Time Trends in Causes of Death in People With HIV: Insights From the Swiss HIV Cohort Study.

BACKGROUND: Advancements in access to antiretroviral therapy (ART) and human immunodeficiency virus (HIV) care have led to a decline in AIDS-related deaths among people with HIV (PWH) in Switzerland. However, data on the ongoing changes in causes of death among PWH over the past 15 years are scarce. METHODS: We investigated all reported deaths in the Swiss HIV Cohort Study between 2005 and 2022. Causes of death were categorized using the Coding Causes of Death in HIV protocol. The statistical analysis included demographic stratification to identify time trends and logistic regression models to determine associated factors for the underlying cause of death. RESULTS: In total, 1630 deaths were reported, with 23.7% of individuals assigned female sex at birth. These deaths included 147 (9.0%) HIV/AIDS-related deaths, 373 (22.9%) due to non-AIDS, non-hepatic cancers, 166 (10.2%) liver-related deaths, and 158 (9.7%) cardiovascular-related deaths. The median age at death (interquartile range) increased from 45.0 (40.0-53.0) years in 2005-2007 to 61.0 (56.0-69.5) years in 2020-2022. HIV/AIDS- and liver-related deaths decreased, whereas deaths from non-AIDS, non-hepatic cancers increased and cardiovascular-related deaths remained relatively stable. CONCLUSIONS: The proportionally decreasing HIV/AIDS and liver-related deaths showcase the effectiveness of ART, comprehensive HIV patient care, and interventions targeting hepatitis C virus coinfection. Future research should focus on managing cancer and cardiovascular-related conditions as the new leading causes of death among PWH. Comprehensive healthcare strategies focusing on non-AIDS-related comorbid conditions, cancer management, and sustaining liver and cardiovascular health are needed to bridge the ongoing health disparities between PWH and the general population.

Using longitudinally sampled viral nucleotide sequences to characterize the drivers of HIV-1 transmission.

OBJECTIVES: Understanding the drivers of HIV-1 transmission is of importance for curbing the ongoing epidemic. Phylogenetic methods based on single viral sequences allow us to assess whether two individuals are part of the same viral outbreak, but cannot on their own assess who potentially transmitted the virus. We developed and assessed a molecular epidemiology method with the main aim to screen cohort studies for and to characterize individuals who are 'potential HIV-1 transmitters', in order to understand the drivers of HIV-1 transmission. METHODS: We developed and validated a molecular epidemiology approach using longitudinally sampled viral Sanger sequences to characterize potential HIV-1 transmitters in the Swiss HIV Cohort Study. RESULTS: Our method was able to identify 279 potential HIV-1 transmitters and allowed us to determine the main epidemiological and virological drivers of transmission. We found that the directionality of transmission was consistent with infection times for 72.9% of 85 potential HIV-1 transmissions with accurate infection date estimates. Being a potential HIV-1 transmitter was associated with risk factors including viral load [adjusted odds ratiomultivariable (95% confidence interval): 1.86 (1.49-2.32)], syphilis coinfection [1.52 (1.06-2.19)], and recreational drug use [1.45 (1.06-1.98)]. By contrast for the potential HIV-1 recipients, this association was weaker or even absent [1.18 (0.82-1.72), 0.89 (0.52-1.55) and 1.53 (0.98-2.39), respectively], indicating that inferred directionality of transmission is useful at the population level. CONCLUSIONS: Our results indicate that longitudinally sampled Sanger sequences do not provide sufficient information to identify transmitters with high certainty at the individual level, but that they allow the drivers of transmission at the population level to be characterized.

Chemsex drugs on the rise: a longitudinal analysis of the Swiss HIV Cohort Study from 2007 to 2017.

