Abacavir (Ziagen)

Published January 23, 2001; Updated June 2018
Susa Coffey, MD
Selected References
2. Rodriguez-French  A, Boghossian  J, Gray  GE, Nadler  JP, Quinones  AR, Sepulveda  GE, Millard  JM, Wannamaker  PG.
The NEAT study: a 48-week open-label study to compare the antiviral efficacy and safety of GW433908 versus nelfinavir in antiretroviral therapy-naive HIV-1-infected patients. J Acquir Immune Defic Syndr. 2004 Jan;35(1):22-32
[PubMed ID: 14707788]
OBJECTIVE: To compare the efficacy, durability, and tolerability of GW433908 (908), 1400 mg twice-daily (BID), with nelfinavir (NFV), 1250 mg BID. METHODS: This was an international, multicenter, randomized, open-label study (NEAT) in antiretroviral therapy (ART)-naive HIV-infected adults with plasma HIV-1 RNA (vRNA) at screening > or =5000 copies/mL (c/mL). Patients were randomly assigned to 908 or NFV (2:1) for a minimum of 48 weeks, with a background of abacavir (ABC) and lamivudine (3TC). RESULTS: A total of 166 patients received randomized treatment with 908 BID and 83 received NFV BID. The population was diverse with regard to race and gender (76% Hispanics and blacks, 31% female) and had advanced HIV disease at screening (45% had vRNA >100,000 c/mL, 48% had CD4 cell counts <200 cells/mm3, 20% had a history of Centers for Disease Control class C events). After 48 weeks of study by an intention-to-treat rebound or discontinuation = failure analysis, a greater proportion of patients in the 908 BID group (66%) than the NFV BID group (51%) achieved vRNA <400 c/mL. Furthermore, more patients with screening vRNA >100,000 c/mL (67 vs. 35%) or CD4 <50 cells/mm3 (48 vs. 24%) achieved undetectable viral loads taking 908 BID compared with NFV BID, respectively. Favorable immunologic responses were observed for both groups. Diarrhea, which was more common in the NFV BID group (18 vs. 5%), was the only drug-related grade 2-4 adverse event with a significant difference (P = 0.002) in incidence between groups. CONCLUSION: Administration of 908 BID resulted in a potent and sustained antiretroviral response, notably in ART-naive patients with advanced HIV disease. GW433908 was generally well tolerated and provides a convenient dosing option without food or fluid restrictions.
3. Gathe  JC, Ive  P, Wood  R, Schürmann  D, Bellos  NC, DeJesus  E, Gladysz  A, Garris  C, Yeo  J.
SOLO: 48-week efficacy and safety comparison of once-daily fosamprenavir /ritonavir versus twice-daily nelfinavir in naive HIV-1-infected patients. AIDS. 2004 Jul;18(11):1529-37
[PubMed ID: 15238771]
OBJECTIVE: To compare the magnitude and durability of the antiviral response to fosamprenavir (FPV) plus ritonavir (RTV) once-daily (FPV/r QD) with nelfinavir twice-daily (NFV BID), each administered with abacavir and lamivudine twice-daily. METHODS: An international, phase III, randomized, open-label study in antiretroviral therapy-naive, HIV-infected adults. RESULTS: Patients with advanced HIV disease received FPV/r QD (n = 322) or NFV BID (n = 327). At week 48, 69% of patients in the FPV/r QD group and 68% in the NFV BID group had plasma HIV-1 RNA (vRNA) < 400 copies/ml, whereas 55% of patients in the FPV/r QD group and 53% in the NFV BID group had vRNA < 50 copies/ml (intent to treat, rebound/discontinuation = failure). More patients in the NFV BID group (17%) experienced virological failure than in the FPV/r QD group (7%). Efficacy of FPV/r QD was maintained in patients with CD4+ cell counts < 50 x 10 cells/l or vRNA >/= 100 000 copies/ml at entry. At week 48, median CD4+ cell counts were increased to 203 x 10 cells/l (FPV/r QD group) and 207 x 10 cells/l (NFV BID group). Both regimens were generally well tolerated. Diarrhea was more common on NFV BID than on FPV/r QD (16 versus 9%; P = 0.008). Fasting lipid profile results were generally favorable in both treatment arms. FPV/r QD maintained plasma amprenavir (APV) trough concentrations above the mean phenotypic drug-susceptibility (IC50) for wild-type virus for APV. CONCLUSION: As a first choice protease inhibitor with a low daily pill burden, FPV/r QD was well tolerated and provided potent, durable antiviral suppression.
4. DeJesus  E, Herrera  G, Teofilo  E, Gerstoft  J, Buendia  CB, Brand  JD, Brothers  CH, Hernandez  J, Castillo  SA, Bonny  T, Lanier  ER, Scott  TR; CNA30024 Study Team.
