Determinants of Virologic and Immunologic Outcomes in Chronically HIV-Infected Subjects Undergoing Repeated Treatment Interruptions: The Istituto Superiore di Sanità-Pulsed Antiretroviral Therapy (ISS-PART) Study

The Effect of HIV Treatment Interruption on Subsequent Immunological Response

Recovery of CD4-positive T lymphocyte count after initiation of antiretroviral therapy (ART) has been thoroughly examined among people with human immunodeficiency virus infection. However, immunological response after restart of ART following care interruption is less well studied. We compared CD4 cell-count trends before disengagement from care and after ART reinitiation. Data were obtained from the East Africa International Epidemiology Databases to Evaluate AIDS (IeDEA) Collaboration (2001-2011; n = 62,534). CD4 cell-count trends before disengagement, during disengagement, and after ART reinitiation were simultaneously estimated through a linear mixed model with 2 subject-specific knots placed at the times of disengagement and treatment reinitiation. We also estimated CD4 trends conditional on the baseline CD4 value. A total of 10,961 patients returned to care after disengagement from care, with the median gap in care being 2.7 (interquartile range, 2.1-5.4) months. Our model showed that CD4 cell-count increases after ART reinitiation were much slower than those before disengagement. Assuming that disengagement from care occurred 12 months after ART initiation and a 3-month treatment gap, CD4 counts measured at 3 years since ART initiation would be lower by 36.5 cells/μL than those obtained under no disengagement. Given that poorer CD4 restoration is associated with increased mortality/morbidity, specific interventions targeted at better retention in care are urgently required.

Systematic Review and Meta-analysis of Treatment Interruptions in Human Immunodeficiency Virus (HIV) Type 1-infected Patients Receiving Antiretroviral Therapy: Implications for Future HIV Cure Trials

BACKGROUND

Safety and tolerability of analytical treatment interruptions (ATIs) as a vital part of human immunodeficiency virus type 1 (HIV-1) cure studies are discussed. We analyzed current evidence for the occurrence of adverse events (AEs) during TIs.

METHODS

Our analysis included studies that reported on AEs in HIV-1-infected patients undergoing TIs. All interventional and observational studies were reviewed, and results were extracted based on predefined criteria. The proportion of AEs was pooled using random-effects models. Metaregression was used to explore the influence of baseline CD4+ T-cell count, viral load, study type, previous time on combined antiretroviral therapy, and follow-up interval during TIs.

RESULTS

We identified 1048 studies, of which 22 studies including 7104 individuals fulfilled the defined selection criteria. Included studies had sample sizes between 6 and 5472 participants, with durations of TI cycles ranging from 7 days to 27 months. The intervals of HIV-1-RNA testing varied from 2 days to 3 months during TIs. The overall proportion of AEs during TIs >4 weeks was 3% (95% confidence interval [CI], 0%-7%) and was lower in studies with follow-up intervals ≤14 days (0%; 95% CI, 0%-1%) than in studies with wider follow-up intervals (6%; 95% CI, 2%-13%; P value for interaction = .01).

CONCLUSIONS

We found moderate-quality evidence indicating that studies with narrow follow-up intervals did not show a substantial increase in AEs during TIs. Our findings indicate that ATI may be a safe strategy as part of HIV-1 cure trials by closely monitoring for HIV-1 rebound.

Brain tissue transcriptomic analysis of SIV-infected macaques identifies several altered metabolic pathways linked to neuropathogenesis and poly (ADP-ribose) polymerases (PARPs) as potential therapeutic targets

Despite improvements in antiretroviral therapy, human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) remain prevalent in subjects undergoing therapy. HAND significantly affects individuals' quality of life, as well as adherence to therapy, and, despite the increasing understanding of neuropathogenesis, no definitive diagnostic or prognostic marker has been identified. We investigated transcriptomic profiles in frontal cortex tissues of Simian immunodeficiency virus (SIV)-infected Rhesus macaques sacrificed at different stages of infection. Gene expression was compared among SIV-infected animals (n = 11), with or without CD8+ lymphocyte depletion, based on detectable (n = 6) or non-detectable (n = 5) presence of the virus in frontal cortex tissues. Significant enrichment in activation of monocyte and macrophage cellular pathways was found in animals with detectable brain infection, independently from CD8+ lymphocyte depletion. In addition, transcripts of four poly (ADP-ribose) polymerases (PARPs) were up-regulated in the frontal cortex, which was confirmed by real-time polymerase chain reaction. Our results shed light on involvement of PARPs in SIV infection of the brain and their role in SIV-associated neurodegenerative processes. Inhibition of PARPs may provide an effective novel therapeutic target for HIV-related neuropathology.

