A phase I/II study of the protease inhibitor indinavir in children with HIV infection

Anti-HIV and anti-HCV small molecule protease inhibitors in-silico repurposing against SARS-CoV-2 Mpro for the treatment of COVID-19

The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is a global health emergency warranting development and implementation of targeted treatment. The enzyme main protease (M^pro; also known as 3C-like protease) is emerging as an attractive drug target. This enzyme plays an indispensable role in processing the translated polyproteins of viral RNA. Inhibiting the activity of M^pro would wedge viral replication. To facilitate the discovery of targeted therapy for COVID-19, we carried out the structure-assisted repurposing of existing protease inhibiting small molecules to target SARS-CoV-2 M^pro. Based on the structure of SARS-CoV-2 M^pro, here we report the small drug molecule namely saquinavir as its potent inhibitor. Findings support the premise that this promising antiviral protease inhibiting small drug molecule can be validated and implemented for the treatment and clinical management of COVID-19 pandemic disease.Communicated by Ramaswamy H. Sarma.

Systematic Review of Early Phase Pediatric Clinical Pharmacology Trials

OBJECTIVE

Children have generally been excluded from early-stage clinical trials owing to safety concerns based in social expectations and not data. However, the repositioning of adult therapeutics for pediatric use and the increase in the development of therapies for pediatric only conditions require the participation of children in phase 1–2 trials. Therefore, the aim of this article is to systematically review the history and current state of early phase pediatric clinical pharmacology trials in order to understand safety concerns, trends, and challenges in pediatric trials.

METHODS

This review analyzed the nature of early phase pediatric clinical trials conducted for nononcology conditions through a systematic search that was performed for pediatric non-oncologic phase 1 or phase 1–2 drug and vaccine studies in MEDLINE.

RESULTS

The data show that the number of early phase pediatric clinical trials is still small relative to adults but has been on the rise in the past decade with relatively few serious adverse effects observed.

CONCLUSIONS

The widespread concerns about children's safety when they participate in early phase clinical trials seem disproportionate, based on our findings. The data confirm that these studies can be conducted safely, and that their results can contribute significantly to pediatric pharmacotherapy.

Development of a Pediatric Relative Bioavailability/Bioequivalence Database and Identification of Putative Risk Factors Associated With Evaluation of Pediatric Oral Products

Generally, bioequivalence (BE) studies of drug products for pediatric patients are conducted in adults due to ethical reasons. Given the lack of direct BE assessment in pediatric populations, the aim of this work is to develop a database of BE and relative bioavailability (relative BA) studies conducted in pediatric populations and to enable the identification of risk factors associated with certain drug substances or products that may lead to failed BE or different pharmacokinetic (PK) parameters in relative BA studies in pediatrics. A literature search from 1965 to 2020 was conducted in PubMed, Cochrane Library, and Google Scholar to identify BE studies conducted in pediatric populations and relative BA studies conducted in pediatric populations. Overall, 79 studies covering 37 active pharmaceutical ingredients (APIs) were included in the database: 4 bioequivalence studies with data that passed BE evaluations; 2 studies showed bioinequivalence results; 34 relative BA studies showing comparable PK parameters, and 39 relative BA studies showing differences in PK parameters between test and reference products. Based on the above studies, common putative risk factors associated with differences in relative bioavailability (DRBA) in pediatric populations include age-related absorption effects, high inter-individual variability, and poor study design. A database containing 79 clinical studies on BE or relative BA in pediatrics has been developed. Putative risk factors associated with DRBA in pediatric populations are summarized.

Nanotechnology: a magic bullet for HIV AIDS treatment

Human immunodeficiency virus (HIV) infection has become devastating in last a few years. Nearly 7400 new infection cases are coming every day. Highly active antiretroviral therapy (HAART), which involves combination of at least three antiretroviral (ARV) drugs, has been used to extend the life span of the HIV-infected patients. HAART has played an important role to reduce mortality rate in the developed countries but in the developing countries condition is still worst with millions of people being infected by this disease. For the improvement of the situation, nanotechnology-based drug system has been explored for the HIV therapeutics. Nanosystems used for HIV therapeutics offer some unique advantage like enhancement of bioavailability, water solubility, stability, and targeting ability of ARV drugs. Main nanotechnology-based systems explored for HIV therapeutics are liposomes, nanoparticles, niosomes, polymeric micelles, and dendrimers. Present manuscript reviews conventional method of HIV therapeutics and recent advances in the field of nanotechnology-based systems for treatment of HIV-AIDS.

