Enter drug's generic or brand name below. Results will appear here. Note: all drug related information obtained on this page is provided by RX List.
Using the RX LIST database:
(1) Enter the drug name in the search box below and hit ENTER
(2) The rx list web site will open here with the drug search completed. Next, scroll down the page to locate the link to the drug you are searching for and then click on the link.
ZIAGEN®
(abacavir) Tablets, Oral Solution
WARNING
HYPERSENSITIVITY REACTIONS, and LACTIC ACIDOSIS AND SEVERE HEPATOMEGALY WITH STEATOSIS
Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with ZIAGEN (abacavir).
Patients who carry the HLA-B*5701 allele are at a higher risk of a hypersensitivity reaction to abacavir; although, hypersensitivity reactions have occurred in patients who do not carry the HLA-B*5701 allele [see WARNINGS AND PRECAUTIONS].
ZIAGEN is contraindicated in patients with a prior hypersensitivity reaction to abacavir and in HLA-B*5701-positive patients [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS]. All patients should be screened for the HLA-B*5701 allele prior to initiating therapy with ZIAGEN or reinitiation of therapy with ZIAGEN, unless patients have a previously documented HLA-B*5701 allele assessment. Discontinue ZIAGEN immediately if a hypersensitivity reaction is suspected, regardless of HLA-B*5701 status and even when other diagnoses are possible [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS].
Following a hypersensitivity reaction to ZIAGEN, NEVER restart ZIAGEN or any other abacavir-containing product because more severe symptoms, including death can occur within hours. Similar severe reactions have also occurred rarely following the reintroduction of abacavir-containing products in patients who have no history of abacavir hypersensitivity [see WARNINGS AND PRECAUTIONS].
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues and other antiretrovirals. Discontinue ZIAGEN if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur [see WARNINGS AND PRECAUTIONS].
ZIAGEN is the brand name for abacavir sulfate, a synthetic carbocyclic nucleoside analogue with inhibitory activity against HIV-1. The chemical name of abacavir sulfate is (1S,cis)-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclopentene-1-methanol sulfate (salt) (2:1). Abacavir sulfate is the enantiomer with 1S, 4R absolute configuration on the cyclopentene ring. It has a molecular formula of (C14H18N6O)2•H2SO4 and a molecular weight of 670.76 g per mol. It has the following structural formula:
 |
Abacavir sulfate is a white to off-white solid and is soluble in water.
ZIAGEN tablets are for oral administration. Each tablet contains abacavir sulfate equivalent to 300 mg of abacavir as active ingredient and the following inactive ingredients: colloidal silicon dioxide, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate. The tablets are coated with a film that is made of hypromellose, polysorbate 80, synthetic yellow iron oxide, titanium dioxide, and triacetin.
ZIAGEN oral solution is for oral administration. Each milliliter (1 mL) of ZIAGEN oral solution contains abacavir sulfate equivalent to 20 mg of abacavir (i.e., 20 mg per mL) as active ingredient and the following inactive ingredients: artificial strawberry and banana flavors, citric acid (anhydrous), methylparaben and propylparaben (added as preservatives), propylene glycol, saccharin sodium, sodium citrate (dihydrate), sorbitol solution, and water.
In vivo, abacavir sulfate dissociates to its free base, abacavir. Dosages are expressed in terms of abacavir.
ZIAGEN tablets and oral solution, in combination with other antiretroviral agents, are indicated for the treatment of human immunodeficiency virus (HIV-1) infection.
Screen for the HLA-B*5701 allele prior to initiating therapy with ZIAGEN [see BOXED WARNING, WARNINGS AND PRECAUTIONS].
The recommended dosage of ZIAGEN for adults is 600 mg daily, administered orally as either 300 mg twice daily or 600 mg once daily, in combination with other antiretroviral agents.
The recommended dosage of ZIAGEN oral solution in HIV-1-infected pediatric patients aged 3 months and older is 8 mg per kg orally twice daily or 16 mg per kg orally once-daily (up to a maximum of 600 mg daily) in combination with other antiretroviral agents.
ZIAGEN is also available as a scored tablet for HIV-1-infected pediatric patients weighing greater than or equal to 14 kg for whom a solid dosage form is appropriate. Before prescribing ZIAGEN tablets, children should be assessed for the ability to swallow tablets. If a child is unable to reliably swallow ZIAGEN tablets, the oral solution formulation should be prescribed. The recommended oral dosage of ZIAGEN tablets for HIV-1-infected pediatric patients is presented in Table 1.
Table 1: Dosing Recommendations for ZIAGEN Scored
Tablets in Pediatric Patients
| Weight (ks) | Once-Daily Dosing Regimena | Twice-Daily Dosing Regimen | ||
| AM Dose | PM Dose | Total Daily Dose | ||
| 14 to < 20 | 1 tablet (300 mg) | ½tablet (150 mg) | ½tablet (150 mg) | 300 mg |
| ≥ 20 to < 25 | 1½tablets (450 mg) | ½tablet (150 mg) | 1 tablet (300 mg) | 450 mg |
| ≥ 25 | 2 tablets (600 mg) | 1 tablet (300 mg) | 1 tablet (300 mg) | 600 mg |
| 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]. | ||||
The recommended dose of ZIAGEN in patients with mild hepatic impairment (Child-Pugh Class A) is 200 mg twice daily. To enable dose reduction, ZIAGEN oral solution (10 mL twice daily) should be used for the treatment of these patients. The safety, efficacy, and pharmacokinetic properties of abacavir have not been established in patients with moderate to severe hepatic impairment; therefore, ZIAGEN is contraindicated in these patients.
ZIAGEN tablets contain 300 mg of abacavir as abacavir sulfate. The tablets are yellow, biconvex, scored, capsule-shaped, film-coated, and imprinted with “GX 623” on both sides.
ZIAGEN oral solution contains 20 mg per mL of abacavir as abacavir sulfate. The solution is a clear to opalescent, yellowish, strawberry-banana-flavored liquid.
ZIAGEN tablets, containing abacavir sulfate equivalent to 300 mg abacavir are yellow, biconvex, scored, capsule-shaped, film-coated, and imprinted with “GX 623” on both sides. They are packaged as follows:
Bottles of 60 tablets (NDC 49702-221-18).