OBJECTIVES: Chemsex refers to the use of sex-enhancing drugs among men who have sex with men (MSM) in combination with specific sexual and social behaviours. Longitudinal data on this development and the associated health risks are scarce. METHODS: Data on all recreational drugs reported in the Swiss HIV Cohort Study (SHCS) from 2007 to 2017 were collected. Drug use was analysed longitudinally for all drug classes. In addition, potential associations between patient characteristics and the consumption of methamphetamine, γ-hydroxybutric acid/γ-butyrolactone (GHB/GBL), 3,4-methylenedioxymethamphetamine (MDMA/XTC), cocaine and amphetamine were analysed. RESULTS: We analysed 166 167 follow-up entries for 12 527 SHCS participants, including 7101 free text field entries containing information about recreational drugs other than cannabis, cocaine and heroin. Overall, we observed a stable percentage (9.0%) of recreational drug use (excluding cannabis, amyl nitrite and prescription drugs). For MSM, however, there was an increase in overall drug use from 8.8% in 2007 to 13.8% in 2017, with particularly large increases for methamphetamine (from 0.2 to 2.4%; P < 0.001) and GHB/GBL (from 1.0 to 3.4%; P < 0.001). The use of each of the potentially sex-enhancing drugs methamphetamine, GHB/GBL, cocaine, XTC/MDMA and amphetamine was significantly associated with condomless sex with nonsteady partners, and higher prevalences of depression, syphilis and hepatitis C. CONCLUSIONS: The significant increase in the use of chemsex drugs among MSM in the SHCS and the strong association with coinfections and depression highlights the need for harm reduction programmes tailored to MSM. According to our results, improving knowledge about recreational drugs is important for all health care professionals working with people living with HIV.

Treatment outcomes of integrase inhibitors, boosted protease inhibitors and nonnucleoside reverse transcriptase inhibitors in antiretroviral-naïve persons starting treatment.

OBJECTIVES: Although outcomes of antiretroviral therapy (ART) have been evaluated in randomized controlled trials, experiences from subpopulations defined by age, CD4 count or viral load (VL) in heterogeneous real-world settings are limited. METHODS: The study design was an international multicohort collaboration. Logistic regression was used to compare virological and immunological outcomes at 12 ± 3 months after starting ART with an integrase strand transfer inhibitor (INSTI), contemporary nonnucleoside reverse transcriptase inhibitor (NNRTI) or boosted protease inhibitor (PI/b) with two nucleos(t)ides after 1 January 2012. The composite treatment outcome (cTO) defined success as VL < 200 HIV-1 RNA copies/mL with no regimen change and no AIDS/death events. Immunological success was defined as a CD4 count > 750 cells/µL or a 33% increase where the baseline CD4 count was ≥ 500 cells/µL. Poisson regression compared clinical failures (AIDS/death ≥ 14 days after starting ART). Interactions between ART class and age, CD4 count, and VL were determined for each endpoint. RESULTS: Of 5198 ART-naïve persons in the International Cohort Consortium of Infectious Diseases (RESPOND), 45.4% started INSTIs, 26.0% PI/b and 28.7% NNRTIs; 880 (17.4%) were aged > 50 years, 2539 (49.4%) had CD4 counts < 350 cells/µL and 1891 (36.8%) had VL > 100 000 copies/mL. Differences in virological and immunological success and clinical failure among ART classes were similar across age groups (≤ 40, 40-50 and > 50 years), CD4 count categories (≤ 350 vs. > 350 cells/µL) and VL categories at ART initiation (≤ 100 000 vs. > 100 000 copies/mL), with all investigated interactions being nonsignificant (P > 0.05). CONCLUSIONS: Differences among ART classes in virological, immunological and clinical outcomes in ART-naïve participants were consistent irrespective of age, immune suppression or VL at ART initiation. While confounding by indication cannot be excluded, this provides reassuring evidence that such subpopulations will equally benefit from contemporary ART.

Quantifying the drivers of HIV transmission and prevention in men who have sex with men: a population model-based analysis in Switzerland.

