LEXIVA

Absorption and Bioavailability: After administration of a single dose of LEXIVA to HIV-1–infected subjects, the time to peak amprenavir concentration (T_max) occurred between 1.5 and 4 hours (median 2.5 hours). The absolute oral bioavailability of amprenavir after administration of LEXIVA in humans has not been established.

After administration of a single 1,400-mg dose in the fasted state, LEXIVA Oral Suspension (50 mg per mL) and LEXIVA Tablets (700 mg) provided similar amprenavir exposures (AUC); however, the C_max of amprenavir after administration of the suspension formulation was 14.5% higher compared with the tablet.

Effects of Food on Oral Absorption: Administration of a single 1,400-mg dose of LEXIVA Tablets in the fed state (standardized high-fat meal: 967 kcal, 67 grams fat, 33 grams protein, 58 grams carbohydrate) compared with the fasted state was associated with no significant changes in amprenavir C_max, T_max, or AUC_0-∞ [see Dosage and Administration (2)].

Administration of a single 1,400-mg dose of LEXIVA Oral Suspension in the fed state (standardized high-fat meal: 967 kcal, 67 grams fat, 33 grams protein, 58 grams carbohydrate) compared with the fasted state was associated with a 46% reduction in C_max, a 0.72-hour delay in T_max, and a 28% reduction in amprenavir AUC_0-∞.

Distribution: In vitro, amprenavir is approximately 90% bound to plasma proteins, primarily to alpha₁-acid glycoprotein. In vitro, concentration-dependent binding was observed over the concentration range of 1 to 10 mcg per mL, with decreased binding at higher concentrations. The partitioning of amprenavir into erythrocytes is low, but increases as amprenavir concentrations increase, reflecting the higher amount of unbound drug at higher concentrations.

Metabolism: After oral administration, fosamprenavir is rapidly and almost completely hydrolyzed to amprenavir and inorganic phosphate prior to reaching the systemic circulation. This occurs in the gut epithelium during absorption. Amprenavir is metabolized in the liver by the CYP3A4 enzyme system. The 2 major metabolites result from oxidation of the tetrahydrofuran and aniline moieties. Glucuronide conjugates of oxidized metabolites have been identified as minor metabolites in urine and feces.

Amprenavir is both a substrate for and inducer of P-glycoprotein.

Elimination: Excretion of unchanged amprenavir in urine and feces is minimal. Unchanged amprenavir in urine accounts for approximately 1% of the dose; unchanged amprenavir was not detectable in feces. Approximately 14% and 75% of an administered single dose of ¹⁴C-amprenavir can be accounted for as metabolites in urine and feces, respectively. Two metabolites accounted for greater than 90% of the radiocarbon in fecal samples. The plasma elimination half-life of amprenavir is approximately 7.7 hours.

Special Populations: Hepatic Impairment: The pharmacokinetics of amprenavir have been studied after the administration of LEXIVA in combination with ritonavir to adult HIV-1–infected subjects with mild, moderate, and severe hepatic impairment. Following 2 weeks of dosing with LEXIVA plus ritonavir, the AUC of amprenavir was increased by approximately 22% in subjects with mild hepatic impairment, by approximately 70% in subjects with moderate hepatic impairment, and by approximately 80% in subjects with severe hepatic impairment compared with HIV-1–infected subjects with normal hepatic function. Protein binding of amprenavir was decreased in subjects with hepatic impairment. The unbound fraction at 2 hours (approximate C_max) ranged between a decrease of -7% to an increase of 57% while the unbound fraction at the end of the dosing interval (C_min) increased from 50% to 102% [see Dosage and Administration (2.3)].

The pharmacokinetics of amprenavir have been studied after administration of amprenavir given as AGENERASE^® Capsules to adult subjects with hepatic impairment. Following administration of a single 600-mg oral dose, the AUC of amprenavir was increased by approximately 2.5-fold in subjects with moderate cirrhosis and by approximately 4.5-fold in subjects with severe cirrhosis compared with healthy volunteers [see Dosage and Administration (2.3)].

Renal Impairment: The impact of renal impairment on amprenavir elimination in adults has not been studied. The renal elimination of unchanged amprenavir represents approximately 1% of the administered dose; therefore, renal impairment is not expected to significantly impact the elimination of amprenavir.

Pediatric Patients: The pharmacokinetics of amprenavir following administration of LEXIVA Oral Suspension and LEXIVA Tablets, with or without ritonavir, have been studied in a total of 212 HIV-1–infected pediatric subjects enrolled in 3 trials. LEXIVA without ritonavir was administered as 30 or 40 mg per kg twice daily to children aged 2 to 5 years. LEXIVA with ritonavir was administered as LEXIVA 30 mg per kg plus ritonavir 6 mg per kg once daily to children aged 2 to 18 years and as LEXIVA 18 to 60 mg per kg plus ritonavir 3 to 10 mg per kg twice daily to children aged at least 4 weeks to 18 years; body weights ranged from 3 to 103 kg.

Amprenavir apparent clearance decreased with increasing weight. Weight-adjusted apparent clearance was higher in children younger than 4 years, suggesting that younger children require higher mg per kg dosing of LEXIVA.

