Baraclude Drug Information

BARACLUDE ® (entecavir) is indicated for the treatment of chronic hepatitis B virus infection in adults and pediatric patients 2 years of age and older with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease. BARACLUDE is a hepatitis B virus nucleoside analogue reverse transcriptase inhibitor indicated for the treatment of chronic hepatitis B virus infection in adults and children at least 2 years of age with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.

Timing of Administration BARACLUDE should be administered on an empty stomach (at least 2 hours after a meal and 2 hours before the next meal).

Recommended Dosage in Adults Compensated Liver Disease

The recommended dose of BARACLUDE for chronic hepatitis B virus infection in nucleoside-inhibitor-treatment-naïve adults and adolescents 16 years of age and older is 0.5 mg once daily. The recommended dose of BARACLUDE in adults and adolescents (at least 16 years of age) with a history of hepatitis B viremia while receiving lamivudine or known lamivudine or telbivudine resistance substitutions rtM204I/V with or without rtL180M, rtL80I/V, or rtV173L is 1 mg once daily. Decompensated Liver Disease The recommended dose of BARACLUDE for chronic hepatitis B virus infection in adults with decompensated liver disease is 1 mg once daily.

Recommended Dosage in Pediatric Patients Table 1 describes the recommended dose of BARACLUDE for pediatric patients 2 years of age or older and weighing at least 10 kg. The oral solution should be used for patients with body weight up to 30 kg. Table 1: Dosing Schedule for Pediatric Patients

Renal Impairment

In adult subjects with renal impairment, the apparent oral clearance of entecavir decreased as creatinine clearance decreased. Dosage adjustment is recommended for patients with creatinine clearance less than 50 mL/min, including patients on hemodialysis or continuous ambulatory peritoneal dialysis (CAPD), as shown in Table 2. The once-daily dosing regimens are preferred.

Table 2: Recommended Dosage of BARACLUDE in Adult Patients with Renal Impairment Although there are insufficient data to recommend a specific dose adjustment of BARACLUDE in pediatric patients with renal impairment, a reduction in the dose or an increase in the dosing interval similar to adjustments for adults should be considered.

Hepatic Impairment

No dosage adjustment is necessary for patients with hepatic impairment.

Duration of Therapy

The optimal duration of treatment with BARACLUDE for patients with chronic hepatitis B virus infection and the relationship between treatment and long-term outcomes such as cirrhosis and hepatocellular carcinoma are unknown.

Clinical Trial 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. Clinical Trial Experience in Adults Compensated Liver Disease Assessment of adverse reactions is based on four studies (AI463014, AI463022, AI463026, and AI463027) in which 1720 subjects with chronic hepatitis B virus infection and compensated liver disease received double-blind treatment with BARACLUDE 0.5 mg/day (n=679), BARACLUDE 1 mg/day (n=183), or lamivudine (n=858) for up to 2 years. Median duration of therapy was 69 weeks for BARACLUDE-treated subjects and 63 weeks for lamivudine-treated subjects in Studies AI463022 and AI463027 and 73 weeks for BARACLUDE-treated subjects and 51 weeks for lamivudine-treated subjects in Studies AI463026 and AI463014.

The safety profiles of BARACLUDE and lamivudine were comparable in these studies. The most common adverse reactions of any severity (≥3%) with at least a possible relation to study drug for BARACLUDE-treated subjects were headache, fatigue, dizziness, and nausea. The most common adverse reactions among lamivudine-treated subjects were headache, fatigue, and dizziness.

One percent of BARACLUDE-treated subjects in these four studies compared with 4% of lamivudine-treated subjects discontinued for adverse events or abnormal laboratory test results. Clinical adverse reactions of moderate-severe intensity and considered at least possibly related to treatment occurring during therapy in four clinical studies in which BARACLUDE was compared with lamivudine are presented in Table 3. Table 3: Clinical Adverse Reactions a of Moderate-Severe Intensity (Grades 2‑4) Reported in Four Entecavir Clinical Trials Through 2 Years Laboratory Abnormalities Frequencies of selected treatment-emergent laboratory abnormalities reported during therapy in four clinical trials of BARACLUDE compared with lamivudine are listed in Table 4.

Table 4: Selected Treatment-Emergent a Laboratory Abnormalities Reported in Four Entecavir Clinical Trials Through 2 Years -treated subjects in these studies, on-treatment ALT elevations greater than 10 times the upper limit of normal (ULN) and greater than 2 times baseline generally resolved with continued treatment. A majority of these exacerbations were associated with a ≥2 log 10 /mL reduction in viral load that preceded or coincided with the ALT elevation. Periodic monitoring of hepatic function is recommended during treatment.

