EPIVIR

1 INDICATIONS AND USAGE EPIVIR is a nucleoside analogue indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus type 1 (HIV‑1) infection. Limitations of Use: • The dosage of this product is for HIV‑1 and not for HBV. EPIVIR is a nucleoside analogue reverse transcriptase inhibitor indicated in combination with other antiretroviral agents for the treatment of HIV‑1 infection. Limitations of Use: The dosage of this product is for HIV‑1 and not for HBV. ( 1 )

2 DOSAGE AND ADMINISTRATION • Adults: 300 mg daily, administered as either 150 mg twice daily or 300 mg once daily. ( 2.1 ) • Pediatric Patients Aged 3 Months and Older: Administered either once or twice daily. Dose should be calculated on body weight (kg) and should not exceed 300 mg daily. ( 2.2 ) • Patients with Renal Impairment: Doses of EPIVIR must be adjusted in accordance with renal function. ( 2.3 ) 2.1 Recommended Dosage for Adult Patients The recommended dosage of EPIVIR in HIV-1–infected adults is 300 mg daily, administered as either 150 mg taken orally twice daily or 300 mg taken orally once daily with or without food. If lamivudine is administered to a patient infected with HIV‑1 and HBV, the dosage indicated for HIV‑1 therapy should be used as part of an appropriate combination regimen [see Warnings and Precautions ( 5.1 )] . 2.2 Recommended Dosage for Pediatric Patients EPIVIR scored tablet is the preferred formulation for HIV-1–infected pediatric patients who weigh at least 14 kg and for whom a solid dosage form is appropriate. Before prescribing EPIVIR scored tablets, pediatric patients should be assessed for the ability to swallow tablets. For patients unable to safely and reliably swallow EPIVIR tablets, the oral solution formulation may be prescribed [see Warnings and Precautions ( 5.5 )] . The recommended oral dosage of EPIVIR tablets for HIV-1–infected pediatric patients is presented in Table 1 . Table 1. Dosing Recommendations for EPIVIR Scored (150-mg) Tablets in Pediatric Patients a Data regarding the efficacy of once-daily dosing is limited to subjects who transitioned from twice-daily dosing to once-daily dosing after 36 weeks of treatment [see Clinical Studies ( 14.2 )] . b Patients may alternatively take one 300-mg tablet, which is not scored. Weight (kg) Once-Daily Dosing Regimen a Twice-Daily Dosing Regimen Using Scored 150-mg Tablet AM Dose PM Dose Total Daily Dose 14 to <20 1 tablet (150 mg) ½ tablet (75 mg) ½ tablet (75 mg) 150 mg ≥20 to <25 1½ tablets (225 mg) ½ tablet (75 mg) 1 tablet (150 mg) 225 mg ≥25 2 tablets (300 mg) b 1 tablet (150 mg) 1 tablet (150 mg) 300 mg Oral Solution The recommended dosage of EPIVIR oral solution in HIV-1–infected pediatric patients aged 3 months and older is 5 mg per kg taken orally twice daily or 10 mg per kg taken orally once daily (up to a maximum of 300 mg daily), administered in combination with other antiretroviral agents [see Clinical Pharmacology ( 12.3 )] . Consider HIV-1 viral load and CD4+ cell count/percentage when selecting the dosing interval for patients initiating treatment with oral solution [see Warnings and Precautions ( 5.5 ), Clinical Pharmacology ( 12.3 )] . 2.3 Patients with Renal Impairment Dosing of EPIVIR is adjusted in accordance with renal function. Dosage adjustments are listed in Table 2 [see Clinical Pharmacology ( 12.3 )] . Table 2. Adjustment of Dosage of EPIVIR in Adults and Adolescents (Greater than or Equal to 25 kg) in Accordance with Creatinine Clearance Creatinine Clearance (mL/min) Recommended Dosage of EPIVIR ≥50 150 mg twice daily or 300 mg once daily 30-49 150 mg once daily 15-29 150 mg first dose, then 100 mg once daily 5-14 150 mg first dose, then 50 mg once daily <5 50 mg first dose, then 25 mg once daily No additional dosing of EPIVIR is required after routine (4-hour) hemodialysis or peritoneal dialysis. Although there are insufficient data to recommend a specific dose adjustment of EPIVIR in pediatric patients with renal impairment, a reduction in the dose and/or an increase in the dosing interval should be considered.

