Mark S. Shaefer

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

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.

High Sensitivity of Human Leukocyte Antigen-B*5701 as a Marker for Immunologically Confirmed Abacavir Hypersensitivity in White and Black Patients

BACKGROUND Although the human leukocyte antigen (HLA)-B*5701 is highly associated with a hypersensitivity reaction (HSR) to abacavir (ABC), variable sensitivities have been reported when clinical data alone have been used to define an ABC HSR. This study evaluated the sensitivity of detection of the HLA-B*5701 allele as a marker of ABC HSRs in both white and black patients, using skin patch testing to supplement clinical diagnosis. METHODS White and black patients, identified through chart review, were classified as having received a diagnosis of an ABC HSR based on clinical findings only (a clinically suspected ABC HSR) or based on clinical findings and a positive skin patch test result (an immunologically confirmed [IC] ABC HSR). Control subjects were racially matched subjects who tolerated ABC for >/=12 weeks without experiencing an ABC HSR. Patients and control subjects were tested for the presence of HLA-B*5701. Sensitivity, specificity, and odds ratios for the detection of HLA-B*5701 as a marker for an ABC HSR were calculated for white and black participants. RESULTS Forty-two (32.3%) of 130 white patients and 5 (7.2%) of 69 black patients who met the criteria for clinically suspected HSRs had IC HSRs. All 42 white patients with IC HSRs were HLA-B*5701 positive (sensitivity, 100%; odds ratio, 1945; 95% confidence interval, 110-34,352). Among all white patients with clinically suspected HSRs, sensitivity was 44% (57 of 130 patients tested positive for HLA-B*5701); specificity among white control subjects was 96%. Five of 5 black patients with IC HSRs were HLA-B*5701 positive (sensitivity, 100%; odds ratio, 900; 95% confidence interval, 38-21,045). Among black patients with clinically suspected HSRs, the sensitivity was 14% (10 of 69 tested positive for HLA-B*5701); specificity among black control subjects was 99%. CONCLUSIONS Although IC ABC HSRs are uncommon in black persons, the 100% sensitivity of HLA-B*5701 as a marker for IC ABC HSRs in both US white and black patients suggests similar implications of the association between HLA-B*5701 positivity and risk of ABC HSRs in both races.

Early Virologic Nonresponse to Tenofovir, Abacavir, and Lamivudine in HIV-Infected Antiretroviral-Naive Subjects

BACKGROUND Antiretroviral combinations that reduce the number of pills and dosing frequency have the potential to simplify therapy. We compared 2 regimens dosed as 2 pills once daily. METHODS This was a randomized, open-label, multicenter study of tenofovir disoproxil fumarate versus efavirenz, both administered once daily with the abacavir/lamivudine fixed-dose combination in treatment-naive human immunodeficiency virus type 1 (HIV-1)-infected subjects. After reports of early nonresponse, an unplanned interim analysis was performed. Virologic nonresponse was defined as (1) a <2.0-log(10) copies/mL decrease in HIV-1 RNA level by week 8, (2) an HIV-1 RNA rebound of > or =1.0 log(10) copies/mL above the nadir, or (3) for subjects with 2 consecutive HIV-1 RNA measurements <50 copies/mL, a subsequent increase to >400 copies/mL on 2 consecutive occasions. RESULTS We randomized 340 subjects. Median baseline HIV-1 RNA level and CD4+ cell count were 4.7 log(10) copies/mL and 251 cells/mm3, respectively; 194 subjects with HIV-1 RNA data from > or =8 weeks were included in the interim analysis. Virologic nonresponse occurred in 50 (49%) of 102 subjects in the tenofovir disoproxil fumarate arm, compared with 5 (5%) of 92 of subjects in the efavirenz arm (P<.001). Within 12 weeks, viral genotypes for nonresponders in the tenofovir disoproxil fumarate arm showed M184V or I/M/V mixtures in 40 (98%) of 41 subjects and K65R and M184V or mixtures in 22 (54%) of 41 subjects. The protocol was immediately amended to modify the tenofovir disoproxil fumarate arm. The efavirenz arm continued unchanged; after 48 weeks, 120 (71%) of 169 subjects achieved HIV-1 RNA levels <50 copies/mL. CONCLUSION The tenofovir disoproxil fumarate/abacavir/lamivudine regimen resulted in an unexpected and unacceptably high rate of nonresponse and incidence of K65R and M184V/I. This 3-drug regimen should not be used.

