Treatment durability and virological response in treatment-experienced HIV-positive patients on an integrase inhibitor-based regimen: an Australian cohort study

Background: Integrase inhibitors (INSTI) are a newer class of antiretroviral (ARV) drugs that offer additional treatment options for experienced patients. Our aim is to describe treatment durability and virological outcomes in treatment-experienced HIV-positive patients using INSTI-based regimens. Methods: All patients in the Australian HIV Observational Database who had received an INSTI-based regimen ≥ 14 days as well as previous therapy were included in the study. We defined two groups of treatment-experienced patients: (1) those starting a second-line regimen with INSTI; and (2) highly experienced patients, defined as having prior exposure to all three main ARV classes, nucleoside reverse transcriptase inhibitor, nonnucleoside reverse transcriptase inhibitors and protease inhibitors, before commencing INSTI. Survival methods were used to determine time to viral suppression and treatment switch, stratified by patient treatment experience. Covariates of interest included age, gender, hepatitis B and C co-infection, previous antiretroviral treatment time, patient treatment experience and baseline viral load. Results: Time to viral suppression and regimen switching from INSTI initiation was similar for second-line and highly experienced patients. The probability of achieving viral suppression at 6 months was 77.7% for second-line patients and 68.4% for highly experienced patients. There were 60 occurrences of regimen switching away from INSTI observed over 1274.0 person-years, a crude rate of 4.71 (95% CI: 3.66-6.07) per 100 person-years. Patient treatment experience was not a significant factor for regimen switch according to multivariate analysis, adjusting for relevant covariates. Conclusions: We found that INSTI-based regimens were potent and durable in experienced HIV-positive patients receiving treatment outside clinical trials. These results confirm that INSTI-based regimens are a robust treatment option.

Tipranavir/Ritonavir (500/200 mg and 500/100 mg) Was Virologically Non-Inferior to Lopinavir/Ritonavir (400/100 mg) at Week 48 in Treatment-Naïve HIV-1-Infected Patients: A Randomized, Multinational, Multicenter Trial

Ritonavir-boosted tipranavir (TPV/r) was evaluated as initial therapy in treatment-naïve HIV-1-infected patients because of its potency, unique resistance profile, and high genetic barrier. Trial 1182.33, an open-label, randomized trial, compared two TPV/r dose combinations versus ritonavir-boosted lopinavir (LPV/r). Eligible adults, who had no prior antiretroviral therapy were randomized to twice daily (BID) 500/100 mg TPV/r, 500/200 mg TPV/r, or 400/100 mg LPV/r. Each treatment group also received Tenofovir 300 mg + Lamivudine 300 mg QD. The primary endpoint was a confirmed viral load (VL) <50 copies/mL at week 48 without prior antiretroviral regimen changes. Primary analyses examined CD4-adjusted response rates for non-inferiority, using a 15% non-inferiority margin. At week 48, VL<50 copies/mL was 68.4%, 69.9%, and 72.4% in TPV/r100, TPV/r200, and LPV/r groups, respectively, and TPV/r groups showed non-inferiority to LPV/r. Discontinuation due to adverse events was higher in TPV/r100 (10.3%) and TPV/r200 (15.3%) recipients versus LPV/r (3.2%) recipients. The frequency of grade ≥3 transaminase elevations was higher in the TPV/r200 group than the other groups, leading to closure of this group. However, upon continued treatment or following re-introduction after treatment interruption, transaminase elevations returned to grade ≤2 in >65% of patients receiving either TPV/r200 or TPV/r100. The trial was subsequently discontinued; primary objectives were achieved and continuing TPV/r100 was less tolerable than standard of care for initial highly active antiretroviral therapy. All treatment groups had similar 48-week treatment responses. TPV/r100 and TPV/r200 regimens resulted in sustained treatment responses, which were non-inferior to LPV/r at 48 weeks. When compared with the LPV/r regimen and examined in the light of more current regimens, these TPV/r regimens do not appear to be the best options for treatment-naïve patients based on their safety profiles.

Immunological biomarkers predict HIV-1 viral rebound after treatment interruption

Treatment of HIV-1 infection with antiretroviral therapy (ART) in the weeks following transmission may induce a state of ‘post-treatment control' (PTC) in some patients, in whom viraemia remains undetectable when ART is stopped. Explaining PTC could help our understanding of the processes that maintain viral persistence. Here we show that immunological biomarkers can predict time to viral rebound after stopping ART by analysing data from a randomized study of primary HIV-1 infection incorporating a treatment interruption (TI) after 48 weeks of ART (the SPARTAC trial). T-cell exhaustion markers PD-1, Tim-3 and Lag-3 measured prior to ART strongly predict time to the return of viraemia. These data indicate that T-cell exhaustion markers may identify those latently infected cells with a higher proclivity to viral transcription. Our results may open new avenues for understanding the mechanisms underlying PTC, and eventually HIV-1 eradication.

In some HIV-1-infected individuals, viraemia remains undetectable after antiretroviral treatment, but which of these patients will experience viral rebound is difficult to predict. Here the authors show that T cell exhaustion markers before treatment are predictive of shorter time to viral rebound.

