Efficacy and safety of emtricitabine/tenofovir alafenamide (FTC/TAF) vs. emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) as a backbone for treatment of HIV-1 infection in virologically suppressed adults: subgroup analysis by third agent of a randomized, double-blind, active-controlled phase 3 trial<sup/>

Two-Drug Regimens for HIV-Current Evidence, Research Gaps and Future Challenges

During the last 30 years, antiretroviral treatment (ART) for human immunodeficiency virus (HIV) infection has been continuously evolving. Since 1996, three-drug regimens (3DR) have been standard-of-care for HIV treatment and are based on a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs). The effectiveness of first-generation 3DRs allowed a dramatic increase in the life expectancy of HIV-infected patients, although it was associated with several side effects and ART-related toxicities. The development of novel two-drug regimens (2DRs) started in the mid-2000s in order to minimize side effects, reduce drug-drug interactions and improve treatment compliance. Several clinical trials compared 2DRs and 3DRs in treatment-naïve and treatment-experienced patients and showed the non-inferiority of 2DRs in terms of efficacy, which led to 2DRs being used as first-line treatment in several clinical scenarios, according to HIV clinical guidelines. In this review, we summarize the current evidence, research gaps and future prospects of 2DRs.

Implications of weight gain with newer anti-retrovirals: 10-year predictions of cardiovascular disease and diabetes

OBJECTIVE

To evaluate the long-term risks of type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) secondary to weight gain and clinical obesity associated with the initiation of integrase strand transfer inhibitors and tenofovir alafenamide (TAF) in the ADVANCE trial using validated risk equation tools.

DESIGN

Retrospective data analysis.

METHODS

In ADVANCE, 1053 treatment-naive participants in South Africa (99% black, 59% female) were randomized to 96 weeks of TAF/emtricitabine + dolutegravir (TAF/FTC + DTG), tenofovir disoproxil fumarate/FTC + DTG (TDF/FTC + DTG), or TDF/FTC + efavirenz (TDF/FTC/EFV). The 5 and 10-year risks of CVD were calculated using D:A:D, QRISK and Framingham, and T2DM risk using QDiabetes, Cambridge Diabetes and Leicester Practice Risk scores. Participants were included in this analysis if they were above 30 years old at baseline.

RESULTS

A total of 217 (TAF/FTC + DTG), 218 (TDF/FTC + DTG), and 215 (TDF/FTC/EFV) participants had 96-week data available. Weight gain was +8.1, +4.2, and +2.4 kg on TAF/FTC + DTG, TDF/FTC + DTG, and TDF/FTC/EFV, respectively. Participants on TAF/FTC + DTG had greatest risk scores for CVD (using QRISK) and T2DM, driven by weight changes. Differences were statistically significant between TAF/FTC + DTG and TDF/FTC/EFV for CVD risk using the QRISK equation, equivalent to one extra case per 1000 people treated over 10 years, and between all treatment groups for T2DM risk. Six extra T2DM cases were predicted on TAF/FTC + DTG vs. TDF/FTC + DTG using QDiabetes.

CONCLUSION

Obesity, especially with TAF/FTC + DTG, drove increased risk of T2DM, with some evidence of greater CVD risk. However, predictive tools have not been validated in the HIV-positive and black African population.

Raman-based metabonomics unravels metabolic changes related to a first-line tenofovir-based treatment in a small cohort of South African HIV-infected patients

In addition to immunological disorders, human immunodeficiency virus (HIV) also causes metabolic abnormalities. Though successful in viral suppression and immune restoration, continued use of antiretroviral therapy (ART) has also been linked to the development of several metabolic ailments. Currently, the only clinical markers used to manage and monitor the development of HIV-induced metabolic disorders, disease progression as well as observing individual's response to antiviral treatment are CD4 count, viral loads and several other single variable colometric assays. Despite the common use of these clinical markers, these markers remain unreliable and limited in the ability to monitor the development of metabolic disorders as well as monitor treatment response. Given these limitations, it is imperative to discover and develop reliable biological markers for overall HIV disease management. Here, Raman spectroscopy was used to profile metabolic changes in the plasma of 22 HIV⁺ receiving a first-line tenofovir-based combination antiretroviral therapy compared to their 8 HIV⁺ ART^- and 10 HIV^- counterparts. Multivariate statistical analysis was performed in order to classify the samples into their respective groups and to identify significantly altered metabolites between the control and experimental groups. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) discriminant analysis identified significant differences (p < 0.05) in 9 different metabolites. Alterations were identified in spectral regions associated with glucose (1124 cm^-1), lipids/phospholipids (1116 cm^-1, 1098 cm^-1, 1077 cm^-1), proteins (1120 cm^-1), nucleic acids (1081 cm^-1) and phenylalanine (1103 cm^-1). Pathway analysis also revealed 3 significantly altered pathways. This study presented the reproducible nature of Raman spectroscopy in distinguishing between HIV-infected (treated and untreated) and uninfected blood plasma and allowed for the detection and identification of treatment induced metabolite changes. The results obtained in the study may, therefore, give insights into understanding the metabolic effect of HIV therapy.