OBJECTIVES: Despite the huge success of antiretroviral therapy (ART), there is an ongoing HIV epidemic among men who have sex with men (MSM) in resource-rich countries. Understanding the driving factors underlying this process is important for curbing the epidemic. METHODS: We simulated the HIV epidemic in MSM in Switzerland by stratifying a mathematical model by CD4 count, the care cascade and condom use. The model was parametrised with clinical, epidemiological and behavioural data from the Swiss HIV Cohort Study and surveys in the HIV-negative population. RESULTS: According to our model, 3.4% of the cases that would otherwise have occurred in 2008-2015 were prevented by early initiation of ART. Only 0.6% of the cases were attributable to a change in condom use in the HIV-positive population, as less usage is mainly seen in virally suppressed MSM. Most new infections were attributable to transmission from recently infected undiagnosed individuals. It was estimated that doubling the diagnosis rate would have resulted in 11.8% fewer cases in 2001-2015. Moreover, it was estimated that introducing pre-exposure prophylaxis (PrEP) for 50% of those MSM not using condoms with occasional partners would have resulted in 22.6% fewer cases in 2012-2015. CONCLUSIONS: By combining observational data on the relevant epidemiological and clinical processes with a mathematical model, we showed that the 'test and treat' approach is most effective in reducing the number of new cases. Only a moderate population-level effect was estimated for early initiation of ART and a weak effect for the change in condom use of diagnosed MSM. Protecting HIV-negative individuals who are not using condoms with PrEP was shown to have a major impact.

On the potential of a short-term intensive intervention to interrupt HCV transmission in HIV-positive men who have sex with men: A mathematical modelling study.

Increasing access to direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) infection and decelerating the rise in high-risk behaviour over the next decade could curb the HCV epidemic among HIV-positive men who have sex with men (MSM). We investigated if similar outcomes would be achieved by short-term intensive interventions like the Swiss-HCVree-trial. We used a HCV transmission model emulating two 12-months intensive interventions combining risk counselling with (i) universal DAA treatment (pangenotypic intervention) and (ii) DAA treatment for HCV genotypes 1 and 4 (replicating the Swiss-HCVree-trial). To capture potential changes outside intensive interventions, we varied time from HCV infection to treatment in clinical routine and overall high-risk behaviour among HIV-positive MSM. Simulated prevalence dropped from 5.5% in 2016 to ≤2.0% over the intervention period (June/2016-May/2017) with the pangenotypic intervention, and to ≤3.6% with the Swiss-HCVree-trial. Assuming time to treatment in clinical routine reflected reimbursement restrictions (METAVIR ≥F2, 16.9 years) and stable high-risk behaviour in the overall MSM population, prevalence in 2025 reached 13.1% without intensive intervention, 11.1% with the pangenotypic intervention and 11.8% with the Swiss-HCVree-trial. If time to treatment in clinical routine was 2 years, prevalence in 2025 declined to 4.8% without intensive intervention, to 2.8% with the pangenotypic intervention, and to 3.5% with the Swiss-HCVree-trial. In this scenario, the pangenotypic intervention and the Swiss-HCVree-trial reduced cumulative (2016-2025) treatment episodes by 36% and 24%, respectively. Therefore, intensive interventions could reduce future HCV treatment costs and boost the benefits of long-term efforts to prevent high-risk behaviour and to reduce treatment delay. But if after intensive interventions treatment is deferred until F2, short-term benefits of intensive interventions would dissipate in the long term.

Mining for pairs: shared clinic visit dates identify steady HIV-positive partnerships.