Rate of candidiasis among HIV-infected children in Spain in the era of highly active antiretroviral therapy (1997-2008)

BACKGROUND

Candidiasis is the most common opportunistic infection seen in human immunodeficiency virus (HIV)-infected individuals. The aim of our study was to estimate the candidiasis rate and evaluate its trend in HIV-infected children in Spain during the era of highly active antiretroviral therapy (HAART) compared to HIV-uninfected children.

METHODS

We carried out a retrospective study. Data were obtained from the records of the Minimum Basic Data Set from hospitals in Spain. All HIV-infected children were under 17 years of age, and a group of HIV-uninfected children with hospital admissions matching the study group by gender and age were randomly selected. The follow-up period (1997-2008) was divided into three calendar periods: a) From 1997 to 1999 for early-period HAART; b) from 2000 to 2002 for mid-period HAART; and c) from 2003 to 2008 for late-period HAART.

RESULTS

Among children with hospital admissions, HIV-infected children had much higher values than HIV-uninfected children during each of the three calendar periods for overall candidiasis rates (150.0 versus 6.1 events per 1,000 child hospital admissions/year (p < 0.001), 90.3 versus 3.1 (p < 0.001), and 79.3 versus 10.7 (p < 0.001), respectively) and for non-invasive Candida mycosis (ICM) rates (118.5 versus 3.8 (p < 0.001), 85.3 versus 2.3 (p < 0.001), and 80.6 versus 6.0 (p < 0.001), respectively). In addition, HIV-infected children also had higher values of ICM rates than HIV-uninfected children, except during the last calendar period when no significant difference was found (32.4 versus 1.2 (p < 0.001), 11.6 versus 0.4 (p < 0.001), and 4.6 versus 2.3 (p = 0.387), respectively). For all children living with HIV/AIDS, the overall candidiasis rate (events per 1,000 HIV-infected children/year) decreased from 1997-1999 to 2000-2002 (18.8 to 10.6; p < 0.001) and from 2000-2002 to 2003-2008 (10.6 to 5.7; p = 0.060). Within each category of candidiasis, both non-ICM and ICM rates experienced significant decreases from 1997-1999 to 2003-2008 (15.9 to 5.7 (p < 0.001) and 4.1 to 0.3 (p < 0.001), respectively).

CONCLUSIONS

Although the candidiasis rate still remains higher than in the general population (from 1997 to 2008), candidiasis diagnoses have decreased among HIV-infected children throughout the HAART era, and it has ceased to be a major health problem among children with HIV infection.

Nutritional assessment and lipid profile in HIV-infected children and adolescents treated with highly active antiretroviral therapy

INTRODUCTION

HIV-infected children and adolescents treated with highly active antiretroviral therapy (HAART) regimens that include a protease inhibitor (PI) can show significant improvements in clinical outcomes, nutritional status and quality of life. The study aimed to report nutritional and metabolic alterations for pediatric patients continuously exposed to HAART and for healthy controls for up to 1 year.

METHODS

Clinical, anthropometric, lipid profile and food intake data were collected prospectively over approximately 12-months for each patient.

RESULTS

Fifty-one individuals were studied, of these, 16 were healthy. After 12 months follow-up, HIV-positive individuals remained below the healthy control group parameters. No change was observed concerning food intake. Triglyceride serum levels were higher in patients using protease inhibitor at the onset of the study [PI groups: 114 (43 - 336), and 136 (63 - 271) versus control group: 54.5 (20 - 162); p = 0.003], but after twelve months follow-up, only the group using protease inhibitor for up to two months presented higher values [140 (73 - 273) versus 67.5 (33 - 117); p = 0.004]. HDL-cholesterol was lower in HIV-positive individuals [HIV-positive groups: 36 (27 - 58) and 36 (23 - 43); control 49.5 (34 - 69); p = 0.004].

CONCLUSIONS

HIV-infected children and adolescents treated with highly active antiretroviral therapy showed compromised nutritional parameters compared to a paired healthy control group. Individuals using protease inhibitor presented worse triglyceride serum levels compared to their healthy counterparts.