Initiation of Antiretroviral Therapy in Early Asymptomatic HIV Infection

BACKGROUND

Data from randomized trials are lacking on the benefits and risks of initiating antiretroviral therapy in patients with asymptomatic human immunodeficiency virus (HIV) infection who have a CD4+ count of more than 350 cells per cubic millimeter.

METHODS

We randomly assigned HIV-positive adults who had a CD4+ count of more than 500 cells per cubic millimeter to start antiretroviral therapy immediately (immediate-initiation group) or to defer it until the CD4+ count decreased to 350 cells per cubic millimeter or until the development of the acquired immunodeficiency syndrome (AIDS) or another condition that dictated the use of antiretroviral therapy (deferred-initiation group). The primary composite end point was any serious AIDS-related event, serious non-AIDS-related event, or death from any cause.

RESULTS

A total of 4685 patients were followed for a mean of 3.0 years. At study entry, the median HIV viral load was 12,759 copies per milliliter, and the median CD4+ count was 651 cells per cubic millimeter. On May 15, 2015, on the basis of an interim analysis, the data and safety monitoring board determined that the study question had been answered and recommended that patients in the deferred-initiation group be offered antiretroviral therapy. The primary end point occurred in 42 patients in the immediate-initiation group (1.8%; 0.60 events per 100 person-years), as compared with 96 patients in the deferred-initiation group (4.1%; 1.38 events per 100 person-years), for a hazard ratio of 0.43 (95% confidence interval [CI], 0.30 to 0.62; P<0.001). Hazard ratios for serious AIDS-related and serious non-AIDS-related events were 0.28 (95% CI, 0.15 to 0.50; P<0.001) and 0.61 (95% CI, 0.38 to 0.97; P=0.04), respectively. More than two thirds of the primary end points (68%) occurred in patients with a CD4+ count of more than 500 cells per cubic millimeter. The risks of a grade 4 event were similar in the two groups, as were the risks of unscheduled hospital admissions.

CONCLUSIONS

The initiation of antiretroviral therapy in HIV-positive adults with a CD4+ count of more than 500 cells per cubic millimeter provided net benefits over starting such therapy in patients after the CD4+ count had declined to 350 cells per cubic millimeter. (Funded by the National Institute of Allergy and Infectious Diseases and others; START ClinicalTrials.gov number, NCT00867048.).

The effect of short-course antiretroviral therapy initiated in primary HIV-1 infection on interleukin-6 and D-dimer levels

OBJECTIVE

Interruption of antiretroviral therapy (ART) in chronic HIV disease is associated with increased mortality, predicted by elevations in interleukin-6 (IL-6) and D-dimer. The effect of ART interruption in primary HIV-1 infection on these biomarkers is unknown.

METHODS

Plasma samples from 200 HIV seroconverters enrolled in the Short Pulse Anti-Retroviral Therapy At HIV Seroconversion trial of deferred ART (standard of care) - 12 or 48 week ART (ART12 or ART48, respectively) - were analysed for IL-6 and D-dimer at weeks 0, 12, 16, 48, 52, 60 and 108 after randomization. Changes in log10 levels from weeks 0 to 12 were analysed using linear regression, as were changes from baseline to 4 weeks after stopping ART. Areas under the biomarker-time curves (AUC) to week 108 were adjusted for baseline values, and compared across all arms.

RESULTS

Median (inter-quartile range) baseline IL-6 and D-dimer were 1.45 (0.88, 2.41) pg/ml and 0.34 (0.20, 0.50) mg/l, respectively. At week 12, D-dimer levels were significantly lower among treated compared to untreated individuals (P < 0.001), whereas IL-6 levels were similar (P = 0.23). Within 4 weeks from stopping ART, IL-6 and D-dimer levels rose by 22 and 18%, reaching pre-ART levels. Over 108-week follow-up, there was no difference between arms in IL-6 AUC (P = 0.53), but D-dimer AUC was significantly lower for ART12 and ART48 compared to standard of care (overall P = 0.008).

CONCLUSION

Stopping ART in primary HIV-1 infection leads to inflammatory biomarker rebound to pre-treatment levels. However, over 108-week follow-up, we found no evidence that biomarker levels were higher for those interrupting ART, compared to those remaining ART-naïve, and D-dimer levels were significantly lower.