5 WARNINGS AND PRECAUTIONS • Co-infected HIV‑1/HBV Patients: Emergence of lamivudine-resistant HBV variants associated with lamivudine‑containing antiretroviral regimens has been reported. ( 5.1 ) • Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues. ( 5.2 ) • Pancreatitis: Use with caution in pediatric patients with a history of pancreatitis or other significant risk factors for pancreatitis. Discontinue treatment as clinically appropriate. ( 5.3 ) • Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy. ( 5.4 ) • Lower virologic suppression rates and increased risk of viral resistance were observed in pediatric subjects who received EPIVIR oral solution concomitantly with other antiretroviral oral solutions compared with those who received tablets. An all-tablet regimen should be used when possible. ( 5.5 ) 5.1 Patients with Hepatitis B Virus Co-Infection Posttreatment Exacerbations of Hepatitis Clinical and laboratory evidence of exacerbations of hepatitis have occurred after discontinuation of lamivudine. These exacerbations have been detected primarily by serum ALT elevations in addition to re‑emergence of HBV DNA. Although most events appear to have been self‑limited, fatalities have been reported in some cases. Similar events have been reported from postmarketing experience after changes from lamivudine‑containing HIV‑1 treatment regimens to non‑lamivudine–containing regimens in patients infected with both HIV‑1 and HBV. The causal relationship to discontinuation of lamivudine treatment is unknown. Patients should be closely monitored with both clinical and laboratory follow‑up for at least several months after stopping treatment. Important Differences among Lamivudine ‑ Containing Products EPIVIR tablets and oral solution contain a higher dose of the same active ingredient (lamivudine) than EPIVIR‑HBV tablets and EPIVIR‑HBV oral solution. EPIVIR‑HBV was developed for patients with chronic hepatitis B. The formulation and dosage of lamivudine in EPIVIR‑HBV are not appropriate for patients co-infected with HIV‑1 and HBV. Safety and efficacy of lamivudine have not been established for treatment of chronic hepatitis B in patients co‑infected with HIV‑1 and HBV. If treatment with EPIVIR‑HBV is prescribed for chronic hepatitis B for a patient with unrecognized or untreated HIV-1 infection, rapid emergence of HIV‑1 resistance is likely to result because of the subtherapeutic dose and the inappropriateness of monotherapy HIV‑1 treatment. If a decision is made to administer lamivudine to patients co‑infected with HIV‑1 and HBV, EPIVIR tablets, EPIVIR oral solution, or another product containing the higher dose of lamivudine should be used as part of an appropriate combination regimen. Emergence of Lamivudine-Resistant HBV Safety and efficacy of lamivudine have not been established for treatment of chronic hepatitis B in subjects dually infected with HIV-1 and HBV (see full prescribing information for EPIVIR-HBV). Emergence of hepatitis B virus variants associated with resistance to lamivudine has also been reported in HIV-1–infected subjects who have received lamivudine-containing antiretroviral regimens in the presence of concurrent infection with hepatitis B virus. 5.2 Lactic Acidosis and Severe Hepatomegaly with Steatosis Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues, including EPIVIR. A majority of these cases have been in women. Female sex and obesity may be risk factors for the development of lactic acidosis and severe hepatomegaly with steatosis in patients treated with antiretroviral nucleoside analogues. Treatment with EPIVIR should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity, which may include hepatomegaly a…

4 CONTRAINDICATIONS EPIVIR is contraindicated in patients with a previous hypersensitivity reaction to lamivudine. EPIVIR is contraindicated in patients with previous hypersensitivity reaction to lamivudine. ( 4 )