The pharmacokinetics of LEXIVA Oral Suspension in protease inhibitor-naive infants younger than 6 months (n = 9) receiving LEXIVA 45 mg per kg plus ritonavir 10 mg per kg twice daily generally demonstrated lower AUC₁₂ and C_min than adults receiving twice-daily LEXIVA 700 mg plus ritonavir 100 mg, the dose recommended for protease-experienced adults. The mean steady-state amprenavir AUC₁₂, C_max, and C_min were 26.6 mcg•hour per mL, 6.25 mcg per mL, and 0.86 mcg per mL, respectively. These data do not support twice-daily dosing of LEXIVA alone or in combination with ritonavir in protease inhibitor-experienced patients younger than 6 months. Because of expected low amprenavir exposure and a requirement for large volume of drug, twice-daily dosing of LEXIVA alone (without ritonavir) in pediatric subjects younger than 2 years was not studied.

Pharmacokinetic parameters for LEXIVA administered with food and with ritonavir in this patient population at the recommended weight-band–based dosage regimens are provided in Table 9.

Table 9. Geometric Mean (95% CI) Steady-State Plasma Amprenavir Pharmacokinetic Parameters by Weight in Pediatric and Adolescent Subjects Aged at Least 4 Weeks to 18 Years Receiving LEXIVA With Ritonavir

^aRecommended dose for pediatric subjects weighing 11 kg to less than 15 kg is based on population pharmacokinetic analysis.

Subjects aged 2 to less than 6 years receiving LEXIVA 30 mg per kg twice daily without ritonavir achieved geometric mean (95% CI) amprenavir C_max (n = 9), AUC₁₂ (n = 9), and C_min (n = 19) of 7.15 (5.05, 10.1), 22.3 (15.3, 32.6), and 0.513 (0.384, 0.686), respectively.

Geriatric Patients: The pharmacokinetics of amprenavir after administration of LEXIVA to patients older than 65 years have not been studied [see Use in Specific Populations (8.5)].

Gender: The pharmacokinetics of amprenavir after administration of LEXIVA do not differ between males and females.

Race: The pharmacokinetics of amprenavir after administration of LEXIVA do not differ between blacks and non-blacks.

Drug Interactions: [See Contraindications (4), Warnings and Precautions (5.1), Drug Interactions (7).]

Amprenavir, the active metabolite of fosamprenavir, is metabolized in the liver by the cytochrome P450 enzyme system. Amprenavir inhibits CYP3A4. Data also suggest that amprenavir induces CYP3A4. Caution should be used when coadministering medications that are substrates, inhibitors, or inducers of CYP3A4, or potentially toxic medications that are metabolized by CYP3A4. Amprenavir does not inhibit CYP2D6, CYP1A2, CYP2C9, CYP2C19, CYP2E1, or uridine glucuronosyltransferase (UDPGT).

Drug interaction trials were performed with LEXIVA and other drugs likely to be coadministered or drugs commonly used as probes for pharmacokinetic interactions. The effects of coadministration on AUC, C_max, and C_min values are summarized in Table 10 (effect of other drugs on amprenavir) and Table 12 (effect of LEXIVA on other drugs). In addition, since LEXIVA delivers comparable amprenavir plasma concentrations as AGENERASE, drug interaction data derived from trials with AGENERASE are provided in Tables 11 and 13. For information regarding clinical recommendations, [see Drug Interactions (7)].

Table 10. Drug Interactions: Pharmacokinetic Parameters for Amprenavir After Administration of LEXIVA in the Presence of the Coadministered Drug(s)

^aConcomitant medication is also shown in this column where appropriate.

^bRitonavir C_max, AUC, and C_min increased by 63%, 45%, and 13%, respectively, compared with historical control.

^cCompared with historical control.

^dSubjects were receiving LEXIVA/ritonavir for 10 days prior to the 4-day treatment period with both ketoconazole and LEXIVA/ritonavir.

^eCompared with LEXIVA 700 mg/ritonavir 100 mg b.i.d. for 2 weeks.

^fSubjects were receiving nevirapine for at least 12 weeks prior to trial.

^gC_last (C_{12 hr} or C_{24 hr}).

^hDoses of LEXIVA and raltegravir were given with food on pharmacokinetic sampling days and without regard to food all other days.

ⁱN = 18 for C_min.

^jCompared with parallel control group.

↑ = Increase; ↓= Decrease; ↔ = No change (↑or ↓ less than or equal to 10%), NA = Not applicable.

Table 11. Drug Interactions: Pharmacokinetic Parameters for Amprenavir After Administration of AGENERASE in the Presence of the Coadministered Drug(s)

^aCompared with parallel control group.

^bMedian percent change; confidence interval not reported.

^cCompared with historical data.

↑ = Increase; ↓ = Decrease; ↔ = No change (↑or ↓ less than 10%); NA = C_min not calculated for single‑dose trial.

^aConcomitant medication is also shown in this column where appropriate.

^bComparison arm of atazanavir 300 mg q.d. plus ritonavir 100 mg q.d. for 10 days.

^cAdministered as a combination oral contraceptive tablet: ethinyl estradiol 0.035 mg/norethindrone 0.5 mg.

^dSubjects were receiving LEXIVA/ritonavir for 10 days prior to the 4-day treatment period with both ketoconazole and LEXIVA/ritonavir.

^eData represent lopinavir concentrations.

^fCompared with lopinavir 400 mg/ritonavir 100 mg b.i.d. for 2 weeks.

^gDose normalized to methadone 100 mg. The unbound concentration of the active moiety, R‑methadone, was unchanged.

^hSubjects were receiving nevirapine for at least 12 weeks prior to trial.

ⁱComparison arm of rifabutin 300 mg q.d. for 2 weeks. AUC is AUC_(0-48 hr).

↑ = Increase; ↓= Decrease; ↔ = No change (↑or ↓less than 10%); ND = Interaction cannot be determined as C_min was below the lower limit of quantitation.