Unit dose blister packs of 60 tablets (NDC 49702-221-44). Each pack contains 6 blister cards of 10 tablets each.
Store at controlled room temperature of 20° to 25°C (68° to 77°F) (see USP).
ZIAGEN oral solution is a clear to opalescent, yellowish, strawberry-banana-flavored liquid. Each mL of the solution contains abacavir sulfate equivalent to 20 mg of abacavir. It is packaged in plastic bottles as follows:
Bottles of 240 mL (NDC 49702-222-48) with child-resistant closure. This product does not require reconstitution.
Store at controlled room temperature of 20° to 25°C (68° to 77°F) (see USP). DO NOT FREEZE. May be refrigerated.
Manufactured For:ViiV Healthecare, Research Triangle Park, NC 27709. by: Research Triangle Park, NC 27709. Revised: Mar 2017
The following adverse reactions are discussed in other sections of the labeling:
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.
In clinical trials, serious and sometimes fatal hypersensitivity reactions have occurred with abacavir [see BOXED WARNING, WARNINGS AND PRECAUTIONS]. These reactions have been characterized by 2 or more of the following signs or symptoms: (1) fever; (2) rash; (3) gastrointestinal symptoms (including nausea, vomiting, diarrhea, or abdominal pain); (4) constitutional symptoms (including generalized malaise, fatigue, or achiness); (5) 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).
Therapy-Naive Adults: Treatment-emergent clinical adverse reactions (rated by the investigator as moderate or severe) with a greater than or equal to 5% frequency during therapy with ZIAGEN 300 mg twice daily, lamivudine 150 mg twice daily, and efavirenz 600 mg daily compared with zidovudine 300 mg twice daily, lamivudine 150 mg twice daily, and efavirenz 600 mg daily from CNA30024 are listed in Table 2.
Table 2: Treatment-Emergent (All Causality) Adverse
Reactions of at Least Moderate Intensity (Grades 2-4, Greater than or Equal to
5% Frequency) in Therapy-Naive Adults (CNA30024a) through 48 Weeks
of Treatment
| Adverse Reaction | ZIAGEN plus Lamivudine plus Efavirenz (n = 324) |
Zidovudine plusLamivudine plus Efavirenz (n = 325) |
| Dreams/sleep disorders | 10% | 10% |
| Drug hypersensitivity | 9% | < 1%b |
| Headaches/migraine | 7% | 11% |
| Nausea | 7% | 11% |
| Fatigue/malaise | 7% | 10% |
| Diarrhea | 7% | 6% |
| Rashes | 6% | 12% |
| Abdominal pain/gastritis/gastrointestinal signs and symptoms | 6% | 8% |
| Depressive disorders | 6% | 6% |
| Dizziness | 6% | 6% |
| Musculoskeletal pain | 6% | 5% |
| Bronchitis | 4% | 5% |
| Vomiting | 2% | 9% |
| a This trial used double-blind ascertainment
of suspected hypersensitivity reactions. During the blinded portion of the
trial, suspected hypersensitivity to abacavir was reported by investigators in
9% of 324 subjects in the abacavir group and 3% of 325 subjects in the
zidovudine group. b Ten (3%) cases of suspected drug hypersensitivity were reclassified as not being due to abacavir following unblinding. |
||
Treatment-emergent clinical adverse reactions (rated by the investigator as moderate or severe) with a greater than or equal to 5% frequency during therapy with ZIAGEN 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 3.
Table 3: Treatment-Emergent (All Causality) Adverse
Reactions of at Least Moderate Intensity (Grades 2-4, 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 ZIAGEN in CNA3005 experienced worsening of pre-existing depression compared with none in the indinavir arm. The background rates of pre-existing depression were similar in the 2 treatment arms.
ZIAGEN Once Daily versus ZIAGEN Twice Daily (CNA30021): Treatment-emergent clinical adverse reactions (rated by the investigator as at least moderate) with a greater than or equal to 5% frequency during therapy with ZIAGEN 600 mg once daily or ZIAGEN 300 mg twice daily, both in combination with lamivudine 300 mg once daily and efavirenz 600 mg once daily from CNA30021, were similar. For hypersensitivity reactions, subjects receiving ZIAGEN once daily showed a rate of 9% in comparison with a rate of 7% for subjects receiving ZIAGEN twice daily. However, subjects receiving ZIAGEN 600 mg once daily experienced a significantly higher incidence of severe drug hypersensitivity reactions and severe diarrhea compared with subjects who received ZIAGEN 300 mg twice daily. Five percent (5%) of subjects receiving ZIAGEN 600 mg once daily had severe drug hypersensitivity reactions compared with 2% of subjects receiving ZIAGEN 300 mg twice daily. Two percent (2%) of subjects receiving ZIAGEN 600 mg once daily had severe diarrhea while none of the subjects receiving ZIAGEN 300 mg twice daily had this event.
Laboratory Abnormalities: Laboratory abnormalities (Grades 3-4) in therapy-naive adults during therapy with ZIAGEN 300 mg twice daily, lamivudine 150 mg twice daily, and efavirenz 600 mg daily compared with zidovudine 300 mg twice daily, lamivudine 150 mg twice daily, and efavirenz 600 mg daily from CNA30024 are listed in Table 4.
Table 4: Laboratory Abnormalities (Grades 3-4) in
Therapy-Naive Adults (CNA30024) through 48 Weeks of Treatment
| Grade 3/4 Laboratory Abnormalities | ZIAGEN plus Lamivudine plus Efavirenz (n = 324) |
Zidovudine plus Lamivudine plus Efavirenz (n = 325) |
| Elevated CPK ( > 4 X ULN) | 8% | 8% |
| Elevated ALT ( > 5 X ULN) | 6% | 6% |
| Elevated AST ( > 5 X ULN) | 6% | 5% |
| Hypertriglyceridemia ( > 750 mg/dL) | 6% | 5% |
| Hyperamylasemia ( > 2 X ULN) | 4% | 5% |
| Neutropenia (ANC < 750/mm³) | 2% | 4% |
| Anemia (Hgb ≤ 6.9 gm/dL) | < 1% | 2% |
| Thrombocytopenia (Platelets < 50,000/mm³) | 1% | < 1% |
| Leukopenia (WBC ≤ 1,500/mm³) | < 1% | 2% |
| ULN = Upper limit of normal. n = Number of subjects assessed. |
||
Laboratory abnormalities in CNA3005 are listed in Table 5.