Long-term clinical, virological and immunological outcomes following planned treatment interruption in HIV-infected children

OBJECTIVES

Planned treatment interruption (PTI) of antiretroviral therapy (ART) in adults is associated with adverse outcomes. The PENTA 11 trial randomized HIV-infected children to continuous ART (CT) vs. CD4-driven PTIs. We report 5 years' follow-up after the end of main trial.

METHODS

Post-trial, all children resumed ART. Clinical, immunological, virological and treatment data were collected annually. A sub-study investigated more detailed immunophenotype. CT and PTI arms were compared using intention-to-treat. Laboratory parameters were compared using linear regression, adjusting for baseline values; mixed models were used to include all data over time.

RESULTS

In all, 101 children (51 CT, 50 PTI) contributed a median of 7.6 years, including 5.1 years of post-trial follow-up. Post-trial, there were no deaths, one pulmonary tuberculosis and no other CDC stage B/C events. At 5 years post-trial, 90% of children in the CT vs. 82% in the PTI arm had HIV RNA < 50 copies/mL (P = 0.26). A persistent increase in CD8 cells was observed in the PTI arm. The sub-study (54 children) suggested that both naïve and memory populations contributed to higher CD8 cells following PTI. Mean CD4/CD8 ratios at 5 years post-trial were 1.22 and 1.08 in CT and PTI arms, respectively [difference (CT - PTI) = -0.15; 95% CI: -0.34-0.05), P = 0.14]. The sub-study also suggested that during the trial and at early timepoints after the end of the trial, reduction in CD4 in the PTI arm was mainly from loss of CD4 memory cells.

CONCLUSIONS

Children tolerated PTI with few long-term clinical, virological or immunological consequences.

CD4 recovery following antiretroviral treatment interruptions in children and adolescents with HIV infection in Europe and Thailand

OBJECTIVES

The aim of the study was to explore factors associated with CD4 percentage (CD4%) reconstitution following treatment interruptions (TIs) of antiretroviral therapy (ART).

METHODS

Data from paediatric HIV-infected cohorts across 17 countries in Europe and Thailand were pooled. Children on combination ART (cART; at least three drugs from at least two classes) for > 6 months before TI of ≥ 30 days while aged < 18 years were included. CD4% at restart of ART (r-ART) and in the long term (up to 24 months after r-ART) following the first TI was modelled using asymptotic regression.

RESULTS

In 779 children with at least one TI, the median age at first TI was 10.1 [interquartile range (IQR) 6.4, 13.6] years and the mean CD4% was 27.3% [standard deviation (SD) 11.0%]; the median TI duration was 9.0 (IQR 3.5, 22.5) months. In regression analysis, the mean CD4% was 19.2% [95% confidence interval (CI) 18.3, 20.1%] at r-ART, and 27.1% (26.2, 27.9%) in the long term, with half this increase in the first 6 months. r-ART and long-term CD4% values were highest in female patients and in children aged < 3 years at the start of TI. Long-term CD4% was highest in those with a TI lasting 1 to <3 months, those with r-ART after year 2000 and those with a CD4% nadir ≥ 25% (all P < 0.001). The effect of CD4% nadir during the TI differed significantly (P = 0.038) by viral suppression at the start of the TI; in children with CD4% nadir < 15% during TI, recovery was better in those virally suppressed prior to the TI; viral suppression was not associated with recovery in children with CD4% nadir ≥ 25%.

CONCLUSIONS

After restart of ART following TI, most children reconstituted well immunologically. Nevertheless, several factors predicted better immunological reconstitution, including younger age and higher nadir CD4% during TI.

Clinical trials of antiretroviral treatment interruption in HIV-infected individuals

: Despite the benefits of antiretroviral therapy (ART) for people living with HIV, there has been a long-standing research interest in interrupting ART as a strategy to minimize adverse effects of ART as well as to test interventions aiming to achieve a degree of virological control without ART. We performed a systematic review of HIV clinical studies involving treatment interruption from 2000 to 2017 to describe the differences between treatment interruption in studies that contained and didn't contain an intervention. We assessed differences in monitoring strategies, threshold to restart ART, duration and adverse outcomes of treatment interruption, and factors aimed at minimizing transmission. We found that treatment interruption has been incorporated into 159 clinical studies since 2000 and is increasingly being included in trials to assess the efficacy of interventions to achieve sustained virological remission off ART. Great heterogeneity was noted in immunological, virological and clinical monitoring strategies, as well as in thresholds to recommence ART. Treatment interruption in recent intervention studies were more closely monitored, had more conservative thresholds to restart ART and had a shorter treatment interruption duration, compared with older treatment interruption studies that didn't include an intervention.

Compartmentalized HIV rebound in the central nervous system after interruption of antiretroviral therapy

To design effective eradication strategies, it may be necessary to target HIV reservoirs in anatomic compartments other than blood. This study examined HIV RNA rebound following interruption of antiretroviral therapy (ART) in blood and cerebrospinal fluid (CSF) to determine whether the central nervous system (CNS) might serve as an independent source of resurgent viral replication.