Post-HAART outcomes in pediatric populations: comparison of resource-limited and developed countries

CONTEXT

No formal comparison has been made between the pediatric post-highly active antiretroviral therapy (HAART) outcomes of resource-limited and developed countries.

OBJECTIVE

To systematically quantify and compare major baseline characteristics and clinical end points after HAART between resource-limited and developed settings.

METHODS

Published articles and abstracts (International AIDS Society 2009, Conference on Retroviruses and Opportunistic Infections 2010) were examined from inception (first available publication for each search engine) to March 2010. Publications that contained data on post-HAART mortality, weight-for-age z score (WAZ), CD4 count, or viral load (VL) changes in pediatric populations were reviewed. Selected studies met the following criteria: (1) patients were younger than 21 years; (2) HAART was given (≥ 3 antiretroviral medications); and (3) there were >20 patients. Data were extracted for baseline age, CD4 count, VL, WAZ, and mortality, CD4 and virologic suppression over time. Studies were categorized as having been performed in a resource-limited country (RLC) or developed country (DC) on the basis of the United Nations designation. Mean percentage of deaths per cohort and deaths per 100 child-years, baseline CD4 count, VL, WAZ, and age were calculated for RLCs and DCs and compared by using independent samples t tests.

RESULTS

Forty RLC and 28 DC publications were selected (N = 17 875 RLCs; N = 1835 DC). Mean percentage of deaths per cohort and mean deaths per 100 child-years after HAART were significantly higher in RLCs than DCs (7.6 vs 1.6, P < .001, and 8.0 vs 0.9, P < .001, respectively). Mean baseline CD4% was 12% in RLCs and 23% in DCs (P = .01). Mean baseline VLs were 5.5 vs 4.7 log(10) copies per mL in RLCs versus DCs (P < .001).

CONCLUSIONS

Baseline CD4% and VL differ markedly between DCs and RLCs, as does mortality after pediatric HAART. Earlier diagnosis and treatment of pediatric HIV in RLCs would be expected to result in better HAART outcomes.

Genetic determinants in HIV-1 Gag and Env V3 are related to viral response to combination antiretroviral therapy with a protease inhibitor

OBJECTIVE

To identify novel viral determinants in HIV-1 protease, Gag, and envelope V3 that relate to outcomes to initial protease inhibitor-based antiretroviral therapy.

DESIGN

A longitudinal cohort study of protease inhibitor-naive, HIV-infected individuals was designed to identify genetic variables in viral Gag and envelope sequences associated with response to antiretroviral therapy.

METHODS

Genetic and statistical models, including amino acid profiles, phylogenetic analyses, receiver operating characteristic analyses, and covariation analyses, were used to evaluate viral sequences and clinical variables from individuals who developed immune reconstitution with or without suppression of viral replication.

RESULTS

Pretherapy chemokine (C-X-C motif) receptor 4-using V3 regions had significant associations with viral failure (P = 0.04). Amino acid residues in protease covaried with Gag residues, particularly in p7(NC), independent of cleavage sites. Pretherapy V3 charge combined with p6(Pol) and p2/p7(NC) cleavage site genotypes produced the best three-variable model to predict viral suppression in 88% of individuals. Combinations of baseline CD4 cell percentage with genetic determinants in Gag-protease predicted viral fitness in 100% of individuals who failed to suppress viral replication.

CONCLUSION

Baseline genetic determinants in Gag p6(Pol) and p2/p7(NC), as well as envelope, provide novel combinations of biomarkers for predicting emergence of viral resistance to initial therapy regimens.

Efficacy of antiretroviral therapy program in children in India: prognostic factors and survival analysis