Pharmacokinetic and Pharmacodynamic Comparison of Once-Daily Efavirenz (400 mg vs. 600 mg) in Treatment-Naïve HIV-Infected Patients: Results of the ENCORE1 Study

Daily efavirenz 400 mg (EFV400) was virologically noninferior to 600 mg (EFV600) at 48 weeks in treatment‐naïve patients. We evaluated EFV400 and EFV600 pharmacokinetics (NONMEM v. 7.2), assessing patient demographics and genetic polymorphisms (CYP2B6, CYP2A6, CYP3A4, NR1I3) as covariates and explored relationships with efficacy (plasma HIV‐RNA (pVL) <200 copies/mL) and safety outcomes at 48 weeks in 606 randomized ENCORE1 patients (female = 32%, African = 37%, Asian = 33%; EFV400 = 311, EFV600 = 295). CYP2B6 516G>T/983T>C/CYP2A6*9B/*17 and weight were associated with efavirenz CL/F. Exposure was significantly lower for EFV400 (geometric mean ratio, GMR; 90% confidence interval, CI: 0.73 (0.68–0.78)) but 97% (EFV400) and 98% (EFV600) of evaluable pVL was <200 copies/mL at 48 weeks (P = 0.802). Four of 20 patients with mid‐dose concentrations <1.0 mg/L had pVL ≥200 copies/mL (EFV400 = 1; EFV600 = 3). Efavirenz exposure was similar between those with and without efavirenz‐related side effects (GMR; 90% CI: 0.95 (0.88–1.02)). HIV suppression was comparable between doses despite significantly lower EFV400 exposure. Comprehensive evaluation of efavirenz pharmacokinetics/pharmacodynamics revealed important limitations in the accepted threshold concentration.

HIV Reactivation from Latency after Treatment Interruption Occurs on Average Every 5-8 Days--Implications for HIV Remission

HIV infection can be effectively controlled by anti-retroviral therapy (ART) in most patients. However therapy must be continued for life, because interruption of ART leads to rapid recrudescence of infection from long-lived latently infected cells. A number of approaches are currently being developed to ‘purge’ the reservoir of latently infected cells in order to either eliminate infection completely, or significantly delay the time to viral recrudescence after therapy interruption. A fundamental question in HIV research is how frequently the virus reactivates from latency, and thus how much the reservoir might need to be reduced to produce a prolonged antiretroviral-free HIV remission. Here we provide the first direct estimates of the frequency of viral recrudescence after ART interruption, combining data from four independent cohorts of patients undergoing treatment interruption, comprising 100 patients in total. We estimate that viral replication is initiated on average once every ≈6 days (range 5.1- 7.6 days). This rate is around 24 times lower than previous thought, and is very similar across the cohorts. In addition, we analyse data on the ratios of different ‘reactivation founder’ viruses in a separate cohort of patients undergoing ART-interruption, and estimate the frequency of successful reactivation to be once every 3.6 days. This suggests that a reduction in the reservoir size of around 50-70-fold would be required to increase the average time-to-recrudescence to about one year, and thus achieve at least a short period of anti-retroviral free HIV remission. Our analyses suggests that time-to-recrudescence studies will need to be large in order to detect modest changes in the reservoir, and that macaque models of SIV latency may have much higher frequencies of viral recrudescence after ART interruption than seen in human HIV infection. Understanding the mean frequency of recrudescence from latency is an important first step in approaches to prolong antiretroviral-free viral remission in HIV.

During treatment of HIV infection the virus persists in infected cells in a quiescent or ‘latent’ state. If treatment is stopped, then virus rebounds to detectable levels usually within 2–3 weeks. This is thought to occur due to release of infectious virus from a reservoir of long-lived latently infected cells. Reducing the number of latently infected cells should allow a prolonged period of HIV remission without antiviral treatment. A fundamental question is ‘how frequently does infectious virus emerge from the pool of latently infected cells?’, and thus how much would we need to reduce the number of latently infected cells to produce remission? Here we directly estimate the frequency of successful viral reactivation in four independent cohorts of patients undergoing treatment interruption. We find that active infection is initiated on average once every 5–8 days, considerably more slowly than previously thought. This has important implications for how much we need to reduce the number of latent cells in order to produce remission. Whereas previous analyses suggested that we would need to reduce the latent cell number 2000 fold to produce an average one-year remission, we show that reducing the latent cell number by 50–70 fold could achieve this aim.

Efficacy and safety of efavirenz 400 mg daily versus 600 mg daily: 96-week data from the randomised, double-blind, placebo-controlled, non-inferiority ENCORE1 study

BACKGROUND

The week 48 primary analysis of the ENCORE1 trial established the virological non-inferiority and safety of efavirenz 400 mg compared with the standard 600 mg dose, combined with tenofovir and emtricitabine, as first-line HIV therapy. This 96-week follow-up of the trial assesses the durability of efficacy and safety of this treatment over 96 weeks.

METHODS

ENCORE1 was a double-blind, placebo-controlled, non-inferiority trial done at 38 clinical sites in 13 countries. HIV-infected adult patients (≥16 years of age) with no previous antiretroviral therapy, a CD4 cell count of 50-500 cells per μL, and plasma HIV-1 viral load of at least 1000 copies per mL were randomly assigned (1:1) by an electronic case report form to receive fixed-dose daily tenofovir 300 mg and emtricitabine 200 mg plus efavirenz either 400 mg daily or 600 mg daily. Participants, physicians, and all other trial staff were masked to treatment assignment. Randomisation was stratified by HIV-1 viral load at baseline (≤ or >100 000 copies per mL). The primary endpoint was the difference in the proportions of patients in the two treatment groups with a plasma HIV-1 viral load below 200 copies per mL at week 96. Treatment groups were deemed to be non-inferior if the lower limit of the 95% CI for the difference in viral load was above -10% by modified intention-to-treat analysis. Non-inferiority was assessed in the modified intention-to-treat, per-protocol, and non-completer=failure (NC=F) populations. Adverse events and serious adverse events were summarised by treatment group. This study is registered with ClinicalTrials.gov, number NCT01011413.

