Abacavir/lamivudine/zidovudine maintenance after standard induction in antiretroviral therapy-naïve patients: FREE randomized trial interim results

A randomized controlled trial of single-class maintenance therapy with abacavir/lamivudine/zidovudine after standard triple antiretroviral induction therapy: final 96-week results from the FREE study

OBJECTIVES

The aim of the study was to test the antiviral efficacy of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen, with potential beneficial metabolic effects, as maintenance therapy after induction with dual NRTIs and a boosted protease inhibitor (PI).

METHODS

An open-label, noninferiority study was carried out. Antiretroviral therapy (ART)-naïve patients with CD4 count ≤ 350 cells/μL and HIV-1 RNA >30000 copies/mL (n=207) were treated with zidovudine/lamivudine and lopinavir/ritonavir. After achieving HIV-1 RNA <50 copies/mL on two consecutive occasions between weeks 12 and 24 after baseline, 120 patients (baseline: median HIV-1 RNA 5.19 log10 copies/mL; median CD4 count 180 cells/μL) were randomized to receive abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) (n=61) or to continue the PI-based ART (n=59).

RESULTS

For the proportions of patients (intention-to-treat; missing=failure) with HIV-1 RNA <400 copies/mL (PI group, 66%; ABC/3TC/ZDV group, 71%) and <50 copies/mL (PI group, 63%; ABC/3TC/ZDV group, 62%) at 96 weeks, switching to ABC/3TC/ZDV was noninferior compared with continuing the PI regimen; the difference in failure rate (ABC/3TC/ZDV minus PI) was -4.4 percentage points [95% confidence interval (CI) -21.0 to +12.3 percentage points] and +0.4 percentage points (95% CI -16.9 to +17.7 percentage points), respectively. In the per protocol analysis, the difference in virological failure for HIV-1 RNA >400 copies/mL (0 of 39 patients in the PI group and two of 45 patients in the NRTI group) and for HIV-1 RNA >50 copies/mL (two of 39 and three of 45 patients, respectively) was +4.4 percentage points (95% CI -2.1 to +11.0 percentage points) and +1.5 percentage points (95% CI -8.6 to +11.7 percentage points), respectively, also showing noninferiority. Serum lipids significantly improved in the NRTI group, but not in the PI arm.

CONCLUSIONS

A single-class NRTI regimen after successful induction with standard ART had similar antiviral efficacy compared to continuation of a PI-based regimen at 96 weeks after baseline, with improved serum lipids.

A systematic review of a single-class maintenance strategy with nucleoside/nucleotide reverse transcriptase inhibitors in HIV/AIDS

BACKGROUND

Single-drug class regimens with nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) are generally not recommended as initial therapy because they are inferior compared with therapy with two NRTIs plus efavirenz. However, triple-NRTI combinations can be useful in specific circumstances such as in tuberculosis coinfection, pregnancy or dyslipidaemia. Here, we review the potential of such combinations to maintain viral suppression after induction of suppression by standard combination antiretroviral therapy (cART) and to evaluate the trade-off of NRTI-only regimens for metabolic control.

METHODS

We conducted a systematic search of the literature in two databases from 1 January 1998 up to 1 March 2013: Medline, through the search engine PubMed, and Embase.

RESULTS

A total of 11 randomized controlled trials (RCTs) with 2,105 patients and 3 observational studies with 2,639 patients were included. Studies including patients with mono- or dual-NRTI treatment before start of effective cART showed a tendency to higher failure rate because of resistance based on archived viral mutations. In studies with ART-naive subjects before start of cART, triple-NRTI combination showed virological activity comparable to two NRTIs plus a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor in all RCTs, but not in one cohort study. Switching improved serum lipids significantly.

CONCLUSIONS

Of the studied triple-NRTI combinations only abacavir/lamivudine/zidovudine was sufficiently potent. Triple-NRTI maintenance after successful induction with two-class cART appeared successful in treatment-naive subjects and remains a useful option in specific circumstances, especially when other drugs are not available or drug interactions are an issue.

Abacavir-based triple nucleoside regimens for maintenance therapy in patients with HIV

BACKGROUND

Regimen simplification can be defined as a change in established effective therapy to reduce pill burden and dosing frequency, to enhance tolerability, or to decrease specific food and fluid requirements. Many patients on suppressive antiretroviral therapy may be considered candidates for a simplification strategy and, among them, those who have achieved virologic suppression. Several clinical trials have evaluated the efficacy of triple nucleoside combination as a simplification therapy in patients who achieved virologic suppression

OBJECTIVES

The aim of this review is to combine randomised, controlled trials to examine whether in patients with undetectable viraemia on a Protease inhibitor (PI) based regimen simplification treatment with abacavir (ABC)-based triple-nucleoside combinations has similar rates of efficacy and tolerability compared with a PI regimen or simplification with a NNRTIs (efavirenz-EFV- or nevirapine-NVP) containing regimen. Studies were included if they had at least two of the three interventions, including one 3NRTI arm.