The objective of this article is to study the survival pattern and the prognostic factors for HIV-infected children on antiretroviral therapy (ART) for two and half years at the Government Hospital of Thoracic Medicine, Tambaram, Chennai, India. We studied 295 children who were initiated on ART from 1 April 2004 to 30 September 2006 at a large, public tertiary care facility in Chennai, India. Weight for age Z-score was calculated. Survival curves and Cox proportional hazard models were used to identify risk factors for mortality. The mean and median follow up was 11 and 10 months, respectively. The cumulative survival probability at 6, 12, 18, 24 and 30 months was 93, 90, 89.7, 89.7 and 89.7%, respectively. Of the children who died, about 50% died within the first month. Nearly 6% of the children had adherence less than 95%. The children who had a baseline CD4 percent less than or equal to 14% had significantly (p < 0.05) higher mortality as compared to children who had 20% or more. The children who had negative or no change in weight for age Z-score and hemoglobin had 18.9 (3.7-95.7) times significantly higher mortality as compared to children who had positive change in both variables (p < 0.001). The sensitivity, specificity and likelihood ratio of the positive test for negative change or no change in HB was 65%, 85% and 4.3, respectively. Similarly, these were 80%, 73% and 3% for negative or no change in Absolute Lymphocyte Count (ALC). These findings indicate the feasibility and effectiveness of implementing an ART program in a large government hospital in India. Simple nutritional variable hemoglobin and immunologic variable ALC could be used to monitor the progression of disease in children.

Long-term effects of highly active antiretroviral therapy on CD4+ cell evolution among children and adolescents infected with HIV: 5 years and counting

BACKGROUND

Lower percentages of CD4(+) T lymphocytes are associated with adverse clinical outcomes among children and adolescents infected with human immunodeficiency virus (HIV). CD4(+) lymphocyte percentage generally increases with receipt of highly active antiretroviral therapy (HAART), but long-term follow-up is required to assess whether these increases in CD4(+) cell percentage are maintained and whether they lead to normal CD4(+) cell percentages in children with severe immunosuppression.

METHODS

The study population included 1236 children and adolescents perinatally infected with HIV who were enrolled in a US-based multicenter prospective cohort study (Pediatric AIDS Clinical Trials Group 219/219C) and who were not receiving HAART at study initiation. We estimated the effects of HAART, HAART with protease inhibitors, and HAART with nonnucleoside reverse-transcriptase inhibitors on CD4(+) cell percentage, using marginal structural models to account for confounding by severity.

RESULTS

Initiation of any type of HAART increased CD4(+) cell percentage by 2.34% (95% confidence interval, 1.35%-3.33%) in the first year, relative to noninitiation of HAART. The substantial increases in CD4(+) cell percentage observed after the first year of experience with these combination therapies were followed by relatively smaller increases that continued for 5 years after initiation. Although larger increases in CD4(+) cell percentage were observed among children with a greater degree of immunosuppression at baseline, the mean CD4(+) cell percentage after 5 years of HAART did not reach normal levels.

CONCLUSIONS

Our study supports the initiation of HAART in children before severe immunosuppression occurs for long-term maintenance of normal CD4(+) cell percentages. This beneficial result must be weighed against the evidence of potential adverse events associated with the prolonged use of such therapy.

Indinavir/ritonavir remains an important component of HAART for the treatment of HIV/AIDS, particularly in resource-limited settings

For over a decade, indinavir has been approved for the treatment of HIV/AIDS; however, following the introduction of new protease inhibitors (PIs) with improved safety and pharmacologic profiles, its use in developed countries has become almost obsolete. In contrast, in resource-limited settings where the majority of people living with HIV/AIDS reside, indinavir is part of the most affordable PI-based highly active antiretroviral treatment regimen. A major drawback of indinavir use is renal toxicity, but low-dose indinavir plus ritonavir (400/100 mg) twice daily is both efficacious and tolerable. Similar low dosing levels in children have also proven successful, but data in pregnant women remains limited. Due to its low cost and proven efficacy indinavir remains a key component of HIV/AIDS treatment in resource-limited settings.

Pharmacokinetics of antiretroviral therapy in HIV-1-infected children

The initiation of antiretroviral therapy has resulted in an impressive reduction in the rate of disease progression in AIDS and HIV-1-related deaths in children; however, there are still several major challenges to be faced in order to improve therapy. A major topic that needs to be dealt with is the establishment of the optimal dosage of antiretroviral therapy for children. This review presents the currently available peer-reviewed data on the pharmacokinetics of nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and fusion inhibitors (FIs) in children. In addition, the data are discussed in relation to the currently available European and US guidelines and the US FDA-approved drug labels. High intra- and interpatient variability in pharmacokinetics are often observed for all antiretroviral drugs. The number of children included in the pharmacokinetic studies is often small and children are often divided into divergent groups using different dosage levels and/or drug formulations. For a substantial number of antiretroviral drugs, dosage recommendations, especially for young children, are still absent in the European and US guidelines. The recommended drug dosages in the guidelines are often different from that in the officially approved drug product label. In addition, the recommended drug dosages may deviate between the European and US guidelines. Thus, while practioners aim to meet the recommendations in the official guidelines, patients may receive highly divergent dosages of medication. The high intra- and interpatient variability in pharmacokinetics of antiretroviral drugs in children hampers the application of fixed dosages of antiretroviral drugs. For PIs and NNRTIs, plasma drug levels correlate with viral suppression and drug toxicity. NRTIs are prodrugs that are intracellularly converted to their active triphosphate form and, therefore, plasma NRTI levels correlate poorly with viral suppression. Therapeutic drug monitoring of PIs and NNRTIs should be considered to optimise HIV therapy in children.