Weight and body mass index increase after switch from tenofovir disoproxil fumarate to tenofovir alafenamide fumarate-containing treatment in an antiretroviral therapy-experienced group

Tenofovir alafenamide fumarate (TAF) is an alternative to tenofovir disoproxil fumarate (TDF). Currently, TAF is increasingly being used because of its non-inferior antiviral properties, lower risk of nephrotoxicity, and lower decrease in bone mineral density than TDF. There is growing evidence of unfavorable effects of TAF on weight and body mass index (BMI) in antiretroviral therapy (ART)-experienced patients treated with TAF-based ART. The aim of this study was to evaluate whether switching from TDF-containing to TAF-containing ART is associated with an increase in BMI and body weight in ART-experienced patients. Two study groups were established: 32 patients who switched from TDF to TAF only and 68 patients who switched from TDF to TAF along with changes to other components of the ART regimen. Significant weight gain and BMI increase was observed during the first year after initiation of TAF-containing ART regimens in both groups (mean change +1.91 kg and +0.61 kg/m2 in the first group and +1.50 kg and +0.49 kg/m² in the second group). During the second year of TAF-based treatment, a sustained trend of body weight and BMI increase was noted only in the second group (mean change +1.46 kg, + 0.46 kg/m²). Analysis of body weight changes in certain subpopulations from the second group (selected based on patients' baseline characteristics) revealed a significant weight gain within two years after the switch in patients over 50 years old and in those whose ART had lasted longer than 10 years. These findings suggest that a possible impact of TAF on weight gain should be taken into account when selecting ART components, especially in older patients or those with a long history of antiretroviral treatment.

Fractures in children and adolescents living with perinatally acquired HIV

BACKGROUND

Across numerous settings, bone mineral density for age and sex is lower in children/adolescents living with perinatally-acquired HIV (PHIV) compared to uninfected peers. We assessed incidences of any fracture/any long bone fracture, and osteoporosis prevalence in PHIV and HIV-exposed uninfected (PHEU) participants in the Pediatric HIV/AIDS Cohort Study (PHACS).

METHODOLOGY

Lifetime history of fracture events from birth up to age 20 years was obtained by chart review and/or interview, including age at fracture, mechanism, and bone(s) fractured. Poisson regression models were fit comparing fracture incidence by HIV status adjusted for age, sex, and race, with effect modification by age (<6, ≥6 yr).

RESULTS

PHIV (N = 412) were older (median 17.5 vs 16.7 yr) and more frequently reported black race (72% vs 61%) than PHEU children/adolescents (N = 206). 17% of PHIV and 12% of PHEU ever reported a fracture. Among children <6 yr, the adjusted incidence rate ratio of ≥1 fracture was higher (7.23; 95% CI 0.98, 53.51) in PHIV than PHEU, but similar among children/adolescents ≥6 years (1.20; 95% CI: 0.77, 1.87). Results were similar for long bone fracture. The most common fracture mechanisms were falling to the ground from a standing height (23.6% PHIV vs 8.8% PHEU) and sports injuries (21.3% vs 32.4%), and the most commonly fractured sites were the forearm and small bones of the wrist/hands. None of the children had osteoporosis.

CONCLUSIONS

Among children/adolescents ≥6 yr of age, fractures were similar by perinatal HIV status. Prospective, targeted collection of fracture history will be necessary to determine rates of fracture as PHIV and PHEU age into adulthood.

SUMMARY

Lifetime fracture history was collected in children/adolescents living with perinatally-acquired HIV (PHIV) and HIV-exposed uninfected (PHEU) children from birth up to age 20 years. Fracture incidence was higher in PHIV compared to PHEU among children <6 years old, but not among older children/adolescents.

Bone mineral density, kidney function, weight gain and insulin resistance in women who switch from TDF/FTC/NNRTI to ABC/3TC/DTG

OBJECTIVES

Tenofovir disoproxil fumarate (TDF) is associated with reduced bone mineral density (BMD). We evaluated changes in BMD in women who switched from TDF, emtricitabine and a nonnucleoside reverse transcriptase inhibitor (TDF/FTC/NNRTI) to abacavir, lamivudine and dolutegravir (ABC/3TC/DTG).

METHODS

We conducted a randomized controlled trial in which women aged ≥40 years were randomized 1:2 to continue TDF/FTC/NNRTI or switch to ABC/3TC/DTG. The primary endpoint was change in total hip BMD measured by dual-energy X-ray absorptiometry at week 48. Secondary endpoints were changes in BMD of the lumbar spine and femoral neck and markers of bone turnover and kidney function up to week 48. We conducted exploratory analyses of weight gain, insulin resistance and metabolic syndrome. Primary and secondary endpoints were analysed by linear regression, with multiple imputation for missing time points.

