Abacavir Lamivudine Drug Information

Abacavir, lamivudine and zidovudine tablet, a combination of abacavir, lamivudine, and zidovudine, each nucleoside analogue HIV-1 reverse transcriptase inhibitors, is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. Abacavir, lamivudine and zidovudine tablet is indicated in combination with other antiretrovirals or alone for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. Limitations of Use: Limited data exist on the use of abacavir, lamivudine and zidovudine tablets alone in patients with higher baseline viral load levels (greater than 100,000 copies per mL) .

Screening for

HLA-B*5701 Allele prior to Starting Abacavir, Lamivudine and Zidovudine Tablets Screen for the HLA-B*5701 allele prior to initiating therapy with abacavir, lamivudine and zidovudine tablets .

Recommended Dosage for Adults and Pediatric Patients Weighing at Least 40 kg

The recommended dosage of abacavir, lamivudine and zidovudine tablet is one tablet taken orally twice daily with or without food.

Not Recommended Due to Lack of Dosage Adjustment

Because abacavir, lamivudine and zidovudine tablet is a fixed-dose tablet and cannot be dose adjusted, abacavir, lamivudine and zidovudine tablet is not recommended for: pediatric patients who weigh less than 40 kg. patients with creatinine clearance less than 50 mL per minute. patients with mild hepatic impairment. Abacavir, lamivudine and zidovudine tablet is contraindicated in patients with moderate or severe hepatic impairment .

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 with rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Serious and Fatal Abacavir-Associated Hypersensitivity Reactions In clinical trials, serious and sometimes fatal hypersensitivity reactions have occurred with abacavir, a component of abacavir, lamivudine and zidovudine tablets. These reactions have been characterized by 2 or more of the following signs or symptoms: fever; rash; gastrointestinal symptoms (including nausea, vomiting, diarrhea, or abdominal pain); constitutional symptoms (including generalized malaise, fatigue, or achiness); respiratory symptoms (including dyspnea, cough, or pharyngitis). Almost all abacavir hypersensitivity reactions include fever and/or rash as part of the syndrome.

Other signs and symptoms have included lethargy, headache, myalgia, edema, arthralgia, and paresthesia. Anaphylaxis, liver failure, renal failure, hypotension, adult respiratory distress syndrome, respiratory failure, myolysis, and death have occurred in association with these hypersensitivity reactions. Physical findings have included lymphadenopathy, mucous membrane lesions (conjunctivitis and mouth ulcerations), and maculopapular or urticarial rash (although some patients had other types of rashes and others did not have a rash). There were reports of erythema multiforme.

Laboratory abnormalities included elevated liver chemistries, elevated creatine phosphokinase, elevated creatinine, and lymphopenia, and abnormal chest x-ray findings (predominantly infiltrates, which were localized). Additional Adverse Reactions with Use of Abacavir, Lamivudine and Zidovudine Tablets Treatment-emergent clinical adverse reactions (rated by the investigator as moderate or severe) with a frequency greater than or equal to 5% during therapy with abacavir 300 mg twice daily, lamivudine 150 mg twice daily, and zidovudine 300 mg twice daily compared with indinavir 800 mg 3 times daily, lamivudine 150 mg twice daily, and zidovudine 300 mg twice daily from CNA3005 are listed in Table 1. Table 1. Treatment-Emergent (All Causality) Adverse Reactions of at Least Moderate Intensity (Grades 2 to 4, Greater than or Equal to 5% Frequency) in Therapy-Naive Adults (CNA3005) through 48 Weeks of Treatment Adverse Reaction ZIAGEN ® plus Lamivudine / Zidovudine ( n = 262 ) Indinavir plus Lamivudine / Zidovudine ( n = 264 ) Nausea 19% 17% Headache 13% 9% Malaise and fatigue 12% 12% Nausea and vomiting 10% 10% Hypersensitivity reaction 8% 2% Diarrhea 7% 5% Fever and/or chills 6% 3% Depressive disorders 6% 4% Musculoskeletal pain 5% 7% Skin rashes 5% 4% Ear/nose/throat infections 5% 4% Viral respiratory infections 5% 5% Anxiety 5% 3% Renal signs/symptoms <1% 5% Pain (non-site-specific) <1% 5% Five subjects receiving abacavir in CNA3005 experienced worsening of pre-existing depression compared to none in the indinavir arm. The background rates of pre-existing depression were similar in the 2 treatment arms. Laboratory Abnormalities Laboratory abnormalities in CNA3005 are listed in Table 2. Table 2. Treatment-Emergent Laboratory Abnormalities (Grades 3/4) in CNA3005 ULN = Upper limit of normal. n = Number of subjects assessed.