Table 5: Treatment-Emergent Laboratory Abnormalities
(Grades 3-4) in CNA3005
| Grade 3/4 Laboratory Abnormalities | 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 ) | 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%) |
| ULN = Upper limit of normal. n = Number of subjects assessed. |
||
The frequencies of treatment-emergent laboratory abnormalities were comparable between treatment groups in CNA30021.
Treatment-emergent clinical adverse reactions (rated by the investigator as moderate or severe) with a greater than or equal to 5% frequency during therapy with ZIAGEN 8 mg per kg twice daily, lamivudine 4 mg per kg twice daily, and zidovudine 180 mg per m² twice daily compared with lamivudine 4 mg per kg twice daily and zidovudine 180 mg per m² twice daily from CNA3006 are listed in Table 6.
Table 6: Treatment-Emergent
(All Causality) Adverse Reactions of at Least Moderate Intensity (Grades 2-4,
Greater than or Equal to 5% Frequency) in Therapy-Experienced Pediatric
Subjects (CNA3006) through 16 Weeks of Treatment
| Adverse Reaction | ZIAGEN plus Lamivudine plus Zidovudine (n = 102) |
Lamivudine plus Zidovudine (n = 103) |
| Fever and/or chills | 9% | 7% |
| Nausea and vomiting | 9% | 2% |
| Skin rashes | 7% | 1% |
| Ear/nose/throat infections | 5% | 1% |
| Pneumonia | 4% | 5% |
| Headache | 1% | 5% |
Laboratory Abnormalities: In CNA3006, laboratory abnormalities (anemia, neutropenia, liver function test abnormalities, and CPK elevations) were observed with similar frequencies as in a trial of therapy-naive adults (CNA30024). Mild elevations of blood glucose were more frequent in pediatric subjects receiving ZIAGEN (CNA3006) as compared with adult subjects (CNA30024).
In addition to adverse reactions and laboratory abnormalities reported in Tables 2, 3, 4, 5, and 6, other adverse reactions observed in the expanded access program were pancreatitis and increased GGT.
Pediatric Subjects Once-Daily versus Twice-Daily Dosing (COL105677): The safety of once-daily compared with twice-daily dosing of ZIAGEN was assessed in the ARROW trial. Primary safety assessment in the ARROW trial was based on Grade 3 and Grade 4 adverse events. The frequency of Grade 3 and 4 adverse events was similar among subjects randomized to once-daily dosing compared with subjects randomized to twice-daily dosing. One event of Grade 4 hepatitis in the once-daily cohort was considered as uncertain causality by the investigator and all other Grade 3 or 4 adverse events were considered not related by the investigator.
The following adverse reactions have been identified during postmarketing use of ZIAGEN. 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 exposures.
Redistribution/accumulation of body fat.
Myocardial infarction.
Lactic acidosis and hepatic steatosis [see WARNINGS AND PRECAUTIONS].
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 [see ADVERSE REACTIONS].
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 [see CLINICAL PHARMACOLOGY]. 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.
Included as part of the PRECAUTIONS section.
Serious and sometimes fatal hypersensitivity reactions have occurred with ZIAGEN (abacavir). These hypersensitivity reactions have included multi-organ failure and anaphylaxis and typically occurred within the first 6 weeks of treatment with ZIAGEN (median time to onset was 9 days); although abacavir hypersensitivity reactions have occurred any time during treatment [see ADVERSE REACTIONS]. Patients who carry the HLA-B*5701 allele are at a higher risk of abacavir hypersensitivity reactions; although, patients who do not carry the HLA-B*5701 allele have developed hypersensitivity reactions. Hypersensitivity to abacavir was reported in approximately 206 (8%) of 2,670 patients in 9 clinical trials with abacavir-containing products where HLA-B*5701 screening was not performed. The incidence of suspected abacavir hypersensitivity reactions in clinical trials was 1% when subjects carrying the HLA-B*5701 allele were excluded. In any patient treated with abacavir, the clinical diagnosis of hypersensitivity reaction must remain the basis of clinical decision making.
Due to the potential for severe, serious, and possibly fatal hypersensitivity reactions with ZIAGEN:
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues and other antiretrovirals. A majority of these cases have been in women. Obesity and prolonged nucleoside exposure may be risk factors. Caution should be exercised when administering ZIAGEN to any patient with known risk factors for liver disease; however, cases have also been reported in patients with no known risk factors. Treatment with ZIAGEN should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations).
Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including ZIAGEN. During the initial phase of combination antiretroviral treatment, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment.
Autoimmune disorders (such as Graves' disease, polymyositis, and Guillain-Barr syndrome) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable and can occur many months after initiation of treatment.
Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and “cushingoid appearance” have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.
In a published prospective, observational, epidemiological trial designed to investigate the rate of myocardial infarction (MI) in patients on combination antiretroviral therapy, the use of abacavir within the previous 6 months was correlated with an increased risk of MI. In a sponsor-conducted pooled analysis of clinical trials, no excess risk of MI was observed in abacavir-treated subjects as compared with control subjects. In totality, the available data from the observational cohort and from clinical trials are inconclusive.
As a precaution, the underlying risk of coronary heart disease should be considered when prescribing antiretroviral therapies, including abacavir, and action taken to minimize all modifiable risk factors (e.g., hypertension, hyperlipidemia, diabetes mellitus, smoking).
Advise the patient to read the FDA-approved patient labeling (Medication Guide).
Inform patients:
Advise patients that lactic acidosis and severe hepatomegaly with steatosis have been reported with use of nucleoside analogues and other antiretrovirals. Advise patients to stop taking ZIAGEN if they develop clinical symptoms suggestive of lactic acidosis or pronounced hepatotoxicity [see BOXED WARNING, WARNINGS AND PRECAUTIONS].
Advise patients to inform their healthcare provider immediately of any signs and symptoms of infection as inflammation from previous infection may occur soon after combination antiretroviral therapy, including when ZIAGEN is started [see WARNINGS AND PRECAUTIONS].
Inform patients that redistribution or accumulation of body fat may occur in patients receiving antiretroviral therapy and that the cause and long-term health effects of these conditions are not known at this time [see WARNINGS AND PRECAUTIONS].