RESULTS

In all, 91 women [mean age = 50.4 (standard deviation [SD] = 6.6) years, median CD4 cell count = 600 (interquartile range: 479-800) cells/µL] were randomized. Women who switched to ABC/3TC/DTG maintained viral suppression and experienced improvements in total hip BMD (mean adjusted difference = 1%, P = 0.027) and lumbar spine BMD (3%, P = 0.002), with no change in specific markers of bone turnover or renal tubular function. Although participants in the ABC/3TC/DTG arm gained more weight (1.8 kg, P = 0.046), the switch strategy was not associated with reduced insulin sensitivity or new-onset metabolic syndrome.

CONCLUSIONS

Switching from TDF/FTC/NNRTI to ABC/3TC/DTG resulted in improved BMD. Although weight gain was common in women who switched from TDF/FTC/NNRTI to ABC/3TC/DTG, we did not detect adverse effects on glucose homeostasis. Larger studies need to confirm these findings.

Rifampicin effect on intracellular and plasma pharmacokinetics of tenofovir alafenamide

OBJECTIVES

Tenofovir alafenamide produces lower plasma tenofovir and higher intracellular tenofovir diphosphate (DP) concentrations than tenofovir disoproxil fumarate but it is likely a victim of interactions with rifampicin. We aimed to investigate the pharmacokinetics of tenofovir alafenamide/emtricitabine with rifampicin.

PATIENTS AND METHODS

Healthy volunteers received tenofovir alafenamide/emtricitabine at 25/200 mg once daily, followed by tenofovir alafenamide/emtricitabine + rifampicin daily followed by tenofovir disoproxil fumarate. Plasma tenofovir alafenamide, tenofovir, emtricitabine and intracellular tenofovir-DP and emtricitabine triphosphate pharmacokinetics and genetic polymorphisms were assessed.

RESULTS

Tenofovir alafenamide exposure decreased when tenofovir alafenamide/emtricitabine + rifampicin was used compared with tenofovir alafenamide/emtricitabine [geometric mean ratio (GMR) (90% CI): 0.45 (0.33-0.60)]. Plasma tenofovir and intracellular tenofovir-DP concentrations decreased with rifampicin [GMR (90% CI): 0.46 (0.40-0.52) and 0.64 (0.54-0.75), respectively]. GMR (90% CI) of intracellular tenofovir-DP AUC0-24 for tenofovir alafenamide/emtricitabine + rifampicin versus tenofovir disoproxil fumarate was 4.21 (2.98-5.95). Rifampicin did not affect emtricitabine pharmacokinetics. CYP3A4*22 rs35599367 was associated with higher plasma tenofovir alafenamide AUC0-24 at day 56.

CONCLUSIONS

Following tenofovir alafenamide/emtricitabine administration with rifampicin, intracellular tenofovir-DP concentrations were still 4.21-fold higher than those achieved by tenofovir disoproxil fumarate, supporting further study during HIV/TB co-infection.

Bone Update: Is It Still an Issue Without Tenofovir Disoproxil Fumarate?

PURPOSE OF REVIEW

In the era of modern bone-friendly antiretroviral therapy (ART) regimens for people living with HIV (PLWH), this review discusses the research gaps and management concerns that remain for individuals who have already been exposed to ART with negative effects on bone metabolism, especially children and adolescents who have not acquired peak bone mass, and older adults who have additional risk factors for fracture.

RECENT FINDINGS

Data now support the use of avoidance of TDF and use of bone-friendly regimens that include integrase strand transfer inhibitors in PLWH with increased risk of fracture for either ART initiation or switch. Despite significant advances in our understanding of ART choice for PLWH with regard to bone health, additional diagnostic tests to determine fracture risk and management strategies beyond ART choice are necessary, especially in vulnerable PLWH populations, such as children and adolescents and older adults.

Clinical Outcomes Following the Use of Archived Proviral HIV-1 DNA Genotype to Guide Antiretroviral Therapy Adjustment

Background

Evidence regarding the safety of using proviral HIV-1 DNA genotype (DNA GT) to guide antiretroviral therapy (ART) is limited. We hypothesized that HIV RNA would not increase following ART adjustment guided by DNA GT in a university HIV clinic.

Methods

Data were obtained from electronic medical records of adult persons living with HIV-1 (PWH) who underwent DNA GT testing and changed ART between October 2014 and November 2017. Logistic regression was used to evaluate the effect of ART switch on HIV RNA over time.