FINDINGS

Between Aug 24, 2011, and March 19, 2012, 636 eligible participants were enrolled and randomly assigned to the two treatment groups (324 to efavirenz 400 mg and 312 to efavirenz 600 mg). The intention-to-treat population who received at least one dose of study drug comprised 630 patients: 321 in the efavirenz 400 mg group and 309 in the efavirenz 600 mg group. 585 patients (93%; 299 in the efavirenz 400 mg group and 286 in the 600 mg group) completed 96 weeks of follow-up. At 96 weeks, 289 (90·0%) of 321 patients in the efavirenz 400 mg group and 280 (90·6%) of 309 in the efavirenz 600 mg group had a plasma HIV-1 viral load less than 200 copies per mL (difference -0·6, 95% CI -5·2 to 4·0; p=0·72), which suggests continued non-inferiority of the lower efavirenz dose. Non-inferiority was recorded for thresholds of less than 50 and less than 400 copies per mL, irrespective of baseline plasma viral load. Adverse events were reported by 291 (91%) of 321 patients in the efavirenz 400 mg group and by 285 (92%) of 309 in the 600 mg group (p=0·48). The proportions of patients reporting an adverse event that was definitely or probably related to efavirenz were 126 (39%) for efavirenz 400 mg and 148 (48%) for efavirenz 600 mg (p=0·03). The number of patients who reported serious adverse events did not differ between the groups (p=0·20).

INTERPRETATION

Our findings confirm that efavirenz 400 mg is non-inferior to the standard dose of 600 mg in combination with tenofovir and emtricitabine as initial HIV therapy over 96 weeks. Fewer efavirenz-related adverse events were reported with the 400 mg efavirenz dose than with the 600 mg dose. These findings support the routine use of efavirenz 400 mg. The coadministration of rifampicin and efavirenz 400 mg needs further investigation.

FUNDING

Bill & Melinda Gates Foundation, and UNSW Australia.

Differences in the direction of change of cerebral function parameters are evident over three years in HIV-infected individuals electively commencing initial cART

Background

Changes in cerebral metabolite ratios (CMR) measured on ¹H-MRS and changes in cognitive function (CF) are described in subjects commencing combination antiretroviral therapy (cART), although the dynamics of such changes are poorly understood.

Methods

Neuroasymptomatic, HIV-infected subjects electively commencing cART were eligible. CMR were assessed in three anatomical voxels and CF assessed at baseline, week 48 and week 144. Overall differences in absolute change in CMRs and CF parameters between 0–48 and 48–144 weeks were assessed.

Results

Twenty-two subjects completed study procedures. Plasma HIV-RNA was <50 copies/mL in all at week 48 and in all, but two subjects at week 144. In general, between weeks 0–48 a rise in N-acetyl-aspartate(NAA)/Creatine(Cr) ratio and a decline in myo-Inositol(mI)/Cr ratio were observed. Between weeks 48–144, small rises in NAA/Cr ratio were observed in two anatomical voxels, whereas a rise in mI/Cr ratio was observed in all anatomical locations (0.31 (0.66) and -0.27 (1.35) between weeks 0–48 and 0.13 (0.91) and 1.13 (1.71) between weeks 48–144 for absolute changes in NAA/Cr and mI/Cr (SD) in frontal-grey voxel, respectively). Global CF score improved between weeks 0–48 and then declined between weeks 48–144 (0.63 (1.16) and -0.63 (0.1.41) for mean absolute change (SD) between weeks 0–48 and weeks 48–144, respectively).

Conclusions

The direction of change of cerebral function parameters differs over time in HIV-infected subjects commencing cART, highlighting the need for long-term follow-up in such studies. The changes we have observed between weeks 48–144 may represent the initial development of cerebral toxicities from cART.

Raltegravir non-inferior to nucleoside based regimens in second-line therapy with lopinavir/ritonavir over 96 weeks: a randomised open label study for the treatment of HIV-1 infection

Objective

To determine the durability over 96 weeks of safety and efficacy of lopinavir/ritonavir (LPV/r) and raltegravir (RAL) which was demonstrated to have non-inferior efficacy relative to a regimen of LPV/r with nucleoside/nucleotide reverse transcriptase inhibitors (N(t)RTIs) (Control) in primary analysis at 48 weeks.

Design

Open label, centrally randomised trial.

Setting

Recruitment was from 37 primary and secondary care sites from Africa, Asia, Australia, Europe and Latin America.

Subjects

541 HIV-1 infected adults virologically failing first-line non-NRTI + 2N(t)RTI, with no previous exposure to protease inhibitors or integrase strand transfer inhibitors were analysed, 425 completed 96 weeks follow up on randomised therapy.

Intervention

Randomisation was 1:1 to Control or RAL.