Advise patients that there is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ZIAGEN during pregnancy [see Use in Specific Populations].
Instruct women with HIV-1 infection not to breastfeed because HIV-1 can be passed to the baby in the breast milk [see Use in Specific Populations].
Instruct patients that if they miss a dose of ZIAGEN, to take it as soon as they remember. Advise patients not to double their next dose or take more than the prescribed dose [see DOSAGE AND ADMINISTRATION].
Instruct patients to read the Medication Guide before starting ZIAGEN and to re-read it each time the prescription is renewed. Instruct patients to inform their physician or pharmacist if they develop any unusual symptom, or if any known symptom persists or worsens.
Abacavir was administered orally at 3 dosage levels to separate groups of mice and rats in 2-year carcinogenicity studies. Results showed an increase in the incidence of malignant and non-malignant tumors. Malignant tumors occurred in the preputial gland of males and the clitoral gland of females of both species, and in the liver of female rats. In addition, non-malignant tumors also occurred in the liver and thyroid gland of female rats. These observations were made at systemic exposures in the range of 6 to 32 times the human exposure at the recommended dose of 600 mg.
Abacavir induced chromosomal aberrations both in the presence and absence of metabolic activation in an in vitro cytogenetic study in human lymphocytes. Abacavir was mutagenic in the absence of metabolic activation, although it was not mutagenic in the presence of metabolic activation in an L5178Y mouse lymphoma assay. Abacavir was clastogenic in males and not clastogenic in females in an in vivo mouse bone marrow micronucleus assay.
Abacavir was not mutagenic in bacterial mutagenicity assays in the presence and absence of metabolic activation.
Abacavir did not affect male or female fertility in rats at a dose associated with exposures (AUC) approximately 3.3 times (male) or 4.1 times (female) those in humans at the clinically recommended dose.
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ZIAGEN during pregnancy. Healthcare Providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.
Available data from the APR show no difference in the overall risk of birth defects for abacavir 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 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 [see Data].
Human Data: Based on prospective reports to the APR of over 2,000 exposures to abacavir during pregnancy resulting in live births (including over 1,000 exposed in the first 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 the U.S. reference population of the MACDP. The prevalence of defects in live births was 2.9% (95% CI: 2.0% to 4.1%) following first trimester exposure to abacavir-containing regimens and 2.7% (95% CI: 1.9% to 3.7%) 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 [see CLINICAL PHARMACOLOGY].
Animal Data: 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.
The Centers for Disease Control and Prevention recommend that HIV-1-infected mothers in the United States not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection. Abacavir is present in human milk. There is no information on the effects of abacavir on the breastfed infant or the effects of the drug on milk production. Because of the potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants), and (3) serious adverse reactions in a breastfed infant, instruct mothers not to breastfeed if they are receiving ZIAGEN.
The safety and effectiveness of ZIAGEN have been established in pediatric patients aged 3 months and older. Use of ZIAGEN is supported by pharmacokinetic trials and evidence from adequate and well-controlled trials of ZIAGEN in adults and pediatric subjects [see DOSAGE AND ADMINISTRATION, ADVERSE REACTIONS, CLINICAL PHARMACOLOGY, Clinical Studies].
Clinical trials of ZIAGEN did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, caution should be exercised in the administration of ZIAGEN in elderly patients reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
A dose reduction is required for patients with mild hepatic impairment (Child-Pugh Class A) [see DOSAGE AND ADMINISTRATION]. The safety, efficacy, and pharmacokinetic properties of abacavir have not been established in patients with moderate or severe hepatic impairment; therefore, ZIAGEN is contraindicated in these patients [see CONTRAINDICATIONS, CLINICAL PHARMACOLOGY].
There is no known specific treatment for overdose with ZIAGEN. If overdose occurs, the patient should be monitored and standard supportive treatment applied as required. It is not known whether abacavir can be removed by peritoneal dialysis or hemodialysis.
ZIAGEN is contraindicated in patients:
Abacavir is an antiretroviral agent [see Microbiology].
The pharmacokinetic properties of abacavir were independent of dose over the range of 300 to 1,200 mg per day.
Absorption and Bioavailability: Following oral administration, abacavir is rapidly absorbed and extensively distributed. The geometric mean absolute bioavailability of the tablet was 83%. Plasma abacavir AUC was similar following administration of the oral solution or tablets. After oral administration of 300 mg twice daily in 20 subjects, the steady-state peak serum abacavir concentration (Cmax) was 3.0 ± 0.89 mcg per mL (mean ± SD) and AUC(0-12 h) was 6.02 ± 1.73 mcg•hour per mL. After oral administration of a single dose of 600 mg of abacavir in 20 subjects, Cmax was 4.26 ± 1.19 mcg per mL (mean ± SD) and AUC∞ was 11.95 ± 2.51 mcg•hour per mL.
Distribution: The apparent volume of distribution after IV administration of abacavir was 0.86 ± 0.15 L per kg, suggesting that abacavir distributes into extravascular space. In 3 subjects, the CSF AUC(0-6 h) to plasma abacavir AUC(0-6 h) ratio ranged from 27% to 33%.
Binding of abacavir to human plasma proteins is approximately 50% and was independent of concentration. Total blood and plasma drug-related radioactivity concentrations are identical, demonstrating that abacavir readily distributes into erythrocytes.
Metabolism and Elimination: In humans, abacavir is not significantly metabolized by cytochrome P450 enzymes. The primary routes of elimination of abacavir are metabolism by alcohol dehydrogenase to form the 5'-carboxylic acid and glucuronyl transferase to form the 5'-glucuronide. The metabolites do not have antiviral activity. In vitro experiments reveal that abacavir does not inhibit human CYP3A4, CYP2D6, or CYP2C9 activity at clinically relevant concentrations.
Elimination of abacavir was quantified in a mass balance trial following administration of a 600-mg dose of 14C-abacavir: 99% of the radioactivity was recovered, 1.2% was excreted in the urine as abacavir, 30% as the 5'-carboxylic acid metabolite, 36% as the 5'-glucuronide metabolite, and 15% as unidentified minor metabolites in the urine. Fecal elimination accounted for 16% of the dose.