Results

Eighty-three PWH had DNA GT performed, 66 (80%) switched ART, and 59 had postswitch follow-up. Data were analyzed pre-/postswitch for these 59 PWH (median age, 54 years; 71% LWH ≥10 years; 46% ≥2 previous regimens; 36% recent low-level viremia; 34% unknown medication history). On DNA GT, 58% had ≥1-class ART resistance, 34% ≥2-class, and 10% 3-class. Median follow-up (range) was 337 (34–647) days. There was no change in probability of HIV RNA ≥50 copies/mL over time (P > .05). At baseline, 76% had HIV RNA <50 vs 88% at last postswitch follow-up (P = .092). Protease inhibitor use decreased from 58% to 24% (P < .001). Average daily pills and dosing frequency decreased from 3.48 to 2.05 (P < .001) and 1.39 to 1.09 (P < .001), respectively; ART cost did not change.

Conclusions

DNA GT facilitated changes in ART in a treatment-experienced population without increases in HIV RNA. Decreased pill burden occurred without increased ART cost. Further studies to identify optimal use of DNA GT are needed.

Reversible effect on lipids by switching from tenofovir disoproxil fumarate to tenofovir alafenamide and back

OBJECTIVE

The aim of the current study is to assess the effect of tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) on lipids in patients switching from TDF to TAF and back.

METHODS

Retrospective data collection on patients who were initially switched from TDF to TAF and switched back to TDF after generics of TDF became available.

RESULTS

In total, 385 patients were included. Median duration of TDF exposure before switch was 317 weeks (interquartile range 172-494). After switching from TDF to TAF, mean total cholesterol (TC) increased from 186 ± 37 mg/dl at baseline to 206 ± 43 and 204 ± 43 mg/dl at weeks 12 and 24 (P < 0.001). The increase in TC was mainly due to an increase in LDL cholesterol. However, ratio of TC/HDL remained unchanged, indicating a simultaneous rise of LDL and HDL cholesterol. Baseline triglycerides increased from mean 153 ± 96 to 176 ± 120 and 176 ± 124 mg/dl at weeks, 12 and 24 (P < 0.001). From 385 patients 168 were switched back from TAF to TDF after median duration on TAF of 96 weeks (interquartile range 89-104). At switching back from TAF to TDF, mean TC was 202 ± 40 mg/dl and decreased at weeks 12 and 24 to 183 ± 41 and 185 ± 35 mg/dl (P < 0.001). Mean triglycerides were 163 ± 119 mg/dl and decreased to 145 ± 108 and 157 ± 112 mg/dl, respectively (P < 0.05). Patients with higher increases in TC after switching from TDF to TAF also showed more pronounced decreases after switching back.

CONCLUSION

The results demonstrate a reversible effect on lipids by switching from TDF to TAF and back.

Switching from Tenofovir Disoproxil Fumarate to Tenofovir Alafenamide Significantly Worsens the Lipid Profile in a Real-World Setting

Tenofovir disoproxil fumarate (TDF) has increasingly been replaced by tenofovir alafenamide (TAF) because of reduced kidney and bone toxicity with TAF. This switch has, however, caused worsening of lipid concentrations in clinical trials, but data from any real-world setting are scarce. The objective of this study was to characterize the effect of TDF to TAF switch on plasma lipid concentrations in a real-world clinic population. This is a retrospective study comparing lipid concentrations and other laboratory parameters between the last visit on TDF and the first visit after at least a 2-month exposure to TAF. A total of 490 HIV-positive subjects were included in the study. The median (interquartile range) increase was 23.2 (0-38.7) mg/dL in total cholesterol (p < 0.001) and 15.5 (0-30.9) mg/dL in low-density lipoprotein (LDL) cholesterol (p < 0.001). The ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol increased by 0.2 (-0.2 to 0.6), p < 0.001. The proportion of patients having optimal LDL cholesterol concentration by National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) decreased from 30.8% to 17.8% and proportion having dyslipidemia or severe dyslipidemia increased from 30.2% to 50.3% after the switch. Demographic characteristics, antiretroviral agents, or comedication did not affect the changes in lipid concentrations. Plasma creatinine decreased by 0.03 (-0.09 to 0.03) mg/dL (p < 0.001) and estimated glomerular filtration rate increased by 0.5 (-2.3 to 3.2) mL/min (p = 0.009). Switching from TDF to TAF caused a statistically significant worsening of the lipid profile that may have clinical relevance. The benefit of the lipid-lowering effect of TDF should be considered in selected patients with low risk for kidney and bone toxicity.

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide in treatment-experienced, virologically suppressed patients with HIV-1: subgroup analyses of the phase 3 EMERALD study

Background

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg is a once-daily, single-tablet regimen for treatment of HIV-1 infection. The efficacy/safety of switching to D/C/F/TAF versus continuing boosted protease inhibitor (bPI) + emtricitabine/tenofovir disoproxil fumarate (control) were demonstrated in a phase 3, randomized study (EMERALD) of treatment-experienced, virologically suppressed adults through week 48. The objective of this analysis was to evaluate EMERALD outcomes across subgroups of patients based on demographic characteristics, prior treatment experience, and baseline antiretroviral regimen.