OBJECTIVES: Here we examined the hypothesis that some stable HIV-infected partnerships can be found in cohort studies, as the patients frequently attend the clinic visits together. METHODS: Using mathematical approximations and shuffling to derive the probabilities of sharing a given number of visits by chance, we identified and validated couples that may represent either transmission pairs or serosorting couples in a stable relationship. RESULTS: We analysed 434 432 visits for 16 139 Swiss HIV Cohort Study patients from 1990 to 2014. For 89 pairs, the number of shared visits exceeded the number expected. Of these, 33 transmission pairs were confirmed on the basis of three criteria: an extensive phylogenetic tree, a self-reported steady HIV-positive partnership, and risk group affiliation. Notably, 12 of the validated transmission pairs (36%; 12 of 33) were of a mixed ethnicity with a large median age gap [17.5 years; interquartile range (IQR) 11.8-22 years] and these patients harboured HIV-1 of predominantly non-B subtypes, suggesting imported infections. CONCLUSIONS: In the context of the surge in research interest in HIV transmission pairs, this simple method widens the horizons of research on within-pair quasi-species exchange, transmitted drug resistance and viral recombination at the biological level and targeted prevention at the public health level.

HIV-1 Transmission During Recent Infection and During Treatment Interruptions as Major Drivers of New Infections in the Swiss HIV Cohort Study.

BACKGROUND: Reducing the fraction of transmissions during recent human immunodeficiency virus (HIV) infection is essential for the population-level success of "treatment as prevention". METHODS: A phylogenetic tree was constructed with 19 604 Swiss sequences and 90 994 non-Swiss background sequences. Swiss transmission pairs were identified using 104 combinations of genetic distance (1%-2.5%) and bootstrap (50%-100%) thresholds, to examine the effect of those criteria. Monophyletic pairs were classified as recent or chronic transmission based on the time interval between estimated seroconversion dates. Logistic regression with adjustment for clinical and demographic characteristics was used to identify risk factors associated with transmission during recent or chronic infection. FINDINGS: Seroconversion dates were estimated for 4079 patients on the phylogeny, and comprised between 71 (distance, 1%; bootstrap, 100%) to 378 transmission pairs (distance, 2.5%; bootstrap, 50%). We found that 43.7% (range, 41%-56%) of the transmissions occurred during the first year of infection. Stricter phylogenetic definition of transmission pairs was associated with higher recent-phase transmission fraction. Chronic-phase viral load area under the curve (adjusted odds ratio, 3; 95% confidence interval, 1.64-5.48) and time to antiretroviral therapy (ART) start (adjusted odds ratio 1.4/y; 1.11-1.77) were associated with chronic-phase transmission as opposed to recent transmission. Importantly, at least 14% of the chronic-phase transmission events occurred after the transmitter had interrupted ART. CONCLUSIONS: We demonstrate a high fraction of transmission during recent HIV infection but also chronic transmissions after interruption of ART in Switzerland. Both represent key issues for treatment as prevention and underline the importance of early diagnosis and of early and continuous treatment.

Protease inhibitors to treat hepatitis C in the Swiss HIV Cohort Study: high efficacy but low treatment uptake.

OBJECTIVES: Direct-acting antiviral agents (DAAs) have become the standard of care for the treatment of chronic hepatitis C virus (HCV) infection. We aimed to assess treatment uptake and efficacy in routine clinical settings among HIV/HCV coinfected patients after the introduction of the first generation DAAs. METHODS: Data on all Swiss HIV Cohort Study (SHCS) participants starting HCV protease inhibitor (PI) treatment between September 2011 and August 2013 were collected prospectively. The uptake and efficacy of HCV therapy were compared with those in the time period before the availability of PIs. RESULTS: Upon approval of PI treatment in Switzerland in September 2011, 516 SHCS participants had chronic HCV genotype 1 infection. Of these, 57 (11%) started HCV treatment during the following 2 years with either telaprevir, faldaprevir or boceprevir. Twenty-seven (47%) patients were treatment-naïve, nine (16%) were patients with relapse and 21 (37%) were partial or null responders. Twenty-nine (57%) had advanced fibrosis and 15 (29%) had cirrhosis. End-of-treatment virological response was 84% in treatment-naïve patients, 88% in patients with relapse and 62% in previous nonresponders. Sustained virological response was 78%, 86% and 40% in treatment-naïve patients, patients with relapse and nonresponders, respectively. Treatment uptake was similar before (3.8 per 100 patient-years) and after (6.1 per 100 patient-years) the introduction of PIs, while treatment efficacy increased considerably after the introduction of PIs. CONCLUSIONS: The introduction of PI-based HCV treatment in HIV/HCV-coinfected patients improved virological response rates, while treatment uptake remained low. Therefore, the introduction of PIs into the clinical routine was beneficial at the individual level, but had only a modest effect on the burden of HCV infection at the population level.