Main outcome measures

Differences between the proportion of participants with plasma HIV-1 RNA (VL) <200 copies/mL by intention to treat were compared with a non-inferiority margin of −12%. Differences in biochemical, haematological and metabolic changes were assessed using T-tests.

Results

VL <200 copies/mL at 96 weeks was: RAL 80.4%, Control 76.0% (difference: 4.4 [95%CI −2.6, 11.3]) and met non-inferiority criteria. The RAL arm had a significantly higher mean change (difference Control-RAL; 95%CI) in haemoglobin (−2.9; −5.7, −1.1), total lymphocytes (−0.2; −0.3, −0.0), total cholesterol (−0.5; −0.8, −0.3), HDL cholesterol (−0.1; −0.1, −0.0) and LDL cholesterol (−0.3; −0.5, −0.2).

Conclusion

At 96 weeks, both RAL and Control maintained efficacy greater than 75% and continued to demonstrate similar safety profiles. These results support the use of a combination LPV/r and RAL regimen as an option following failure of 1st line NNRTI + 2N(t)RTIs.

Trial Registration

ClinicalTrials.gov NCT00931463

Progression of Lipodystrophy (LD) with Continued Thymidine Analogue Usage: Long-Term Follow-Up from a Randomized Clinical Trial (The PIILR Study)

PURPOSE

During the 24-week PIILR study of protease inhibitor (PI) withdrawal, improved lipids and reduction in intraabdominal visceral fat was seen, however, there was also a loss of subcutaneous limb fat in patients with HIV-lipodystrophy (LD). It was hypothesized that overall improvement in LD may require a longer period of time off PIs.

METHOD

Follow-up of patients randomized to stop or continue PI-based therapy for 24 weeks, in a multicenter study, was continued for up to 120 weeks. Biochemistry and lipid parameters were assessed every 3 months. DEXA and CT scans were performed annually. Limb fat, visceral adipose tissue, and the lipodystrophy case definition score (LCDS) were used as indicators of LD severity.

RESULTS

Forty-five male patients with baseline and week 120 body composition data were assessed. There were no significant changes in the limb fat or visceral adipose tissue (VAT) components of LD, with the exception of the LCDS (change from baseline +5.79, p < .001). Control of viral replication was maintained and lipid and glycemic parameters were unchanged over the 120-week follow-up. Linear regression analysis showed on-study usage of stavudine was independently and significantly correlated with both decreased limb fat mass and a higher LCDS.

CONCLUSION

Body composition or metabolic features of LD did not improve over 2 years of observation in patients remaining on predominantly PI-sparing therapy. LD was adversely influenced by continued stavudine use.

Baseline HIV-1 resistance, virological outcomes, and emergent resistance in the SECOND-LINE trial: an exploratory analysis

BACKGROUND

WHO-recommended second-line antiretroviral therapy (ART) of a pharmacologically enhanced (boosted) protease inhibitor plus nucleoside or nucleotide reverse transcriptase inhibitors (NtRTIs) might be compromised by resistance. Results of the 96 week SECOND-LINE randomised trial showed that NtRTI-sparing ART with ritonavir-boosted lopinavir and raltegravir (raltegravir-group) provided non-inferior efficacy to ritonavir-boosted lopinavir and two or three NtRTIs (NtRTI-group) in participants with virological failure composed of a first-line regimen of a non-nucleoside reverse transcriptase inhibitor plus two NtRTIs. We report the relation of baseline virological resistance with virological failure and emergent resistance on study.

METHODS

As part of the randomised open-label SECOND-LINE trial, second-line ART NtRTI selection was made by either genotype (local laboratory) or algorithm. Genotypic resistance for the entire cohort at baseline was assessed on stored samples at a central laboratory. Virological failure was defined as plasma viral load greater than 200 copies per mL. Baseline viral isolates were assigned genotypic sensitivity scores (GSSs) by use of the Stanford HIV Database version 6.3.1: a global GSS (gGSS), defined as the combined GSS for lamivudine or emtricitabine, abacavir, zidovudine, stavudine, didanosine, and tenofovir and a specific GSS (sGSS) defined as the GSS for the ART regimen initiated by a specific participant. Emergent resistance was reported on samples with a viral load greater than 500 copies per mL. We used multivariate logistic regression with backward elimination to assess predictors of virological failure and emergent resistance.