7 DRUG INTERACTIONS Sorbitol: Coadministration of lamivudine and sorbitol may decrease lamivudine concentrations; when possible, avoid chronic coadministration. ( 7.2 ) 7.1 Drugs Inhibiting Organic Cation Transporters Lamivudine is predominantly eliminated in the urine by active organic cationic secretion. The possibility of interactions with other drugs administered concurrently should be considered, particularly when their main route of elimination is active renal secretion via the organic cationic transport system (e.g., trimethoprim) [see Clinical Pharmacology ( 12.3 )] . No data are available regarding interactions with other drugs that have renal clearance mechanisms similar to that of lamivudine. 7.2 Sorbitol Coadministration of single doses of lamivudine and sorbitol resulted in a sorbitol dose-dependent reduction in lamivudine exposures. When possible, avoid use of sorbitol-containing medicines with lamivudine [see Warnings and Precautions ( 5.5 ), Clinical Pharmacology ( 12.3 )] .

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to EPIVIR during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary Available data from the APR show no difference in the overall risk of birth defects for lamivudine compared with the background rate for birth defects of 2.7% in the Metropolitan Atlanta Congenital Defects Program (MACDP) reference population (see Data) . The APR uses the MACDP as the U.S. reference population for birth defects in the general population. The MACDP evaluates women and infants from a limited geographic area and does not include outcomes for births that occurred at less than 20 weeks’ gestation. The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15% to 20%. The background risk for major birth defects and miscarriage for the indicated population is unknown. In animal reproduction studies, oral administration of lamivudine to pregnant rabbits during organogenesis resulted in embryolethality at systemic exposure (AUC) similar to the recommended clinical dose; however, no adverse development effects were observed with oral administration of lamivudine to pregnant rats during organogenesis at plasma concentrations (C max ) 35 times the recommended clinical dose ( see Data ). Data Human Data: Based on prospective reports to the APR of over 11,000 exposures to lamivudine during pregnancy resulting in live births (including over 4,500 exposed in the first trimester), there was no difference between the overall risk of birth defects for lamivudine compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of defects in live births was 3.1% (95% CI: 2.6% to 3.6%) following first trimester exposure to lamivudine-containing regimens and 2.8% (95% CI: 2.5% to 3.3%) following second/third trimester exposure to lamivudine-containing regimens. Lamivudine pharmacokinetics were studied in pregnant women during 2 clinical trials conducted in South Africa. The trials assessed pharmacokinetics in 16 women at 36 weeks’ gestation using 150 mg lamivudine twice daily with zidovudine, 10 women at 38 weeks’ gestation using 150 mg lamivudine twice daily with zidovudine, and 10 women at 38 weeks’ gestation using lamivudine 300 mg twice daily without other antiretrovirals. These trials were not designed or powered to provide efficacy information. Lamivudine concentrations were generally similar in maternal, neonatal, and umbilical cord serum samples. In a subset of subjects, amniotic fluid specimens were collected following natural rupture of membranes and confirmed that lamivudine crosses the placenta in humans. Based on limited data at delivery, median (range) amniotic fluid concentrations of lamivudine were 3.9 (1.2 to 12.8)–fold greater compared with paired maternal serum concentration (n = 8). Animal Data: Lamivudine was administered orally to pregnant rats (at 90, 600, and 4,000 mg per kg per day) and rabbits (at 90, 300, and 1,000 mg per kg per day and at 15, 40, and 90 mg per kg per day) during organogenesis (on Gestation Days 7 through 16 [rat] and 8 through 20 [rabbit]). No evidence of fetal malformations due to lamivudine was observed in rats and rabbits at doses producing plasma concentrations (C max ) approximately 35 times higher than human exposure at the recommended daily dose. Evidence of early embryolethality was seen in the rabbit at system exposures (AUC) similar to those observed in humans, but there was no indication of this effect in the rat at plasma concentrations (C max ) 35 times higher than human exposure at the recommended daily dose. Studies in pregnant rats showed that lamivudine is transferred to the fetus through the placenta. In the fertili…