Paired blood and CSF samples were collected longitudinally from 14 chronically HIV-infected individuals undergoing ART interruption. HIV env (C2-V3), gag (p24) and pol (reverse transcriptase) were sequenced from cell-free HIV RNA and cell-associated HIV DNA in blood and CSF using the Roche 454 FLX Titanium platform. Comprehensive sequence and phylogenetic analyses were performed to search for evidence of unique or differentially represented viral subpopulations emerging in CSF supernatant as compared with blood plasma.

Using a conservative definition of compartmentalization based on four distinct statistical tests, nine participants presented a compartmentalized HIV RNA rebound within the CSF after interruption of ART, even when sampled within 2 weeks from viral rebound. The degree and duration of viral compartmentalization varied considerably between subjects and between time-points within a subject. In 10 cases, we identified viral populations within the CSF supernatant at the first sampled time-point after ART interruption, which were phylogenetically distinct from those present in the paired blood plasma and mostly persisted over time (when longitudinal time-points were available). Our data suggest that an independent source of HIV RNA contributes to viral rebound within the CSF after treatment interruption. The most likely source of compartmentalized HIV RNA is a CNS reservoir that would need to be targeted to achieve complete HIV eradication.

Adherence to Antiretroviral Therapy Among Children Living with HIV in South India

Adherence to ART, fundamental to treatment success, has been poorly studied in India. Caregivers of children attending HIV clinics in southern India were interviewed using structured questionnaires. Adherence was assessed using a visual analogue scale representing past-month adherence and treatment interruptions >48 h during the past 3 months. Clinical features, correlates of adherence and HIV-1 viral-load were documented. Based on caregiver reports, 90.9 % of the children were optimally adherent. In multivariable analysis, experiencing ART-related adverse effects was significantly associated with suboptimal adherence (p = 0.01). The proportion of children who experienced virological failure was 16.5 %. Virological failure was not linked to suboptimal adherence. Factors influencing virological failure included running out of medications (p = 0.002) and the child refusing to take medications (p = 0.01). Inclusion of drugs with better safety profiles and improved access to care could further enhance outcomes.

Immunity, inflammation and reservoir in patients at an early stage of HIV infection on intermittent ART (ANRS 141 TIPI Trial)

OBJECTIVES

The objective of this study was to assess clinical and biological changes during intermittent ART (I-ART) started early, with significant time spent on versus off ART, which has never before been studied in ART-naive patients with high nadir and current CD4 cell count.

PATIENTS AND METHODS

ART-naive HIV-1-infected patients with baseline CD4 ≥ 500/mm(3) and nadir CD4 ≥ 400/mm(3) received 2 years of I-ART (6 month periods on once-daily boosted-PI-based ART, alternating with 6 month periods without ART) in a 2 year, Phase II, non-comparative multicentre trial. The trial is registered with ClinicalTrials.gov, number NCT 00820118.

RESULTS

The CD4 cell count remained ≥ 500/mm(3) at 2 years in all 44 patients included in the study. The mean 2 year count was higher than the mean count at baseline in 24 patients overall (55%; 95% CI 40%-69%) and in 20 (65%; 95% CI 48%-81%) of the 31 patients who fully adhered to the trial strategy. All but three of these latter patients had HIV-1 RNA concentrations below 50 copies/mL after each 6 month 'on' period. Only one strategy-related genotypic mutation (M184I) was detected. The HIV-1 DNA median load fluctuated, but it did not differ between month 0 and month 24 (2.8 versus 2.6 log10 copies/10(6) leucocytes, P = 0.29). Biomarkers of inflammation and endothelial activation remained stable between month 0 and month 24. Naive CD4, CD8+CCR5+ and CD8+CD38+ T cell numbers tended to decline. One patient developed Burkitt's lymphoma and 12 patients reported sexually transmitted infections.

CONCLUSIONS

In patients with high nadir and current CD4 cell counts, 2 year I-ART maintained the CD4 cell count above 500/mm(3), with no increase in the viral reservoir. Immune activation seems related to HIV replication, while inflammation seems to evolve independently and require specific attention.

The immunological and virological consequences of planned treatment interruptions in children with HIV infection

OBJECTIVES

To evaluate the immunological and viral consequences of planned treatment interruptions (PTI) in children with HIV.

DESIGN

This was an immunological and virological sub-study of the Paediatric European Network for Treatment of AIDS (PENTA) 11 trial, which compared CD4-guided PTI of antiretroviral therapy (ART) with continuous therapy (CT) in children.

METHODS

HIV-1 RNA and lymphocyte subsets, including CD4 and CD8 cells, were quantified on fresh samples collected during the study; CD45RA, CD45RO and CD31 subpopulations were evaluated in some centres. For 36 (18 PTI, 18 CT) children, immunophenotyping was performed and cell-associated HIV-1 DNA analysed on stored samples to 48 weeks.