FINDINGS

From April 19, 2010, to July 22, 2013, 271 patients were included in the NtRTI group and and 270 in the raltegravir group. In the NtRTI group 215 had available baseline sequence data, and 240 had viral load measurements at 96 weeks; in the raltegravir group 236 had baseline sequence data and 255 had viral load measurements at 96 weeks. Median (IQR) gGSS was 3.0 (1.3-4.3) in the NtRTI group and 3.0 (1.0-4.3) in the raltegravir group. The median sGSS in the NtRTI group was 1.0 (0.5-1.8). Multivariate analysis showed significant associations between virological failure and less than complete adherence at week 4 (odds ratio [OR] 2.18, 95%CI 1.07-4.47; p=0·03) and week 48 (2.49, 1.09-5.69; p=0.03), baseline plasma viral load greater than 100,000 copies per mL (3.43, 1.70-6.94; p=0.0006), baseline gGSS >4.25 (4.73, 1.94-11.6; p=0.0007), and being Hispanic (3.13, 1.21-8.13; p=0.02) or African (3.49, 1.68-7.28; p=0.0008) rather than Asian. We observed emergent major mutations in one (1%) of 129 participants for protease (both groups), eight (13%) of 64 for reverse transcriptase (NtRTI group) and 16 (20%) of 79 for integrase. Emergent resistance was associated with the raltegravir group (OR 2.47, 95% CI 1.02-5.99; p=0.05), baseline log10 viral load (1.83, 1.12-2.97; p=0.02), and absence of the Lys65Arg (K65R) or Lys70Glu (K70E) mutation at baseline (3.18, 1.12-9.02; p=0.03).

INTERPRETATION

Poor adherence was a major determinant of virological failure in people on second-line ART. In settings with limited resources, investment in optimisation of adherence rather than implementation of drug resistance testing might be advisable.

FUNDING

University of New South Wales Australia, Merck, AbbVie, and the Foundation for AIDS Research.

Cerebrospinal fluid exposure of efavirenz and its major metabolites when dosed at 400 mg and 600 mg once daily: a randomized controlled trial

BACKGROUND

The optimal penetration of antiretroviral agents into the central nervous system may be a balance between providing adequate drug exposure to inhibit human immunodeficiency virus (HIV) replication while avoiding concentrations associated with neuronal toxicities.

METHODS

Cerebrospinal fluid (CSF) exposure of efavirenz and the metabolites 7-hydroxy (7OH) and 8-hydroxy (8OH) efavirenz were assessed after at least 12 weeks of therapy in HIV-infected subjects randomized to commence antiretroviral regimens containing efavirenz at either 400 mg or 600 mg once daily.

RESULTS

Of 28 subjects (14 and 14 on efavirenz 400 mg and 600 mg, respectively), CSF HIV RNA was undetectable in all. Geometric mean CSF efavirenz, 7OH-, and 8OH-efavirenz concentrations (with 90% confidence intervals [CIs]) for the 400-mg and 600-mg dosing groups were 16.5 (13-21) and 19.5 (15-25) ng/mL; 0.6 (.4-.9) and 0.6 (.4-1) ng/mL; and 5.1 (4.0-6.4) and 3.1 (2.1-4.4) ng/mL, respectively. Efavirenz concentration in CSF was >0.51 ng/mL (proposed CSF 50% maximal inhibitory concentration for wild-type virus) in all subjects, and 8OH-efavirenz concentration in CSF was >3.3 ng/mL (a proposed toxicity threshold) in 11 of 14 and 7 of 14 subjects randomized to the 400 mg and 600 mg doses of efavirenz, respectively. Whereas CSF efavirenz concentration was significantly associated with plasma concentration (P < .001) and cytochrome P450 2B6 genotype (CSF efavirenz GG to GT/TT geometric mean ratio, 0.56 [90% CI, .42-.74]), CSF 8OH-efavirenz concentration was not (P = .242 for association and CSF 8OH-efavirenz GG to GT/TT geometric mean ratio, 1.52 [90% CI, .97-2.36]).

CONCLUSIONS

With both doses of efavirenz studied, CSF concentrations were considered adequate to inhibit HIV replication, although concentrations of 8OH-efavirenz were greater than those reportedly associated with neuronal toxicity. CSF exposure of 8OH-efavirenz was not dependent on plasma exposure and, as we postulate, may be subject to saturable pharmacokinetic effects.

CLINICAL TRIALS REGISTRATION

NCT01011413.

Association between first-year virological response to raltegravir and long-term outcomes in treatment-experienced patients with HIV-1 infection

BACKGROUND

We explored the relationship between virological response in the first year of treatment and long-term outcomes in the BENCHMRK studies.

METHODS

Patients failing antiretroviral treatment with 3-class resistant HIV-1 received double-blinded raltegravir (or placebo) with optimized background therapy (OBT) until week 156, followed by open-label raltegravir with OBT up to week 240. In this exploratory analysis of patients randomized to raltegravir, virological response over weeks 16-48 was categorized as continuous suppression (CS; viral RNA [vRNA] always <50 copies/ml), low-level viraemia (LLV; vRNA always <400 copies/ml, >50 copies/ml at least once), or not suppressed (NS; vRNA >400 copies/ml at least once). The association between these first-year vRNA response categories and baseline factors was analysed with univariate and multivariate models. Virological and immunological outcomes for years 2-5 were assessed by first-year vRNA response category (observed failure approach).

RESULTS

Baseline vRNA, baseline CD4(+) T-cell count and rapid viral decay (vRNA <50 copies/ml between weeks 2-12) correlated with first-year vRNA response (P<0.001); only rapid viral decay remained significant by multiple regression. Virological response rates were similar in the LLV and CS groups and lowest in the NS group. CD4(+) T-cell count increased through week 240 in the CS and LLV groups. Time to loss of virological response (confirmed vRNA ≥400 copies/ml) through week 240 did not support as strong a difference between the LLV and CS groups (log-rank P=0.11) as previously reported through weeks 156 and 192 (P<0.05).