Exacerbations of Hepatitis After Discontinuation of Treatment An exacerbation of hepatitis or ALT flare was defined as ALT greater than 10 times ULN and greater than 2 times the subject’s reference level (minimum of the baseline or last measurement at end of dosing). For all subjects who discontinued treatment (regardless of reason), Table 5 presents the proportion of subjects in each study who experienced post-treatment ALT flares. In these studies, a subset of subjects was allowed to discontinue treatment at or after 52 weeks if they achieved a protocol-defined response to therapy.

If BARACLUDE is discontinued without regard to treatment response, the rate of post-treatment flares could be higher. Table 5: Exacerbations of Hepatitis During Off-Treatment Follow-up, Subjects in Studies AI463022, AI463027, and AI463026 Decompensated Liver Disease Study AI463048 was a randomized, open-label study of BARACLUDE 1 mg once daily versus adefovir dipivoxil 10 mg once daily given for up to 48 weeks in adult subjects with chronic HBV infection and evidence of hepatic decompensation, defined as a Child-Turcotte-Pugh (CTP) score of 7 or higher. Among the 102 subjects receiving BARACLUDE, the most common treatment-emergent adverse events of any severity, regardless of causality, occurring through Week 48 were peripheral edema .

The majority of deaths (11 in the BARACLUDE group and 16 in the adefovir dipivoxil group) were due to liver-related causes such as hepatic failure, hepatic encephalopathy, hepatorenal syndrome, and upper gastrointestinal hemorrhage. Five percent of subjects in either treatment arm discontinued therapy due to an adverse event through Week 48. No subject in either treatment arm experienced an on-treatment hepatic flare (ALT >2 × baseline and >10 × ULN) through Week 48.

HIV/HBV Co-infected The safety profile of BARACLUDE 1 mg (n=51) in HIV/HBV co-infected subjects enrolled in Study AI463038 was similar to that of placebo (n=17) through 24 weeks of blinded treatment and similar to that seen in non-HIV infected subjects. Liver Transplant Recipients Among 65 subjects receiving BARACLUDE in an open-label, post-liver transplant trial, the frequency and nature of adverse events were consistent with those expected in patients who have received a liver transplant and the known safety profile of BARACLUDE. Clinical Trial Experience in Pediatric Subjects The safety of BARACLUDE in pediatric subjects 2 to less than 18 years of age is based on two clinical trials in subjects with chronic HBV infection (one Phase 2 pharmacokinetic trial and one Phase 3 trial ).

These trials provided experience in 168 HBeAg-positive subjects treated with BARACLUDE for a median duration of 72 weeks. The adverse reactions observed in pediatric subjects who received treatment with BARACLUDE were consistent with those observed in clinical trials of BARACLUDE in adults. Adverse drug reactions reported in greater than 1% of pediatric subjects included abdominal pain, rash events, poor palatability (“product taste abnormal”), nausea, diarrhea, and vomiting.

Postmarketing Experience Data from Long-Term Observational Study Study AI463080 was a randomized, global, observational, open-label Phase 4 study to assess long-term risks and benefits of BARACLUDE (0.5 mg/day or 1 mg/day) treatment as compared to other standard-of-care HBV nucleos(t)ide analogues in subjects with chronic HBV infection. A total of 12,378 patients were treated with BARACLUDE (n=6,216) or other HBV nucleos(t)ide treatment (n=6,162). Patients were evaluated at baseline and subsequently every 6 months for up to 10 years.

The principal clinical outcome events assessed during the study were overall malignant neoplasms, liver-related HBV disease progression, HCC, non-HCC malignant neoplasms, and death. The study showed that BARACLUDE was not significantly associated with an increased risk of malignant neoplasms compared to other standard-of-care HBV nucleos(t)ides, as assessed by either the composite endpoint of overall malignant neoplasms or the individual endpoint of non-HCC malignant neoplasms. The most commonly reported malignancy in both the BARACLUDE and non-ETV groups was HCC followed by gastrointestinal malignancies.

The data also showed that long-term BARACLUDE use was not associated with a lower occurrence of HBV disease progression or a lower rate of death overall compared to other HBV nucleos(t)ides. The principal clinical outcome event assessments are shown in Table 6. Table 6: Principal Analyses of Time to Adjudicated Events - Randomized Treated Subjects 0.87 Limitations of the study included population changes over the long-term follow-up period and more frequent post-randomization treatment changes in the non-ETV group.