^aCompared with historical data.

^bMedian percent change; confidence interval not reported.

↑ = Increase; ↓ = Decrease; ↔= No change (↑or ↓ less than 10%); NA = C_min not calculated for single-dose trial; ND = Interaction cannot be determined as C_min was below the lower limit of quantitation.

12.4 Microbiology

Mechanism of Action: Fosamprenavir is a prodrug that is rapidly hydrolyzed to amprenavir by cellular phosphatases in the gut epithelium as it is absorbed. Amprenavir is an inhibitor of HIV-1 protease. Amprenavir binds to the active site of HIV-1 protease and thereby prevents the processing of viral Gag and Gag-Pol polyprotein precursors, resulting in the formation of immature non-infectious viral particles.

Antiviral Activity: Fosamprenavir has little or no antiviral activity in cell culture. The antiviral activity of amprenavir was evaluated against HIV-1 IIIB in both acutely and chronically infected lymphoblastic cell lines (MT-4, CEM-CCRF, H9) and in peripheral blood lymphocytes in cell culture. The 50% effective concentration (EC₅₀) of amprenavir ranged from 0.012 to 0.08 microM in acutely infected cells and was 0.41 microM in chronically infected cells (1 microM = 0.50 mcg per mL). The median EC₅₀ value of amprenavir against HIV-1 isolates from clades A to G was 0.00095 microM in peripheral blood mononuclear cells (PBMCs). Similarly, the EC₅₀ values for amprenavir against monocytes/macrophage tropic HIV-1 isolates (clade B) ranged from 0.003 to 0.075 microM in monocyte/macrophage cultures. The EC₅₀ values of amprenavir against HIV-2 isolates grown in PBMCs were higher than those for HIV-1 isolates, and ranged from 0.003 to 0.11 microM. Amprenavir exhibited synergistic anti–HIV–1 activity in combination with the nucleoside reverse transcriptase inhibitors (NRTIs) abacavir, didanosine, lamivudine, stavudine, tenofovir, and zidovudine; the non-nucleoside reverse transcriptase inhibitors (NNRTIs) delavirdine and efavirenz; and the protease inhibitors atazanavir and saquinavir. Amprenavir exhibited additive anti–HIV–1 activity in combination with the NNRTI nevirapine, the protease inhibitors indinavir, lopinavir, nelfinavir, and ritonavir; and the fusion inhibitor enfuvirtide. These drug combinations have not been adequately studied in humans.

Resistance: HIV-1 isolates with decreased susceptibility to amprenavir have been selected in cell culture and obtained from subjects treated with fosamprenavir. Genotypic analysis of isolates from treatment-naive subjects failing amprenavir-containing regimens showed substitutions in the HIV-1 protease gene resulting in amino acid substitutions primarily at positions V32I, M46I/L, I47V, I50V, I54L/M, and I84V, as well as substitutions in the p7/p1 and p1/p6 Gag and Gag-Pol polyprotein precursor cleavage sites. Some of these amprenavir resistance-associated substitutions have also been detected in HIV-1 isolates from antiretroviral-naive subjects treated with LEXIVA. Of the 488 antiretroviral-naive subjects treated with LEXIVA 1,400 mg twice daily or LEXIVA 1,400 mg plus ritonavir 200 mg once daily in Trials APV30001 and APV30002, respectively, 61 subjects (29 receiving LEXIVA and 32 receiving LEXIVA/ritonavir) with virologic failure (plasma HIV-1 RNA greater than 1,000 copies per mL on 2 occasions on or after Week 12) were genotyped. Five of the 29 antiretroviral-naive subjects (17%) receiving LEXIVA without ritonavir in Trial APV30001 had evidence of genotypic resistance to amprenavir: I54L/M (n = 2), I54L + L33F (n = 1), V32I + I47V (n = 1), and M46I + I47V (n = 1). No amprenavir resistance-associated substitutions were detected in antiretroviral-naive subjects treated with LEXIVA/ritonavir for 48 weeks in Trial APV30002. However, the M46I and I50V substitutions were detected in isolates from 1 virologic failure subject receiving LEXIVA/ritonavir once daily at Week 160 (HIV-1 RNA greater than 500 copies per mL). Upon retrospective analysis of stored samples using an ultrasensitive assay, these resistant substitutions were traced back to Week 84 (76 weeks prior to clinical virologic failure).

Cross-Resistance: Varying degrees of cross-resistance among HIV-1 protease inhibitors have been observed. An association between virologic response at 48 weeks (HIV-1 RNA level less than 400 copies per mL) and protease inhibitor-resistance substitutions detected in baseline HIV-1 isolates from protease inhibitor-experienced subjects receiving LEXIVA/ritonavir twice daily (n = 88), or lopinavir/ritonavir twice daily (n = 85) in Trial APV30003 is shown in Table 14. The majority of subjects had previously received either one (47%) or 2 protease inhibitors (36%), most commonly nelfinavir (57%) and indinavir (53%). Out of 102 subjects with baseline phenotypes receiving twice-daily LEXIVA/ritonavir, 54% (n = 55) had resistance to at least one protease inhibitor, with 98% (n = 54) of those having resistance to nelfinavir. Out of 97 subjects with baseline phenotypes in the lopinavir/ritonavir arm, 60% (n = 58) had resistance to at least one protease inhibitor, with 97% (n = 56) of those having resistance to nelfinavir.

^aResults should be interpreted with caution because the subgroups were small.

