Long-term lopinavir/ritonavir monotherapy in HIV-infected children

Recent Advances on Targeting Proteases for Antiviral Development

Viral proteases are an important target for drug development, since they can modulate vital pathways in viral replication, maturation, assembly and cell entry. With the (re)appearance of several new viruses responsible for causing diseases in humans, like the West Nile virus (WNV) and the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), understanding the mechanisms behind blocking viral protease's function is pivotal for the development of new antiviral drugs and therapeutical strategies. Apart from directly inhibiting the target protease, usually by targeting its active site, several new pathways have been explored to impair its activity, such as inducing protein aggregation, targeting allosteric sites or by inducing protein degradation by cellular proteasomes, which can be extremely valuable when considering the emerging drug-resistant strains. In this review, we aim to discuss the recent advances on a broad range of viral proteases inhibitors, therapies and molecular approaches for protein inactivation or degradation, giving an insight on different possible strategies against this important class of antiviral target.

Protease Inhibition-An Established Strategy to Combat Infectious Diseases

Therapeutic agents with novel mechanisms of action are urgently needed to counter the emergence of drug-resistant infections. Several decades of research into proteases of disease agents have revealed enzymes well suited for target-based drug development. Among them are the three recently validated proteolytic targets: proteasomes of the malarial parasite Plasmodium falciparum, aspartyl proteases of P. falciparum (plasmepsins) and the Sars-CoV-2 viral proteases. Despite some unfulfilled expectations over previous decades, the three reviewed targets clearly demonstrate that selective protease inhibitors provide effective therapeutic solutions for the two most impacting infectious diseases nowadays-malaria and COVID-19.

The HIV protease inhibitor Saquinavir attenuates sepsis-induced acute lung injury and promotes M2 macrophage polarization via targeting matrix metalloproteinase-9

Imbalance of macrophage polarization plays an indispensable role in acute lung injury (ALI), which is considered as a promising target. Matrix metalloproteinase-9 (MMP-9) is expressed in the macrophage, and has a pivotal role in secreting inflammatory cytokines. We reported that saquinavir (SQV), a first-generation human immunodeficiency virus-protease inhibitor, restricted exaggerated inflammatory response. However, whether MMP-9 could regulate macrophage polarization and inhibit by SQV is still unknown. We focused on the important role of macrophage polarization in CLP (cecal ligation puncture)-mediated ALI and determined the ability of SQV to maintain M2 over M1 phenotype partially through the inhibition of MMP-9. We also performed a limited clinical study to determine if MMP-9 is a biomarker of sepsis. Lipopolysaccharide (LPS) increased MMP-9 expression and recombinant MMP-9 (rMMP-9) exacerbated LPS-mediated M1 switching. Small interfering RNA to MMP-9 inhibited LPS-mediated M1 phenotype and SQV inhibition of this switching was reversed with rMMP-9, suggesting an important role for MMP-9 in mediating LPS-induced M1 phenotype. MMP-9 messenger RNA levels in peripheral blood mononuclear cells of these 14 patients correlated with their clinical assessment. There was a significant dose-dependent decrease in mortality and ALI after CLP with SQV. SQV significantly inhibited LPS-mediated M1 phenotype and increased M2 phenotype in cultured RAW 264.7 and primary murine bone marrow-derived macrophages as well as lung macrophages from CLP-treated mice. This study supports an important role for MMP-9 in macrophage phenotypic switching and suggests that SQV-mediated inhibition of MMP-9 may be involved in suppressing ALI during systemic sepsis.

Second- and Third-line Antiretroviral Therapy for Children and Adolescents: A Scoping Review

BACKGROUND

The World Health Organization identified a need for evidence to inform revision of second- and third-line antiretroviral therapy (ART) options in children failing ART. We performed an in-depth scoping review of all available literature on second-line and subsequent ART regimens in children younger than 18 years.