Abacavir versus zidovudine combined with lamivudine and efavirenz, for the treatment of antiretroviral-naive HIV-infected adults. Clin Infect Dis. 2004 Oct;39(7):1038-46
[PubMed ID: 15472858]
BACKGROUND: Zidovudine, lamivudine, and efavirenz comprise a highly effective and well-tolerated triple regimen for antiretroviral-naive patients. Evaluating other unique nucleoside reverse-transcriptase inhibitor (NRTI) combinations for long-term viral suppression is desirable. METHODS: This multicenter, randomized, double-blind noninferiority clinical trial compared the efficacy and safety of abacavir with that of zidovudine plus lamivudine and efavirenz in 649 antiretroviral-naive HIV-infected patients. The primary objective was a comparison of proportions of patients achieving plasma HIV-1 RNA levels <or=50 copies/mL through week 48 of the study. RESULTS: At study week 48, 70% of patients in the abacavir group, compared with 69% in the zidovudine group, maintained confirmed plasma HIV-1 RNA levels of <or=50 copies/mL (in the intent-to-treat exposed population). Virologic failure was infrequent (6% in the abacavir group and 4% in the zidovudine group). There was a significant CD4(+) cell response (209 cells/mm(3) in the abacavir group and 155 cells/mm(3) in the zidovudine group). Safety profiles were as expected. CONCLUSION: Abacavir provided an effective and durable antiretroviral response that was noninferior to zidovudine, when combined with lamivudine and efavirenz.
5. Moyle  GJ, DeJesus  E, Cahn  P, Castillo  SA, Zhao  H, Gordon  DN, Craig  C, Scott  TR; Ziagen Once-Daily in Antiretroviral Combination Therapy (CNA30021) Study Team.
Abacavir once or twice daily combined with once-daily lamivudine and efavirenz for the treatment of antiretroviral-naive HIV-infected adults: results of the Ziagen Once Daily in Antiretroviral Combination Study. J Acquir Immune Defic Syndr. 2005 Apr;38(4):417-25
[PubMed ID: 15764958]
The long intracellular half-life of abacavir (ABC) supports its once-daily use, and this would be expected to simplify treatment if ABC could be given as part of a complete once-daily regimen. A randomized double-blind clinical trial compared the efficacy and safety of 600 mg of ABC administered once daily (n = 384) versus 300 mg of ABC administered twice daily (n = 386) in combination with 300 mg of lamivudine (3TC) and 600 mg of efavirenz (EFV) administered once daily in antiretroviral-naive patients over 48 weeks. The baseline median plasma HIV-1 RNA level was 4.89 log10 copies/mL (44% with viral load >100,000 copies/mL), and the median CD4 cell count was 262 cells/mm. ABC administered once daily was non-inferior to the twice-daily regimen, with 66% and 68% of patients in these respective treatment arms achieving a confirmed plasma HIV-1 RNA level <50 copies/mL (95% confidence interval: -8.4%, 4.9%). The ABC once-daily and twice-daily regimens were similar with respect to infrequency of virologic failure (10% vs. 8%), emergence of resistance mutations, CD4 cell increases from baseline (median, 188 vs. 200 cells/mm), safety profile, and incidence of ABC-related hypersensitivity reactions (9% vs. 7%). ABC administered once daily in combination with 3TC and EFV administered once daily was non-inferior to the ABC twice-daily dosing schedule when combined with 3TC and EFV over 48 weeks.
6. Eron  J, Yeni  P, Gathe  J, Estrada  V, DeJesus  E, Staszewski  S, Lackey  P, Katlama  C, Young  B, Yau  L, Sutherland-Phillips  D, Wannamaker  P, Vavro  C, Patel  L, Yeo  J, Shaefer  M; KLEAN study team.
The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial. Lancet. 2006 Aug;368(9534):476-82
[PubMed ID: 16890834]
BACKGROUND: Lopinavir-ritonavir is a preferred protease inhibitor co-formulation for initial HIV-1 treatment. Fosamprenavir-ritonavir has shown similar efficacy and safety to lopinavir-ritonavir when each is combined with two nucleoside reverse transcriptase inhibitors. We compared the two treatments directly in antiretroviral-naive patients. METHODS: This open-label, non-inferiority study included 878 antiretroviral-naive, HIV-1-infected patients randomised to receive either fosamprenavir-ritonavir 700 mg/100 mg twice daily or lopinavir-ritonavir 400 mg/100 mg twice daily, each with the co-formulation of abacavir-lamivudine 600 mg/300 mg once daily. Primary endpoints were proportion of patients achieving HIV-1 RNA less than 400 copies per mL at week 48 and treatment discontinuations because of an adverse event. The intent-to-treat analysis included all patients exposed to at least one dose of randomised study medication. This study is registered with ClinicalTrials.gov, number NCT00085943. FINDINGS: At week 48, non-inferiority of fosamprenavir-ritonavir to lopinavir-ritonavir (95% CI around the treatment difference -4.84 to 7.05) was shown, with 315 of 434 (73%) patients in the fosamprenavir-ritonavir group and 317 of 444 (71%) in the lopinavir-ritonavir group achieving HIV-1 RNA less than 400 copies per mL. Treatment discontinuations due to an adverse event were few and occurred with similar frequency in the two treatment groups (fosamprenavir-ritonavir 53, 12%; lopinavir-ritonavir 43, 10%). Diarrhoea, nausea, and abacavir hypersensitivity were the most frequent drug-related grade 2-4 adverse events. Treatment-emergent drug resistance was rare; no patient had virus that developed reduced susceptibility to fosamprenavir-ritonavir or lopinavir-ritonavir. INTERPRETATION: Fosamprenavir-ritonavir twice daily in treatment-naive patients provides similar antiviral efficacy, safety, tolerability, and emergence of resistance as lopinavir-ritonavir, each in combination with abacavir-lamivudine.