Virological efficacy of abacavir: systematic review and meta-analysis

HTA and HIV: The Case of Dual NRTI Backbones in the Italian Setting

The aim of this study is to analyze the potential advantages of emtricitabine/tenofovir alafenamide (FTC/TAF) introduction, creating evidence-based information to orient strategies to reduce costs, thus preserving effectiveness and appropriateness. An Health Technology Assessment (HTA) was implemented in the years 2017–2018 comparing the dual backbones available in the Italian market: FTC/TAF, FTC/TDF (tenofovir disoproxil fumarate/emtricitabine) and ABC/3TC (abacavir/lamivudine). From an efficacy point of view, FTC/TAF ensured a higher percentage of virologic control and a better safety impact than FTC/TDF (improving the renal and bone safety profile, as well as the lipid picture). From an economic point of view, the results revealed a 4% cost saving for the Italian National Healthcare Service NHS with FTC/TAF introduction compared with the baseline scenario. Qualitative perceptions’ results showed that FTC/TAF would decrease the burden of adverse events management, increasing the accessibility of patients to healthcare providers (FTC/TAF: 0.95, FTC/TDF: 0.10, ABC/3TC: 0.28; p-value: 0.016) and social costs (FTC/TDF: −0.23, FTC/TAF: 1.04, ABC/3TC: 0.23; p-value < 0.001), improving patient quality of life (FTC/TDF: 0.31, FTC/TAF: 1.85, ABC/3TC: 0.38; p-value < 0.001). Healthcare services may consider the evidence provided by the present study as an opportunity to include HIV patients in a more adequate antiretroviral treatment arm, guaranteeing a personalized clinical pathway, thus becoming more efficient and effective over time.

Rates and Correlates of Short Term Virologic Response among Treatment-Naïve HIV-Infected Children Initiating Antiretroviral Therapy in Ethiopia: A Multi-Center Prospective Cohort Study

There is limited data on virologic outcome and its correlates among HIV-infected children in resource-limited settings. We investigated rate and correlates of virologic outcome among treatment naïve HIV-infected Ethiopian children initiating cART, and were followed prospectively at baseline, 8, 12, 24 and 48 weeks using plasma viral load, clinical examination, laboratory tests and pretreatment HIV drug resistance (PDR) screening. Virologic outcome was assessed using two endpoints–virological suppression defined as having “undetectable” plasma viral load < 150 RNA copies/mL, and rebound defined as viral load ≥150 copies/mL after achieving suppression. Cox Proportional Hazards Regression was employed to assess correlates of outcome. At the end of follow up, virologic outcome was measured for 110 participants. Overall, 94(85.5%) achieved virological suppression, of which 36(38.3%) experienced virologic rebound. At 48 weeks, 9(8.2%) children developed WHO-defined virological treatment failure. Taking tenofovir-containing regimen (Hazard Ratio (HR) 3.1-[95% confidence interval (95%CI) 1.0–9.6], p = 0.049) and absence of pretreatment HIV drug resistance (HR 11.7-[95%CI 1.3–104.2], p = 0.028) were independently associated with earlier virologic suppression. In conclusion, PDR and cART regimen type correlate with rate of virologic suppression which was prominent during the first year of cART initiation. However, the impact of viral rebound in 38.3% of the children needs evaluation.

Abacavir Hypersensitivity Reaction Reporting Rates During a Decade of HLA-B*5701 Screening as a Risk-Mitigation Measure

INTRODUCTION

Human leukocyte antigen (HLA)-B*5701 screening identifies patients at increased risk for abacavir (ABC) hypersensitivity reaction (HSR). Screening was adopted in GlaxoSmithKline and ViiV Healthcare clinical trials in 2007 and human immunodeficiency virus treatment guidelines in 2008. Company meta-analyses of trials pre-HLA-B*5701 screening reported HSR rates of 4-8%. We analyzed the effectiveness of HLA-B*5701 screening on reducing HSR rates using clinical trial, Observational Pharmaco-Epidemiology Research & Analysis (OPERA) cohort, and spontaneous reporting data.