Switch from Ritonavir to Indinavir in Combination Therapy for HIV‐1–Infected Children

BACKGROUND

Protease inhibitors are an effective component of combination antiretroviral treatment for children infected with human immunodeficiency virus 1 (HIV-1), but tolerance or toxicity issues sometimes require an alternative therapeutic strategy.

METHODS

HIV-1-infected children aged 2-17 years received combination therapy with either stavudine plus ritonavir or with zidovudine, lamivudine, and ritonavir as part of a randomized clinical trial. Twenty-one months after the start of the trial, ritonavir in capsule formulation became unavailable. The treatment regimen for 25 children was switched from ritonavir capsules to indinavir capsules (500 mg/m(2) every 8 h). The other study drugs remained unchanged. A matched-pairs analysis was performed to compare the results for these 25 children with the results for 25 matched children whose treatment regimen continued to include ritonavir (in liquid formulation).

RESULTS

There were no significant differences in the percentage of children with an HIV-1 RNA load of <or=200 copies/mL between the group receiving indinavir and the matched group receiving ritonavir (52% vs. 68%, at the start of indinavir treatment; 42% vs. 52%, at week 12; and 50% vs. 56%, at week 24). Similarly, there were no significant differences between the treatment groups with respect to median CD4 cell counts over time. Toxicities observed in the children treated with indinavir were most often flank pain or headache (16%), renal dysfunction (16%), hematuria (12%), and skin rash (12%) and were consistent with toxicities reported elsewhere. There was no evidence that the switch from ritonavir to indinavir therapy altered the pharmacokinetics of indinavir as a result of residual cytochrome P450 induction or inhibition caused by ritonavir.

CONCLUSIONS

The switch from one protease inhibitor (ritonavir) to another (indinavir) as a component of combination antiretroviral treatment in this patient population was a practical therapeutic strategy.

Single-dose safety and pharmacokinetics of amprenavir (141W94), a human immunodeficiency virus type 1 (HIV-1) protease inhibitor, in HIV-infected children

A phase I, open-label, dose-escalating trial was conducted to evaluate the safety, tolerability, and pharmacokinetics of single, oral doses of amprenavir (141W94), a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) protease, in 20 HIV-infected children 4 to 12 years of age. The doses of amprenavir evaluated, 5, 10, 15, and 20 mg/kg of body weight, were comparable to those evaluated in adult phase I and II studies. The most common clinical adverse event associated with amprenavir, administered as soft gelatin capsules, was nausea. Amprenavir was rapidly absorbed, with a mean time to maximum concentration (T(max)) occurring 0.95 to 1.58 h after dosing. The area under the concentration-time curve (AUC(0)(-->)(infinity)) was dose proportional, and the mean maximum plasma concentration (C(max)) increased linearly in a less than dose-proportional manner. Amprenavir was eliminated relatively slowly, with a mean terminal-phase half-life (t(1/2)) of 6.17 to 8.28 h. The t(1/2), apparent total clearance, and apparent volume of distribution during the elimination phase were dose independent. Considerable interpatient variability was seen for all pharmacokinetic parameters of amprenavir. The results of this study suggest that 20 mg of amprenavir/kg administered twice a day should be used in future pediatric studies.

Two-year clinical and immune outcomes in human immunodeficiency virus-infected children who reconstitute CD4 T cells without control of viral replication after combination antiretroviral therapy

OBJECTIVE

To evaluate 96-week clinical and immune outcomes to protease inhibitor-containing antiretroviral therapy.