Efficacy of etravirine combined with darunavir or other ritonavir-boosted protease inhibitors in HIV-1-infected patients: an observational study using pooled European cohort data.

OBJECTIVES: This observational study in antiretroviral treatment-experienced, HIV-1-infected adults explored the efficacy of etravirine plus darunavir/ritonavir (DRV group; n = 999) vs. etravirine plus an alternative boosted protease inhibitor (other PI group; n = 116) using pooled European cohort data. METHODS: Two international (EuroSIDA; EUResist Network) and five national (France, Italy, Spain, Switzerland and UK) cohorts provided data (collected in 2007-2012). Stratum-adjusted (for confounding factors) Mantel-Haenszel differences in virological responses (viral load < 50 HIV-1 RNA copies/mL) and odds ratios (ORs) with 95% confidence intervals (CIs) were derived. RESULTS: Baseline characteristics were balanced between groups except for previous use of antiretrovirals (≥ 10: 63% in the DRV group vs. 49% in the other PI group), including previous use of at least three PIs (64% vs. 53%, respectively) and mean number of PI resistance mutations (2.3 vs. 1.9, respectively). Week 24 responses were 73% vs. 75% (observed) and 49% vs. 43% (missing = failure), respectively. Week 48 responses were 75% vs. 73% and 32% vs. 30%, respectively. All 95% CIs around unadjusted and adjusted differences encompassed 0 (difference in responses) or 1 (ORs). While ORs by cohort indicated heterogeneity in response, for pooled data the difference between unadjusted and adjusted for cohort ORs was small. CONCLUSIONS: These data do not indicate a difference in response between the DRV and other PI groups, although caution should be applied given the small size of the other PI group and the lack of randomization. This suggests that the efficacy and virology results from DUET can be extrapolated to a regimen of etravirine with a boosted PI other than darunavir/ritonavir.

Expansion of interferon-γ-secreting HIV-specific T cells during successful antiretroviral therapy.

OBJECTIVES: Antiretroviral therapy (ART) suppresses HIV viraemia, thereby reducing the antigenic drive for T cells to proliferate. Accordingly, selected HIV-specific T-cell responses have been described to contract within weeks of ART initiation. Here, we sought to investigate whether these findings apply to the entire repertoire of HIV-specific T cells. METHODS: Using interferon (IFN)-γ enzyme linked immuno spot (ELISpot), we performed retrospective 2-year proteome-wide monitoring of HIV-specific T cells in 17 individuals with undetectable viral loads during ART. The sample pool for each study subject consisted of one pre-ART time-point and at least two time-points after initiation of therapy. RESULTS: Peripheral pools of HIV-specific T cells decreased nonsignificantly within the first 2 years under ART in our cohort of patients, in terms of both breadth and magnitude. However, in most cases, the seeming decrease masked ongoing expansion of individual HIV-specific T-cell responses. We detected synchronous contraction and expansion of T-cell responses - with different peptide specificities - in 12 out of 17 study participants during follow-up. Importantly, the observed expansions and contractions of individual HIV-specific T-cell responses reached similar ranges, supporting the biological relevance of our findings. CONCLUSIONS: We conclude that successful ART enables both contraction and expansion of HIV-specific T-cell responses. Our results should prompt a renewed interest in HIV-specific T-cell dynamics under ART, in particular to elucidate the mechanisms that uncouple, to some extent, particular HIV-specific T-cell responses from variations in circulating antigen load and functionally characterize expanding/contracting T-cell populations beyond IFN-γ secretion. Assuming that expanding HIV-specific T-cell responses under ART are protective and functional, harnessing those mechanisms may provide novel opportunities for assisting viral control in chronically infected individuals.