Methods

EMERALD patients were virologically suppressed (viral load [VL] < 50 copies/mL for ≥ 2 months at screening). Prior non-darunavir virologic failure (VF) was allowed. Primary endpoint was proportion of patients with virologic rebound (confirmed VL ≥ 50 copies/mL) cumulative through week 48. Virologic response was VL < 50 copies/mL (FDA snapshot). Safety was assessed by adverse events, renal proteinuria markers, and bone mineral density. Outcomes were examined for prespecified subgroups by age (≤/> 50 years), gender, race (black/non-black), prior number of antiretrovirals used (4/5/6/7/> 7), prior VF (0/≥ 1), baseline bPI (darunavir/atazanavir or lopinavir), and baseline boosting agent (ritonavir/cobicistat).

Results

Among 1141 patients in the D/C/F/TAF (n = 763) and control (n = 378) arms, virologic rebound rates (2.5% and 2.1%, respectively) were similar, and this was consistent across all subgroups. Virologic response rates ranged from 91 to 97% (D/C/F/TAF) and 89 to 99% (control) across all subgroups, with differences between treatment arms of 0 and 6%. Adverse event rates were low in both arms and across subgroups. Improvements in renal and bone parameters were observed with D/C/F/TAF across demographic subgroups.

Conclusions

For treatment-experienced, virologically suppressed patients, switching to D/C/F/TAF was highly effective and safe, regardless of demographic characteristics, prior treatment experience, or pre-switch bPI.

Trial registration ClinicalTrials.gov Identifier: NCT02269917. Registered 21 October 2014. https://clinicaltrials.gov/ct2/show/NCT02269917

Electronic supplementary material

The online version of this article (10.1186/s12981-019-0235-1) contains supplementary material, which is available to authorized users.

Virologically suppressed HIV-infected patients on TDF-containing regimens significantly benefit from switching to TAF-containing regimens: A meta-analysis of randomized controlled trials

BACKGROUND

To investigate whether TDF-containing regimens significantly benefited efficacy, safety, and tolerability in TAF-containing regimens in virologically suppressed HIV-infected patients.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Trial Registry were systematically searched for eligible studies. We extracted and evaluated the pooled data from available randomized controlled trials (RCTs).

RESULTS

Eight eligible RCTs were included. In the intention-to-treat (ITT) analysis, patients who switched to TAF-containing regimens had significantly better viral suppression than those continuing TDF-containing regimens at weeks 48 and 96 (RR, 1.02; 95CI, 1.00-1.03; p<0.05), but no significant difference in the per-protocol (PP) analysis (RR, 1.00; 95CI, 0.99-1.01; p>0.05). Compared with those receiving the TDF-containing regimens, virologically suppressed HIV-infected patients on the TAF-containing regimens had significant increases in CD4 cell counts (SMD, 0.12; 95CI, 0.08 to 0.17; p<0.05), renal and bone parameters at the hip (RR, 2.86; 95CI, 2.24-3.64; p<0.05) and the spine (RR, 2.43; 95 CI, 2.03-2.90; p<0.05) between weeks 48 and 96.

CONCLUSIONS

Virologically suppressed HIV-infected patients on TDF-containing regimens significantly benefit from switching to TAF-containing regimens, resulting in better viral suppression, better immune reconstruction, and less bone and renal problems.

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide in treatment-naïve patients with HIV-1: subgroup analyses of the phase 3 AMBER study

Background: The once-daily, single-tablet regimen darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg is approved for the treatment of HIV-1 infection. The 48-week efficacy and safety of D/C/F/TAF versus darunavir/cobicistat + emtricitabine/tenofovir disoproxil fumarate (control) in treatment-naïve adults were demonstrated in the phase 3 AMBER study. Objective: To describe AMBER outcomes across patient subgroups based on demographic and clinical characteristics at baseline. Methods: AMBER patients had viral load (VL) ≥1000 copies/mL, CD4⁺ cell count >50 cells/µL, and genotypic susceptibility to darunavir, emtricitabine, and tenofovir. Primary endpoint was the proportion of patients with virologic response (VL <50 copies/mL; FDA snapshot). Safety was assessed by adverse events, estimated glomerular filtration rate (cystatin C; eGFR_cystC), and bone mineral density. Outcomes were assessed by age (≤/>50 years), gender, race (black/non-black), baseline VL (≤/>100,000 copies/mL), baseline CD4⁺ cell count (</≥200 cells/µL), and baseline WHO clinical stage of HIV infection (1/2). Results: For the 725 AMBER patients (D/C/F/TAF: 362; control: 363), virologic response rates at week 48 were similar with D/C/F/TAF (91%) and control (88%), and this was consistent across all subgroups. Adverse event rates were similar in both arms, although numerically higher among patients >50 years and women, relative to their comparator groups, regardless of treatment arm (notably, sample sizes were small for patients >50 years and women). Improvements in eGFR_cystC and stable bone mineral density were observed with D/C/F/TAF overall, and results were generally consistent across subgroups. Conclusions: For treatment-naïve patients in AMBER, initiating therapy with the D/C/F/TAF single-tablet regimen was an effective and well-tolerated option, regardless of demographic or clinical characteristics.