^bMost subjects had greater than 1 protease inhibitor resistance-associated substitution at baseline.

The virologic response based upon baseline phenotype was assessed. Baseline isolates from protease inhibitor-experienced subjects responding to LEXIVA/ritonavir twice daily had a median shift in susceptibility to amprenavir relative to a standard wild-type reference strain of 0.7 (range: 0.1 to 5.4, n = 62), and baseline isolates from individuals failing therapy had a median shift in susceptibility of 1.9 (range: 0.2 to 14, n = 29). Because this was a select patient population, these data do not constitute definitive clinical susceptibility break points. Additional data are needed to determine clinically relevant break points for LEXIVA.

Isolates from 15 of the 20 subjects receiving twice-daily LEXIVA/ritonavir up to Week 48 and experiencing virologic failure/ongoing replication were subjected to genotypic analysis. The following amprenavir resistance-associated substitutions were found either alone or in combination: V32I, M46I/L, I47V, I50V, I54L/M, and I84V. Isolates from 4 of the 16 subjects continuing to receive twice-daily LEXIVA/ritonavir up to Week 96 who experienced virologic failure underwent genotypic analysis. Isolates from 2 subjects contained amprenavir resistance-associated substitutions: V32I, M46I, and I47V in 1 isolate and I84V in the other.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

In long-term carcinogenicity studies, fosamprenavir was administered orally for up to 104 weeks at doses of 250, 400, or 600 mg per kg per day in mice and at doses of 300, 825, or 2,250 mg per kg per day in rats. Exposures at these doses were 0.3- to 0.7-fold (mice) and 0.7- to 1.4-fold (rats) those in humans given 1,400 mg twice daily of fosamprenavir alone, and 0.2- to 0.3-fold (mice) and 0.3- to 0.7-fold (rats) those in humans given 1,400 mg once daily of fosamprenavir plus 200 mg ritonavir once daily. Exposures in the carcinogenicity studies were 0.1- to 0.3-fold (mice) and 0.3- to 0.6-fold (rats) those in humans given 700 mg of fosamprenavir plus 100 mg ritonavir twice daily. There was an increase in hepatocellular adenomas and hepatocellular carcinomas at all doses in male mice and at 600 mg per kg per day in female mice, and in hepatocellular adenomas and thyroid follicular cell adenomas at all doses in male rats, and at 835 mg per kg per day and 2,250 mg per kg per day in female rats. The relevance of the hepatocellular findings in the rodents for humans is uncertain. Repeat dose studies with fosamprenavir in rats produced effects consistent with enzyme induction, which predisposes rats, but not humans, to thyroid neoplasms. In addition, in rats only there was an increase in interstitial cell hyperplasia at 825 mg per kg per day and 2,250 mg per kg per day, and an increase in uterine endometrial adenocarcinoma at 2,250 mg per kg per day. The incidence of endometrial findings was slightly increased over concurrent controls, but was within background range for female rats. The relevance of the uterine endometrial adenocarcinoma findings in rats for humans is uncertain.

Fosamprenavir was not mutagenic or genotoxic in a battery of in vitro and in vivo assays. These assays included bacterial reverse mutation (Ames), mouse lymphoma, rat micronucleus, and chromosome aberrations in human lymphocytes.

The effects of fosamprenavir on fertility and general reproductive performance were investigated in male (treated for 4 weeks before mating) and female rats (treated for 2 weeks before mating through postpartum day 6). Systemic exposures (AUC_{0-24 hr}) to amprenavir in these studies were 3 (males) to 4 (females) times higher than exposures in humans following administration of the MRHD of fosamprenavir alone or similar to those seen in humans following administration of fosamprenavir in combination with ritonavir. Fosamprenavir did not impair mating or fertility of male or female rats and did not affect the development and maturation of sperm from treated rats.

14 CLINICAL STUDIES

14.1 Therapy-Naive Adult Trials

APV30001: A randomized, open-label trial evaluated treatment with LEXIVA Tablets (1,400 mg twice daily) versus nelfinavir (1,250 mg twice daily) in 249 antiretroviral treatment-naive subjects. Both groups of subjects also received abacavir (300 mg twice daily) and lamivudine (150 mg twice daily).

The mean age of the subjects in this trial was 37 years (range: 17 to 70 years); 69% of the subjects were male, 20% were CDC Class C (AIDS), 24% were Caucasian, 32% were black, and 44% were Hispanic. At baseline, the median CD4+ cell count was 212 cells per mm³ (range: 2 to 1,136 cells per mm³; 18% of subjects had a CD4+ cell count of less than 50 cells per mm³ and 30% were in the range of 50 to less than 200 cells per mm³). Baseline median HIV-1 RNA was 4.83 log₁₀ copies per mL (range: 1.69 to 7.41 log₁₀ copies per mL; 45% of subjects had greater than 100,000 copies per mL).

The outcomes of randomized treatment are provided in Table 15.

^aSubjects achieved and maintained confirmed HIV-1 RNA less than 400 copies per mL (less than 50 copies per mL) through Week 48 (Roche AMPLICOR HIV-1 MONITOR Assay Version 1.5).

^bIncludes consent withdrawn, lost to follow up, protocol violations, those with missing data, and other reasons.

Treatment response by viral load strata is shown in Table 16.

Through 48 weeks of therapy, the median increases from baseline in CD4+ cell counts were 201 cells per mm³ in the group receiving LEXIVA and 216 cells per mm³ in the nelfinavir group.