Laboratory Parameter ZIAGEN ® plus Lamivudine / Zidovudine ( n = 262 ) Indinavir plus Lamivudine / Zidovudine ( n = 264 ) Elevated CPK (>4 x ULN) 18 (7%) 18 (7%) ALT (>5.0 x ULN) 16 (6%) 16 (6%) Neutropenia (<750/mm 3 ) 13 (5%) 13 (5%) Hypertriglyceridemia (>750 mg/dL) 5 (2%) 3 (1%) Hyperamylasemia (>2.0 x ULN) 5 (2%) 1 (<1%) Hyperglycemia (>13.9 mmol/L) 2 (<1%) 2 (<1%) Anemia (Hgb ≤6.9 g/dL) 0 (0%) 3 (1%) Other Adverse Events In addition to adverse reactions in Tables 1 and 2, other adverse events observed in the expanded access program for abacavir were pancreatitis and increased GGT.

Postmarketing Experience

The following adverse reactions have been identified during postmarketing use. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Abacavir Cardiovascular : Myocardial infarction.

Skin : Suspected Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported in patients receiving abacavir primarily in combination with medications known to be associated with SJS and TEN, respectively. Because of the overlap of clinical signs and symptoms between hypersensitivity to abacavir and SJS and TEN, and the possibility of multiple drug sensitivities in some patients, abacavir should be discontinued and not restarted in such cases. There have also been reports of erythema multiforme with abacavir use . Abacavir, Lamivudine, and/or Zidovudine Body as a Whole : Redistribution/accumulation of body fat.

Cardiovascular : Cardiomyopathy. Digestive : Stomatitis. Endocrine and Metabolic : Gynecomastia.

Gastrointestinal: Anorexia and/or decreased appetite, abdominal pain, dyspepsia, oral mucosal pigmentation. General : Vasculitis, weakness. Hemic and Lymphatic : Aplastic anemia, anemia (including pure red cell aplasia and severe anemias progressing on therapy), lymphadenopathy, splenomegaly, thrombocytopenia.

Hepatic : Lactic acidosis and hepatic steatosis , elevated bilirubin, elevated transaminases, posttreatment exacerbations of hepatitis B . Hypersensitivity : Sensitization reactions (including anaphylaxis), urticaria. Musculoskeletal : Arthralgia, myalgia, muscle weakness, rhabdomyolysis. Nervous : Dizziness, paresthesia, peripheral neuropathy, seizures.

Psychiatric : Insomnia and other sleep disorders. Respiratory : Abnormal breath sounds/wheezing. Skin : Alopecia, erythema multiforme, Stevens-Johnson syndrome.

Abacavir Methadone

In a trial of 11 HIV-1-infected subjects receiving methadone-maintenance therapy with 600 mg of ZIAGEN ® twice daily (twice the currently recommended dose), oral methadone clearance increased . This alteration will not result in a methadone dose modification in the majority of patients; however, an increased methadone dose may be required in a small number of patients. Riociguat Coadministration with fixed-dose abacavir/dolutegravir/lamivudine resulted in increased riociguat exposure, which may increase the risk of riociguat adverse reactions. The riociguat dose may need to be reduced.

See full prescribing information for ADEMPAS (riociguat).

Lamivudine 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-containing medicines .

Zidovudine Agents Antagonistic with Zidovudine

Concomitant use of zidovudine with the following drugs should be avoided since an antagonistic relationship has been demonstrated in vitro : Stavudine Doxorubicin Nucleoside analogues, e.g., ribavirin Hematologic/Bone Marrow Suppressive/Cytotoxic Agents Coadministration with the following drugs may increase the hematologic toxicity of zidovudine: Ganciclovir Interferon alfa Ribavirin Other bone marrow suppressive or cytotoxic agents

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to abacavir, lamivudine and zidovudine tablets 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 abacavir, lamivudine, or zidovudine compared with the background rate for birth defects of 2.7% in the Metropolitan Atlanta Congenital Defects Program (MACDP) reference population . 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. Hyperlactatemia, which may be due to mitochondrial dysfunction, has been reported in infants with in utero exposure to zidovudine-containing products. These events were transient and asymptomatic in most cases.

There have been few reports of developmental delay, seizures, and other neurological disease. However, a causal relationship between these events and exposure to zidovudine-containing products in utero or peri-partum has not been established (see Data). In animal reproduction studies, oral administration of abacavir to pregnant rats during organogenesis resulted in fetal malformations and other embryonic and fetal toxicities at exposures 35 times the human exposure (AUC) at the recommended clinical daily dose. However, no adverse developmental effects were observed following oral administration of abacavir to pregnant rabbits during organogenesis, at exposures approximately 9 times the human exposure (AUC) at the recommended clinical dose.