SEARCH METHODS

Electronic databases and conference proceedings were searched (1996-2012) with relevant search terms without limits to language.

SELECTION CRITERIA

Randomised controlled trials (RCTs) only are included in this review. Patients population is represented by HIV-infected adult patients treated with a PI-containing regimen (PI or boosted PI),  with undetectable viral load. Patients on a PI-containing regimen had three possibilities: continue the PI regimen or switch to a simplification maintenance regimen, including switch to a NNRTI (EFV or NVP) containing regimen, or switch to a triple-NRTI regimen (ABC-zidovudine-lamivudine)

DATA COLLECTION AND ANALYSIS

The primary outcomes were: proportion of patients discontinuing or switching antiretroviral therapy due to virologic failure or to adverse events; death (all cause) and AIDS defining illness; occurrence of myocardial infarction and cardiovascular disease. Secondary outcomes  were: proportion of patients maintaining an undetectable viral load (e.g. HIV-RNA <50 or <400 copies/mm(3)); change in mean CD4+ cell count; occurrence of lipodystrophy. We applied Cochrane Collaboration tools to assess each individual study for risk for bias.

MAIN RESULTS

We included eight RCT, for a total of 1,610 patients. All the studies included HIV-1 infected patients virologically suppressed after a successful treatment with PI containing ART. Articles included in the analysis were published between 2001 and 2010, and could be classified as low risk of bias trials in most of the domains considered. Overall, there was no significant difference between the participants on triple nucleoside combination and controls, either PI-based or NNRTI based in terms of overall failures, death and AIDS related events, and rates of patients with viral load below the detectability cut-off. For the outcomes discontinuation for adverse events and virologic failures, the RRs were not significant , albeit  being not far from the alpha level of 0.05, thus suggesting a weak evidence of lower incidence of side effects  and an higher incidence of virologic failure in the 3NRTI group compared to controls . Change in lipids and in CD4 cells from baselines were reported in 7 studies, but inconsistency in reporting these data did not allow quantitative analysis. However, all agreed that simplification with ABC had a favourable and significant impact on lipid metabolism compared to control group. An increase in CD4 cells count from baseline was evident in all analysed studies, without significant differences between ABC and controls in individual studies.

AUTHORS' CONCLUSIONS

The strategy of switching to triple nucleoside regimens shows weak evidence of lower incidence of side effects and a higher incidence of virologic failure in the 3NRTI group compared to controls. Simplification with 3NRTI holds the advantages of preserving other classes of antiretroviral drugs, to lower blood lipids, and to be cost effective and simple to administer.Thus, simplification with triple nucleoside regimens AZT + 3TC + ABC should be still considered for individuals who are unable to tolerate or have contraindications to NNRTI or PI based regimens. Additional data are needed on longer-term efficacy of triple NRTI regimens, particularly on the development of antiretroviral resistance. Though studies in the current review were conducted between 2001 and 2010, the large majority of patients from studies analysed received old PI regimens (e.g., indinavir, ritonavir, nelfinavir, saquinavir) not longer recommended by International Guidelines. Since current guidelines recommend new "lipid -friendly" PI, future studies should compare regimens containing these news PIs to triple NRTI regimens. More realistically, however, there are opportunities to examine these issues in existing cohorts.

Co-formulated abacavir-lamivudine-zidovudine for initial treatment of HIV infection and AIDS

BACKGROUND

UNAIDS estimates that 34 million people are currently living with the human immunodeficiency virus (HIV) worldwide. Currently recommended regimens for initiating HIV treatment consist of either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or ritonavir-boosted protease inhibitor (PI) combined with two nucleoside reverse transcriptase inhibitors (NRTIs). However, there may be some patients for whom NNRTIs and PIs may not be appropriate. This is an update of the review published in the Cochrane Library Issue 3, 2009.

OBJECTIVES

To evaluate the effects of any fixed-dose combination of three NRTIs (co-formulated abacavir-lamivudine-zidovudine) for initial treatment of HIV infection.

SEARCH METHODS

Between December 2010 and July 2011, we used standard Cochrane methods to search electronic databases and conference proceedings with relevant search terms without limits to language or publication status.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) with a minimum follow-up time of six months which compared co-formulated abacavir-lamivudine-zidovudine with either PI-based or NNRTI-based therapy among antiretroviral-naive HIV-infected patients aged at least 13 years.

DATA COLLECTION AND ANALYSIS

Three authors independently selected eligible studies, assessed risk of bias, and extracted data; resolving discrepancies by consensus. We calculated the risk ratio (RR) or mean difference (MD), as appropriate, with its 95% confidence interval (CI) and conducted meta-analysis using the random-effects method because of significant statistical heterogeneity (P<0.1).