HLA-Bw4 identifies a population of HIV-infected patients with an increased capacity to control viral replication after structured treatment interruption.

OBJECTIVES: After structured treatment interruption (STI) of treatment for HIV-1, a fraction of patients maintain suppressed viral loads. Prospective identification of such patients might improve HIV-1 treatment, if selected patients are offered STI. METHODS: We analysed the effect of previously identified genetic modulators of HIV-1 disease progression on patients' ability to suppress viral replication after STI. Polymorphisms in the genes killer cell immunoglobulin-like receptor 3DLI (KIR3DL1)/KIR3DS1, human leucocyte antigen B (HLA-B) and HLA Complex P5 (HCP5), and a polymorphism affecting HLA-C surface expression were analysed in 130 Swiss HIV Cohort Study patients undergoing STI. Genotypes were correlated with viral load levels after STI. RESULTS: We observed a statistically significant reduction in viral load after STI in carriers of HLA-B alleles containing either the Bw480Thr or the Bw480Ile epitope (mean adjusted effect on post-STI viral load: -0.82 log HIV-1 RNA copies/ml, P < 0.001; and -1.12 log copies/ml, P < 0.001, respectively). No significant effects were detected for the other polymorphisms analysed. The likelihood of being able to control HIV-1 replication using a prespecified cut-off (viral load increase < 1000 copies/ml) increased from 39% in Bw4-negative patients to 53% in patients carrying Bw4-80Thr, and to 65% in patients carrying Bw4-80Ile (P = 0.02). CONCLUSIONS: These data establish a significant impact of HLA-Bw4 on the control of viral replication after STI.

Efficacy, tolerability and risk factors for virological failure of darunavir-based therapy for treatment-experienced HIV-infected patients: the Swiss HIV Cohort Study.

OBJECTIVES: Darunavir was designed for activity against HIV resistant to other protease inhibitors (PIs). We assessed the efficacy, tolerability and risk factors for virological failure of darunavir for treatment-experienced patients seen in clinical practice. METHODS: We included all patients in the Swiss HIV Cohort Study starting darunavir after recording a viral load above 1000 HIV-1 RNA copies/mL given prior exposure to both PIs and nonnucleoside reverse transcriptase inhibitors. We followed these patients for up to 72 weeks, assessed virological failure using different loss of virological response algorithms and evaluated risk factors for virological failure using a Bayesian method to fit discrete Cox proportional hazard models. RESULTS: Among 130 treatment-experienced patients starting darunavir, the median age was 47 years, the median duration of HIV infection was 16 years, and 82% received mono or dual antiretroviral therapy before starting highly active antiretroviral therapy. During a median patient follow-up period of 45 weeks, 17% of patients stopped taking darunavir after a median exposure of 20 weeks. In patients followed beyond 48 weeks, the rate of virological failure at 48 weeks was at most 20%. Virological failure was more likely where patients had previously failed on both amprenavir and saquinavir and as the number of previously failed PI regimens increased. CONCLUSIONS: As a component of therapy for treatment-experienced patients, darunavir can achieve a similar efficacy and tolerability in clinical practice to that seen in clinical trials. Clinicians should consider whether a patient has failed on both amprenavir and saquinavir and the number of failed PI regimens before prescribing darunavir.

Pulmonary toxoplasmosis, a rare but severe manifestation of a common opportunistic infection in late HIV presenters: report of two cases.

Pulmonary toxoplasmosis is rare, particularly in the era of highly active antiretroviral therapy (HAART). Here, we describe two severe cases in patients not known to be HIV-infected. In both patients, early diagnosis and therapy led to a favourable outcome. Pulmonary toxoplasmosis should be considered in the differential diagnosis in potentially HIV-infected patients with respiratory symptoms.