In single-dose trials, the observed elimination half-life (t½) was 1.54 ± 0.63 hours. After intravenous administration, total clearance was 0.80 ± 0.24 L per hour per kg (mean ± SD).
Bioavailability of abacavir tablets was assessed in the fasting and fed states with no significant difference in systemic exposure (AUC∞); therefore, ZIAGEN tablets may be administered with or without food. Systemic exposure to abacavir was comparable after administration of ZIAGEN oral solution and ZIAGEN tablets. Therefore, these products may be used interchangeably.
Renal Impairment: The pharmacokinetic properties of ZIAGEN have not been determined in patients with impaired renal function. Renal excretion of unchanged abacavir is a minor route of elimination in humans.
Hepatic Impairment: The pharmacokinetics of abacavir have been studied in subjects with mild hepatic impairment (Child-Pugh Class A). Results showed that there was a mean increase of 89% in the abacavir AUC and an increase of 58% in the half-life of abacavir after a single dose of 600 mg of abacavir. The AUCs of the metabolites were not modified by mild liver disease; however, the rates of formation and elimination of the metabolites were decreased [see CONTRAINDICATIONS, Use in Specific Populations].
Pregnancy: Abacavir: Abacavir pharmacokinetics were studied in 25 pregnant women during the last trimester of pregnancy receiving abacavir 300 mg twice daily. Abacavir exposure (AUC) during pregnancy was similar to those in postpartum and in HIV-infected non-pregnant historical controls. Consistent with passive diffusion of abacavir across the placenta, abacavir concentrations in neonatal plasma cord samples at birth were essentially equal to those in maternal plasma at delivery.
Pediatric Patients: The pharmacokinetics of abacavir have been studied after either single or repeat doses of ZIAGEN in 169 pediatric subjects. Subjects receiving abacavir oral solution according to the recommended dosage regimen achieved plasma concentrations of abacavir similar to adults. Subjects receiving abacavir oral tablets achieved higher plasma concentrations of abacavir than subjects receiving oral solution.
The pharmacokinetics of abacavir dosed once daily in HIV-1-infected pediatric subjects aged 3 months through 12 years was evaluated in 3 trials (PENTA 13 [n = 14], PENTA 15 [n = 18], and ARROW [n = 36]). All 3 trials were 2-period, crossover, open-label pharmacokinetic trials of twice- versus once-daily dosing of abacavir and lamivudine. For the oral solution as well as the tablet formulation, these 3 trials demonstrated that once-daily dosing provides comparable AUC0-24 to twice-daily dosing of abacavir at the same total daily dose. The mean Cmax was approximately 1.6- to 2.3-fold higher with abacavir once-daily dosing compared with twice-daily dosing.
Geriatric Patients: The pharmacokinetics of ZIAGEN have not been studied in subjects older than 65 years.
Gender: A population pharmacokinetic analysis in HIV-1-infected male (n = 304) and female (n = 67) subjects showed no gender differences in abacavir AUC normalized for lean body weight.
Race: There are no significant or clinically relevant racial differences between blacks and whites in abacavir pharmacokinetics.
In human liver microsomes, abacavir did not inhibit cytochrome P450 isoforms (2C9, 2D6, 3A4). Based on these data, it is unlikely that clinically significant drug interactions will occur between abacavir and drugs metabolized through these pathways.
Lamivudine and/or Zidovudine: Fifteen HIV-1-infected subjects were enrolled in a crossover-designed drug interaction trial evaluating single doses of abacavir (600 mg), lamivudine (150 mg), and zidovudine (300 mg) alone or in combination. Analysis showed no clinically relevant changes in the pharmacokinetics of abacavir with the addition of lamivudine or zidovudine or the combination of lamivudine and zidovudine. Lamivudine exposure (AUC decreased 15%) and zidovudine exposure (AUC increased 10%) did not show clinically relevant changes with concurrent abacavir.
Ethanol: Abacavir has no effect on the pharmacokinetic properties of ethanol. Ethanol decreases the elimination of abacavir causing an increase in overall exposure. Due to the common metabolic pathways of abacavir and ethanol via alcohol dehydrogenase, the pharmacokinetic interaction between abacavir and ethanol was studied in 24 HIV-1-infected male subjects. Each subject received the following treatments on separate occasions: a single 600-mg dose of abacavir, 0.7 g per kg ethanol (equivalent to 5 alcoholic drinks), and abacavir 600 mg plus 0.7 g per kg ethanol. Coadministration of ethanol and abacavir resulted in a 41% increase in abacavir AUC∞ and a 26% increase in abacavir t½. Abacavir had no effect on the pharmacokinetic properties of ethanol, so no clinically significant interaction is expected in men. This interaction has not been studied in females.
Methadone: In a trial of 11 HIV-1-infected subjects receiving methadone-maintenance therapy (40 mg and 90 mg daily), with 600 mg of ZIAGEN twice daily (twice the currently recommended dose), oral methadone clearance increased 22% (90% CI: 6% to 42%). 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 [see DRUG INTERACTIONS]. The addition of methadone had no clinically significant effect on the pharmacokinetic properties of abacavir.
Abacavir is a carbocyclic synthetic nucleoside analogue. Abacavir is converted by cellular enzymes to the active metabolite, carbovir triphosphate (CBV-TP), an analogue of deoxyguanosine-5'-triphosphate (dGTP). CBV-TP inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA.
The antiviral activity of abacavir against HIV-1 was assessed in a number of cell lines including primary monocytes/macrophages and peripheral blood mononuclear cells (PBMCs). EC50 values ranged from 3.7 to 5.8 microM (1 microM = 0.28 mcg per mL) and 0.07 to 1.0 microM against HIV-1IIIB and HIV-1BaL, respectively, and the mean EC50 value was 0.26 ± 0.18 microM against 8 clinical isolates. The median EC50 values of abacavir were 344 nM (range: 14.8 to 676 nM), 16.9 nM (range: 5.9 to 27.9 nM), 8.1 nM (range: 1.5 to 16.7 nM), 356 nM (range: 35.7 to 396 nM), 105 nM (range: 28.1 to 168 nM), 47.6 nM (range: 5.2 to 200 nM), 51.4 nM (range: 7.1 to 177 nM), and 282 nM (range: 22.4 to 598 nM) against HIV-1 clades A-G and group O viruses (n = 3 except n = 2 for clade B), respectively. The EC50 values against HIV-2 isolates (n = 4), ranged from 0.024 to 0.49 microM. The antiviral activity of abacavir in cell culture was not antagonized when combined with the nucleoside reverse transcriptase inhibitors (NRTIs) didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine or zidovudine, the non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine, or the protease inhibitor (PI) amprenavir. Ribavirin (50 microM) used in the treatment of chronic HCV infection had no effect on the anti-HIV-1 activity of abacavir in cell culture.
