Incident Hepatitis C Virus Infections in the Swiss HIV Cohort Study : changes in treatment uptake and outcomes between 1991 and 2013

Background: The hepatitis C virus (HCV) epidemic is evolving rapidly in patients infected with human immunodeficiency virus (HIV). We aimed to describe changes in treatment uptake and outcomes of incident HCV infections before and after 2006, the time-point at which major changes in HCV epidemic became apparent. Methods.  We included all adults with an incident HCV infection before June 2012 in the Swiss HIV Cohort Study, a prospective nationwide representative cohort of individuals infected with HIV. We assessed the following outcomes by time period: the proportion of patients starting an HCV therapy, the proportion of treated patients achieving a sustained virological response (SVR), and the proportion of patients with persistent HCV infection during follow-up. Results.  Of 193 patients with an HCV seroconversion, 106 were diagnosed before and 87 after January 2006. The proportion of men who have sex with men increased from 24% before to 85% after 2006 (P < .001). Hepatitis C virus treatment uptake increased from 33% before 2006 to 77% after 2006 (P < .001). Treatment was started during early infection in 22% of patients before and 91% after 2006 (P < .001). An SVR was achieved in 78% and 29% (P = .01) of patients treated during early and chronic HCV infection. The probability of having a detectable viral load 5 years after diagnosis was 0.67 (95% confidence interval [CI], 0.58-0.77) in the group diagnosed before 2006 and 0.24 (95% CI, 0.16-0.35) in the other group (P < .001). Conclusions. In recent years, increased uptake and earlier initiation of HCV therapy among patients with incident infections significantly reduced the proportion of patients with replicating HCV.

HBV genotypes and response to tenofovir disoproxil fumarate in HIV/HBV-coinfected persons.

BACKGROUND: Hepatitis B virus (HBV) genotypes can influence treatment outcome in HBV-monoinfected and human immunodeficiency virus (HIV)/HBV-coinfected patients. Tenofovir disoproxil fumarate (TDF) plays a pivotal role in antiretroviral therapy (ART) of HIV/HBV-coinfected patients. The influence of HBV genotypes on the response to antiviral drugs, particularly TDF, is poorly understood. METHODS: HIV/HBV-co-infected participants with detectable HBV DNA prior to TDF therapy were selected from the Swiss HIV Cohort Study. HBV genotypes were identified and resistance testing was performed prior to antiviral therapy, and in patients with delayed treatment response (>6 months). The efficacy of TDF to suppress HBV (HBV DNA <20 IU/mL) and the influence of HBV genotypes were determined. RESULTS: 143 HIV/HBV-coinfected participants with detectable HBV DNA were identified. The predominant HBV genotypes were A (82 patients, 57 %); and D (35 patients, 24 %); 20 patients (14 %) were infected with multiple genotypes (3 % A + D and 11 % A + G); and genotypes B, C and E were each present in two patients (1 %). TDF completely suppressed HBV DNA in 131 patients (92 %) within 6 months; and in 12 patients (8 %), HBV DNA suppression was delayed. No HBV resistance mutations to TDF were found in patients with delayed response, but all were infected with HBV genotype A (among these, 5 patients with genotype A + G), and all had previously been exposed to lamivudine. CONCLUSION: In HIV/HBV-coinfected patients, infection with multiple HBV genotypes was more frequent than previously reported. The large majority of patients had an undetectable HBV viral load at six months of TDF-containing ART. In patients without viral suppression, no TDF-related resistance mutations were found. The role of specific genotypes and prior lamivudine treatment in the delayed response to TDF warrant further investigation.