APV30002: A randomized, open-label trial evaluated treatment with LEXIVA Tablets (1,400 mg once daily) plus ritonavir (200 mg once daily) versus nelfinavir (1,250 mg twice daily) in 649 treatment-naive subjects. Both treatment groups also received abacavir (300 mg twice daily) and lamivudine (150 mg twice daily).

The mean age of the subjects in this trial was 37 years (range: 18 to 69 years); 73% of the subjects were male, 22% were CDC Class C, 53% were Caucasian, 36% were black, and 8% were Hispanic. At baseline, the median CD4+ cell count was 170 cells per mm³ (range: 1 to 1,055 cells per mm³; 20% of subjects had a CD4+ cell count of less than 50 cells per mm³ and 35% were in the range of 50 to less than 200 cells per mm³). Baseline median HIV-1 RNA was 4.81 log₁₀ copies per mL (range: 2.65 to 7.29 log₁₀ copies per mL; 43% of subjects had greater than 100,000 copies per mL).

The outcomes of randomized treatment are provided in Table 17.

Table 17. Outcomes of Randomized Treatment Through Week 48 (APV30002)

^aSubjects achieved and maintained confirmed HIV-1 RNA less than 400 copies per mL (less than 50 copies per mL) through Week 48 (Roche AMPLICOR HIV-1 MONITOR Assay Version 1.5).

^bIncludes consent withdrawn, lost to follow up, protocol violations, those with missing data, and other reasons.

Treatment response by viral load strata is shown in Table 18.

Through 48 weeks of therapy, the median increases from baseline in CD4+ cell counts were 203 cells per mm³ in the group receiving LEXIVA and 207 cells per mm³ in the nelfinavir group.

14.2 Protease Inhibitor-Experienced Adult Trials

APV30003: A randomized, open-label, multicenter trial evaluated 2 different regimens of LEXIVA plus ritonavir (LEXIVA Tablets 700 mg twice daily plus ritonavir 100 mg twice daily or LEXIVA Tablets 1,400 mg once daily plus ritonavir 200 mg once daily) versus lopinavir/ritonavir (400 mg/100 mg twice daily) in 315 subjects who had experienced virologic failure to 1 or 2 prior protease inhibitor-containing regimens.

The mean age of the subjects in this trial was 42 years (range: 24 to 72 years); 85% were male, 33% were CDC Class C, 67% were Caucasian, 24% were black, and 9% were Hispanic. The median CD4+ cell count at baseline was 263 cells per mm³ (range: 2 to 1,171 cells per mm³). Baseline median plasma HIV-1 RNA level was 4.14 log₁₀ copies per mL (range: 1.69 to 6.41 log₁₀ copies per mL).

The median durations of prior exposure to NRTIs were 257 weeks for subjects receiving LEXIVA/ritonavir twice daily (79% had greater than or equal to 3 prior NRTIs) and 210 weeks for subjects receiving lopinavir/ritonavir (64% had greater than or equal to 3 prior NRTIs). The median durations of prior exposure to protease inhibitors were 149 weeks for subjects receiving LEXIVA/ritonavir twice daily (49% received greater than or equal to 2 prior protease inhibitors) and 130 weeks for subjects receiving lopinavir/ritonavir (40% received greater than or equal to 2 prior protease inhibitors).

The time-averaged changes in plasma HIV-1 RNA from baseline (AAUCMB) at 48 weeks (the endpoint on which the trial was powered) were -1.4 log₁₀ copies per mL for twice-daily LEXIVA/ritonavir and -1.67 log₁₀ copies per mL for the lopinavir/ritonavir group.

The proportions of subjects who achieved and maintained confirmed HIV-1 RNA less than 400 copies per mL (secondary efficacy endpoint) were 58% with twice-daily LEXIVA/ritonavir and 61% with lopinavir/ritonavir (95% CI for the difference: -16.6, 10.1). The proportions of subjects with HIV-1 RNA less than 50 copies per mL with twice-daily LEXIVA/ritonavir and with lopinavir/ritonavir were 46% and 50%, respectively (95% CI for the difference: -18.3, 8.9). The proportions of subjects who were virologic failures were 29% with twice-daily LEXIVA/ritonavir and 27% with lopinavir/ritonavir.

The frequency of discontinuations due to adverse events and other reasons, and deaths were similar between treatment arms.

Through 48 weeks of therapy, the median increases from baseline in CD4+ cell counts were 81 cells per mm³ with twice-daily LEXIVA/ritonavir and 91 cells per mm³ with lopinavir/ritonavir.

This trial was not large enough to reach a definitive conclusion that LEXIVA/ritonavir and lopinavir/ritonavir are clinically equivalent.

Once-daily administration of LEXIVA plus ritonavir is not recommended for protease inhibitor-experienced patients. Through Week 48, 50% and 37% of subjects receiving LEXIVA 1,400 mg plus ritonavir 200 mg once daily had plasma HIV-1 RNA less than 400 copies per mL and less than 50 copies per mL, respectively.

14.3 Pediatric Trials

Three open-label trials in pediatric subjects aged at least 4 weeks to 18 years were conducted. In one trial (APV29005), twice-daily dosing regimens (LEXIVA with or without ritonavir) were evaluated in combination with other antiretroviral agents in pediatric subjects aged 2 to 18 years. In a second trial (APV20002), twice-daily dosing regimens (LEXIVA with ritonavir) were evaluated in combination with other antiretroviral agents in pediatric subjects aged at least 4 weeks to less than 2 years. A third trial (APV20003) evaluated once-daily dosing of LEXIVA with ritonavir; the pharmacokinetic data from this trial did not support a once-daily dosing regimen in any pediatric patient population.