HIV-1 isolates with reduced susceptibility to abacavir have been selected in cell culture. Genotypic analysis of isolates selected in cell culture and recovered from abacavir-treated subjects demonstrated that amino acid substitutions K65R, L74V, Y115F, and M184V/I emerged in HIV-1 RT. M184V or I substitutions resulted in an approximately 2-fold decrease in susceptibility to abacavir. Substitutions K65R, L74M, or Y115F with M184V or I conferred a 7-to 8-fold reduction in abacavir susceptibility, and combinations of three substitutions were required to confer more than an 8-fold reduction in susceptibility.
Thirty-nine percent (7 of 18) of the isolates from subjects who experienced virologic failure in the abacavir once-daily arm had a greater than 2.5-fold mean decrease in abacavir susceptibility with a median-fold decrease of 1.3 (range: 0.5 to 11) compared with 29% (5 of 17) of the failure isolates in the twice-daily arm with a median-fold decrease of 0.92 (range: 0.7 to 13).
Cross-resistance has been observed among NRTIs. Isolates containing abacavir resistance-associated substitutions, namely, K65R, L74V, Y115F, and M184V, exhibited cross-resistance to didanosine, emtricitabine, lamivudine, and tenofovir in cell culture and in subjects. An increasing number of thymidine analogue mutation substitutions (TAMs: M41L, D67N, K70R, L210W, T215Y/F, K219E/R/H/Q/N) is associated with a progressive reduction in abacavir susceptibility.
Myocardial degeneration was found in mice and rats following administration of abacavir for 2 years. The systemic exposures were equivalent to 7 to 24 times the expected systemic exposure in humans at a dose of 600 mg. The clinical relevance of this finding has not been determined.
CNA30024 was a multicenter, double-blind, controlled trial in which 649 HIV-1-infected, therapy-naive adults were randomized and received either ZIAGEN (300 mg twice daily), lamivudine (150 mg twice daily), and efavirenz (600 mg once daily); or zidovudine (300 mg twice daily), lamivudine (150 mg twice daily), and efavirenz (600 mg once daily). The duration of double-blind treatment was at least 48 weeks. Trial participants were male (81%), white (51%), black (21%), and Hispanic (26%). The median age was 35 years; the median pretreatment CD4+ cell count was 264 cells per mm³, and median plasma HIV-1 RNA was 4.79 log10 copies per mL. The outcomes of randomized treatment are provided in Table 7.
Table 7: Outcomes of Randomized Treatment through Week
48 (CNA30024)
| Outcome | ZIAGEN plus Lamivudine plus Efavirenz (n = 324) |
Zidovudine plus Lamivudine plus Efavirenz (n = 325) |
| Respondera | 69% (73%) | 69% (71%) |
| Virologic failuresb | 6% | 4% |
| Discontinued due to adverse reactions | 14% | 16% |
| Discontinued due to other reasonsc | 10% | 11% |
| a Subjects achieved and maintained confirmed
HIV-1 RNA less than or equal to 50 copies per mL (less than 400 copies per mL)
through Week 48 (Roche AMPLICOR Ultrasensitive HIV-1 MONITOR® standard test 1.0
PCR). b Includes viral rebound, insufficient viral response according to the investigator, and failure to achieve confirmed less than or equal to 50 copies per mL by Week 48. c Includes consent withdrawn, lost to follow up, protocol violations, those with missing data, clinical progression, and other. |
||
After 48 weeks of therapy, the median CD4+ cell count increases from baseline were 209 cells per mm³ in the group receiving ZIAGEN and 155 cells per mm³ in the zidovudine group. Through Week 48, 8 subjects (2%) in the group receiving ZIAGEN (5 CDC classification C events and 3 deaths) and 5 subjects (2%) on the zidovudine arm (3 CDC classification C events and 2 deaths) experienced clinical disease progression.
CNA3005 was a multicenter, double-blind, controlled trial in which 562 HIV-1-infected, therapy-naive adults were randomized to receive either ZIAGEN (300 mg twice daily) plus COMBIVIR® (lamivudine 150 mg/zidovudine 300 mg twice daily), or indinavir (800 mg 3 times a day) plus COMBIVIR twice daily. The trial was stratified at randomization by pre-entry plasma HIV-1 RNA 10,000 to 100,000 copies per mL and plasma HIV-1 RNA greater than 100,000 copies per mL. Trial participants were male (87%), white (73%), black (15%), and Hispanic (9%). At baseline the median age was 36 years; the median baseline CD4+ cell count was 360 cells per mm³, and median baseline plasma HIV-1 RNA was 4.8 log10 copies per mL. Proportions of subjects with plasma HIV-1 RNA less than 400 copies per mL (using Roche AMPLICOR HIV-1 MONITOR Test) through 48 weeks of treatment are summarized in Table 8.
Table 8. Outcomes of Randomized Treatment through Week
48 (CNA3005)
| Outcome | ZIAGEN plus Lamivudine/Zidovudine (n = 262) |
Indinavir plus Lamivudine/Zidovudine (n = 265) |
| Respondera | 49% | 50% |
| Virologic failureb | 31% | 28% |
| Discontinued due to adverse reactions | 10% | 12% |
| Discontinued due to other reasonsc | 11% | 10% |
| a Subjects achieved and maintained confirmed
HIV-1 RNA less than 400 copies per mL. b Includes viral rebound and failure to achieve confirmed less than 400 copies per mL by Week 48. c Includes consent withdrawn, lost to follow up, protocol violations, those with missing data, clinical progression, and other. |
||
Treatment response by plasma HIV-1 RNA strata is shown in Table 9.