CONCLUSIONS

Treatment-experienced patients on a raltegravir-based regimen with early LLV may have long-term virological and immunological benefit when their therapy is maintained.

Dose-Response Relationship of DNA and Recombinant Fowlpox Virus Prime-Boost HIV Vaccines: Implications for Future Trials

Estimating effective doses of novel HIV vaccines is challenging. Dose-response analyses of DNA and fowlpox virus HIV vaccines showed that 1 mg of DNA vaccine and 5 x 10(7)pfu of fowlpox virus booster was immunogenic in macaques. However, this dose was poorly immunogenic in humans. When adjusted for body surface area, the human dose studied was equivalent to a poorly immunogenic lower dose in monkeys. These data provide a rationale for guiding dosing in future trials of HIV vaccine technologies.

The Opposites Attract Study of viral load, HIV treatment and HIV transmission in serodiscordant homosexual male couples: design and methods

BACKGROUND

Studies in heterosexual HIV serodiscordant couples have provided critical evidence on the role of HIV treatments and undetectable viral load in reducing the risk of HIV transmission. There is very limited data on the risk of transmission from anal sex in homosexual male serodiscordant couples.

METHODS/DESIGN

The Opposites Attract Study is an observational prospective longitudinal cohort study of male homosexual serodiscordant partnerships running from 2012 to 2015 and conducted in clinics throughout Australia, Brazil and Thailand. Couples attend two or more clinic visits per year. The HIV-positive partner's viral load is tested and the HIV-negative partner is tested for HIV antibodies at every clinic visit. Results from any tests for sexually transmitted infections are also collected. Detailed behavioural questionnaires are completed by both partners at the time of each visit. The primary research question is whether HIV incidence is lower in those couples where the HIV-positive partner is receiving HIV treatment compared to couples where he is not receiving treatment. A voluntary semen sub-study will examine semen plasma viral load in a subsample of HIV-positive partners in Sydney, Rio de Janeiro and Bangkok. In cases of seroconversion of the initially HIV-negative partner, phylogenetic analysis will be conducted at the end of the study on virus from stored blood samples from both partners to determine if the infection came from the HIV-positive study partner. Men in new serodiscordant relationships will specifically be targeted for recruitment.

DISCUSSION

This study will provide critical data on the reduction in HIV transmission risk associated with being on HIV treatment in homosexual male serodiscordant couples in different regions of the world. Data from men in new relationships will be particularly valuable given that the highest transmission risk is in the first year of serodiscordant relationships. Furthermore, the detailed behavioural and attitudinal data from the participant questionnaires will allow exploration of many contextual factors associated with HIV risk, condom use and the negotiation of sexual practice within couples.

Antibody-dependent effector functions against HIV decline in subjects receiving antiretroviral therapy

BACKGROUND

Combination antiretroviral therapy (cART) effectively controls human immunodeficiency virus (HIV) infection but does not eliminate HIV, and lifelong treatment is therefore required. HIV-specific cytotoxic T lymphocyte (CTL) responses decline following cART initiation. Alterations in other HIV-specific immune responses that may assist in eliminating latent HIV infection, specifically antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent phagocytosis (ADP), are unclear.

METHODS

A cohort of 49 cART-naive HIV-infected subjects from Thailand (mean baseline CD4 count, 188 cells/µL; mean viral load, 5.4 log10 copies/mL) was followed for 96 weeks after initiating cART. ADCC and ADP assays were performed using serum samples obtained at baseline and after 96 weeks of cART.

RESULTS

A 35% reduction in HIV type 1 envelope (Env)-specific ADCC-mediated killing of target cells (P<.001) was observed after 96 weeks of cART. This was corroborated by a significant reduction in the ability of Env-specific ADCC antibodies to activate natural killer cells (P<.001). Significantly reduced ADP was also observed after 96 weeks of cART (P=.018).

CONCLUSIONS

This longitudinal study showed that cART resulted in significant reductions of HIV-specific effector antibody responses, including ADCC and ADP. Therapeutic vaccines or other immunomodulatory approaches may be required to improve antibody-mediated control of HIV during cART.

Moving away from Ritonavir, Abacavir, Tenofovir, and Efavirenz (RATE)--agents that concern prescribers and patients: a feasibility study and call for a trial

Objectives

Regimens sparing RATE (ritonavir, abacavir, tenofovir, efavirienz) agents might have better long-term safety. We conducted a feasibility exercise to assess the potential for a randomised trial evaluating RATE-sparing regimens.

Design

Observational.