RESULTS

In the PTI group, CD4 cell count fell rapidly in the first 12 weeks off ART, with decreases in both naïve and memory cells. However, the proportion of CD4 cells expressing CD45RA and CD45RO remained constant in both groups. The increase in CD8 cells in the first 12 weeks off ART in the PTI group was predominantly due to increases in RO-expressing cells. PTI was associated with a rapid and sustained increase in CD4 cells expressing Ki67 and HLA-DR, and increased levels of HIV-1 DNA.

CONCLUSIONS

PTI in children is associated with rapid changes in CD4 and CD8 cells, likely due to increased cell turnover and immune activation. However, children off treatment may be able to maintain stable levels of naïve CD4 cells, at least in proportion to the memory cell pool, which may in part explain the observed excellent CD4 cell recovery with re-introduction of ART.

HIV-1 coreceptor switch during 2 years of structured treatment interruptions

The purpose of this investigation was to determine the impact on human immunodeficiency virus (HIV) tropism of uncontrolled virus exposure during 2 years of intermittent highly active antiretroviral therapy (HAART). The Istituto Superiore di Sanità-Pulsed Antiretroviral Therapy (ISS-PART) randomized study compared the outcome of 2 years of structured treatment interruptions (STIs) versus standard continuous treatment in first-line HAART responder subjects. The STI schedule consisted of five STIs of 1, 1, 2, 2, and 3 months, respectively, separated by four periods of 3-month therapy. In the present study, coreceptor tropism was assessed in 12 patients of the STI arm at different time points over a period of 2 years. Tropism was determined on DNA and RNA by V3 loop region sequencing. The Geno2pheno algorithm (false-positive rate, FPR: 20%) was used for data interpretation. At baseline, 9/12 subjects (75.0%) had CCR5-tropic viruses in their HIV. Three had a CXCR4-tropic virus. Ten patients maintained the same coreceptor in DNA after 2 years, whereas in two patients, a shift occurred (one R5-X4, one X4-R5). In a patient with an R5 virus at baseline, a transient change to X4 tropism was seen in the rebounding virus during STI. Changes in tropism were not associated with the amplitude and duration of virus exposure during STIs, residual viremia at baseline, or the development of resistance mutations in the RT region. Our preliminary results suggest that viral replication, observed after short periods of treatment interruption, is not enough to drive the evolution of HIV tropism.

Adherence to antiretroviral therapy and acceptability of planned treatment interruptions in HIV-infected children

There have been no paediatric randomised trials describing the effect of planned treatment interruptions (PTIs) of antiretroviral therapy (ART) on adherence, or evaluating acceptability of such a strategy. In PENTA 11, HIV-infected children were randomised to CD4-guided PTIs (n = 53) or continuous therapy (CT, n = 56). Carers, and children if appropriate, completed questionnaires on adherence to ART and acceptability of PTIs. There was no difference in reported adherence on ART between CT and PTI groups; non-adherence (reporting missed doses over the last 3 days or marking <100 % adherence since the last clinical visit on a visual analogue scale) was 18 % (20/111) and 14 % (12/83) on carer questionnaires in the CT and PTI groups respectively (odds ratios, OR (95 % CI) = 1.04 (0.20, 5.41), χ² (1) = 0.003, p = 0.96). Carers in Europe/USA reported non-adherence more often (31/121, 26 %) than in Thailand (1/73, 1 %; OR (95 % CI) = 54.65 (3.68, 810.55), χ² (1) = 8.45, p = 0.004). The majority of families indicated they were happy to have further PTIs (carer: 23/36, 64 %; children: 8/13, 62 %), however many reported more clinic visits during PTI were a problem (carer: 15/36, 42 %; children: 6/12, 50 %).

Standing genetic variation and the evolution of drug resistance in HIV

Drug resistance remains a major problem for the treatment of HIV. Resistance can occur due to mutations that were present before treatment starts or due to mutations that occur during treatment. The relative importance of these two sources is unknown. Resistance can also be transmitted between patients, but this process is not considered in the current study. We study three different situations in which HIV drug resistance may evolve: starting triple-drug therapy, treatment with a single dose of nevirapine and interruption of treatment. For each of these three cases good data are available from literature, which allows us to estimate the probability that resistance evolves from standing genetic variation. Depending on the treatment we find probabilities of the evolution of drug resistance due to standing genetic variation between and . For patients who start triple-drug combination therapy, we find that drug resistance evolves from standing genetic variation in approximately 6% of the patients. We use a population-dynamic and population-genetic model to understand the observations and to estimate important evolutionary parameters under the assumption that treatment failure is caused by the fixation of a single drug resistance mutation. We find that both the effective population size of the virus before treatment, and the fitness of the resistant mutant during treatment, are key-parameters which determine the probability that resistance evolves from standing genetic variation. Importantly, clinical data indicate that both of these parameters can be manipulated by the kind of treatment that is used.