Table 9: Proportions of
Responders through Week 48 by Screening Plasma HIV-1 RNA Levels (CNA3005)
| Screening HIV-1 RNA (copies/mL) | ZIAGEN plus Lamivudine/ Zidovudine (n = 262) |
Indinavir plus Lamivudine/ Zidovudine (n = 265) |
||
| < 400 copies/mL | n | < 400 copies/mL | n | |
| ≥ 10,000 - ≤ 100,000 | 50% | 166 | 48% | 165 |
| > 100,000 | 48% | 96 | 52% | 100 |
In subjects with baseline viral load greater than 100,000 copies per mL, percentages of subjects with HIV-1 RNA levels less than 50 copies per mL were 31% in the group receiving abacavir versus 45% in the group receiving indinavir.
Through Week 48, an overall mean increase in CD4+ cell count of about 150 cells per mm³ was observed in both treatment arms. Through Week 48, 9 subjects (3.4%) in the group receiving abacavir (6 CDC classification C events and 3 deaths) and 3 subjects (1.5%) in the group receiving indinavir (2 CDC classification C events and 1 death) experienced clinical disease progression.
CNA30021 was an international, multicenter, double-blind, controlled trial in which 770 HIV-1-infected, therapy-naive adults were randomized and received either abacavir 600 mg once daily or abacavir 300 mg twice daily, both in combination with lamivudine 300 mg once daily and efavirenz 600 mg once daily. The double-blind treatment duration was at least 48 weeks. Trial participants had a mean age of 37 years; were male (81%), white (54%), black (27%), and American Hispanic (15%). The median baseline CD4+ cell count was 262 cells per mm³ (range: 21 to 918 cells per mm³) and the median baseline plasma HIV-1 RNA was 4.89 log10 copies per mL (range: 2.60 to 6.99 log10 copies per mL).
The outcomes of randomized treatment are provided in Table 10.
Table 10: Outcomes of Randomized Treatment through
Week 48 (CNA30021)
| Outcome | ZIAGEN 600 mg q.d. plus EPIVIR® plus Efavirenz (n = 384) |
ZIAGEN 300 mg b.i.d. plus EPIVIR plus Efavirenz (n = 386) |
| Respondera | 64% (71%) | 65% (72%) |
| Virologic failureb | 11% (5%) | 11% (5%) |
| Discontinued due to adverse reactions | 13% | 11% |
| Discontinued due to other reasonsc | 11% | 13% |
| a Subjects achieved and maintained confirmed
HIV-1 RNA less than 50 copies per mL (less than 400 copies per mL) through Week
48 (Roche AMPLICOR Ultrasensitive HIV-1 MONITOR standard test version 1.0). b Includes viral rebound, failure to achieve confirmed less than 50 copies per mL (less than 400 copies per mL) by Week 48, and insufficient viral load response. c Includes consent withdrawn, lost to follow up, protocol violations, clinical progression, and other. |
||
After 48 weeks of therapy, the median CD4+ cell count increases from baseline were 188 cells per mm³ in the group receiving abacavir 600 mg once daily and 200 cells per mm³ in the group receiving abacavir 300 mg twice daily. Through Week 48, 6 subjects (2%) in the group receiving ZIAGEN 600 mg once daily (4 CDC classification C events and 2 deaths) and 10 subjects (3%) in the group receiving ZIAGEN 300 mg twice daily (7 CDC classification C events and 3 deaths) experienced clinical disease progression. None of the deaths were attributed to trial medications.
CNA3006 was a randomized, double-blind trial comparing ZIAGEN 8 mg per kg twice daily plus lamivudine 4 mg per kg twice daily plus zidovudine 180 mg per m² twice daily versus lamivudine 4 mg per kg twice daily plus zidovudine 180 mg per m² twice daily. Two hundred and five therapy-experienced pediatric subjects were enrolled: female (56%), white (17%), black (50%), Hispanic (30%), median age of 5.4 years, baseline CD4+ cell percent greater than 15% (median = 27%), and median baseline plasma HIV-1 RNA of 4.6 log10 copies per mL. Eighty percent and 55% of subjects had prior therapy with zidovudine and lamivudine, respectively, most often in combination. The median duration of prior nucleoside analogue therapy was 2 years. At 16 weeks the proportion of subjects responding based on plasma HIV-1 RNA less than or equal to 400 copies per mL was significantly higher in subjects receiving ZIAGEN plus lamivudine plus zidovudine compared with subjects receiving lamivudine plus zidovudine, 13% versus 2%, respectively. Median plasma HIV-1 RNA changes from baseline were -0.53 log10 copies per mL in the group receiving ZIAGEN plus lamivudine plus zidovudine compared with -0.21 log10 copies per mL in the group receiving lamivudine plus zidovudine. Median CD4+ cell count increases from baseline were 69 cells per mm³ in the group receiving ZIAGEN plus lamivudine plus zidovudine and 9 cells per mm³ in the group receiving lamivudine plus zidovudine.
ARROW (COL105677) was a 5-year randomized, multicenter trial which evaluated multiple aspects of clinical management of HIV-1 infection in pediatric subjects. HIV-1-infected, treatment-naive subjects aged 3 months to 17 years were enrolled and treated with a first-line regimen containing ZIAGEN and lamivudine, dosed twice daily according to World Health Organization recommendations. After a minimum of 36 weeks of treatment, subjects were given the option to participate in Randomization 3 of the ARROW trial, comparing the safety and efficacy of once-daily dosing with twice-daily dosing of ZIAGEN and lamivudine, in combination with a third antiretroviral drug, for an additional 96 weeks. Of the 1,206 original ARROW subjects, 669 participated in Randomization 3. Virologic suppression was not a requirement for participation at baseline for Randomization 3 (following a minimum of 36 weeks of twice-daily treatment), 75% of subjects in the twice-daily cohort were virologically suppressed compared with 71% of subjects in the once-daily cohort.
The proportions of subjects with HIV-1 RNA less than 80 copies per mL through 96 weeks are shown in Table 11. The differences between virologic responses in the two treatment arms were comparable across baseline characteristics for gender and age.