METHODS

We comprehensively searched, without language or date limitations, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, the World Health Organization's International Clinical Trials Registry Platform and ClinicalTrials.gov.

RESULTS

The search retrieved 1982 records. Eighteen studies provided efficacy data: 1 randomized controlled trial, 7 phase II trials, 5 prospective and 5 retrospective cohorts. Five studies evaluated regimens in children failing first-line ART, 4 in children with multidrug resistance and 9 in children with variable treatment experience. Only 10/18 studies reported week 48 or month 12 outcomes. The overall proportion of children with virologic suppression defined by study at week 48 was 61.8%. Although the randomized controlled trial had low risk of bias, outcomes were similar between groups because of highly active optimized background regimens. All phase II and prospective studies were judged to have moderate to high risk of bias. No study compared currently recommended lopinavir-based second-line regimens for nonnucleoside reverse transcriptase inhibitor failures to other non-nonnucleoside reverse transcriptase inhibitor regimens head-to-head.

CONCLUSIONS

We found no evidence comparing current World Health Organization-recommended second- and third-line ART regimens with regimens including drugs of interest: raltegravir, darunavir, etravirine and atazanavir. Randomized controlled trials or prospective cohort studies with comparator arms, and bridging studies, ideally conducted in resource-limited settings, are required to guide future recommendations.

Risk of first-line antiretroviral therapy failure in HIV-infected Thai children and adolescents

BACKGROUND

Adolescence may affect adherence and response to highly active antiretroviral therapy (HAART). Limited data are available regarding the long-term treatment outcomes of perinatal HIV-infected adolescents.

METHODS

Data from perinatally acquired HIV-infected Thai children who started first-line nonnucleoside analog-based HAART before 18 years of age and treated for ≥24 weeks were analyzed. Children were categorized by age at HAART initiation; age<3 years, 3-9 years, early adolescence (10-13 years) and middle adolescence (14-16 years). CD4 and HIV-RNA were monitored every 6-12 months. Virologic failure (VF) was defined as HIV-RNA≥1000 copies/mL after ≥24 weeks of HAART.

RESULTS

Of 840 children, 68% were in pre-adolescence. Median baseline CD4% was 7.9%. Use of nevirapine versus efavirenz was 77:23%. Median duration of nonnucleoside reverse transcriptase inhibitor-based HAART was 5.6 years. No differences between groups were observed for rate of HIV-RNA<50 copies/mL (68%, P=0.18) and rate of VF (28%, P=0.82), median time to VF (22 months, P=0.13). Incidence of VF per 100 child-year in children age<3 years, 3-9 years, early adolescence and middle adolescence were 7.9, 4.7, 7.4 and 10.8, respectively (P=0.012). Median adherence by pill count was 97.3% (P=0.23). By multivariate analysis, predictors for VF were age at HAART initiation of <3 years (HR: 1.73, 95% CI: 1.18-2.55), age 10-16 years (HR: 1.47, 95% CI: 1.09-1.97), and nevirapine use (HR: 1.63, 95% CI: 1.14-2.32).

CONCLUSIONS

VF rates were observed in one-third of long-term treated Thai children on first-line HAART. Age 3-9 years at HAART initiation was associated with less VF compared with those younger or older, whereas children who used nevirapine had higher VF.

Comparison of adherence monitoring tools and correlation to virologic failure in a pediatric HIV clinical trial