In addition, the study was underpowered to demonstrate a difference in the non-HCC malignancy rate because of the lower than expected background rate. Adverse Reactions from Postmarketing Spontaneous Reports The following adverse reactions have been reported during postmarketing use of BARACLUDE. Because these reactions were reported voluntarily from a population of unknown size, it is not possible to reliably estimate their frequency or establish a causal relationship to BARACLUDE exposure.

Immune system disorders: Anaphylactoid reaction. Metabolism and nutrition disorders: Lactic acidosis. Hepatobiliary disorders: Increased transaminases.

Skin and subcutaneous tissue disorders: Alopecia, rash.

Since entecavir is primarily eliminated by the kidneys, coadministration of BARACLUDE with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the coadministered drug. Coadministration of entecavir with lamivudine, adefovir dipivoxil, or tenofovir disoproxil fumarate did not result in significant drug interactions. The effects of coadministration of BARACLUDE with other drugs that are renally eliminated or are known to affect renal function have not been evaluated, and patients should be monitored closely for adverse events when BARACLUDE is coadministered with such drugs.

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to BARACLUDE during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary Prospective pregnancy data from the APR are not sufficient to adequately assess the risk of birth defects, miscarriage or adverse maternal or fetal outcomes.

Entecavir use during pregnancy has been evaluated in a limited number of individuals reported to the APR and the number of exposures to entecavir is insufficient to make a risk assessment compared to a reference population. The estimated background rate for major birth defects is 2.7% in the U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). The rate of miscarriage is not reported in the APR.

All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of miscarriage in clinically recognized pregnancies is 15–20%. In animal reproduction studies, no adverse developmental effects were observed with entecavir at clinically relevant exposures.

No developmental toxicities were observed at systemic exposures (AUC) approximately 25 (rats) and 200 (rabbits) times the exposure at the maximum recommended human dose (MRHD) of 1 mg/day (see Data). In rats, embryofetal toxicity including post-implantation loss, resorptions, tail and vertebral malformations, skeletal variations including reduced ossification (vertebrate, sternebrae, and phalanges) and extra lumbar vertebrae and ribs, and lower fetal body weights were observed at systemic exposures (AUC) 3,100 times those in humans at the MRHD. Maternal toxicity was also observed at this dose level.

In rabbits, embryofetal toxicity including post-implantation loss, resorptions and skeletal variations, including reduced ossification (hyoid) and increased incidence of 13 th rib, were observed at systemic exposures (AUC) 883 times those in humans at the MRHD. There were no signs of embryofetal toxicity when pregnant animals received oral entecavir at 28 (rat) and 212 (rabbit) times the human exposure (AUC) at the MRHD. No adverse effects on the offspring occurred at up to the highest dose evaluated, resulting in exposures (AUC) greater than 94 times those in humans at the MRHD.

Pediatric Use BARACLUDE was evaluated in two clinical trials of pediatric subjects 2 years of age and older with HBeAg-positive chronic HBV infection and compensated liver disease. The exposure of BARACLUDE in nucleoside-inhibitor-treatment-naïve and lamivudine-experienced pediatric subjects 2 years of age and older with HBeAg-positive chronic HBV infection and compensated liver disease receiving 0.015 mg/kg (up to 0.5 mg once daily) or 0.03 mg/kg (up to 1 mg once daily), respectively, was evaluated in Study AI463028. Safety and efficacy of the selected dose in treatment-naïve pediatric subjects were confirmed in Study AI463189, a randomized, placebo-controlled treatment trial.

There are limited data available on the use of BARACLUDE in lamivudine-experienced pediatric patients; BARACLUDE should be used in these patients only if the potential benefit justifies the potential risk to the child. Since some pediatric patients may require long-term or even lifetime management of chronic active hepatitis B, consideration should be given to the impact of BARACLUDE on future treatment options. The efficacy and safety of BARACLUDE have not been established in patients less than 2 years of age.

Use of BARACLUDE in this age group has not been evaluated because treatment of HBV in this age group is rarely required.

There is limited experience of entecavir overdosage reported in patients. Healthy subjects who received single entecavir doses up to 40 mg or multiple doses up to 20 mg/day for up to 14 days had no increase in or unexpected adverse events. If overdose occurs, the patient must be monitored for evidence of toxicity, and standard supportive treatment applied as necessary.

Following a single 1 mg dose of entecavir, a 4-hour hemodialysis session removed approximately 13% of the entecavir dose.