APV29005: LEXIVA: Twenty (18 therapy-naive and 2 therapy-experienced) pediatric subjects received LEXIVA Oral Suspension without ritonavir twice daily. At Week 24, 65% (13/20) achieved HIV-1 RNA less than 400 copies per mL, and the median increase from baseline in CD4+ cell count was 350 cells per mm³.

LEXIVA plus Ritonavir: Forty-nine protease inhibitor-naive and 40 protease inhibitor-experienced pediatric subjects received LEXIVA Oral Suspension or Tablets with ritonavir twice daily. At Week 24, 71% of protease inhibitor-naive (35/49) and 55% of protease inhibitor-experienced (22/40) subjects achieved HIV-1 RNA less than 400 copies per mL; median increases from baseline in CD4+ cell counts were 184 cells per mm³ and 150 cells per mm³ in protease inhibitor-naive and experienced subjects, respectively.

APV20002: Fifty-four pediatric subjects (49 protease inhibitor-naive and 5 protease inhibitor-experienced) received LEXIVA Oral Suspension with ritonavir twice daily. At Week 24, 72% of subjects achieved HIV-1 RNA less than 400 copies per mL. The median increases from baseline in CD4+ cell counts were 400 cells per mm³ in subjects aged at least 4 weeks to less than 6 months and 278 cells per mm³ in subjects aged 6 months to 2 years.

16 HOW SUPPLIED/STORAGE AND HANDLING

LEXIVA Tablets, 700 mg, are pink, film-coated, capsule-shaped, biconvex tablets, with “GX LL7” debossed on one face.

Bottle of 60 with child-resistant closure (NDC 49702-207-18).

Store at controlled room temperature of 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) (see USP Controlled Room Temperature). Keep container tightly closed.

LEXIVA Oral Suspension, a white to off-white grape-bubblegum-peppermint–flavored suspension, contains 50 mg of fosamprenavir as fosamprenavir calcium equivalent to approximately 43 mg of amprenavir in each 1 mL.

Bottle of 225 mL with child-resistant closure (NDC 49702-208-53).

This product does not require reconstitution.

Store in refrigerator or at room temperature (5° to 30°C; 41° to 86°F). Shake vigorously before using. Do not freeze.

17 PATIENT COUNSELING INFORMATION

See FDA-approved Patient Labeling (Patient Information)

17.1 Drug Interactions

A statement to patients and healthcare providers is included on the product’s bottle label: ALERT: Find out about medicines that should NOT be taken with LEXIVA.

LEXIVA may interact with many drugs; therefore, patients should be advised to report to their healthcare provider the use of any other prescription or nonprescription medication or herbal products, particularly St. John’s wort.

Patients receiving PDE5 inhibitors should be advised that they may be at an increased risk of PDE5 inhibitor-associated adverse events, including hypotension, visual changes, and priapism, and should promptly report any symptoms to their healthcare provider.

Patients receiving hormonal contraceptives should be instructed to use alternate contraceptive measures during therapy with LEXIVA because hormonal levels may be altered, and if used in combination with LEXIVA and ritonavir, liver enzyme elevations may occur.

17.2 Sulfa Allergy

Patients should inform their healthcare provider if they have a sulfa allergy. The potential for cross-sensitivity between drugs in the sulfonamide class and fosamprenavir is unknown.

17.3 Redistribution/Accumulation of Body Fat

Patients should be informed that redistribution or accumulation of body fat may occur in patients receiving antiretroviral therapy, including LEXIVA, and that the cause and long-term health effects of these conditions are not known at this time.

17.4 Information About Therapy With LEXIVA

LEXIVA is not a cure for HIV-1 infection and patients may continue to experience illnesses associated with HIV-1 infection, including opportunistic infections. Patients should remain under the care of a physician when using LEXIVA.

Patients should be advised to avoid doing things that can spread HIV-1 infection to others.

• • Do not share needles or other injection equipment.
• • Do not share personal items that can have blood or body fluids on them, like toothbrushes and razor blades.
• • Do not have any kind of sex without protection. Always practice safe sex by using a latex or polyurethane condom to lower the chance of sexual contact with semen, vaginal secretions, or blood.
• • Do not breastfeed. We do not know if LEXIVA can be passed to your baby in your breast milk and whether it could harm your baby. Also, mothers with HIV-1 should not breastfeed because HIV-1 can be passed to the baby in the breast milk.

Patients should be told that sustained decreases in plasma HIV-1 RNA have been associated with a reduced risk of progression to AIDS and death. Patients should be advised to take LEXIVA every day as prescribed. LEXIVA must always be used in combination with other antiretroviral drugs. Patients should not alter the dose or discontinue therapy without consulting their physician. If a dose is missed, patients should take the dose as soon as possible and then return to their normal schedule. However, if a dose is skipped, the patient should not double the next dose.

17.5 Oral Suspension

Patients should be instructed to shake the bottle vigorously before each use and that refrigeration of the oral suspension may improve the taste for some patients.

LEXIVA and AGENERASE are registered trademarks of ViiV Healthcare.

The brands listed are trademarks of their respective owners and are not trademarks of ViiV Healthcare. The makers of these brands are not affiliated with and do not endorse ViiV Healthcare or its products.

Manufactured for:

by:

GlaxoSmithKline

Research Triangle Park, NC 27709

©2013, ViiV Healthcare. All rights reserved.