For HIV patients who are treated with antiretroviral drugs, treatment usually works well. However, the virus can, and sometimes does, become resistant against one or more drugs. HIV drug resistance results from the acquisition of specific and well known mutations. It is currently unknown whether drug resistance mutations usually stem from standing genetic variation, i.e., they were already present at low frequency before treatment started, or whether they tend to occur during treatment. In the current manuscript, I make use of several large datasets and evolutionary modeling to estimate the probability that drug resistance mutations are present before treatment starts and lead to viral failure. I find that for the most common type of treatment with a combination of three drugs, drug resistance evolves from pre-existing mutations in 6% of the patients. With other types of treatment, this probability varies from 0 to 39%. I conclude that there is room for improvement in preventing the evolution of drug resistance from pre-existing mutations.

Limited risk of drug resistance after discontinuation of antiretroviral prophylaxis for the prevention of breastfeeding transmission of HIV

We evaluated 70 HIV-infected pregnant women with CD4⁺ cell count >350 cells per cubic millimeter who received zidovudine, lamivudine, and nevirapine from week 25 of gestation until 6 months after delivery and a 3-week tail of zidovudine and lamivudine at the moment of drug discontinuation. Forty days after the interruption of all drugs resistance mutations were present in 5 of 70 (7.1%) women. Two of them had the same mutation archived in baseline HIV DNA. The other 3 women had, at least once, detectable viral load and presence of mutations during treatment. Overall, the risk of developing resistance mutations in compliant women was low.

Randomized trial of time-limited interruptions of protease inhibitor-based antiretroviral therapy (ART) vs. continuous therapy for HIV-1 infection

Background

The clinical outcomes of short interruptions of PI-based ART regimens remains undefined.

Methods

A 2-arm non-inferiority trial was conducted on 53 HIV-1 infected South African participants with viral load <50 copies/ml and CD4 T cell count >450 cells/µl on stavudine (or zidovudine), lamivudine and lopinavir/ritonavir. Subjects were randomized to a) sequential 2, 4 and 8-week ART interruptions or b) continuous ART (cART). Primary analysis was based on the proportion of CD4 count >350 cells(c)/ml over 72 weeks. Adherence, HIV-1 drug resistance, and CD4 count rise over time were analyzed as secondary endpoints.

Results

The proportions of CD4 counts >350 cells/µl were 82.12% for the intermittent arm and 93.73 for the cART arm; the difference of 11.95% was above the defined 10% threshold for non-inferiority (upper limit of 97.5% CI, 24.1%; 2-sided CI: −0.16, 23.1). No clinically significant differences in opportunistic infections, adverse events, adherence or viral resistance were noted; after randomization, long-term CD4 rise was observed only in the cART arm.

Conclusion

We are unable to conclude that short PI-based ART interruptions are non-inferior to cART in retention of immune reconstitution; however, short interruptions did not lead to a greater rate of resistance mutations or adverse events than cART suggesting that this regimen may be more forgiving than NNRTIs if interruptions in therapy occur.

Trial Registration

ClinicalTrials.gov NCT00100646

CD8 T-Cell Responses before and after Structured Treatment Interruption in Ugandan Adults Who Initiated ART with CD4 T Cells <200 Cell/μL: The DART Trial STI Substudy

Objective. To better understand attributes of ART-associated HIV-induced T-cell responses that might be therapeutically harnessed. Methods. CD8(+) T-cell responses were evaluated in some HIV-1 chronically infected participants of the fixed duration STI substudy of the DART trial. Magnitudes, breadths, and functionality of IFN-γ and Perforin responses were compared in STI (n = 42) and continuous treatment (CT) (n = 46) before and after a single STI cycle when the DART STI trial was stopped early due to inferior clinical outcome in STI participants. Results. STI and CT had comparable magnitudes and breadths of monofunctional CD8(+)IFNγ(+) and CD8(+)Perforin(+) responses. However, STI was associated with significant decline in breadth of bi-functional (CD8(+)IFNγ(+)Perforin(+)) responses; P = .02, Mann-Whitney test. Conclusions. STI in individuals initiated onto ART at <200 CD4(+) T-cell counts/μl significantly reduced occurrence of bifunctional CD8(+)IFNγ(+)/Perforin(+) responses. These data add to others that found no evidence to support STI as a strategy to improve HIV-specific immunity during ART.

