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

HIV tropism switch in archived DNA of HIV-HCV subjects successfully treated with direct-acting antivirals for HCV infection

We described short-term HIV tropism changes occurring in peripheral blood mononuclear cells and the correlations with HIV DNA value in HIV-HCV co-infected patients cured for HCV disease and with undetectable HIV viremia or residual viremia (RV). Plasma HIV RNA, cellular HIV DNA and tropism were evaluated pre-HCV treatment (baseline, BL) and at 12(T1) and 24(T2) weeks after HCV treatment start. V3 sequences were interpreted using Geno2pheno and classified as R5 only if all three sequences had an FPR ≥ 10% and as X4 when at least one replicate sequence had an FPR < 10%. Forty-nine patients (21 with X4 and 28 with R5 virus) were enrolled. Five X4 patients and 9 R5 subjects experienced at least one tropism change,11 with RV:1/5 patients with X4 infection at BL switched at T1 versus 8/9 in the R5 group (p = 0.022977) and the difference was confirmed in subjects with RV (p = 0.02);6/9 R5 patients switching at T1 confirmed the tropism change at T2. No significant differences in HIV DNA values between patients with RV starting with a R5 or X4 tropism and experienced tropism switch or not were found. Short-term tropism switch involved almost a third of patients, in all but three cases with HIV RV. Being R5 at BL is associated to a higher instability, expressed as number of tropism changes and confirmed switch at T2.

Antiretroviral therapy interruptions: impact on HIV treatment and transmission

Introduction

Successful management of pediatric and adult human immunodeficiency virus (HIV) disease includes lifelong administration of antiretroviral therapy (ART). The need for the continuous use of antiretroviral drugs throughout the life course poses a challenge to children, adolescents, and adults living with HIV and their caregivers. Historically, treatment interruptions have been viewed as a negative therapeutic strategy. Recently, however, treatment interruptions or treatment reduction strategies have become a focus of investigations as innovative approaches to the long-term management of HIV disease. Current challenges with treatment interruptions include identifying an appropriate timeframe for length of interruptions and identifying HIV patient populations in whom the treatment interruption can be successful.

Objective

In this review, we aimed at summarizing recent studies of planned and unplanned treatment interruptions in children and adults living with HIV.

Materials and methods

We searched two databases (PubMed and Cochrane Controlled Trials Register) using keywords (HIV OR AIDS OR acquired immunodeficiency syndrome OR HIV-1 OR antiretroviral) AND (treatment interruption OR planned interruption OR therapeutic interruption OR unplanned interruption), for published randomized and nonrandomized clinical trials and observational cohort studies in children and adults (from birth to 99 years of age) in global settings covering a period from 2012 to 2018. In this review, only the studies that contained pediatric and adolescent populations with baseline immunological, virological, and clinical characteristics and outcomes after treatment interruption were included.

Results

A total of 174 eligible citations from the two databases were identified. We identified 10 prospective treatment interruption studies on children (five studies) and adults (five studies) during 2012–2018 with a total of 863 pediatric and 273 adult subjects. Collectively, recent studies on children and adults with HIV infection suggest that treatment interruptions with proper monitoring can be successful by instituting well-defined immunological and virological parameters or thresholds such as CD4 count, CD4%, and HIV RNA viral load that identify low-risk populations with treatment failure. In addition to standard virological and immunological outcome measurements, selected biomarkers that help detect early immune activation may also be useful in the monitoring of treatment interruption.

Conclusion

Treatment interruptions in adult and especially pediatric patients with well-controlled HIV disease may provide an alternative opportunity to optimize long-term HIV management by minimizing drug-associated toxicity and improving long-term adherence and quality of life.

Differential evolution of a CXCR4-using HIV-1 strain in CCR5wt/wt and CCR5∆32/∆32 hosts revealed by longitudinal deep sequencing and phylogenetic reconstruction

Rare individuals homozygous for a naturally-occurring 32 base pair deletion in the CCR5 gene (CCR5∆32/∆32) are resistant to infection by CCR5-using ("R5") HIV-1 strains but remain susceptible to less common CXCR4-using ("X4") strains. The evolutionary dynamics of X4 infections however, remain incompletely understood. We identified two individuals, one CCR5wt/wt and one CCR5∆32/∆32, within the Vancouver Injection Drug Users Study who were infected with a genetically similar X4 HIV-1 strain. While early-stage plasma viral loads were comparable in the two individuals (~4.5-5 log10 HIV-1 RNA copies/ml), CD4 counts in the CCR5wt/wt individual reached a nadir of <20 CD4 cells/mm(3) within 17 months but remained >250 cells/mm(3) in the CCR5∆32/∆32 individual. Ancestral phylogenetic reconstructions using longitudinal envelope-V3 deep sequences suggested that both individuals were infected by a single transmitted/founder (T/F) X4 virus that differed at only one V3 site (codon 24). While substantial within-host HIV-1 V3 diversification was observed in plasma and PBMC in both individuals, the CCR5wt/wt individual's HIV-1 population gradually reverted from 100% X4 to ~60% R5 over ~4 years whereas the CCR5∆32/∆32 individual's remained consistently X4. Our observations illuminate early dynamics of X4 HIV-1 infections and underscore the influence of CCR5 genotype on HIV-1 V3 evolution.

A cure for HIV: is it in sight?

HIV is a devastating disease affecting millions of people worldwide despite the advent of successful antiretroviral therapy (ART). However, ART does not result in a cure and has to be taken for life. Accordingly, researchers are turning towards cure efforts, particularly in the light of two patients whose HIV has been seemingly eradicated. Numerous approaches and strategies have been considered for curing HIV, but no scalable and safe solution has yet been reached. With newly discovered difficulties in measuring the HIV reservoir, the main barrier to a cure, the only true test of cure is to stop ART and see whether the virus becomes detectable. However, it is possible that this treatment interruption may be associated with certain risks for patients. Here, we compare the current major approaches and recent advances for curing HIV, as well as discuss ways of evaluating HIV cure and the safety concerns involved.