Effect of Maraviroc Intensification on HIV-1-Specific T Cell Immunity in Recently HIV-1-Infected Individuals

Background The effect of maraviroc on the maintenance and the function of HIV-1-specific T cell responses remains unknown. Methods Subjects recently infected with HIV-1 were randomized to receive anti-retroviral treatment with or without maraviroc intensification for 48 weeks, and were monitored up to week 60. PBMC and in vitro-expanded T cells were tested for responses to the entire HIV proteome by ELISpot analyses. Intracellular cytokine staining assays were conducted to monitor the (poly)-functionality of HIV-1-specific T cells. Analyses were performed at baseline and week 24 after treatment start, and at week 60 (3 months after maraviroc discontinuation). Results Maraviroc intensification was associated with a slower decay of virus-specific T cell responses over time compared to the non-intensified regimen in both direct ex-vivo as well as in in-vitro expanded cells. The effector function profiles of virus-specific CD8+ T cells were indistinguishable between the two arms and did not change over time between the groups. Conclusions Maraviroc did not negatively impact any of the measured parameters, but was rather associated with a prolonged maintenance of HIV-1-specific T cell responses. Maraviroc, in addition to its original effect as viral entry inhibitor, may provide an additional benefit on the maintenance of virus-specific T cells which may be especially important for future viral eradication strategies.

Prevalence of Ischemic Heart Disease and Management of Coronary Risk in Daily Clinical Practice: Results from a Mediterranean Cohort of HIV-Infected Patients

There are conflicting data on the prevalence of coronary events and the quality of the management of modifiable cardiovascular risk factors (CVRF) inHIV-infected patients. Methods.We performed a retrospective descriptive study to determine the prevalence of coronary events and to evaluate the management of CVRF in a Mediterranean cohort of 3760 HIV-1-infected patients from April 1983 through June 2011. Results.We identified 81 patients with a history of a coronary event (prevalence 2.15%); 83% of them suffered an acute myocardial infarction. At the time of the coronary event, CVRF were highly prevalent (60.5% hypertension, 48% dyslipidemia, and 16% diabetes mellitus).OtherCVRF, such as smoking, hypertension, lack of exercise, and body mass index, were not routinely assessed. After the coronary event, a significant decrease in total cholesterol ( � = 0.025) and LDLcholesterol ( � = 0.004) was observed. However, the percentage of patients whomaintained LDL-cholesterol > 100mg/dL remained stable (from 46% to 41%, � = 0.103). Patients using protease inhibitors associated with a favorable lipid profile increased over time ( � = 0.028). Conclusions.The prevalence of coronary events in our cohort is low. CVRF prevalence is high and theirmanagement is far from optimal. More aggressive interventions should be implemented to diminish cardiovascular risk in HIV-infected patients.

Decreasing Proportion of Recent Infections among Newly Diagnosed HIV-1 Cases in Switzerland, 2008 to 2013 Based on Line-Immunoassay-Based Algorithms.

BACKGROUND: HIV surveillance requires monitoring of new HIV diagnoses and differentiation of incident and older infections. In 2008, Switzerland implemented a system for monitoring incident HIV infections based on the results of a line immunoassay (Inno-Lia) mandatorily conducted for HIV confirmation and type differentiation (HIV-1, HIV-2) of all newly diagnosed patients. Based on this system, we assessed the proportion of incident HIV infection among newly diagnosed cases in Switzerland during 2008-2013. METHODS AND RESULTS: Inno-Lia antibody reaction patterns recorded in anonymous HIV notifications to the federal health authority were classified by 10 published algorithms into incident (up to 12 months) or older infections. Utilizing these data, annual incident infection estimates were obtained in two ways, (i) based on the diagnostic performance of the algorithms and utilizing the relationship 'incident = true incident + false incident', (ii) based on the window-periods of the algorithms and utilizing the relationship 'Prevalence = Incidence x Duration'. From 2008-2013, 3'851 HIV notifications were received. Adult HIV-1 infections amounted to 3'809 cases, and 3'636 of them (95.5%) contained Inno-Lia data. Incident infection totals calculated were similar for the performance- and window-based methods, amounting on average to 1'755 (95% confidence interval, 1588-1923) and 1'790 cases (95% CI, 1679-1900), respectively. More than half of these were among men who had sex with men. Both methods showed a continuous decline of annual incident infections 2008-2013, totaling -59.5% and -50.2%, respectively. The decline of incident infections continued even in 2012, when a 15% increase in HIV notifications had been observed. This increase was entirely due to older infections. Overall declines 2008-2013 were of similar extent among the major transmission groups. CONCLUSIONS: Inno-Lia based incident HIV-1 infection surveillance proved useful and reliable. It represents a free, additional public health benefit of the use of this relatively costly test for HIV confirmation and type differentiation.