Nonnucleoside reverse transcriptase inhibitor concentrations during treatment interruptions and the emergence of resistance: a substudy of the ISS-PART Trial

Emergence of resistance is one of the drawbacks associated with treatment interruptions (TI), especially when regimens include nonnucleoside reverse transcriptase inhibitors (NNRTIs), because of their long half-life. ISS-PART was a randomized trial comparing a continuous treatment arm with a TI arm in which 136 patients underwent five treatment interruptions, each followed by 3 months of therapy, over 2 years. To minimize the potential risk of developing resistance, patients on NNRTIs were requested, at each TI, to interrupt nevirapine (NVP) or efavirenz (EFV) 3 or 6 days before the other drugs, respectively. To determine if a difference in drug levels existed during TIs between patients with and without resistance we compared NNRTI concentrations in the 12 patients (6 on NVP and 6 on EFV) who developed NNRTI mutations during TIs with those of 20 patients (10 on NVP and 10 on EFV) who retained a wild-type virus. Genotypic resistance and drug concentrations were analyzed on plasma samples collected 15 days after each drug interruption. Overall, EFV was quantifiable in 28% (16/57) and NVP in 22.9% (14/61) of evaluable samples collected during TIs, with no difference between patients with and without mutations. Median EFV or NVP concentrations at each TI were not significantly different between patients with and without mutations. Although the staggered stop strategy was not completely effective in preventing exposure to suboptimal levels, no evident correlation was found between NNRTI concentrations and the emergence of resistance, suggesting that other factors (such as the presence of drug-resistant minority variants) could also play an important role in these patients.

Response to planned treatment interruptions in HIV infection varies across childhood

OBJECTIVE

To evaluate clinical, immunological and virological consequences of CD4-guided antiretroviral therapy (ART) planned treatment interruptions (PTIs) compared with continuous therapy in children with chronic HIV infection in the Paediatric European Network for Treatment of AIDS 11 trial.

DESIGN

This was a multicentre, 72-week, open, randomized, phase II trial.

METHODS

One hundred and nine children with HIV-RNA below 50 copies/ml and CD4% of at least 30% (2-6 years) or at least 25% and CD4 cell count of at least 500 cells/microl (7-15 years) were randomized to continuous therapy (53) or PTI (56). In PTI, ART was restarted if confirmed CD4% was less than 20% or more than 48 weeks had been spent off ART. The primary outcome was Centers for Disease Control and Prevention (CDC) stage C event, death or CD4% less than 15% (and CD4 cell count less than 200 cells/microl for children aged 7-15 years).

RESULTS

At baseline, median (interquartile range) age was 9 (6-12) years, CD4% 37% (33-41), CD4 cell count 966 (793-1258) cells/microl, nadir CD4% before combination ART 18% (10-27), time on ART 6 (3-6) years and 26% were CDC stage C. After median (range) 130 (33-180) weeks of follow-up, 4 versus 48% of time was spent off ART in continuous therapy and PTI, respectively. No child died or had a new CDC stage C event; one (2%) continuous therapy versus four (7%) PTI children had a primary outcome based on CD4%/cell count (P = 0.2). Lower nadir CD4% predicted faster CD4% decline after stopping ART. Younger age and higher nadir CD4% predicted being off ART for at least 48 weeks and better CD4% recovery following PTI.

CONCLUSION

In this first paediatric trial of PTI, there were no serious clinical outcomes. Younger children had better CD4% recovery after PTIs. Immunology substudies and long-term follow-up in Paediatric European Network for Treatment of AIDS 11 trial are ongoing. Further research into the role of treatment interruption in children is required, particularly, as guidelines now recommend early ART for all infected infants.

Incidence and risk factors of thrombocytopenia in patients receiving intermittent antiretroviral therapy: a substudy of the ANRS 106-window trial

BACKGROUND

Incidence and risk factors for thrombocytopenia in patients discontinuing highly active antiretroviral therapy (HAART) have not been fully investigated.

METHODS

Well-suppressed patients on HAART were randomized to continuous (CT) or intermittent therapy (IT) for 96 weeks. Incidence of thrombocytopenia (<150 x 10(3) platelets/mm(3)) was assessed and multivariate analysis performed to identify baseline predictors. Correlations were assessed between platelet, CD4, CD8 T-cell counts, and viral load after treatment interruption.

RESULTS

Three hundred ninety-one patients were included, with a median baseline platelet count of 243,000/mm(3). The incidence of thrombocytopenia at week 96 was significantly higher in the IT versus the CT arm (25.4% versus 9.8%, respectively, P < 0.001) and median time to thrombocytopenia was 9 weeks. In multivariate analysis, the IT strategy: odds ratio (OR) = 4.1 (2.1-7.9; P < 0.0001), a history of thrombocytopenia: OR = 11.9 (2.4-57.9; P = 0.002), and a low baseline platelet count: OR = 3.4 (2.3-5.1; P < 0.0001) were associated with an increased risk of thrombocytopenia. Also, after treatment interruption, changes from baseline in platelet counts were correlated with changes in CD4 T-cell counts and plasma HIV RNA levels (P < 0.001 for both).

CONCLUSIONS

Intermittent therapy is associated with a high incidence of thrombocytopenia, especially among patients with low platelet counts and a history of thrombocytopenia.