Pharmacological impact of antiretroviral therapy on platelet function to investigate human immunodeficiency virus-associated cardiovascular risk

BACKGROUND AND PURPOSE

Some clinical studies have reported increased myocardial infarction in people living with human immunodeficiency virus (HIV) taking the antiretroviral abacavir sulphate (ABC). Given that clinical studies contain confounding variables (e.g., HIV-associated factors), we investigated the pharmacological effects of antiretrovirals on platelet function in HIV-negative volunteers in order to identify mechanisms of increased cardiovascular risk.

EXPERIMENTAL APPROACH

Platelets were isolated from healthy volunteers and HIV-negative subjects enrolled on a Phase I clinical trial and platelet function evaluated using aggregometry and flow cytometry. In vivo platelet thromboembolism was monitored in anaesthetized mice.

KEY RESULTS

Human platelet aggregation was unaffected by all antiretrovirals tested, but ABC treatment led uniquely to increased platelet granule release. ABC also interrupted NO-mediated inhibition of platelet aggregation and increased in vivo aggregation in mice. Another antiretroviral, tenofovir, did not affect platelet function. Furthermore, aggregation and activation of platelets isolated from 20 subjects taking clinically relevant doses of tenofovir were comparable to baseline samples.

CONCLUSIONS AND IMPLICATIONS

ABC can enhance platelet activation, independently of variables that confound clinical studies, suggesting a potential pharmacological effect that is absent with tenofovir. Mechanistically, we propose that ABC enhances platelet degranulation and interrupts NO-mediated platelet inhibition. The interaction of ABC with NO signalling is demonstrated by ABC-mediated enhancement of aggregation in vivo and in vitro that persisted in the presence of NO. Although an association between ABC and platelet activation has not been confirmed in patients, these findings provide evidence of a mechanistic link between platelet activation and antiretroviral therapy.

Severe rhabdomyolysis-induced acute kidney injury following concomitant use of Genvoya® (EVG/COBI/FTC/TAF) and simvastatin; a case report

Background

Genvoya® (elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide) is a recent single regimen for the treatment of Human Immunodeficiency Virus (HIV). However, because of its complexity, it is difficult to predict drug interactions, especially when associated with HMG-CoA reductase inhibitors and/or in the setting of other comorbidities. We discuss the mechanisms of these potential drug interactions as the cause of rhabdomyolysis and acute kidney injury in the context of prior and current medication therapy with possible underlying liver and kidney dysfunction.

Case presentation

We describe the case of a 54-year-old man diagnosed with HIV who developed severe rhabdomyolysis-induced anuric acute kidney injury (AKI) requiring renal replacement therapy following introduction of Genvoya® concomitantly with simvastatin, in the context of recently diagnosed hepatitis C and hepatitis A. Haemodialysis was continued over 5 weeks followed by progressive clinical and biological improvements. Five months later, a new antiretroviral regimen was started and has been well tolerated.

Conclusion

Simvastatin, as well as lovastatin, because of their CYP3A4 metabolism, and to a lesser extent atorvastatin, which is only partially metabolized by CYP3A4, are the HMG-CoA reductase inhibitors with the greatest risk of drug interactions and should not be used in patients under HIV-therapy. Patients receiving HMG-CoA reductase inhibitors should be monitored regularly for the occurrence of muscular adverse effects and drug interactions should be considered with each new prescription or change in clinical status. There are many online tools that enable clinicians to rapidly check for drug interactions. We recommend the one from the University of Liverpool for patients under HIV-therapy (https://www.hiv-druginteractions.org/checker), while for patients under hepatitis C-therapy, we advise to consult http://www.hep-druginteractions.org/. This case illustrates the importance of multidisciplinary collaboration in the treatment of HIV-positive patients because of their complexity, associated comorbidities and the potential of multiple drug-drug interactions potentially exacerbated by underlying liver and/or kidney dysfunction.