Hemophagocytic syndrome caused by primary herpes simplex virus 1 infection: report of a first case.

INTRODUCTION: Hemophagocytic syndrome represents a severe hyperinflammatory condition by activated macrophages. Leading viral triggering agents are Epstein-Barr virus (EBV), cytomegalovirus (CMV), and adenovirus. MATERIALS AND METHODS: We present a patient with Wegener's granulomatosis on azathioprine and prednisone medication, who developed a life-threatening hemophagocytic syndrome. Positive plasma polymerase chain reaction (PCR) with negative serology revealed a primary, disseminated infection with herpes simplex virus-1 as the triggering pathogen. After treatment with acyclovir, high-dose steroids, immunoglobulins, and etoposide, the patient recovered. CONCLUSION: Early diagnosis of potentially underlying infections of hemophagocytic syndrome influences the therapeutic approach. It is important to consider a variety of infectious agents, particularly in immunosuppressed individuals. The reported case emphasizes the importance of screening for herpes simplex virus 1.

Prevalence of etravirine mutations and impact on response to treatment in routine clinical care: the Swiss HIV Cohort Study (SHCS).

OBJECTIVES: Etravirine (ETV) is a novel nonnucleoside reverse transcriptase inhibitor (NNRTI) with reduced cross-resistance to first-generation NNRTIs, which has been primarily studied in randomized clinical trials and not in routine clinical settings. METHODS: ETV resistance-associated mutations (RAMs) were investigated by analysing 6072 genotypic tests. The antiviral activity of ETV was predicted using different interpretation systems: International AIDS Society-USA (IAS-USA), Stanford, Rega and Agence Nationale de Recherches sur le Sida et les hépatites virales (ANRS). RESULTS: The prevalence of ETV RAMs was higher in NNRTI-exposed patients [44.9%, 95% confidence interval (CI) 41.0-48.9%] than in treatment-naïve patients (9.6%, 95% CI 8.5-10.7%). ETV RAMs in treatment-naïve patients mainly represent polymorphism, as prevalence estimates in genotypic tests for treatment-naïve patients with documented recent (<1 year) infection, who had acquired HIV before the introduction of NNRTIs, were almost identical (9.8%, 95% CI 3.3-21.4). Discontinuation of NNRTI treatment led to a marked drop in the detection of ETV RAMs, from 51.7% (95% CI 40.8-62.6%) to 34.5% (95% CI 24.6-45.4%, P=0.032). Differences in prevalence among subtypes were found for V90I and V179T (P<0.001). Estimates of restricted virological response to ETV varied among algorithms in patients with exposure to efavirenz (EFV)/nevirapine (NVP), ranging from 3.8% (95% CI 2.5-5.6%) for ANRS to 56.2% (95% CI 52.2-60.1%) for Stanford. The predicted activity of ETV decreased as the sensitivity of potential optimized background regimens decreased. The presence of major IAS-USA mutations (L100I, K101E/H/P and Y181C/I/V) reduced the treatment response at week 24. CONCLUSIONS: Most ETV RAMs in drug-naïve patients are polymorphisms rather than transmitted RAMs. Uncertainty regarding predictions of antiviral activity for ETV in NNRTI-treated patients remains high. The lowest activity was predicted for patients harbouring extensive multidrug-resistant viruses, thus limiting ETV use in those who are most in need.

Recovery of replication-competent HIV despite prolonged suppression of plasma viremia.

In evaluating current combination drug regimens for treatment of human immunodeficiency virus (HIV) disease, it is important to determine the existence of viral reservoirs. After depletion of CD8 cells from the peripheral blood mononuclear cells (PBMCs) of both patients and normal donors, activation of patient CD4 lymphocytes with immobilized antibodies to CD3 and CD28 enabled the isolation of virus from PBMCs of six patients despite the suppression of their plasma HIV RNA to fewer than 50 copies per milliliter for up to 2 years. Partial sequencing of HIV pol revealed no new drug resistance mutations or discernible evolution, providing evidence for viral latency rather than drug failure.