Microbial translocation is associated with residual viral replication in HAART-treated HIV+ subjects with <50copies/ml HIV-1 RNA

BACKGROUND

Recent data have shown that plasma levels of lipopolysaccharide (LPS) are a quantitative indicator of microbial translocation in HIV infected individuals.

OBJECTIVES

To assess the impact of residual viral replication on plasma LPS in HAART-treated HIV+ subjects with <50copies/ml HIV-1 RNA and to evaluate LPS changes during repeated HAART interruptions not exceeding 2-month duration.

STUDY DESIGN

LPS was measured in 44 HIV+ subjects at T0 (during HAART) and at day 15 of the first and fourth HAART interruption. Ten uninfected, healthy donors were studied as well. Residual plasma HIV-1 RNA was measured at T0 by an ultra-ultrasensitive method with limit of detection of 2.5copies HIV-1 RNA/ml. Subjects with less than 2.5copies/ml (fully suppressed - FS) were compared to those with 2.5-50copies/ml (partially suppressed - PS).

RESULTS

At T0, plasma LPS levels were comparable in FS and uninfected subjects, whereas in PS they were higher than in uninfected subjects (p=0.049). After 4 HAART interruptions, they did not change significantly. However, LPS values were lower in FS than in PS (p=0.020). An inverse correlation was found between CD4 and LPS levels (p=0.044) in PS group only.

CONCLUSIONS

A reduced degree of microbial translocation was seen in subjects with a more complete suppression of viral replication. Repeated HAART interruptions had no significant impact on plasma LPS levels.

The impact of combination antiretroviral therapy and its interruption on anxiety, stress, depression and quality of life in Thai patients

OBJECTIVE

Investigation on anxiety, stress, depression, and quality of life (QoL) within STACCATO, a randomised trial of two treatment strategies: CD4 guided scheduled treatment interruption (STI) compared to continuous treatment (CT).

PARTICIPANTS

Thai patients with HIV-infection enrolled in the STACCATO trial.

METHODS

Anxiety, depression assessed by the questionnaires Hospital Anxiety and Depression Scale (HADS) and DASS, stress assessed by the Depression Anxiety Stress Scale (DASS), and QoL evaluated by the HIV Medical Outcome Study (MOS-HIV) questionnaires. Answers to questionnaires were evaluated at 4 time-points: baseline, 24 weeks, 48 weeks and at the end of STACCATO.

RESULTS

A total of 251 patients answered the HADS/DASS and 241 answered the MOS-HIV of the 379 Thai patients enrolled into STACCATO (66.2 and 63.6% respectively). At baseline 16.3% and 7.2% of patients reported anxiety and depression using HADS scale. Using the DASS scale, 35.1% reported mild to moderate and 9.6% reported severe anxiety; 8.8% reported mild to moderate and 2.0% reported severe depression; 42.6% reported mild to moderate and 4.8% reported severe stress. We showed a significant improvement of the MHS across time (p=0.001), but no difference between arms (p=0.17). The summarized physical health status score (PHS) did not change during the trial (p=0.15) nor between arm (p=0.45). There was no change of MHS or PHS in the STI arm, taking into account the number of STI cycle (p=0.30 and 0.57) but MHS significant increased across time-points (p=0.007).

CONCLUSION

Antiretroviral therapy improved mental health and QOL, irrespective of the treatment strategy.

Two-months-off, four-months-on antiretroviral regimen increases the risk of resistance, compared with continuous therapy: a randomized trial involving West African adults

BACKGROUND

A randomized trial was launched in Côte d'Ivoire in 2002 to compare continuous antiretroviral treatment (hereafter, "C-ART") to an ART regimen of 2 months off and 4 months on therapy (hereafter, "2/4-ART"). We report the final analysis.

METHODS

A total of 435 adults who were receiving successful ART ((median CD4 cell count prior to ART, 272 cells/mm(3); 88% were receiving a zidovudine-lamivudine-efavirenz regimen) were randomized to receive C-ART or 2/4-ART. The main primary end point was the percentage of patients with <350 CD4 cells/mm(3) at 24 months. The sample size ensured 80% power to demonstrate noninferiority (noninferiority bound, -15%), assuming that 30% of the patients in the C-ART arm would have <350 CD4 cells/mm(3). Other end points were mortality, morbidity, cost of care, genotypic resistance, adherence, and toxicity.

RESULTS

The percentage of patients with <350 CD4 cells/mm(3) at 24 months was 5.6% (6 of 107) in the C-ART arm and 14.6% (46 of 315) in the 2/4-ART arm (lower bound of the 95% CI for the difference, -14%). Cost was 18% higher in the C-ART arm, and resistance to nonnucleoside reverse-transcriptase inhibitors (NNRTIs) was 20% higher in the 2/4-ART arm. Other end points were nonconclusive.