Transient detectable viremia and the risk of viral rebound in patients from the Swiss HIV Cohort Study.

BACKGROUND: Temporary increases in plasma HIV RNA ('blips') are common in HIV patients on combination antiretroviral therapy (cART). Blips above 500 copies/mL have been associated with subsequent viral rebound. It is not clear if this relationship still holds when measurements are made using newer more sensitive assays. METHODS: We selected antiretroviral-naive patients that then recorded one or more episodes of viral suppression on cART with HIV RNA measurements made using more sensitive assays (lower limit of detection below 50 copies/ml). We estimated the association in these episodes between blip magnitude and the time to viral rebound. RESULTS: Four thousand ninety-four patients recorded a first episode of viral suppression on cART using more sensitive assays; 1672 patients recorded at least one subsequent suppression episode. Most suppression episodes (87 %) were recorded with TaqMan version 1 or 2 assays. Of the 2035 blips recorded, 84 %, 12 % and 4 % were of low (50-199 copies/mL), medium (200-499 copies/mL) and high (500-999 copies/mL) magnitude respectively. The risk of viral rebound increased as blip magnitude increased with hazard ratios of 1.20 (95 % CI 0.89-1.61), 1.42 (95 % CI 0.96-2.19) and 1.93 (95 % CI 1.24-3.01) for low, medium and high magnitude blips respectively; an increase of hazard ratio 1.09 (95 % CI 1.03 to 1.15) per 100 copies/mL of HIV RNA. CONCLUSIONS: With the more sensitive assays now commonly used for monitoring patients, blips above 200 copies/mL are increasingly likely to lead to viral rebound and should prompt a discussion about adherence.

High hepatic and extrahepatic mortality and low treatment uptake in HCV-coinfected persons in the Swiss HIV cohort study between 2001 and 2013.

BACKGROUND & AIMS: The landscape of HCV treatments is changing dramatically. At the beginning of this new era, we highlight the challenges for HCV therapy by assessing the long-term epidemiological trends in treatment uptake, efficacy and mortality among HIV/HCV-coinfected people since the availability of HCV therapy. METHODS: We included all SHCS participants with detectable HCV RNA between 2001 and 2013. To identify predictors for treatment uptake uni- and multivariable Poisson regression models were applied. We further used survival analyses with Kaplan-Meier curves and Cox regression with drop-out as competing risk. RESULTS: Of 12,401 participants 2107 (17%) were HCV RNA positive. Of those, 636 (30%) started treatment with an incidence of 5.8/100 person years (PY) (95% CI 5.3-6.2). Sustained virological response (SVR) with pegylated interferon/ribavirin was achieved in 50% of treated patients, representing 15% of all participants with replicating HCV-infection. 344 of 2107 (16%) HCV RNA positive persons died, 59% from extrahepatic causes. Mortality/100 PY was 2.9 (95% CI 2.6-3.2) in untreated patients, 1.3 (1.0-1.8) in those treated with failure, and 0.6 (0.4-1.0) in patients with SVR. In 2013, 869/2107 (41%) participants remained HCV RNA positive. CONCLUSIONS: Over the last 13years HCV treatment uptake was low and by the end of 2013, a large number of persons remain to be treated. Mortality was high, particularly in untreated patients, and mainly due to non-liver-related causes. Accordingly, in HIV/HCV-coinfected patients, integrative care including the diagnosis and therapy of somatic and psychiatric disorders is important to achieve mortality rates similar to HIV-monoinfected patients.

Prévention des troubles du rythme cardiaque en hémodialyse: quels sont les facteurs modulables [Prevention of cardiac arrhythmias in hemodialysis: what are the modulating factors?].