There is no consensus on a gold standard for monitoring adherence to antiretroviral therapy (ART). We compared different adherence monitoring tools in predicting virologic failure as part of a clinical trial. HIV-infected Thai and Cambodian children aged 1-12 years (N=207) were randomized to immediate-ART or deferred-ART until CD4% <15%. Virologic failure (VF) was defined as HIV-RNA >1000 copies/mL after ≥6 months of ART. Adherence monitoring tools were: (1) announced pill count, (2) PACTG adherence questionnaire (form completed by caregivers), and (3) child self-report (self-reporting from children or caregivers to direct questioning by investigators during the clinic visit) of any missed doses in the last 3 days and in the period since the last visit. The Kappa statistic was used to describe agreement between each tool. The median age at ART initiation was 7 years with median CD4% 17% and HIV-RNA 5.0 log(10)copies/mL and 92% received zidovudine/lamivudine/nevirapine. Over 144 weeks, 13% had VF. Mean adherence by announced pill count before VF in VF children was 92% compared to 98% in children without VF (p=0.03). Kappa statistics indicated slight to fair agreement between tools. In multivariate analysis adjusting for gender, treatment arm ethnicity and caregiver education, significant predictors of VF were poor adherence by announced pill count (OR 4.56; 95%CI 1.78-11.69), reporting any barrier to adherence in the PACTG adherence questionnaire (OR 7.08; 95%CI 2.42-20.73), and reporting a missed dose in the 24 weeks since the last HIV-RNA assessment (OR 8.64; 95%CI 1.96-38.04). In conclusion, we recommend the child self-report of any missed doses since last visit for use in HIV research and in routine care settings, because it is easy and quick to administer and a strong association with development of VF.

HIV disclosure and its effect on treatment outcomes in perinatal HIV-infected Thai children

The World Health Organization guideline recommends informing children of their HIV status between the ages of 6-12 years. Primary caregivers of perinatal HIV-infected Thai children ≥6 years were interviewed in order to assess the HIV status disclosure rate. In addition, pill counts of antiretroviral therapy (ART) were performed every three months. CD4 and HIV-RNA were performed every six months. Of the 260 children/adolescents included, the median age of disclosure was 14.8 years. The disclosure rate among those from 6 to 12 years was 21% and for those greater than 12 years of age was 84%. When comparing children aged 6-12 years whose HIV status had been disclosed to them, to children whose HIV had yet to be disclosed, no difference was noted in median ART adherence by pill count, CD4 count, or proportion of HIV-RNA <50 copies/ml (p > 0.05). Factors associated with HIV disclosure were an age of ≥12 years (OR 17.8, 95% CI 8.86-35.79) and a current CD4 ≤ 30% (OR 2.09, 95% CI 1.20-3.62). In conclusion, although the majority of adolescents ≥12 years were aware of their HIV status only one-fifth of children aged 6-12 years were aware. Moreover, the child's/adolescent's disclosure status had no bearing on ART adherence by pill count or immunological and virological outcomes.

Simplifying antiretroviral therapy to lopinavir/ritonavir monotherapy did not improve quality of life and therapy adherence in pretreated HIV-infected children

We reported quality of life (QOL) and adherence in HIV-infected children after simplifying the antiretroviral regimen by switching to lopinavir/ritonavir monotherapy (mLPV/r). HIV-infected children with HIV-RNA <50 copies/ml while using second-line double boosted protease inhibitors were switched to mLPV/r. Primary caregivers completed PACTG QOL questionnaires at weeks 0, 48, 96, and 144. Adherence by pill count was performed at every visit. Thirty-eight pretreated HIV-infected Thai children were enrolled. The median (IQR) age was 11.5 (10.2-13.2) years and 53% were female. At enrollment, 34 used LPV/r+saquinavir and four used LPV/r+indinavir. The median (IQR) CD4% was 27 (23-30)%. At week 144, QOL scores were similar to baseline for all domains. A transient increase in the symptoms domain score was seen at week 96 (p=0.01), whereas the physical resilience domain score was decreased at weeks 48 and 96 (both p<0.05). Despite the mean number of pills decreasing from 7.9 pills/day before and 3.7 pills/day after mLPV/r (p<0.001), there were no differences over time in adherence rates by pill count and proportion of children with poor adherence (all p>0.05). Our study did not demonstrate improvement of QOL scores and adherence rates by pill count in pretreated HIV-infected children after simplification of the antiretroviral regimen to lopinavir/ritonavir monotherapy.