LXV:17PI

PHARMACIST-DETACH HERE AND GIVE INSTRUCTIONS TO PATIENT

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _

PATIENT INFORMATION

LEXIVA^® (lex-EE-vah)

(fosamprenavir calcium)

Tablets

and

Oral Suspension

Important: LEXIVA can interact with other medicines and cause serious side effects. It is important to know the medicines that should not be taken with LEXIVA. See the section “Who should not take LEXIVA?”

Read this Patient Information before you start taking LEXIVA and each time you get a refill. There may be new information. This information does not take the place of talking with your healthcare provider about your medical condition or treatment.

What is LEXIVA?

LEXIVA is a prescription anti-HIV medicine used with other anti-HIV medicines to treat human immunodeficiency (HIV-1) infections in adults and children 4 weeks of age and older. LEXIVA is a type of anti-HIV medicine called a protease inhibitor. HIV-1 is the virus that causes AIDS (Acquired Immune Deficiency Syndrome).

When used with other anti-HIV medicines, LEXIVA may help:

• 1.Reduce the amount of HIV-1 in your blood. This is called “viral load”.
• 2.Increase the number of white blood cells called CD4 (T) cells, which help fight off other infections. Reducing the amount of HIV-1 and increasing the CD4 (T) cell count may improve your immune system. This may reduce your risk of death or infections that can happen when your immune system is weak (opportunistic infections).

It is not known if LEXIVA is safe and effective in children less than 4 weeks of age.

LEXIVA does not cure HIV-1 infection or AIDS. People taking LEXIVA may develop infections or other conditions associated with HIV-1 infection, including opportunistic infections (for example, pneumonia and herpes virus infections).

You should remain under the care of your healthcare provider when using LEXIVA.

Avoid doing things that can spread HIV-1 infection to others.

• • Do not share needles or other injection equipment.
• • Do not share personal items that can have blood or body fluids on them, like toothbrushes and razor blades.
• • Do not have any kind of sex without protection. Always practice safe sex by using a latex or polyurethane condom to lower the chance of sexual contact with semen, vaginal secretions, or blood.

Ask your healthcare provider if you have any questions on how to prevent passing HIV to other people.

Who should not take LEXIVA?

Do not take LEXIVA if you take any of the following medicines:

• •alfuzosin (UROXATRAL^®)
• •flecainide (TAMBOCOR™)
• •propafenone (RYTHMOL SR^®)
• •rifampin (RIFADIN^®, RIFAMATE^®, RIFATER^®, RIMACTANE^®)
• •ergot including:
  • ∘dihydroergotamine mesylate (D.H.E. 45^®, MIGRANAL^®)
  • ∘ergotamine tartrate (CAFERGOT^®, MIGERGOT^®, ERGOMAR^®, MEDIHALER ERGOTAMINE^®)
  • ∘methylergonovine (METHERGINE^®)
• •St. John’s wort (Hypericum perforatum)
• •lovastatin (ADVICOR^®, ALTOPREV^®, MEVACOR^®)
• •simvastatin (ZOCOR^®, VYTORIN^®, SIMCOR^®)
• •pimozide (ORAP^®)
• •delavirdine mesylate (RESCRIPTOR^®)
• •sildenafil (REVATIO^®), for treatment of pulmonary arterial hypertension
• •triazolam (HALCION^®)

Serious problems can happen if you or your child take any of the medicines listed above with LEXIVA.

Do not take LEXIVA if you are allergic to AGENERASE^® (amprenavir), fosamprenavir calcium, or any of the ingredients in LEXIVA. See the end of this leaflet for a complete list of ingredients in LEXIVA.

What should I tell my healthcare provider before taking LEXIVA?

Before taking LEXIVA, tell your healthcare provider if you:

• •are allergic to medicines that contain sulfa
• •have liver problems, including hepatitis B or C
• •have kidney problems
• •have high blood sugar (diabetes)
• •have hemophilia
• •have any other medical condition
• •are pregnant or plan to become pregnant. It is not known if LEXIVA will harm your unborn baby.

Pregnancy Registry. There is a pregnancy registry for women who take antiviral medicines during pregnancy. The purpose of the registry is to collect information about the health of you and your baby. Talk to your healthcare provider about how you can take part in this registry.

• • Do not breastfeed. We do not know if LEXIVA can be passed to your baby in your breast milk and whether it could harm your baby. Also, mothers with HIV-1 should not breastfeed because HIV-1 can be passed to the baby in the breast milk.

Tell your healthcare provider about all prescription and non-prescription medicines you take. Also tell your healthcare provider about any vitamins, herbal supplements, and dietary supplements you are taking.

Taking LEXIVA with certain other medicines may cause serious side effects. LEXIVA may affect the way other medicines work, and other medicines may affect how LEXIVA works.

Especially tell your healthcare provider if you take estrogen-based contraceptives (birth control pills). LEXIVA may reduce effectiveness of estrogen-based contraceptives. During treatment with LEXIVA, you should use a different contraceptive method.

Know all the medicines that you take. Keep a list of them with you to show healthcare providers and pharmacists when you get a new medicine.

How should I take LEXIVA?

• • Stay under the care of a healthcare provider while taking LEXIVA.
• •Take LEXIVA exactly as prescribed by your healthcare provider.
• •Do not change your dose or stop taking LEXIVA without talking with your healthcare provider.
• •If your child is taking LEXIVA, your child’s healthcare provider will decide the right dose based on your child’s weight.
• •You can take LEXIVA Tablets with or without food.
• • Adults should take LEXIVA Oral Suspension without food.
• • Children should take LEXIVA Oral Suspension with food. If your child vomits within 30 minutes after taking a dose of LEXIVA, the dose should be repeated.
• •Shake LEXIVA Oral Suspension well before each use.
• •If you miss a dose of LEXIVA, take the next dose as soon as possible and then take your next dose at the regular time. Do not double the next dose. If you take too much LEXIVA, call your healthcare provider or go to the nearest hospital emergency room right away.