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. Administration of oral zidovudine to female rats prior to mating and throughout gestation resulted in embryotoxicity at doses that produced systemic exposure (AUC) approximately 33 times higher than exposure at the recommended clinical dose. However, no embryotoxicity was observed after oral administration of zidovudine to pregnant rats during organogenesis at doses that produced systemic exposure (AUC) approximately 117 times higher than exposures at the recommended clinical dose.

Administration of oral zidovudine to pregnant rabbits during organogenesis resulted in embryotoxicity at doses that produced systemic exposure (AUC) approximately 108 times higher than exposure at the recommended clinical dose. However, no embryotoxicity was observed at doses that produced systemic exposure (AUC) approximately 23 times higher than exposures at the recommended clinical dose (see Data). Data Human Data: Abacavir Based on prospective reports to the APR of exposures to abacavir during pregnancy resulting in live births (including over 1,300 exposed in the first trimester and over 1,300 exposed in the second/third trimester), there was no difference between the overall risk of birth defects for abacavir compared with the background birth defect rate of 2.7% in a U.S. reference population of the MACDP. The prevalence of defects in live births was 3.2% (95% CI: 2.3% to 4.3%) following first trimester exposure to abacavir-containing regimens and 2.9% (95% CI: 2.1% to 4%) following second/third trimester exposure to abacavir-containing regimens. Abacavir has been shown to cross the placenta and concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery . Lamivudine Based on prospective reports to the APR of of exposures to lamivudine during pregnancy resulting in live births (including over 5300 exposed in the first trimester and over 7,400 exposed in the second/third 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 a U.S. reference population of the MACDP. The prevalence of birth defects in live births was 3.1% (95% CI: 2.7% to 3.6%) following first trimester exposure to lamivudine-containing regimens and 2.9% (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). Zidovudine Based on prospective reports to the APR of exposures to zidovudine during pregnancy resulting in live births (including over 4,200 exposed in the first trimester and over 9,700 exposed in the second/third trimester), there was no difference between the overall risk of birth defects for zidovudine compared with the background birth defect rate of 2.7% in a U.S. reference population of the MACDP. The prevalence of birth defects in live births was 3.2% (95% CI: 2.7% to 3.8%) following first trimester exposure to zidovudine-containing regimens and 2.8% (95% CI: 2.5% to 3.1%) following second/third trimester exposure to zidovudine-containing regimens. A randomized, double-blind, placebo-controlled trial was conducted in HIV-1-infected pregnant women to determine the utility of zidovudine for the prevention of maternal-fetal HIV-1 transmission.

Zidovudine treatment during pregnancy reduced the rate of maternal-fetal HIV-1 transmission from 24.9% for infants born to placebo-treated mothers to 7.8% for infants born to mothers treated with zidovudine. There were no differences in pregnancy-related adverse events between the treatment groups. Of the 363 neonates that were evaluated, congenital abnormalities occurred with similar frequency between neonates born to mothers who received zidovudine and neonates born to mothers who received placebo.

The observed abnormalities included problems in embryogenesis (prior to 14 weeks) or were recognized on ultrasound before or immediately after initiation of trial drug. See full prescribing information for RETROVIR ® (zidovudine) and COMBIVIR ® (lamivudine and zidovudine). Zidovudine has been shown to cross the placenta and concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery . There have been reports of mild, transient elevations in serum lactate levels, which may be due to mitochondrial dysfunction, in neonates and infants exposed in utero or peri-partum to zidovudine-containing products. There have been few reports of developmental delay, seizures, and other neurological disease.

However, a causal relationship between these events and exposure to zidovudine-containing products in utero or peri-partum has not been established. The clinical relevance of transient elevations in serum lactate is unknown. Animal Data: Abacavir Abacavir was administered orally to pregnant rats (at 100, 300, and 1,000 mg per kg per day) and rabbits (at 125, 350, or 700 mg per kg per day) during organogenesis (on Gestation Days 6 through 17 and 6 through 20, respectively). Fetal malformations (increased incidences of fetal anasarca and skeletal malformations) or developmental toxicity (decreased fetal body weight and crown-rump length) were observed in rats at doses up to 1,000 mg per kg per day, resulting in exposures approximately 35 times the human exposure (AUC) at the recommended daily dose.