Optimizing Antiretroviral Therapy in Treatment-Experienced Patients Living with HIV: A Critical Review of Switch and Simplification Strategies. An Opinion of the HIV Practice and Research Network of the American College of Clinical Pharmacy

Simplifying or switching antiretroviral therapy (ART) in treatment-experienced people living with HIV (PLWH) may improve adherence, tolerability, toxicities, and/or drug-drug interactions. The purpose of this review is to critically evaluate the literature for efficacy and safety associated with switching or simplifying ART in treatment-experienced PLWH. A systematic literature search using MEDLINE was performed from January 1, 2010 to April 30, 2018. References within articles of interest, the Department of Health and Human Services guidelines, and conference abstracts were also reviewed. Switch/simplification strategies were categorized as those supported by high-level clinical evidence and those with emerging data. Rates of virologic suppression were noninferior for several switch/simplification strategies when compared to baseline ART. Potential for reducing adverse events was also seen. Additional evidence for some strategies, including most 2-drug regimens, is needed before they can be recommended.

Changes in renal function with long-term exposure to antiretroviral therapy in HIV-infected adults in Asia

PURPOSE

Renal disease is common among people living with human immunodeficiency virus (HIV). However, there is limited information on the incidence and risk factors associated with renal dysfunction among this population in Asia.

METHODS

We used data from the TREAT Asia HIV Observational Database. Patients were included if they started antiretroviral therapy during or after 2003, had a serum creatinine measurement at antiretroviral therapy initiation (baseline), and had at least 2 follow-up creatinine measurements taken ≥3 months apart. Patients with a baseline estimated glomerular filtration rate (eGFR) ≤60 mL/min/1.73 m2 were excluded. Chronic kidney disease was defined as 2 consecutive eGFR values ≤60 mL/min/1.73 m2 taken ≥3 months apart. Generalized estimating equations were used to identify factors associated with eGFR change. Competing risk regression adjusted for study site, age and sex, and cumulative incidence plots were used to evaluate factors associated with chronic kidney disease (CKD).

RESULTS

Of 2547 patients eligible for this analysis, tenofovir was being used by 703 (27.6%) at baseline. Tenofovir use, high baseline eGFR, advanced HIV disease stage, and low nadir CD4 were associated with a decrease in eGFR during follow-up. Chronic kidney disease occurred at a rate of 3.4 per 1000 patient/years. Factors associated with CKD were tenofovir use, old age, low baseline eGFR, low nadir CD4, and protease inhibitor use.

CONCLUSIONS

There is an urgent need to enhance renal monitoring and management capacity among at-risk groups in Asia and improve access to less nephrotoxic antiretrovirals.

A retrospective analysis of weight changes in HIV-positive patients switching from a tenofovir disoproxil fumarate (TDF)- to a tenofovir alafenamide fumarate (TAF)-containing treatment regimen in one German university hospital in 2015-2017

Purpose

To determine whether changing from a tenofovir disoproxil fumarate (TDF)- to a tenofovir alafenamide fumarate (TAF)-containing regimen is correlated with weight changes in a human immunodeficiency virus (HIV)-positive adult cohort.

Methods

Retrospective analysis was conducted of data gathered from routine care in a university hospital in Munich, Germany, between July 2015 and June 2017. Data from patients’ charts were extracted and a two-step approach was applied. First, weight/BMI progression within 1 year after initiation of either TDF or TAF was compared. Subsequently, weight measurements within subjects changing from a TDF- to a TAF-containing antiretroviral regimen were analyzed by means of a repeated measurements general linear model.

Results

After 360 days of initiating TAF, patients showed a mean (± standard deviation) percentual weight increase of 3.17 ± 0.21, whereas after 360 days of initiating TDF, patients only showed a mean (± standard deviation) percentual weight increase of 0.55 ± 0.17. The repeated measurements general linear model for within-subjects design showed a statistically significant correlation in weight after changing from a TDF to a TAF containing antiretroviral regimen. The weight difference between the two measurements while on TDF was not statistically significant, but every measure after switching to TAF was significantly higher than the previous.

Conclusion

Changing from a TDF- to a TAF-containing regimen is correlated with weight gain in this retrospectively analyzed real-world cohort in Munich, Germany.

Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2018 Recommendations of the International Antiviral Society-USA Panel

Importance

Antiretroviral therapy (ART) is the cornerstone of prevention and management of HIV infection.

Objective

To evaluate new data and treatments and incorporate this information into updated recommendations for initiating therapy, monitoring individuals starting therapy, changing regimens, and preventing HIV infection for individuals at risk.

Evidence Review

New evidence collected since the International Antiviral Society-USA 2016 recommendations via monthly PubMed and EMBASE literature searches up to April 2018; data presented at peer-reviewed scientific conferences. A volunteer panel of experts in HIV research and patient care considered these data and updated previous recommendations.