La mort subite est la première cause de mortalité chez les patients souffrant d'une insuffisance rénale terminale traités par dialyse chronique. La technique de dialyse utilisée et la composition chimique du dialysat influencent l'incidence des arythmies. Des études pilotes démontrent que l'utilisation d'un dialysat sans acétate avec perfusion de bicarbonate de sodium en aval du filtre de dialyse, couplée à une modulation du profil de potassium pendant la séance de dialyse, ou acetate free biofiltration with potassium profiled dialysate, permet de réduire l'incidence des arythmies, l'intervalle QT et sa dispersion. La limitation du volume de soustraction liquidienne pendant la dialyse et l'augmentation de la concentration de calcium dans le dialysat constituent d'autres stratégies anti-arythmogènes possibles Sudden death is the first cause of mortality in patients with end stage renal disease undergoing chronic dialysis treatment. The technique of dialysis as well as the chemical composition of the dialysate can impact on the incidence of cardiac arrhythmias. Pilot studies reveal that the use of an acetate-free dialysate with a downstream filter infusion of sodium bicarbonate, coupled with a modulated potassium-profiled dialysate during hemodialysis, or acetate free biofiltration with potassium profiled dialysate, reduces the incidence of arrhythmias, the QT interval and QT dispersion. The limitation of the ultrafiltration volume during the dialysis session, and the increase in calcium concentration in the dialysate are other possible strategies to reduce cardiac arrhythmias.

Assessing the Paradox Between Transmitted and Acquired HIV Type 1 Drug Resistance Mutations in the Swiss HIV Cohort Study From 1998 to 2012.

BACKGROUND: Transmitted human immunodeficiency virus type 1 (HIV) drug resistance (TDR) mutations are transmitted from nonresponding patients (defined as patients with no initial response to treatment and those with an initial response for whom treatment later failed) or from patients who are naive to treatment. Although the prevalence of drug resistance in patients who are not responding to treatment has declined in developed countries, the prevalence of TDR mutations has not. Mechanisms causing this paradox are poorly explored. METHODS: We included recently infected, treatment-naive patients with genotypic resistance tests performed ≤1 year after infection and before 2013. Potential risk factors for TDR mutations were analyzed using logistic regression. The association between the prevalence of TDR mutations and population viral load (PVL) among treated patients during 1997-2011 was estimated with Poisson regression for all TDR mutations and individually for the most frequent resistance mutations against each drug class (ie, M184V/L90M/K103N). RESULTS: We included 2421 recently infected, treatment-naive patients and 5399 patients with no response to treatment. The prevalence of TDR mutations fluctuated considerably over time. Two opposing developments could explain these fluctuations: generally continuous increases in the prevalence of TDR mutations (odds ratio, 1.13; P = .010), punctuated by sharp decreases in the prevalence when new drug classes were introduced. Overall, the prevalence of TDR mutations increased with decreasing PVL (rate ratio [RR], 0.91 per 1000 decrease in PVL; P = .033). Additionally, we observed that the transmitted high-fitness-cost mutation M184V was positively associated with the PVL of nonresponding patients carrying M184V (RR, 1.50 per 100 increase in PVL; P < .001). Such association was absent for K103N (RR, 1.00 per 100 increase in PVL; P = .99) and negative for L90M (RR, 0.75 per 100 increase in PVL; P = .022). CONCLUSIONS: Transmission of antiretroviral drug resistance is temporarily reduced by the introduction of new drug classes and driven by nonresponding and treatment-naive patients. These findings suggest a continuous need for new drugs, early detection/treatment of HIV-1 infection.

Ribavirin Concentrations Do Not Predict Sustained Virological Response in HIV/HCV-Coinfected Patients Treated with Ribavirin and Pegylated Interferon in the Swiss HIV Cohort Study.

