simplify presentation; direct comparison across trials should not be made due to differing trial designs. The most common adverse events (at least 20%) for SOVALDI + ribavirin combination therapy were fatigue and headache. The most common adverse events (at least 20%) for SOVALDI + peginterferon alfa + ribavirin combination therapy were fatigue, headache, nausea, insomnia and anemia.

Table 5 Adverse Events (All Grades and without Regard to Causality) Reported in ≥15% of Subjects with HCV in Any Treatment Arm Interferon-free Regimens Interferon-containing Regimens PBO 12 weeks SOVALDI + RBV Subjects received weight-based ribavirin (1000 mg per day if weighing <75 kg or 1200 mg per day if weighing ≥75 kg). 12 weeks SOVALDI + RBV 24 weeks Peg-IFN alfa + RBV Subjects received 800 mg ribavirin per day regardless of weight. 24 weeks SOVALDI + Peg-IFN alfa + RBV 12 weeks N=71 N=650 N=250 N=243 N=327 Fatigue 24% 38% 30% 55% 59% Headache 20% 24% 30% 44% 36% Nausea 18% 22% 13% 29% 34% Insomnia 4% 15% 16% 29% 25% Pruritus 8% 11% 27% 17% 17% Anemia 0% 10% 6% 12% 21% Asthenia 3% 6% 21% 3% 5% Rash 8% 8% 9% 18% 18% Decreased Appetite 10% 6% 6% 18% 18% Chills 1% 2% 2% 18% 17% Influenza Like Illness 3% 3% 6% 18% 16% Pyrexia 0% 4% 4% 14% 18% Diarrhea 6% 9% 12% 17% 12% Neutropenia 0% <1% <1% 12% 17% Myalgia 0% 6% 9% 16% 14% Irritability 1% 10% 10% 16% 13% With the exception of anemia and neutropenia, the majority of events presented in Table 5 occurred at severity of grade 1 in SOVALDI-containing regimens. Less Common Adverse Reactions Reported in Clinical Trials (less than 1%): The following adverse reactions occurred in less than 1% of subjects receiving SOVALDI in a combination regimen in any one trial. These events have been included because of their seriousness or assessment of potential causal relationship.

Hematologic Effects: pancytopenia (particularly in subjects receiving concomitant pegylated interferon). Psychiatric Disorders: severe depression (particularly in subjects with pre-existing history of psychiatric illness), including suicidal ideation and suicide. Laboratory Abnormalities: Changes in selected hematological parameters are described in Table 6. A side-by-side tabulation is displayed to simplify presentation; direct comparison across trials should not be made due to differing trial designs. Table 6 Percentage of Subjects Reporting Selected Hematological Parameters Hematological Parameters Interferon-free Regimens Interferon-containing Regimens PBO 12 weeks SOVALDI + RBV Subjects received weight-based ribavirin (1000 mg per day if weighing <75 kg or 1200 mg per day if weighing ≥75 kg). 12 weeks SOVALDI + RBV 24 weeks Peg-IFN + RBV Subjects received 800 mg ribavirin per day regardless of weight. 24 weeks SOVALDI + Peg-IFN + RBV 12 weeks N=71 N=647 N=250 N=242 N=327 Hemoglobin (g/dL) <10 0 8% 6% 14% 23% <8.5 0 1% <1% 2% 2% Neutrophils (×10 9 /L) ≥0.5 – <0.75 1% <1% 0 12% 15% <0.5 0 <1% 0 2% 5% Platelets (×10 9 /L) ≥25 – <50 3% <1% 1% 7% <1% <25 0 0 0 0 0 Bilirubin Elevations Total bilirubin elevation of more than 2.5×ULN was observed in none of the subjects in the SOVALDI + peginterferon alfa + ribavirin 12 weeks group and in 1%, 3% and 3% of subjects in the peginterferon alfa + ribavirin 24 weeks, SOVALDI + ribavirin 12 weeks and SOVALDI + ribavirin 24 weeks groups, respectively.

Bilirubin levels peaked during the first 1 to 2 weeks of treatment and subsequently decreased and returned to baseline levels by post-treatment Week 4. These bilirubin elevations were not associated with transaminase elevations. Creatine Kinase Elevations Creatine kinase was assessed in the FISSION and NEUTRINO trials. Isolated, asymptomatic creatine kinase elevation of greater than or equal to 10×ULN was observed in less than 1%, 1% and 2% of subjects in the peginterferon alfa + ribavirin 24 weeks, SOVALDI + peginterferon alfa + ribavirin 12 weeks and SOVALDI + ribavirin 12 weeks groups, respectively.

Lipase Elevations Isolated, asymptomatic lipase elevation of greater than 3×ULN was observed in less than 1%, 2%, 2%, and 2% of subjects in the SOVALDI + peginterferon alfa + ribavirin 12 weeks, SOVALDI + ribavirin 12 weeks, SOVALDI + ribavirin 24 weeks and peginterferon alfa + ribavirin 24 weeks groups, respectively. Patients with HCV/HIV-1 Coinfection SOVALDI used in combination with ribavirin was assessed in 223 HCV/HIV-1 coinfected subjects . The safety profile in HCV/HIV-1 coinfected subjects was similar to that observed in HCV mono-infected subjects. Elevated total bilirubin (grade 3 or 4) was observed in 30/32 (94%) subjects receiving atazanavir as part of the antiretroviral regimen.