METHODS

A meta-analysis examined 12 trials in 3063 HLA-B*5701-negative patients receiving an ABC-containing regimen from April 9, 2007, to September 22, 2015. Potential cases were identified using prespecified Medical Dictionary for Regulatory Activities (MedDRA) preferred terms (drug hypersensitivity, hypersensitivity, anaphylactic reaction, anaphylaxis) and adjudicated against a Company ABC HSR case definition. Investigator-diagnosed cases were identified and rates were calculated. In the OPERA cohort, 9619 patients initiating their first ABC-containing regimen from January 1, 1999, to January 1, 2016, were identified. Patients were observed from regimen start until the earliest-following censoring event: ABC discontinuation, loss to follow-up, death, or study end (July 31, 2016). OPERA physicians evaluated events against OPERA definitions for definite/probable cases of ABC HSR; rates were calculated pre- and post-2008. The Company case definition was used to identify spontaneously reported cases for four marketed ABC-containing products; reporting rates were calculated using estimated exposure from sales data, through December 31, 2016.

RESULTS

Suspected ABC HSR rates were 1.3% or less in the meta-analysis. In the OPERA cohort, the rate was 0.4% among patients initiating ABC post-2008 versus 1.3% pre-2008 (p<0.0001). Spontaneous reporting rates were low post-2008 (54 to 22 cases per 100,000 patient-years exposure [PYE]) versus pre-2008 (618 to 55 cases per 100,000 PYE).

CONCLUSIONS

Clinically suspected ABC HSR rates were 1.3% or less in HLA-B*5701-negative patients. Recognizing their limitations, data from the OPERA cohort and spontaneous reporting indicate that HLA-B*5701 screening has reduced reporting rates of suspected HSR in clinical practice. Where screening for HLA-B*5701 is standard care, patients should be confirmed negative for this allele before starting ABC treatment.

Risk of cardiovascular events from current, recent, and cumulative exposure to abacavir among persons living with HIV who were receiving antiretroviral therapy in the United States: a cohort study

BACKGROUND

There is ongoing controversy regarding abacavir use in the treatment of HIV infection and the risk of subsequent development of cardiovascular disease. It is unclear how the risk varies as exposure accumulates.

METHODS

Using an administrative health-plan dataset, risk of cardiovascular disease events (CVDe), defined as the first episode of an acute myocardial infarction or a coronary intervention procedure, associated with abacavir exposure was assessed among HIV-infected individuals receiving antiretroviral therapy across the U.S. from October 2009 through December 2014. The data were longitudinal, and analyzed using marginal structural models.

RESULTS

Over 114,470 person-years (n = 72,733) of ART exposure, 714 CVDe occurred at an incidence rate (IR) (95% CI) of 6·23 (5·80, 6·71)/1000 person-years. Individuals exposed to abacavir had a higher IR of CVDe of 9·74 (8·24, 11·52)/1000 person-years as compared to 5·75 (5·30, 6·24)/1000 person-years for those exposed to other antiretroviral agents. The hazard (HR; 95% CI) of CVDe was increased for current (1·43; 1·18, 1·73), recent (1·41; 1·16, 1·70), and cumulative [(1·18; 1·06, 1·31) per year] exposure to abacavir. The risk for cumulative exposure followed a bell-shaped dose-response curve peaking at 24-months of exposure. Risk was similarly elevated among participants free of pre-existing heart disease or history of illicit substance use at baseline.

CONCLUSION

Current, recent, and cumulative use of abacavir was associated with an increased risk of CVDe. The findings were consistent irrespective of underlying cardiovascular risk factors.

Adult antiretroviral therapy guidelines 2017

These guidelines are intended as an update to those published in the Southern African Journal of HIV Medicine in 2014 and the update on when to initiate antiretroviral therapy in 2015. Since the release of the previous guidelines, the scale-up of antiretroviral therapy (ART) in southern Africa has continued. New antiretroviral drugs have become available with improved efficacy, safety and robustness. The guidelines are intended for countries in the southern African region, which vary between lower and middle income.

Abacavir + dolutegravir + lamivudine for the treatment of HIV

INTRODUCTION

Since the last revision of both European and American guidelines (EACS and DHHS), new data from clinical trials and cohort studies, as well as experience in clinical practice, have prompted significant changes to the list of recommended/preferred options for the treatment of HIV infected patients, highlighted the role of INSTI-based regimens. Dolutegravir (DTG) in combination with abacavir/lamivudine (ABC/3TC) is one of these preferred regimens in multiple clinical scenarios, including treatment-naive and treatment-experienced patients.