BACKGROUND: Ribavirin (RBV) is an essential component of most current hepatitis C (HCV) treatment regimens and still standard of care in the combination with pegylated interferon (pegIFN) to treat chronic HCV in resource limited settings. Study results in HIV/HCV-coinfected patients are contradicting as to whether RBV concentration correlates with sustained virological response (SVR). METHODS: We included 262 HCV treatment naïve HIV/HCV-coinfected Swiss HIV Cohort Study (SHCS) participants treated with RBV and pegIFN between 01.01.2001-01.01.2010, 134 with HCV genotype (GT) 1/4, and 128 with GT 2/3 infections. RBV levels were measured retrospectively in stored plasma samples obtained between HCV treatment week 4 and end of therapy. Uni- and multivariable logistic regression analyses were used to evaluate the association between RBV concentration and SVR in GT 1/4 and GT 2/3 infections. The analyses were repeated stratified by treatment phase (week 4-12, 13-24, >24) and IL28B genotype (CC versus CT/TT). RESULTS: SVR rates were 35.1% in GT 1/4 and 70.3% in GT 2/3 infections. Overall, median RBV concentration was 2.0 mg/L in GT 1/4, and 1.9 mg/L in GT 2/3, and did not change significantly across treatment phases. Patients with SVR had similar RBV concentrations compared to patients without SVR in both HCV genotype groups. SVR was not associated with RBV levels ≥2.0 mg/L (GT 1/4, OR 1.19 [0.5-2.86]; GT 2/3, 1.94 [0.78-4.80]) and ≥2.5 mg/L (GT 1/4, 1.56 [0.64-3.84]; GT 2/3 2.72 [0.85-8.73]), regardless of treatment phase, and IL28B genotype. CONCLUSION: In HIV/HCV-coinfected patients treated with pegIFN/RBV, therapeutic drug monitoring of RBV concentrations does not enhance the chance of HCV cure, regardless of HCV genotype, treatment phase and IL28B genotype.

Schistosoma mansoni and HIV acquisition in fishing communities of Lake Victoria, Uganda: a nested case-control study.

OBJECTIVE: It has been suggested that Schistosoma mansoni, which is endemic in African fishing communities, might increase susceptibility to human immunodeficiency virus (HIV) acquisition. If confirmed, this would be of great public health importance in these high HIV-risk communities. This study was undertaken to determine whether S. mansoni infection is a risk factor for HIV infection among the fishing communities of Lake Victoria, Uganda. We conducted a matched case-control study, nested within a prospective HIV incidence cohort, including 50 HIV seroconverters (cases) and 150 controls during 2009-2011. METHODS: S. mansoni infection prior to HIV seroconversion was determined by measuring serum circulating anodic antigen (CAA) in stored serum. HIV testing was carried out using the Determine rapid test and infection confirmed by enzyme-linked immunosorbent assays. RESULTS: About 49% of cases and 52% of controls had S. mansoni infection prior to HIV seroconversion (or at the time of a similar study visit, for controls): odds ratio, adjusting for ethnicity, religion, marital status, education, occupation, frequency of alcohol consumption in previous 3 months, number of sexual partners while drunk, duration of stay in the community, and history of schistosomiasis treatment in the past 2 years was 1.23 (95% CI 0.3-5.7) P = 0.79. S. mansoni infections were chronic (with little change in status between enrolment and HIV seroconversion), and there was no difference in median CAA concentration between cases and controls. CONCLUSIONS: These results do not support the hypothesis that S. mansoni infection promotes HIV acquisition.

Synthetic long peptide booster immunization in rhesus macaques primed with replication-competent NYVAC-C-KC induces a balanced CD4/CD8 T-cell and antibody response against the conserved regions of HIV-1.

The Thai trial (RV144) indicates that a prime-boost vaccine combination that induces both T-cell and antibody responses may be desirable for an effective HIV vaccine. We have previously shown that immunization with synthetic long peptides (SLP), covering the conserved parts of SIV, induced strong CD4 T-cell and antibody responses, but only modest CD8 T-cell responses. To generate a more balanced CD4/CD8 T-cell and antibody response, this study evaluated a pox-vector prime/SLP boost strategy in rhesus macaques. Priming with a replication-competent NYVAC, encoding HIV-1 clade C gag, pol and nef, induced modest IFNγ T-cell immune responses, predominantly directed against HIV-1 Gag. Booster immunization with SLP, covering the conserved parts of HIV-1 Gag, Pol and Env, resulted in a more than 10-fold increase in IFNγ ELISpot responses in four of six animals, which were predominantly HIV-1 Pol-specific. The animals showed a balanced polyfunctional CD4 and CD8 T-cell response and high Ab titres.

Frequency of and Risk Factors for Depression among Participants in the Swiss HIV Cohort Study (SHCS).