Table 11: Virologic Outcome of Randomized Treatment at
Week 96a (ARROW Randomization 3)
| Outcome | ZIAGEN plus Lamivudine Twice-Daily Dosing (n = 333) |
ZIAGEN plus Lamivudine Once-Daily Dosing (n = 336) |
| HIV-1 RNA < 80 copies/mLb | 70% | 67% |
| HIV-1 RNA ≥ 80 copies/mLc | 28% | 31% |
| No virologic data | ||
| Discontinued due to adverse event or death | 1% | < 1% |
| Discontinued study for other reasonsd | 0% | < 1% |
| Missing data during window but on study | 1% | 1% |
| a Analyses were based on the last observed
viral load data within the Week 96 window. b Predicted difference (95% CI) of response rate is -4.5% (-11% to 2%) at Week 96. c Includes subjects who discontinued due to lack or loss of efficacy or for reasons other than an adverse event or death, and had a viral load value of greater than or equal to 80 copies per mL, or subjects who had a switch in background regimen that was not permitted by the protocol. d Other includes reasons such as withdrew consent, loss to follow-up, etc. and the last available HIV-1 RNA less than 80 copies per mL (or missing). |
||
ZIAGEN®
(ZY-uh-jen)
(abacavir) Tablets
ZIAGEN®
(abacavir) Oral Solution
What is the most important information I should know about ZIAGEN?
ZIAGEN can cause serious side effects, including:
If you get a symptom from 2 or more of the following groups while taking ZIAGEN, call your healthcare provider right away to find out if you should stop taking ZIAGEN.
| Symptom(s) | |
| Group 1 | Fever |
| Group 2 | Rash |
| Group 3 | Nausea, vomiting, diarrhea, abdominal (stomach area) pain |
| Group 4 | Generally ill feeling, extreme tiredness, or achiness |
| Group 5 | Shortness of breath, cough, sore throat |
A list of these symptoms is on the Warning Card your pharmacist gives you. Carry this Warning Card with you at all times.
If you stop ZIAGEN because of an allergic reaction, never take ZIAGEN (abacavir) or any other abacavir-containing medicine (EPZICOM®, TRIUMEQ®, or TRIZIVIR®) again.
If your healthcare provider tells you that you can take ZIAGEN again, start taking it when you are around medical help or people who can call a healthcare provider if you need one.
You may be more likely to get lactic acidosis or serious liver problems if you are female, very overweight (obese), or have been taking nucleoside analogue medicines for a long time.
What is ZIAGEN?
ZIAGEN is a prescription HIV-1 (Human Immunodeficiency Virus type 1) medicine used with other antiretroviral medicines to treat HIV-1 infection. HIV-1 is the virus that causes Acquired Immune Deficiency Syndrome (AIDS).
The safety and effectiveness of ZIAGEN has not been established in children under 3 months of age.
When used with other antiretroviral medicines to treat HIV-1 infection, ZIAGEN may help:
Reducing the amount of HIV-1 and increasing the CD4+ (T) cells in your blood may help improve your immune system. This may reduce your risk of death or getting infections that can happen when your immune system is weak (opportunistic infections).
ZIAGEN does not cure HIV-1 infection or AIDS. You must keep taking HIV-1 medicines to control HIV1 infection and decrease HIV-related illnesses.
Who should not take ZIAGEN?
Do not take ZIAGEN if you:
What should I tell my healthcare provider before taking ZIAGEN?
Before you take ZIAGEN, tell your healthcare provider if you:
Tell your healthcare provider about all the medicines you take, including prescription and over-thecounter medicines, vitamins, and herbal supplements.
Some medicines interact with ZIAGEN. Keep a list of your medicines to show your healthcare provider and pharmacist. You can ask your healthcare provider or pharmacist for a list of medicines that interact with ZIAGEN. Do not start taking a new medicine without telling your healthcare provider. Your healthcare provider can tell you if it is safe to take ZIAGEN with other medicines.
Tell your healthcare provider if you take:
How should I take ZIAGEN?
What are the possible side effects of ZIAGEN?
The most common side effects of ZIAGEN in adults include:
The most common side effects of ZIAGEN in children include:
Tell your healthcare provider if you have any side effect that bothers you or that does not go away.
These are not all the possible side effects of ZIAGEN. 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 ZIAGEN?
Keep ZIAGEN and all medicines out of the reach of children.
General information for safe and effective use of ZIAGEN
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use ZIAGEN for a condition for which it was not prescribed. Do not give ZIAGEN to other people, even if they have the same symptoms that you have. It may harm them.
If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for the information about ZIAGEN that is written for health professionals.
For more information go to www.ZIAGEN.com or call 1-877-844-8872.
What are the ingredients in ZIAGEN?
Active ingredient: abacavir
Inactive ingredients:
Tablets:
Colloidal silicon dioxide, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate
Tablet film-coating contains: hypromellose, polysorbate 80, synthetic yellow iron oxide, titanium dioxide, and triacetin.
Oral Solution:
Artificial strawberry and banana flavors, citric acid (anhydrous), methylparaben and propylparaben (added as preservatives), propylene glycol, saccharin sodium, sodium citrate (dihydrate), sorbitol solution, and water.
WARNING CARD
ZIAGEN®
(abacavir) Tablets and Oral Solution
Patients taking ZIAGEN may have a serious allergic reaction (hypersensitivity reaction) that can cause death. If you get a symptom from 2 or more of the following groups while taking ZIAGEN, call your healthcare provider right away to find out if you should stop taking this medicine.
| Symptom(s) | |
| Group 1 | Fever |
| Group 2 | Rash |
| Group 3 | Nausea, vomiting, diarrhea, or abdominal (stomach area) pain |
| Group 4 | Generally ill feeling, extreme tiredness, or achiness |
| Group 5 | Shortness of breath, cough, or sore throat |
Always carry this Warning Card with you to help recognize symptoms of this allergic reaction.
(Back of Card)
WARNING CARD
ZIAGEN® (abacavir) tablets and oral solution
If you must stop treatment with ZIAGEN because you have had an allergic reaction to abacavir, NEVER take ZIAGEN or another abacavir-containing medicine (EPZICOM®, TRIUMEQ®, or TRIZIVIR®) again. If you have an allergic reaction, dispose of any unused ZIAGEN. Ask your pharmacist how to properly dispose of medicines. If you take ZIAGEN or another abacavir-containing medicine again after you have had an allergic reaction, WITHIN HOURS you may get life-threatening symptoms that may include very low blood pressure or death.
Please read the Medication Guide for additional information on ZIAGEN.