Prevalence of Antiretroviral Drug Resistance and Resistance-Associated Mutations in Antiretroviral Therapy-Naïve HIV-Infected Individuals from 40 United States Cities

Abstract Background: Transmission of drug-resistant HIV strains to antiretroviral therapy (ART)-naïve subjects can negatively impact therapy response. As treatment strategies and utilization of antiretroviral drugs evolve, patterns of transmitted mutations may shift. Method: Paired genotypic and phenotypic susceptibility data were retrospectively analyzed for 317 ART-naïve, HIV–infected subjects from 40 small and major metropolitan cities in the Northeastern, Midwestern, Southern, Southwestern, and Northwestern United States during 2003. Results: Using current (January 2007) PhenoSense cutoffs, HIV-from 8% of subjects had reduced susceptibility to ⩾1 drug. By class, >% had reduced susceptibility to protease inhibitors (PIs), and % had reduced susceptibility to nucleoside reverse transcriptase inhibitors (NRTIs); reduced susceptibility to ⩾1 non–nucleoside reverse transcriptase inhibitor (NNRTIs) was seen in 7% of subjects, with 4% of all subjects having reduced susceptibility to all NNRTIs. IAS–USA–defined NRTI, NNRTI, and/or major PI HIV–drug resistance–associated mutations were detected for 0% of the subjects. HIV risk factors included homosexual contact (74%), heterosexual contact (28%), and injectable drug use/transfusion/other (7%.Reduced susceptibility to ⩾1 drug was significantly higher (p = .034) for white subjects than African Americansand Hispanics/others. Conclusion: The high prevalence of drug resistance in these ART–naïve subjects suggests thattransmitted resistance is occurring widely within the United States. HIV genotyping and/or phenotyping for antiretroviral-naïve patients seeking treatment should be considered, especially if the therapy will include an NNRTI.

First large, multicenter, open-label study utilizing Hla-b*5701 screening for abacavir hypersensitivity in North America

A hypersensitivity reaction is associated with abacavir in approximately 2–8% of exposed patients. The frequency of the HLA-B*5701 allele varies across racial groups and significantly correlates with risk of hypersensitivity. Studies in Europe and Western Australia demonstrated that prospective screening can significantly reduce the rate of hypersensitivity by avoiding the use of abacavir in patients carrying the HLA-B*5701 allele. Prospective HLA-B*5701 screening in a large, racially diverse North American population resulted in less than 1% of individuals diagnosed with a suspected abacavir hypersensitivity reaction (ABC HSR) and no positive skin patch test through 30 weeks among HLA-B*5701-negative individuals.

Similar efficacy and tolerability of atazanavir compared with atazanavir/ritonavir, each with abacavir/lamivudine after initial suppression with abacavir/lamivudine plus ritonavir-boosted atazanavir in HIV-infected patients.

Background:Treatment simplification strategies involving induction with a ritonavir (RTV)-boosted (/r) protease inhibitor regimen followed by simplification (without RTV) are appealing because they may offer sustained virologic suppression while minimizing potential long-term adverse effects associated with RTV. Methods:This open-label, randomized, noninferiority study enrolled 515 antiretroviral therapy-naive patients to receive abacavir/lamivudine plus atazanavir/RTV (ATV/r) followed by randomization at week 36 (N = 419) to maintain or discontinue RTV for an additional 48 weeks. Eligibility for randomization required confirmed HIV RNA level below 50 copies/ml and no virologic failure. Protocol-defined virologic failure after week 36 was confirmed rebound of HIV RNA level at least 400 copies/ml. The primary endpoint was the proportion of patients with HIV RNA level below 50 copies/ml at week 84 (time to loss of virologic response). This study is registered with ClinicalTrials.gov number NCT00440947. Results:At week 84, noninferiority of ATV to ATV/r (95% confidence interval around the treatment difference −1.75 to 12.48%) was demonstrated with 181 of 210 (86%) patients in the ATV group and 169 of 209 (81%) in the ATV/r group maintaining HIV RNA level below 50 copies/ml. During the randomized phase (weeks 36–84), 10 versus 14% of patients in the ATV and ATV/r arms, respectively, experienced a drug-related grades 2–4 adverse event with hyperbilirubinemia being the most frequently reported (4 versus 10%). The overall rate of protocol-defined virologic failure was 2%; no patient had virus that developed a major protease inhibitor mutation. Conclusion:ATV in combination with abacavir/lamivudine is a potent and well tolerated regimen in patients who have achieved initial suppression on an induction regimen and represents a viable treatment simplification strategy.