OBJECTIVES: We studied the incidence and prevalence of, and co-factors for depression in the Swiss HIV Cohort Study. METHODS: Depression-specific items were introduced in 2010 and prospectively collected at semiannual cohort visits. Clinical, laboratory and behavioral co-factors of incident depression among participants free of depression at the first two visits in 2010 or thereafter were analyzed with Poisson regression. Cumulative prevalence of depression at the last visit was analyzed with logistic regression. RESULTS: Among 4,422 participants without a history of psychiatric disorders or depression at baseline, 360 developed depression during 9,348 person-years (PY) of follow-up, resulting in an incidence rate of 3.9 per 100 PY (95% confidence interval (CI) 3.5-4.3). Cumulative prevalence of depression during follow-up was recorded for 1,937/6,756 (28.7%) participants. Incidence and cumulative prevalence were higher in injection drug users (IDU) and women. Older age, preserved work ability and higher physical activity were associated with less depression episodes. Mortality (0.96 per 100 PY, 95% CI 0.83-1.11) based upon 193 deaths over 20,102 PY was higher among male IDU (2.34, 1.78-3.09), female IDU (2.33, 1.59-3.39) and white heterosexual men (1.32, 0.94-1.84) compared to white heterosexual women and homosexual men (0.53, 0.29-0.95; and 0.71, 0.55-0.92). Compared to participants free of depression, mortality was slightly elevated among participants with a history of depression (1.17, 0.94-1.45 vs. 0.86, 0.71-1.03, P = 0.033). Suicides (n = 18) did not differ between HIV transmission groups (P = 0.50), but were more frequent among participants with a prior diagnosis of depression (0.18 per 100 PY, 95%CI 0.10-0.31; vs. 0.04, 0.02-0.10; P = 0.003). CONCLUSIONS: Depression is a frequent co-morbidity among HIV-infected persons, and thus an important focus of care.

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.

Once-daily dolutegravir versus darunavir plus ritonavir for treatment-naive adults with HIV-1 infection (FLAMINGO): 96 week results from a randomised, open-label, phase 3b study.

BACKGROUND: The primary analysis of the FLAMINGO study at 48 weeks showed that patients taking dolutegravir once daily had a significantly higher virological response rate than did those taking ritonavir-boosted darunavir once daily, with similar tolerability. We present secondary efficacy and safety results analysed at 96 weeks. METHODS: FLAMINGO was a multicentre, open-label, phase 3b, non-inferiority study of HIV-1-infected treatment-naive adults. Patients were randomly assigned (1:1) to dolutegravir 50 mg or darunavir 800 mg plus ritonavir 100 mg, with investigator-selected combination tenofovir and emtricitabine or combination abacavir and lamivudine background treatment. The main endpoints were plasma HIV-1 RNA less than 50 copies per mL and safety. The non-inferiority margin was -12%. If the lower end of the 95% CI was greater than 0%, then we concluded that dolutegravir was superior to ritonavir-boosted darunavir. This trial is registered with ClinicalTrials.gov, number NCT01449929. FINDINGS: Of 595 patients screened, 488 were randomly assigned and 484 included in the analysis (242 assigned to receive dolutegravir and 242 assigned to receive ritonavir-boosted darunavir). At 96 weeks, 194 (80%) of 242 patients in the dolutegravir group and 164 (68%) of 242 in the ritonavir-boosted darunavir group had HIV-1 RNA less than 50 copies per mL (adjusted difference 12·4, 95% CI 4·7-20·2; p=0·002), with the greatest difference in patients with high viral load at baseline (50/61 [82%] vs 32/61 [52%], homogeneity test p=0·014). Six participants (three since 48 weeks) in the dolutegravir group and 13 (four) in the darunavir plus ritonavir group discontinued because of adverse events. The most common drug-related adverse events were diarrhoea (23/242 [10%] in the dolutegravir group vs 57/242 [24%] in the darunavir plus ritonavir group), nausea (31/242 [13%] vs 34/242 [14%]), and headache (17/242 [7%] vs 12/242 [5%]). INTERPRETATION: Once-daily dolutegravir is associated with a higher virological response rate than is once-daily ritonavir-boosted darunavir. Dolutegravir compares favourably in efficacy and safety to a boosted darunavir regimen with nucleoside reverse transcriptase inhibitor background treatment for HIV-1-infected treatment-naive patients. FUNDING: ViiV Healthcare and Shionogi & Co.