None of the subjects had concomitant transaminase increases. Among subjects not taking atazanavir, grade 3 or 4 elevated total bilirubin was observed in 2 (1.5%) subjects, similar to the rate observed with HCV mono-infected subjects receiving SOVALDI + ribavirin in Phase 3 trials. Adverse Reactions in Pediatric Subjects 3 Years of Age and Older The safety assessment of SOVALDI in pediatric subjects 3 years of age and older is based on data from 106 subjects who were treated with SOVALDI plus ribavirin for 12 weeks (genotype 2 subjects) or 24 weeks (genotype 3 subjects) in a Phase 2, open-label clinical trial.

The adverse reactions observed were consistent with those observed in clinical studies of SOVALDI plus ribavirin in adults. Among pediatric subjects 3 years to < 12 years of age taking SOVALDI in combination with ribavirin oral solution, decreased appetite was observed in 13% (7/54) of subjects . In a 5-year follow-up study, 88 of the 106 subjects from the Phase 2 open-label clinical trial (Study 1112) were followed for a median (Q1, Q3) duration of 239 weeks. No notable effects on growth as assessed by changes from baseline through end of study were observed for height, weight, BMI percentiles, and Z-scores for any age group.

No notable effects were observed on the development of secondary sexual characteristics of subjects as assessed by changes from baseline through end of study in Tanner pubertal stages.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of SOVALDI. Because postmarketing 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. Skin and Subcutaneous Tissue Disorders Skin rashes, sometimes with blisters or angioedema-like swelling Angioedema

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 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.

Pregnancy Risk Summary If SOVALDI is administered with ribavirin or peginterferon alfa and ribavirin, the combination regimen is contraindicated in pregnant women and in men whose female partners are pregnant. Refer to the ribavirin and/or peginterferon alfa prescribing information for more information on ribavirin- and peginterferon alfa-associated risks of use during pregnancy. No adequate human data are available to establish whether or not SOVALDI poses a risk to pregnancy outcomes.

In animal reproduction studies, no evidence of adverse developmental outcomes was observed with sofosbuvir at exposures greater than those in humans at the recommended human dose (RHD) . During organogenesis in the rat and rabbit, systemic exposures (AUC) to the predominant circulating metabolite of sofosbuvir (GS-331007) were ≥5 (rats) and 12 (rabbits) times the exposure in humans at the RHD. In the rat pre/postnatal development study, maternal systemic exposure (AUC) to GS-331007 was ≥6 times 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 Animal Data Sofosbuvir was administered orally to pregnant rats (up to 500 mg/kg/day) and rabbits (up to 300 mg/kg/day) on gestation days 6 to 18 and 6 to 19, respectively, and also to rats (oral doses up to 500 mg/kg/day) on gestation day 6 to lactation/post-partum day 20. No significant effects on embryo-fetal (rats and rabbits) or pre/postnatal (rats) development were observed at the highest doses tested.

Systemic exposures (AUC) to the predominant circulating metabolite of sofosbuvir (GS-331007) were ≥5 (rats) and 12 (rabbits) times the exposure in humans at the RHD, with exposures increasing during gestation from approximately 5 to 10 (rats) and 12 to 28 (rabbits) times the exposure in humans at the RHD.

Pediatric Use The safety, pharmacokinetics, and efficacy of SOVALDI in pediatric patients 3 years of age and older with genotype 2 and 3 infection have been established. SOVALDI was evaluated in an open-label clinical trial (Study 1112), which included 106 subjects (31 genotype 2; 75 genotype 3) 3 years of age and older. The safety, pharmacokinetics, and efficacy were comparable to that observed in adults . The safety and efficacy of SOVALDI in pediatric patients 3 years of age and older with compensated cirrhosis is supported by comparable sofosbuvir and GS-331007 exposures between: 1) adults and pediatric patients without cirrhosis and 2) adults without cirrhosis and adults with compensated cirrhosis.

Thus, similar efficacy would be expected for pediatric patients with compensated cirrhosis as adults with compensated cirrhosis. The safety and efficacy of SOVALDI have not been established in pediatric patients less than 3 years of age with HCV genotype 2 or 3. The safety and efficacy of SOVALDI have not been established in pediatric patients with HCV genotype 1 or 4. In a 5-year follow-up study, the long-term effects of SOVALDI on pediatric growth were assessed in 88 pediatric subjects 3 years of age and older treated with SOVALDI in Study 1112. No notable effects on growth from baseline through end of study were observed. All subjects who had achieved SVR12 maintained SVR through end of study.

When SOVALDI is used in combination with ribavirin or peginterferon alfa/ribavirin, the contraindications applicable to those agents are applicable to combination therapies. Refer to the prescribing information of peginterferon alfa and ribavirin for a list of their contraindications. When used in combination with peginterferon alfa/ribavirin or ribavirin alone, all contraindications to peginterferon alfa and/or ribavirin also apply to SOVALDI combination therapy.

The highest documented dosage of sofosbuvir was a single dose of sofosbuvir 1200 mg (three times the recommended dosage) administered to 59 healthy subjects. In that trial, there were no untoward effects observed at this dosage level, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups. The effects of higher dosages are not known.

No specific antidote is available for overdose with SOVALDI. If overdose occurs, the patient must be monitored for evidence of toxicity. Treatment of overdose with SOVALDI consists of general supportive measures including monitoring of vital signs as well as observation of the clinical status of the patient. A 4-hour hemodialysis session removed 18% of the administered dose.