No developmental effects were observed in rats at 100 mg per kg per day, resulting in exposures (AUC) 3.5 times the human exposure at the recommended daily dose. In a fertility and early embryo-fetal development study conducted in rats (at 60, 160, or 500 mg per kg per day), embryonic and fetal toxicities (increased resorptions, decreased fetal body weights) or toxicities to the offspring (increased incidence of stillbirth and lower body weights) occurred at doses up to 500 mg per kg per day. No developmental effects were observed in rats at 60 mg per kg per day, resulting in exposures (AUC) approximately 4 times the human exposure at the recommended daily dose.

Studies in pregnant rats showed that abacavir is transferred to the fetus through the placenta. In pregnant rabbits, no developmental toxicities and no increases in fetal malformations occurred at up to the highest dose evaluated, resulting in exposures (AUC) approximately 9 times the human exposure at the recommended dose. Lamivudine 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 and 8 through 20 ). 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 systemic 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 fertility/pre-and postnatal development study in rats, lamivudine was administered orally at doses of 180, 900, and 4,000 mg per kg per day (from prior to mating through postnatal Day 20). In the study, development of the offspring, including fertility and reproductive performance, was not affected by maternal administration of lamivudine.

Zidovudine A study in pregnant rats (at 50, 150, or 450 mg per kg per day starting 26 days prior to mating through Gestation to postnatal Day 21) showed increased fetal resorptions at doses that produced systemic exposures (AUC) approximately 33 times higher than exposure at the recommended daily human dose (300 mg twice daily). However, in an oral embryo-fetal development study in rats (at 125, 250, or 500 mg per kg per day on Gestation Days 6 through 15), no fetal resorptions were observed at doses that produced systemic exposure (AUC) approximately 117 times higher than exposures at the recommended daily human dose. An oral embryo-fetal development study in rabbits (at 75, 150, or 500 mg per kg per day on gestation Days 6 through 18) showed increased fetal resorptions at the 500-mg-per-kg-per-day dose which produced systemic exposures (AUC) approximately 108 times higher than exposure at the recommended daily human dose; however, no fetal resorptions were noted at doses up to 150 mg per kg per day, which produced systemic exposure (AUC) approximately 23 times higher than exposures at the recommended daily human dose. These oral embryo-fetal development studies in the rat and rabbit revealed no evidence of fetal malformations with zidovudine.

In another developmental toxicity study, pregnant rats (dosed at 3,000 mg per kg per day from Days 6 through 15 of gestation) showed marked maternal toxicity and an increased incidence of fetal malformations at exposures greater than 300 times the recommended daily human dose based on AUC. However, there were no signs of fetal malformations at doses up to 600 mg per kg per day.

Pediatric Use Abacavir, lamivudine and zidovudine tablet is not recommended in children who weigh less than 40 kg because it is a fixed-dose tablet that cannot be adjusted for these patient populations . Therapy-Experienced Pediatric Trial A randomized, double-blind trial, CNA3006, compared ZIAGEN ® plus lamivudine and zidovudine versus lamivudine and zidovudine in pediatric subjects, most of whom were extensively pretreated with nucleoside analogue antiretroviral agents. Subjects in this trial had a limited response to abacavir.

Presence of HLA-B*5701 allele. Prior hypersensitivity reaction to abacavir, lamivudine, or zidovudine Moderate or severe hepatic impairment. Abacavir, lamivudine and zidovudine tablets are contraindicated in patients: who have the HLA-B*5701 allele. with prior hypersensitivity reaction to abacavir, lamivudine, or zidovudine. with moderate or severe hepatic impairment .

There is no known specific treatment for overdose with abacavir, lamivudine and zidovudine tablets. If overdose occurs, the patient should be monitored and standard supportive treatment applied as required. Abacavir It is not known whether abacavir can be removed by peritoneal dialysis or hemodialysis.

Lamivudine Because a negligible amount of lamivudine was removed via (4-hour) hemodialysis, continuous ambulatory peritoneal dialysis, and automated peritoneal dialysis, it is not known if continuous hemodialysis would provide clinical benefit in a lamivudine overdose event. Zidovudine Acute overdoses of zidovudine have been reported in pediatric patients and adults. These involved exposures up to 50 grams.

No specific symptoms or signs have been identified following acute overdosage with zidovudine apart from those listed as adverse events such as fatigue, headache, vomiting, and occasional reports of hematological disturbances. Patients recovered without permanent sequelae. Hemodialysis and peritoneal dialysis appear to have a negligible effect on the removal of zidovudine, while elimination of its primary metabolite, 3′- azido-3′-deoxy-5′- O -β- D -glucopyranuronosylthymidine (GZDV), is enhanced.