Predictive value of known and novel alleles of CYP2B6 for efavirenz plasma concentrations in HIV-infected individuals.

To assess the association of CYP2B6 allelic diversity with efavirenz (EFV) pharmacokinetics, we performed extensive genotyping of 15 relevant single nucleotide polymorphism in 169 study participants, and full resequencing of CYP2B6 in individuals with abnormal EFV plasma levels. Seventy-seven (45.5%) individuals carried a known (CYP2B6*6, *11, *15, or *18) or new loss/diminished-function alleles. Resequencing defined two new loss-of-function alleles: allele *27 (marked by 593T>C [M198T]), that results in 85% decrease in enzyme activity and allele *28 (marked by 1132C>T), that results in protein truncation at arginine 378. Median AUC levels were 188.5 microg h/ml for individuals homozygous for a loss/diminished-function allele, 58.6 microg h/ml for carriers, and 43.7 microg h/ml for noncarriers (P<0.0001). Individuals with a poor metabolizer genotype had a likelihood ratio of 35 (95% CI, 11-110) of presenting very high EFV plasma levels. CYP2B6 poor metabolizer genotypes explain to a large extent EFV pharmacokinetics and identify individuals at risk of extremely elevated EFV plasma levels.

Contribution of APOBEC3G/F activity to the development of low-abundance drug-resistant human immunodeficiency virus type 1 variants.

Plasma drug-resistant minority human immunodeficiency virus type 1 variants (DRMVs) increase the risk of virological failure to first-line non-nucleoside reverse transcriptase inhibitor antiretroviral therapy (ART). The origin of DRMVs in ART-naive patients, however, remains unclear. In a large pan-European case-control study investigating the clinical relevance of pre-existing DRMVs using 454 pyrosequencing, the six most prevalent plasma DRMVs detected corresponded to G-to-A nucleotide mutations (V90I, V106I, V108I, E138K, M184I and M230I). Here, we evaluated if such DRMVs could have emerged from apolipoprotein B mRNA editing enzyme, catalytic polypeptide 3G/F (APOBEC3G/F) activity. Out of 236 ART-naive subjects evaluated, APOBEC3G/F hypermutation signatures were detected in plasma viruses of 14 (5.9%) individuals. Samples with minority E138K, M184I, and M230I mutations, but not those with V90I, V106I or V108I, were significantly associated with APOBEC3G/F activity (Fisher's P < 0.005), defined as the presence of > 0.5% of sample sequences with an APOBEC3G/F signature. Mutations E138K, M184I and M230I co-occurred in the same sequence as APOBEC3G/F signatures in 3/9 (33%), 5/11 (45%) and 4/8 (50%) of samples, respectively; such linkage was not found for V90I, V106I or V108I. In-frame STOP codons were observed in 1.5% of all clonal sequences; 14.8% of them co-occurred with APOBEC3G/F signatures. APOBEC3G/F-associated E138K, M184I and M230I appeared within clonal sequences containing in-frame STOP codons in 2/3 (66%), 5/5 (100%) and 4/4 (100%) of the samples. In a re-analysis of the parent case control study, the presence of APOBEC3G/F signatures was not associated with virological failure. In conclusion, the contribution of APOBEC3G/F editing to the development of DRMVs is very limited and does not affect the efficacy of non-nucleoside reverse transcriptase inhibitor ART.

Efavirenz intoxication due to slow hepatic metabolism.

We describe a human immunodeficiency virus-positive woman who presented with severe psychosis while she was receiving therapy with efavirenz. Her plasma efavirenz level was excessively high. Genetic investigation showed that she was homozygous for the CYP2B6 G516T allele, resulting in slow hepatic metabolism. After the dosage of efavirenz was lowered, all neuropsychiatric symptoms subsided.