AREAS COVERED

In this article we describe the coformulation of ABC/3TC/DTG in a fixed-dose combination (FDC) approved in September 2014 for the treatment of HIV infection. We focused our research on the efficacy and safety data resulting from phase 2 and 3 clinical study, particularly on the results of both SPRING (1 and 2) and SINGLE studies.

EXPERT OPINION

Triple combination therapy with ABC/3TC/DTG should be considered among the initial options for treatment-naive patients, being effective, well tolerated, with a high genetic barrier to resistance along with a convenient once-daily administration. In treatment-experienced patients the single-tablet regimen (STR) based on ABC/3TC/DTG could be used as simplification strategy in subjects with sustained viral suppression, as the high genetic barrier of DTG should ensure a safe switch from both NNRTI or PI based regimens.

Comparative effectiveness of tenofovir in treatment-naïve HIV-infected patients: systematic review and meta-analysis

INTRODUCTION

Benefits and harms of tenofovir disoproxil fumarate (TDF) in HIV-infected, antiretroviral treatment (ART)-naïve patients of any age have not been systematically reviewed since recent milestone trials were published.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, SCI, LILACS, WHO GHL, and ClinicalTrials.gov for randomized controlled trials (RCTs) comparing TDF-based treatments with any other ART-regimen (last search 01/2015). Trial characteristics and results were extracted, risks of bias systematically assessed, and treatment effects synthesized in meta-analyses using random-effects models.

RESULTS

We included 22 RCTs (8297 patients). We found no differences between groups for mortality, AIDS, fractures, CD4 cell count, and virological failure; and inconclusive information due to inadequate reporting for cardiovascular events, renal failure, proteinuria, rash, and quality of life. Tenofovir disoproxil fumarate-based regimens significantly reduced total cholesterol (mean difference -18.42 mg/dl; 95% confidence interval [CI] -22.80 to -14.0), LDL-cholesterol (-9.53 mg/dl; -12.16 to -6.89), HDL-cholesterol (-2.97 mg/dl; -4.41 to -1.53), and triglycerides (-29.77 mg/dl; -38.61 to -20.92), bone mineral density (BMD) (hip: -1.41%; -1.87 to -0.94), and glomerular filtration rate (eGFR) (-3.47 ml/minute; -5.89 to -1.06) over 48 weeks of follow-up. Effects were similar in trials comparing fixed-dose TDF/FTC-based regimens with ABC/3TC-based regimens. We found no influence of baseline viral load on virological failure.

DISCUSSION

Moderate-quality evidence suggests similar effects of TDF-based treatment regimens and other ART on virological failure. Tenofovir disoproxil fumarate-based regimens are associated with a more favorable lipid profile, but with increased risk of reduced BMD and eGFR. Improved reporting quality is vital to allow assessment of clinical outcomes in future trials.

Efficacy and safety of abacavir-containing combination antiretroviral therapy as first-line treatment of HIV infected children and adolescents: a systematic review and meta-analysis

BACKGROUND

Abacavir is one of the recommended nucleoside reverse transcriptase inhibitors (NRTIs) for the treatment of HIV infections among children and adolescents. However, there are concerns that the antiviral efficacy of abacavir might be low when compared to other NRTIs especially among children. There are also concerns that abacavir use may lead to serious adverse events such as hypersensitivity reactions and has potential predisposition to developing cardiovascular diseases

METHODS

We searched four electronic databases, four conference proceedings and two clinical trial registries in August 2014, without language restrictions. Experimental and observational studies with control groups that examined the efficacy and safety of abacavir-containing regimens in comparison with other NRTIs as first-line treatment for HIV-infected children and adolescents aged between one month and eighteen years were eligible. Two authors independently screened search results, extracted data and assessed the risk of bias of included studies using a pre-specified, standardised data extraction form and validated risk of bias tools. We also assessed the quality of evidence per outcome with the GRADE tool.

RESULTS

We included two randomised controlled trials (RCTs) and two analytical cohort studies with a total of 10,595 participants. Among the RCTs we detected no difference in virologic suppression after a mean duration of 48 weeks between abacavir- and stavudine-containing regimens (2 trials; n = 326: RR 1.28; 95 % CI 0.67-2.42) with significant heterogeneity (P = 0.02; I(2) = 81 %). We also found no significant differences between the two groups for adverse events and death. After five years of follow-up, virologic suppression improved with abacavir (1 trial; n = 69: RR 1.96; 95 % CI 1.11-3.44). For cohort studies, we detected that the virologic suppression activity of abacavir was less effective than stavudine in both the lopinavir/ritonavir (1 study, n = 2165: RR 0.79, 95 % CI 0.67-0.92) and efavirenz sub-groups (1 study, n = 3204: RR 0.79, 95 % CI 0.67-0.92) respectively. The quality of evidence from RCTs was moderate for virologic suppression but low for death and adverse events, while that of cohort studies was low for all three these outcomes.