MAIN RESULTS

We identified 15 potentially eligible RCTs, four of which met our inclusion criteria. The four included RCTs were conducted in the United States of America (USA); USA, Puerto Rico, Guatemala, Dominican Republic, and Panama; USA and Mexico; and Botswana, respectively. The RCTs compared co-formulated abacavir-lamivudine-zidovudine to treatment based on efavirenz (NNRTI), nelfinavir (PI), atazanavir (PI), and co-formulated lopinavir-ritonavir (PI), respectively. Overall, there was no significant difference in virological suppression between co-formulated abacavir-lamivudine-zidovudine and NNRTI- or PI-based therapy (4 trials; 2247 participants: RR 0.73, 95% CI 0.39 to 1.36). However, the results showed significant heterogeneity (I(2)=79%); with co-formulated abacavir-lamivudine-zidovudine inferior to NNRTI (1 trial, 1147 participants: RR 0.35, 95%CI 0.26 to 0.49) but with a trend towards co-formulated abacavir-lamivudine-zidovudine being superior to PI (3 trials, 1110 participants: RR 1.07, 95%CI 1.00 to 1.16; I(2)=0%). We found no significant differences between co-formulated abacavir-lamivudine-zidovudine and either PI or NNRTI on CD4+ cell counts (3 trials, 1687 participants: MD -0.01, 95%CI -0.11 to 0.09; I(2)=0%), severe adverse events (4 trials: RR 1.22, 95%CI 0.78 to 1.92; I(2)=62%) and hypersensitivity reactions (4 trials: RR 4.04, 95% CI 0.41 to 40.02; I(2)=72%). Only two studies involving PIs reported data on the lipid profile. One study found that the mean increase in total cholesterol from baseline to 96 weeks was significantly lower with co-formulated abacavir-lamivudine-zidovudine than with nelfinavir, but there were no differences with triglyceride levels. The second study found the fasting lipid profile to be comparable in both co-formulated abacavir-lamivudine-zidovudine and atazanavir arms at 48 weeks.The significant heterogeneity of effects for most outcomes evaluated was largely due to differences in the control therapy used in the included trials (i.e. NNRTIs or PIs). Using the GRADE approach, we rated the overall quality of the evidence on the relative effects of co-formulated abacavir-lamivudine-zidovudine for initial treatment of HIV infection as moderate. The main reason for downgrading the quality of the evidence was imprecision of the findings. The estimate of the treatment effect for each outcome has wide confidence intervals, which extend from the fixed-dose NRTI combination regimen being appreciably better to the regimen being appreciably worse than PI- or NNRTI-based regimens.

AUTHORS' CONCLUSIONS

This review provides evidence that co-formulated abacavir-lamivudine-zidovudine remains a viable option for initiating antiretroviral therapy, especially in HIV-infected patients with pre-existing hyperlipidaemia. The varied geographical locations of the included trials augment the external validity of these findings. We are moderately confident in our estimate of the treatment effects of the triple NRTI regimen as initial therapy for HIV infection. In the context of the GRADE approach, such moderate quality of evidence implies that the true effects of the regimen are likely to be close to the estimate of effects found in this review; but there is a possibility that they could be substantially different.  Further research should be geared towards defining the subgroup of HIV patients for whom this regimen will be most beneficial.

Does a simplified regimen give a better adherence, treatment satisfaction, and quality of life?

Background

Adherence to treatment is the key to the success of combination antiretroviral therapy (cART) for HIV infection. It is generally assumed that simplification of cART will lead to better adherence, higher treatment satisfaction, and quality of life (QoL), but randomized studies demonstrating such advantages of simplified regimens are scarce.

Methods

Antiretroviral-naïve patients who achieved viral load <50 c/ml in two consecutive samples between 12–24 weeks after commencing induction therapy with bid lopinavir/ritonavir (LPV/r) and fixed-dose combination AZT/3TC (Combivir^®) were randomly assigned to either continue LPV/r/Combivir^® or switch to simplified therapy with bid fixed-dose AZT/3TC/abacavir (Trizivir^®). Both arms yielded similar antiviral efficacy after 48 weeks as reported previously [1]. Patients completed standardized questionnaires on adherence (Simplified Medication Adherence Questionnaire (SMAQ)), treatment satisfaction (HIVTSQ) and QoL (MOS-HIV) at randomization and at weeks 48, 72 and 96. Adherence data were analyzed using generalized estimating equations, and satisfaction and QoL using mixed linear models.

Results

Patients in the Trizivir^®-group (n=30) tended to skip fewer doses both during the preceding 7 days (p=0.055) and during the preceding weekend (p=0.09) than patients in the LPV/r-group (n=20). Moreover, patients in the Trizivir^®-group found their regimen significantly more convenient (p=0.022) than patients in the LPV/r-group. However, patients in the LPV/r-group reported a better QoL than patients in the Trizivir^®-group in the domains measuring cognitive functioning (p=0.003), energy/fatigue (p=0.046) and social functioning (p=0.074).

Conclusions

In this randomized trial simplification of therapy to fixed-dose Trizivir^® was perceived to be more convenient, and tended to result in improved adherence, but at the expense of a lower level of QoL. Our findings suggest that the choice for simplified regimens should be individualized and may involve a trade-off between convenience and QoL.