Findings

ART is recommended for virtually all HIV-infected individuals, as soon as possible after HIV diagnosis. Immediate initiation (eg, rapid start), if clinically appropriate, requires adequate staffing, specialized services, and careful selection of medical therapy. An integrase strand transfer inhibitor (InSTI) plus 2 nucleoside reverse transcriptase inhibitors (NRTIs) is generally recommended for initial therapy, with unique patient circumstances (eg, concomitant diseases and conditions, potential for pregnancy, cost) guiding the treatment choice. CD4 cell count, HIV RNA level, genotype, and other laboratory tests for general health and co-infections are recommended at specified points before and during ART. If a regimen switch is indicated, treatment history, tolerability, adherence, and drug resistance history should first be assessed; 2 or 3 active drugs are recommended for a new regimen. HIV testing is recommended at least once for anyone who has ever been sexually active and more often for individuals at ongoing risk for infection. Preexposure prophylaxis with tenofovir disoproxil fumarate/emtricitabine and appropriate monitoring is recommended for individuals at risk for HIV.

Conclusions and Relevance

Advances in HIV prevention and treatment with antiretroviral drugs continue to improve clinical management and outcomes for individuals at risk for and living with HIV.

Role of tenofovir alafenamide (TAF) in the treatment and prophylaxis of HIV and HBV infections

Tenofovir (TFV) is the cornerstone of the treatment and prophylaxis of HIV infections. It has been routinely used in its prodrug form TDF (tenofovir disoproxil fumarate) combined with emtricitabine ((-)FTC) and other antiretroviral agents. TDF has now been replaced by TAF (tenofovir alafenamide) which allows better uptake by the lymphoid tissue. In combination with elvitegravir (E), cobicistat (C), emtricitabine (F), TAF can be advocated as an STR (single tablet regimen, Genvoya®) for the treatment of HIV infections. In this combination, E and C may in the future be replaced by bictegravir. The prophylaxis of HIV infection is momentarily based upon Truvada®, the combination of F with TDF, which in the future may also be replaced by TAF. TAF (Vemlidy®) has also replaced TDF (Viread®) for the treatment of hepatitis B virus (HBV) infections. Both TDF and TAF offer little or no risk for virus-drug resistance. As compared to TDF, TAF limits the risk for nephrotoxicity and loss of bone mineral density. What remains to be settled, however, before the universal use of TAF could be recommended, is its safety during pregnancy and its applicability in the treatment of tuberculosis, in combination with rifampicin.

Diagnostic challenges of kidney diseases in HIV-infected patients

INTRODUCTION

Chronic kidney disease (CKD) is a prevalent comorbidity in persons living with HIV infection (PLWH) associated with an increase in cardiovascular morbidity and all-cause mortality. Furthermore, early diagnosis of CKD is difficult in PLWH. Areas covered: We reviewed the main diagnostic tools for CKD in PLWH, and discussed their strengths and limits. We performed a literature search on PubMed to identify reviews and clinical trials dealing with attractive kidney biomarkers of CKD in PLWH, with the following key words: 'HIV AND kidney', 'HIV AND Kidney biomarkers', 'CKD AND Kidney biomarkers'. Expert commentary: Currently, CKD diagnosis is based on the estimation of Glomerular Filtration Rate (GFR), and measurement of proteinuria by urine protein/creatinine ratio (uPCR). These parameters are independent and complementary predictors of outcomes. GFR estimates are lacking in accuracy in PLWH. The best GFR estimate is CKD-EPI study equation. Moreover, low-grade proteinuria is associated with an increased risk of kidney disease progression in PLWH, and guidelines derived from the general population may lack sensitivity. Different biomarkers of kidney diseases like N-acetyl beta glucosaminidase (NAG), Kidney Injury Molecule-1 (KIM-1), and Alpha-1-microglobulin may predict kidney disease progression and mortality in PLWH. Others may help clinicians detect antiretroviral-induced tubulopathy, or predict cardiovascular events. More studies are needed to validate the routine use of these types of biomarkers.

Nonhuman Primate Models for Studies of AIDS Virus Persistence During Suppressive Combination Antiretroviral Therapy

Nonhuman primate (NHP) models of AIDS represent a potentially powerful component of the effort to understand in vivo sources of AIDS virus that persist in the setting of suppressive combination antiretroviral therapy (cART) and to develop and evaluate novel strategies for more definitive treatment of HIV infection (i.e., viral eradication "cure", or sustained off-cART remission). Multiple different NHP models are available, each characterized by a particular NHP species, infecting virus, and cART regimen, and each with a distinct capacity to recapitulate different aspects of HIV infection. Given these different biological characteristics, and their associated strengths and limitations, different models may be preferred to address different questions pertaining to virus persistence and cure research, or to evaluate different candidate intervention approaches. Recent developments in improved cART regimens for use in NHPs, new viruses, a wider array of sensitive virologic assay approaches, and a better understanding of pathogenesis should allow even greater contributions from NHP models to this important area of HIV research in the future.