CONCLUSIONS

Although 2/4-ART met the predetermined criteria for noninferiority, the percentage of patients with <350 CD4 cells/mm(3) in the C-ART arm was lower than anticipated, which makes the clinical significance of this noninferiority uncertain. In addition, 2/4-ART led to an unacceptable additional risk of selecting for drug-resistant virus. This new argument against episodic ART strategies is also a caveat against any unplanned ART interruptions in Africa, where most patients receive NNRTIs.

Modifications of residual viraemia in human immunodeficiency virus-1-infected subjects undergoing repeated highly active antiretroviral therapy interruptions

Residual viraemia is detectable in the majority of human immunodeficiency virus (HIV)-infected subjects with plasma HIV-1 RNA <50 copies ml(-1). In the present study, the impact of repeated treatment interruptions on residual HIV-1 viraemia was investigated in 58 subjects enrolled in the ISS-PART, a multicentre, randomized clinical trial comparing 24 months of continuous (arm A) and intermittent (arm B) highly active antiretroviral therapy (HAART). Residual viraemia was measured by a modified Roche Amplicor HIV-1 RNA assay (limit of detection 2.5 copies ml(-1)). At baseline, the median value of residual viraemia was 2.5 copies ml(-1) in both arms; after 24 months, the median value was 2.5 in arm A and 8.3 in arm B. The median change from baseline to month 24 was significantly different between patients under continuous or intermittent HAART: 0 copies ml(-1) (range -125.2 to +82.7) of HIV-1 RNA in arm A versus 2.1 copies ml(-1) (range -80 to +46.8) in arm B (P=0.024). These results suggest that intermittent HAART tends to modify HIV-1 viraemia set point even if a virological response is achieved after HAART reinstitution.

Viral resuppression and detection of drug resistance following interruption of a suppressive non-nucleoside reverse transcriptase inhibitor-based regimen

BACKGROUND

Interruption of a non-nucleoside reverse transcriptase inhibitor (NNRTI)-regimen is often necessary, but must be performed with caution because NNRTIs have a low genetic barrier to resistance. Limited data exist to guide clinical practice on the best interruption strategy to use.

METHODS

Patients in the drug-conservation arm of the Strategies for Management of Antiretroviral Therapy (SMART) trial who interrupted a fully suppressive NNRTI-regimen were evaluated. From 2003, SMART recommended interruption of an NNRTI by a staggered interruption, in which the NNRTI was stopped before the NRTIs, or by replacing the NNRTI with another drug before interruption. Simultaneous interruption of all antiretrovirals was discouraged. Resuppression rates 4-8 months after reinitiating NNRTI-therapy were assessed, as was the detection of drug-resistance mutations within 2 months of the treatment interruption in a subset (N = 141).

RESULTS

Overall, 601/688 (87.4%) patients who restarted an NNRTI achieved viral resuppression. The adjusted odds ratio (95% confidence interval) for achieving resuppression was 1.94 (1.02-3.69) for patients with a staggered interruption and 3.64 (1.37-9.64) for those with a switched interruption compared with patients with a simultaneous interruption. At least one NNRTI-mutation was detected in the virus of 16.4% patients with simultaneous interruption, 12.5% patients with staggered interruption and 4.2% patients with switched interruption. Fewer patients with detectable mutations (i.e. 69.2%) achieved HIV-RNA of 400 copies/ml or less compared with those in whom no mutations were detected (i.e. 86.7%; P = 0.05).

CONCLUSION

In patients who interrupt a suppressive NNRTI-regimen, the choice of interruption strategy may influence resuppression rates when restarting a similar regimen. NNRTI drug-resistance mutations were observed in a relatively high proportion of patients. These data provide additional support for a staggered or switched interruption strategy for NNRTI drugs.

Treatment interruption strategies: how great are the risks?

PURPOSE OF REVIEW

This review brings together the results of recent definitive trials of treatment interruption strategies in order to evaluate the risks and to examine whether there is evidence to support this approach in clinical practice.

RECENT FINDINGS

Recent studies confirm that there is no clear benefit of treatment interruption in the settings of virological failure or acute infection. The most important recent data relate to the use of structured treatment interruption in the setting of chronic HIV disease. The SMART and Trivacan trials found that a CD4 lymphocyte count guided interruption strategy was clearly inferior to continuous therapy, but Staccato (using a higher threshold for treatment re-initiation) did not. The largest fixed-schedule treatment interruption trial also reported inferior clinical outcomes with interruption, although the evidence of harm was less clear in other smaller studies. A broad spectrum of clinical effects of treatment interruption was highlighted by this research.

SUMMARY

Overall, recent studies indicate that treatment interruption is associated with a variable degree of net harm. Continuous treatment should remain the strongly preferred approach, although, if it is carefully managed, there may be some clinical situations in which the benefits of a short period of interruption may potentially outweigh the risks.