6 ADVERSE REACTIONS The following adverse reactions are discussed in other sections of the labeling: • Exacerbations of hepatitis B [see Boxed Warning , Warnings and Precautions ( 5.1 )]. • Lactic acidosis and severe hepatomegaly with steatosis [see Warnings and Precautions ( 5.2 )] . • Pancreatitis [see Warnings and Precautions ( 5.3 )]. • Immune reconstitution syndrome [see Warnings and Precautions ( 5.4 )] . • The most common reported adverse reactions (incidence greater than or equal to 15%) in adults were headache, nausea, malaise and fatigue, nasal signs and symptoms, diarrhea, and cough. ( 6.1 ) • The most common reported adverse reactions (incidence greater than or equal to 15%) in pediatric subjects were fever and cough. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact ViiV Healthcare at 1-877-844-8872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Clinical Trials Experience in Adult Subjects Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety profile of EPIVIR in adults is primarily based on 3,568 HIV-1–infected subjects in 7 clinical trials. The most common adverse reactions are headache, nausea, malaise, fatigue, nasal signs and symptoms, diarrhea, and cough. Selected clinical adverse reactions in greater than or equal to 5% of subjects during therapy with EPIVIR 150 mg twice daily plus RETROVIR 200 mg 3 times daily for up to 24 weeks are listed in Table 3 . Table 3. Selected Clinical Adverse Reactions (Greater than or Equal to 5% Frequency) in Four Controlled Clinical Trials (NUCA3001, NUCA3002, NUCB3001, NUCB3002) a Either zidovudine monotherapy or zidovudine in combination with zalcitabine. Adverse Reaction EPIVIR 150 mg Twice Daily plus RETROVIR (n = 251) RETROVIR a (n = 230) Body as a Whole Headache 35% 27% Malaise & fatigue 27% 23% Fever or chills 10% 12% Digestive Nausea 33% 29% Diarrhea 18% 22% Nausea & vomiting 13% 12% Anorexia and/or decreased appetite 10% 7% Abdominal pain 9% 11% Abdominal cramps 6% 3% Dyspepsia 5% 5% Nervous System Neuropathy 12% 10% Insomnia & other sleep disorders 11% 7% Dizziness 10% 4% Depressive disorders 9% 4% Respiratory Nasal signs & symptoms 20% 11% Cough 18% 13% Skin Skin rashes 9% 6% Musculoskeletal Musculoskeletal pain 12% 10% Myalgia 8% 6% Arthralgia 5% 5% Pancreatitis: Pancreatitis was observed in 9 out of 2,613 adult subjects (0.3%) who received EPIVIR in controlled clinical trials EPV20001, NUCA3001, NUCB3001, NUCA3002, NUCB3002, and NUCB3007 [see Warnings and Precautions ( 5.3 )]. EPIVIR 300 mg Once Daily: The types and frequencies of clinical adverse reactions reported in subjects receiving EPIVIR 300 mg once daily or EPIVIR 150 mg twice daily (in 3-drug combination regimens in EPV20001 and EPV40001) for 48 weeks were similar. Selected laboratory abnormalities observed during therapy are summarized in Table 4 . Table 4. Frequencies of Selected Grade 3-4 Laboratory Abnormalities in Adults in Four 24-Week Surrogate Endpoint Trials (NUCA3001, NUCA3002, NUCB3001, NUCB3002) and a Clinical Endpoint Trial (NUCB3007) a The median duration on study was 12 months. b Either zidovudine monotherapy or zidovudine in combination with zalcitabine. c Current therapy was either zidovudine, zidovudine plus didanosine, or zidovudine plus zalcitabine. ULN = Upper limit of normal. ND = Not done. Test (Threshold Level) 24-Week Surrogate Endpoint Trials a Clinical Endpoint Trial a EPIVIR plus RETROVIR RETROVIR b EPIVIR plus Current Therapy c Placebo plus Current Therapy c Absolute neutrophil count (<750/mm 3 ) 7.2% 5.4% 15% 13% Hemoglobin (<8.0 g/dL) 2.9% 1.8% 2.2% 3.4% Platelets (<50,000/mm 3 ) 0.4% 1.3% 2.8% 3.8% ALT (>5.0 x ULN) 3.7% 3.6% 3.8% 1.9% AST (>5.0 x ULN) 1.7% 1.8% 4.0% 2.1% Bilirubin (>2.5 x ULN) 0.8% 0.4% ND…