Induction with abacavir/lamivudine/zidovudine plus efavirenz for 48 weeks followed by 48-week maintenance with abacavir/lamivudine/zidovudine alone in antiretroviral-naive HIV-1-infected patients

Background:The ESS40013 study tested 4-drug induction followed by 3-drug maintenance as initial antiretroviral therapy (ART) to reduce HIV RNA rapidly and then to simplify to an effective yet more convenient and tolerable regimen. Methods:Four hundred forty-eight antiretroviral-naive adults were treated with abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) and efavirenz (EFV) for the 48-week induction phase. Two hundred eighty-two patients were randomized in a 1:1 ratio to continue ABC/3TC/ZDV + EFV or to simplify to ABC/3TC/ZDV for the 48-week maintenance phase. Results:The baseline median HIV RNA level and CD4 cell count were 5.08 log10 copies/mL (56% ≥100,000 copies/mL) and 210 cells/mm3 (48% <200 cells/mm3), respectively. No significant differences were noted between ABC/3TC/ZDV + EFV and ABC/3TC/ZDV for an HIV RNA level <50 copies/mL (79% vs. 77% [intent to treat (ITT), missing = failure]; P = 0.697) or time to treatment failure (P = 0.75) at week 96. Drug-related adverse events were more commonly reported for ABC/3TC/ZDV + EFV than for ABC/3TC/ZDV (15% vs. 6%). Improvements in total cholesterol, low-density lipoprotein cholesterol, and triglycerides were observed in the ABC/3TC/ZDV group. Virologic failure occurred in 22 patients during induction and in 24 patients (16 in ABC/3TC/ZDV group and 8 in ABC/3TC/ZDV + EFV group; P = 0.134) during maintenance. A greater proportion of patients receiving ABC/3TC/ZDV than ABC/3TC/ZDV + EFV reported perfect adherence at week 96 (88.8% vs. 79.6%; P = 0.057). Conclusions:After induction with ABC/3TC/ZDV + EFV, simplification to ABC/3TC/ZDV alone maintained virologic control and immunologic response, reduced fasting lipids and ART-associated adverse events, and improved adherence.

Correlation between self-reported adherence to highly active antiretroviral therapy (HAART) and virologic outcome.

The Patient Medication Adherence Questionnaire Version 1.0 (PMAQ-V1.0) is a patient-reported adherence instrument to assess medication-taking behaviors and identify barriers to adherence with antiretroviral therapy. To assess the correlation between adherence and virologic outcome, the PMAQ-V1.0 was administered to 194 antiretroviral-experienced adults with HIV infection enrolled in a 16-week evaluation of protease inhibitor-containing regimens featuring a lamivudine/ zidovudine combination tablet. At baseline, plasma HIV-1 RNA levels were less than 10,000 copies/mL and CD4+-cell counts were equal to or greater than 300 x 106/L; patients had been receiving a conventional regimen of lamivudine + zidovudine (separately) plus a protease inhibitor for at least 10 weeks immediately prior to the study. Forty-eight percent of patients who reported missing at least one dose of a nucleoside reverse-transcriptase inhibitor (NRTI) during the study had detectable plasma HIV-1 RNA, compared with 26% of patients who reported no missed doses (P = .002). Patients who missed at least one dose of an NRTI or protease inhibitor were 2.5 times more likely to have quantifiable HIV-1 RNA than those who reported no missed doses. Patients who reported fewer barriers and more motivators to adherence had better virologic outcomes (P = .001). Several dimensions of the PMAQ-V1.0 did not function as well as hypothesized. In this study, self-reported adherence derived from the PMAQ-V1.0 predicted virologic outcomes, but further refinement of the dimensions appears warranted.