What are the possible side effects of LEXIVA?

LEXIVA may cause serious side effects including:

• • Severe skin rash. LEXIVA may cause severe or life-threatening skin reactions or rash.

If you get a rash with any of the following symptoms, stop taking LEXIVA and call your healthcare provider or get medical help right away:

• • ∘hives or sores in your mouth, or your skin blisters and peels
  • ∘trouble swallowing or breathing
  • ∘swelling of your face, eyes, lips, tongue, or throat
• • Liver problems. Your healthcare provider should do blood tests before and during your treatment with LEXIVA to check your liver function. Some people with liver problems, including hepatitis B or C, may have an increased risk of developing worsening liver problem during treatment with LEXIVA.
• • Diabetes and high blood sugar (hyperglycemia). Some people who take protease inhibitors, including LEXIVA, can get high blood sugar, develop diabetes, or your diabetes can get worse. Tell your healthcare provider if you notice an increase in thirst or urinate often while taking LEXIVA.
• • Changes in your immune system (Immune Reconstitution Syndrome) can happen when you start taking HIV medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time. Call your healthcare provider right away if you start having new symptoms after starting your HIV medicine.
• • Changes in body fat. These changes can happen in people who take antiretroviral therapy. The changes may include an increased amount of fat in the upper back and neck (“buffalo hump”), breast, and around the back, chest, and stomach area. Loss of fat from the legs, arms, and face may also happen. The exact cause and long-term health effects of these conditions are not known.
• • Changes in blood tests. Some people have changes in blood tests while taking LEXIVA. These include increases seen in liver function tests, blood fat levels, and decreases in white blood cells. Your healthcare provider should do regular blood tests before and during your treatment with LEXIVA.
• • Increased bleeding problems in some people with hemophilia. Some people with hemophilia have increased bleeding with protease inhibitors, including LEXIVA.
• • Kidney stones. Some people have developed kidney stones while taking LEXIVA. Tell your healthcare provider right away if you develop signs or symptoms of kidney stones:
  • ∘pain in your side
  • ∘blood in your urine
  • ∘pain when you urinate

The most common side effects of LEXIVA in adults include:

• •nausea
• •vomiting
• •diarrhea
• •headache

Vomiting is the most common side effect in children when taking LEXIVA.

Tell your healthcare provider about any side effect that bothers you or that does not go away.

These are not all the possible side effects of LEXIVA. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How should I store LEXIVA?

• •Store LEXIVA Tablets at room temperature between 68°F to 77°F (20°C to 25°C).
• •Keep the bottle of LEXIVA Tablets tightly closed.
• •Store LEXIVA Oral Suspension between 41°F to 86°F (5°C to 30°C). Refrigeration of LEXIVA Oral Suspension may improve taste for some people.
• •Do not freeze.

  Keep LEXIVA and all medicines out of the reach of children.

General information about LEXIVA

Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use LEXIVA for a condition for which it was not prescribed. Do not give LEXIVA to other people, even if they have the same symptoms you have. It may harm them.

This leaflet summarizes the most important information about LEXIVA. If you would like more information, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about LEXIVA that is written for health professionals.

For more information call 877-844-8872 or go to www.LEXIVA.com.

What are the ingredients in LEXIVA?

Tablets:

Active ingredient: fosamprenavir calcium

Inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, microcrystalline cellulose, and povidone K30. The tablet film-coating contains the inactive ingredients hypromellose, iron oxide red, titanium dioxide, and triacetin.

Oral Suspension:

Active ingredient: fosamprenavir calcium

Inactive ingredients: artificial grape-bubblegum flavor, calcium chloride dihydrate, hypromellose, methylparaben, natural peppermint flavor, polysorbate 80, propylene glycol, propylparaben, purified water, and sucralose.

This Patient Information has been approved by the U.S. Food and Drug Administration.

LEXIVA and AGENERASE are registered trademarks of ViiV Healthcare.

The brands listed are trademarks of their respective owners and are not trademarks of ViiV Healthcare. The makers of these brands are not affiliated with and do not endorse ViiV Healthcare or its products.

Manufactured for:

by:

GlaxoSmithKline

Research Triangle Park, NC 27709

©2013, ViiV Healthcare. All rights reserved.

February 2013

LXV:14PIL

Principal Display Panel

NDC 49702-208-53

LEXIVA^®

(fosamprenavir calcium)

Oral Suspension

50 mg/mL

225 mL

ALERT: Find out about medicines that should NOT be taken with LEXIVA.

Note to Pharmacist: Do not cover ALERT box with pharmacy label.

SHAKE VIGOROUSLY BEFORE USING.

R_x only

For use in combination regimens with or without ritonavir.

Each mL contains fosamprenavir calcium equivalent to 50 mg of fosamprenavir.

Store at 5° to 30°C (41° to 86°F). Do not freeze.

See prescribing information for dosage information.

LEXlVA is a trademark of ViiV Healthcare.

Licensed from

Vertex Pharmaceuticals Incorporated

Cambridge, MA 02139

Manufactured for:

ViiV Healthcare

Research Triangle Park, NC 27709

by:

GlaxoSmithKline, Research Triangle Park, NC 27709

Made in Canada

A118192 Rev. 7/13