CONCLUSIONS

Available evidence showed little or no difference between abacavir-containing regimen and other NRTIs regarding efficacy and safety when given to children and adolescents as a first-line antiretroviral therapy.

Clinical pharmacokinetics and pharmacodynamics of dolutegravir used as a single tablet regimen for the treatment of HIV-1 infection

INTRODUCTION

With the introduction of the coformulated dolutegravir, abacavir and lamivudine , a new single tablet regimen (STR) is made available for the use in treatment-naive and treatment-experienced HIV-infected patients. This drug combination is the fourth STR that will be positioned next to the STRs with efavirenz, rilpivirine or elvitegravir as third agents, respectively.

AREAS COVERED

The objective of this review is to provide an overview of the efficacy and safety of the combined dolutegravir/abacavir/lamivudine coformulation. The review will focus on dolutegravir and includes both published data as well as data presented at recent major international HIV/AIDS conferences.

EXPERT OPINION

The dolutegravir/abacavir/lamivudine regimen is highly effective in achieving sustained suppression of HIV-1 RNA plasma concentrations. The STR has a favorable safety profile and a low potential for drug interactions, which will contribute to a prominent role in therapy. As this STR contains abacavir as backbone component, the use requires patients to be HLA-B*5701 negative, with good hepatic function. Other first-line treatment combinations are preferred for patients with hepatitis B co-infection or with a high cardiovascular risk.

Tenofovir: What We Have Learnt After 7.5 Million Person-Years of Use

Tenofovir was licensed for use in patients with HIV in 2001 and since then has become a firmly established anti-retroviral in both guidelines and routine practice. Data have been presented from many pivotal studies—informing on its efficacy, use, and adverse features—and there are also over 7.5 million patient-years of experience to date. We explore the data on this nucleotide reverse transcriptase inhibitor in HIV presented since 2008—focusing on efficacy, side effects, and utility.

Combination dolutegravir-abacavir-lamivudine in the management of HIV/AIDS: clinical utility and patient considerations

The current standard of care for human immunodeficiency virus (HIV) treatment is a three-drug regimen containing a nonnucleoside reverse transcriptase inhibitor, a protease inhibitor, or an integrase strand transfer inhibitor (INSTI) plus two nucleoside/tide reverse transcriptase inhibitors. Given their potency, safety, and distinctive mechanism of action, INSTIs represent an important advance in HIV type 1 (HIV-1) therapy. Dolutegravir (DTG) is a new-generation INSTI recently approved for the treatment of HIV-1-infected adult patients, with distinct advantages compared with other available antiretroviral agents. In well-designed, large clinical trials, DTG-containing regimens have demonstrated either noninferiority or superiority to current first-line agents such as raltegravir-, darunavir/ritonavir-, and efavirenz-containing regimens. The favorable safety profile, low potential for drug interactions, minimal impact on lipids, good tolerability, and high resistance barrier of DTG makes this compound one of the preferred choices for HIV therapy in multiple clinical scenarios, including treatment-naïve and treatment-experienced patients. DTG is the only antiretroviral drug not yet associated with de novo emergence of resistance mutations in treatment-naïve individuals. However, data from in vitro studies and clinical trial suggest the possibility of cross-resistance between first- and second-generation INSTIs. Even though these profiles are infrequent at the moment, they need to be monitored in all current patients treated with INSTIs. With its potent activity, good tolerability, simplicity of dosing, and minimal drug interaction profile, DTG will likely play a major role in the management of patients with HIV-1 infection. On the basis of clinical trial data, current guidelines endorse DTG in combination with nucleoside/tide reverse transcriptase inhibitors as one of the recommended regimens in antiretroviral therapy-naïve patients. Most of the favorable clinical experiences from clinical trials are based on the combination of DTG with abacavir/lamivudine, and DTG is planned to be coformulated with abacavir/lamivudine. This will provide a further advantage, given that single tablet regimens are associated with higher adherence rates as well as improvement in quality of life and enhanced patient preference.