Methods

We first calculated RATE-sparing options available to an average patient receiving RATE agents. We reviewed treatment history and all resistance assays from patients attending the St. Vincent’s Hospital (Sydney) clinic and receiving ≥2 RATE agents (n = 120). A viable RATE-sparing regimen with 2 or 3 fully-active agents was constructed from the following six ‘safer’ agents: rilpivirine or etravirine; atazanavir; raltegravir; maraviroc; and lamivudine. Activity for each drug was predicted as 1 (full-activity), 0.5 or 0 (no activity) using the Stanford mutation database. The utility of maraviroc was calculated assuming both maraviroc activity and inactivity where unknown. The analysis was restricted to regimens for which supporting evidence was identified in the literature or conference proceedings. Finally, we calculated the proportion of patients in the nationally representative Australian HIV Observational Database (AHOD) cohort receiving ≥2 RATE agents (n = 1473) to measure the potential population-level uptake of RATE-sparing agents.

Results

Assuming full maraviroc activity, 117(97.5%) and 107(89.2%) individuals had at least one option with 2 or 3 active RATE-sparing agents, respectively. Assuming no maraviroc activity this decreased to 113(94.2%) and 104(86.7%), respectively. In AHOD, 837(56.8%) patients were receiving ≥2 RATE agents.

Conclusion

Feasible treatment switch options sparing RATE agents exist for the majority of patients. Understanding the pros and cons of switching stable patients onto new RATE-sparing regimens requires evidence derived from randomised controlled trials.

HLA alleles association with changes in bone mineral density in HIV-1-infected adults changing treatment to tenofovir-emtricitabine or abacavir-lamivudine

Background

There are limited data regarding the influence of human leukocyte antigen (HLA) polymorphisms on reduced bone mineral density (BMD). We investigated the relationship between HLA supertypes and BMD in HIV-infected adults changing their existing treatment to tenofovir-emtricitabine (TDF-FTC) or abacavir-lamivudine (ABC-3TC) in the STEAL study.

Methods

Lumbar spine and right hip BMD were measured by Dual-energy X-ray absorptiometry (DXA). HLA genotypes at the 2-digit level were classified into class I and II supertypes. Student's t-tests were used to test the association between HLA supertypes and changes in hip and spine BMD over 96 weeks for the whole cohort and stratified by randomised groups. The relationship between HLA supertypes and BMD was also assessed in the subgroup of participants that were naïve to both ABC and TDF at study entry.

Results

Class II supertypes were mainly associated with hip BMD change. Overall, compared to participants not carrying HLA-DQ3, participants expressing DQ3 had less bone loss over 96 weeks at both the hip and spine (hip: 0.003 vs. −0.006 g/cm², 95%CI 0.002 to 0.017, p = 0.016; spine: 0.006 vs. −0.006 g/cm², 95%CI 0.001 to 0.023, p = 0.041). In participants that were naïve to both ABC and TDF at baseline and randomised to TDF-FTC, DQ3 was significantly associated with less bone loss compared with those not carrying DQ3 (hip: 0.001 vs. −0.032 g/cm²; diff 0.033; 95%CI 0.017 to 0.049; p<0.001; spine: 0.007 vs. −0.023 g/cm²; diff 0.035; 95%CI 0.014 to 0.056; p = 0.001).

Conclusions

In this cohort of HIV-infected adults, there was an association between bone status and HLA supertypes, particularly HLA-DQ3.

Trial Registration

Clinicaltrials.gov NCT00192634

Determinants of suicide and accidental or violent death in the Australian HIV Observational Database

Background

Rates of suicide and accidental or violent death remain high in HIV-positive populations despite significantly improved prognosis since the introduction of cART.

Methods

We conducted a nested case-control study of suicide and accidental or violent death in the Australian HIV Observational Database (AHOD) between January 1999 and March 2012. For each case, 2 controls were matched by clinic, age, sex, mode of exposure and HIV-positive date to adjust for potential confounding by these covariates. Risk of suicide and accidental or violent death was estimated using conditional logistic regression.

Results

We included 27 cases (17 suicide and 10 violent/accidental death) and 54 controls. All cases were men who have sex with men (MSM) or MSM/ injecting drug use (IDU) mode of exposure. Increased risk was associated with unemployment (Odds Ratio (OR) 5.86, 95% CI: 1.69–20.37), living alone (OR 3.26, 95% CI: 1.06–10.07), suicidal ideation (OR 6.55, 95% CI: 1.70–25.21), and >2 psychiatric/cognitive risk factors (OR 4.99, 95% CI: 1.17–30.65). CD4 cell count of >500 cells/µL (OR 0.25, 95% CI: 0.07–0.87) and HIV-positive date ≥1990 (1990–1999 (OR 0.31, 95% CI: 0.11–0.89), post-2000 (OR 0.08, 95% CI: 0.01–0.84)) were associated with decreased risk. CD4 cell count ≥500 cells/µL remained a significant predictor of reduced risk (OR 0.15, 95% CI: 0.03–0.70) in a multivariate model adjusted for employment status, accommodation status and HIV-positive date.

Conclusions

After adjustment for psychosocial factors, the immunological status of HIV-positive patients contributed to the risk of suicide and accidental or violent death. The number of psychiatric/cognitive diagnoses contributed to the level of risk but many psychosocial factors were not individually significant. These findings indicate a complex interplay of factors associated with risk of suicide and accidental or violent death.