Abacavir and lamivudine fixed-dose combination tablet once daily compared with abacavir and lamivudine twice daily in HIV-infected patients over 48 weeks (ESS30008, seal)

Background:Abacavir (ABC) and lamivudine (3TC) administered twice daily were compared with an ABC + 3TC fixed-dose combination (Epzicom, Kivexa; EPZ) administered once daily, both in combination with a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI). Methods:Two hundred sixty HIV-infected subjects with more than 6 months of ABC and 3TC administered twice daily plus a PI or NNRTI with an HIV-1 RNA level less than 400 copies/mL for more than 3 months and a CD4+ count greater than 50 cells/mm3 were randomized 1:1 to ABC + 3TC administered twice daily or EPZ administered once daily. Results:At baseline, median time on ABC and 3TC administered twice daily was 22 months, and median CD4+ count and HIV-1 RNA level were 554 cells/mm3 and <50 copies/mL, respectively. EPZ administered once daily was established as not inferior to ABC + 3TC administered twice daily based on the proportion of nonvirologic failures (confirmed HIV-1 RNA level ≥1265 copies/mL; 90% confidence interval: −3.4 to 6.4; (intent to treat [ITT]: missing [M] = failure [F]). Proportions with an HIV-1 RNA level <50 copies/mL were 81% of those taking EPZ once daily and 82% of those taking ABC + 3TC twice daily at week 48 (ITT: M = F). Virologic failure was rare (2 patients taking the once-daily regimen, 4 patients taking the twice-daily regimen). There was a low incidence of grade 2 through 4 adverse events (AEs) and no drug-related serious AEs or hypersensitivity reactions. Conclusions:EPZ administered once daily was established as not inferior to ABC + 3TC administered twice daily in a regimen containing an NNRTI or a PI over 48 weeks. A dual-nucleoside backbone of ABC and 3TC administered once or twice daily is effective, durable, and well tolerated.

ARIES 144 week results: durable virologic suppression in HIV-infected patients simplified to unboosted atazanavir/abacavir/lamivudine.

Abstract Background: The open-label study ARIES (http://ClinicalTrials.gov NCT00440947) utilized a ritonavir (/r)-boosted protease inhibitor treatment simplification strategy. Antiretroviral-naïve subjects received abacavir/lamivudine (ABC/3TC) + atazanavir/ ritonavir (ATV/r) from baseline through randomization at week 36, then maintained or discontinued ritonavir for an additional 108 weeks. Non-inferiority of the unboosted regimen was demonstrated at week 84. In this optional extension phase, virologic suppression and adverse events were assessed through week 144.Methods: Patients were randomized at week 36 if they had confirmed HIV RNA <50 copies/mL by week 30 and no previous virologic failure (VF; defined as failure to achieve HIV RNA <400 copies/mL or confirmed rebound after achieving HIV RNA ≥400 copies/mL). Three hundred sixty-nine subjects who completed 84 weeks in ARIES participated in the extension phase and maintained their randomized regimen for an additional 60 weeks post randomization.Results: At week 144, 146/189 (77%) versus 132/180 (73%) subjects in the unboosted ATV and ATV/r groups, respectively, maintained HIV RNA <50 copies/mL. Post randomization (weeks 36-144), treatment-related grade 2x–4 adverse events were more common in the ATV/r-treated (23%) compared to the ATV-treated (13%) group; the most frequently reported was increased serum bilirubin (6% of ATV-treated subjects vs 14 % of ATV/r-treated subjects). During the extension phase, 3% (11/369) of subjects met protocol-defined VF (5 ATV-treated and 6 ATV/ r-treated subjects); one ATV/r-treated subject had treatment-emergent major viral resistance-associated mutations. The median change in fasting triglycerides from baseline to week 144 was significantly different (P=.001) in the ATV-treated (-8.5 mg/dL) compared to the ATV/r-treated (28.5 mg/dL) groups.Conclusions: These long-term study results demonstrate that ATV in combination with ABC/3TC is a potent, well-tolerated regimen in patients who have achieved initial suppression on a ritonavir-boosted regimen.