METHODS

A prospective study was conducted of 40 human immunodeficiency virus (HIV)-infected children who displayed viral suppression (VS) with successful immune reconstitution (IS), failure to suppress virus (VF) or develop immune reconstitution (IF), or discordant immune and viral responses (VF/IS) at 24 weeks posttherapy. All children enrolled had viral RNA >4.0 log10 copies per mL and were Centers for Disease Control ad Prevention immune stage 2 or 3. Clinical, viral, and immune outcomes were assessed during the subsequent 72 weeks.

RESULTS

VS/IS and VF/IS groups displayed similar sustained increases in CD4 T cells, although viral levels rebounded by 48 and 96 weeks posttherapy to pretherapy levels in the discordant group. The VF/IS outcome group had significant increases in height and weight z scores compared with entry and were similar to the VS/IS group. After treatment, antigen-specific responses after tetanus immunization were similar in the VF/IS and VS/IS groups. Prevalence of HIV-associated illnesses decreased in both VS/IS and VF/IS but not in VF/IF response groups.

CONCLUSIONS

The findings indicate that viral replication under the selective pressure of protease inhibitors fails to exhibit the same deleterious impact on T-cell immunity as pretherapy viruses. CD4 T-cell counts may be a better predictor of disease progression and improvement in growth than viral burden in HIV-infected children who receive a protease inhibitor as part of a highly active antiretroviral therapy regimen.

Impact of highly active antiretroviral therapy on CD4+ T cells and viral load of children with AIDS: a population-based study

In this study, we sought to characterize the changes over time at the population level on CD4(+) T cells and plasma viral load (VL) levels of HIV-1-infected children with or without AIDS. We carried out a retrospective study in 114 HIV-infected children during the calendar period that a highly active antiretroviral therapy (HAART) protocol was used. The HAART protocol consisted of three drugs: nucleoside analogue HIV-1 reverse transcriptase inhibitors, and/or HIV protease inhibitors, and/or nonnucleoside analogue HIV-1 reverse transcriptase inhibitors. The mean of CD4(+) T cells percentage and log(10) VL per calendar year were stratified by AIDS diagnostic. As new HAART strategies become available, an increase of CD4(+) T cells and a decrease of VL were observed over time, in children with and without AIDS. In 2001, children with AIDS reached values of CD4(+) T cells and VL similar to children without AIDS. In conclusion, our study shows that the generalized use of HAART has permitted improvement in immunological and virological status of HIV-infected children without AIDS, and more importantly in children with AIDS.

Pharmacokinetics of indinavir combined with low-dose ritonavir in human immunodeficiency virus type 1-infected children

So far, no pediatric doses for indinavir combined with ritonavir have been defined. This study evaluated the pharmacokinetics of 400 mg of indinavir/m(2) combined with 125 mg of ritonavir/m(2) every 12 h (q12h) in 14 human immunodeficiency virus type 1-infected children. The area under the concentration-time curve from 0 to 24 h and the minimum concentration of drug in serum for indinavir were similar to those for 800 mg of indinavir-100 mg of ritonavir q12h in adults, while the maximum concentration of drug in serum was slightly decreased, with geometric mean ratios (90% confidence intervals in parentheses) of 1.1 (0.87 to 1.3), 0.96 (0.60 to 1.5), and 0.80 (0.68 to 0.94), respectively.

Long-term effects of protease-inhibitor-based combination therapy on CD4 T-cell recovery in HIV-1-infected children and adolescents

BACKGROUND

There is limited evidence about longer-term effects of combination antiretroviral therapy that includes protease inhibitors (PIs) on the immunological status of HIV-1-infected children. Better understanding might help to resolve questions on when to initiate treatment.

METHODS

The change in percentage of CD4-positive T lymphocytes (CD4%) was investigated in 1012 previously treated HIV-1-infected children (aged 0-17 years) who were enrolled in research clinics in the USA before 1996 and followed up to 2000. 702 started PI-based combination therapy. Data analyses ignored subsequent treatment changes.

FINDINGS

Among the 1012 children, the median CD4% increased from 22% to 28% between 1996, when PIs were first prescribed, and 2000. For the 702 who started PI-based therapy, the mean CD4% increase after 3 years was largest among participants with the greatest immunosuppression (15.7%, 10.6%, 5.1%, and 2.0% for participants with CD4% before therapy of <5%, 5-14%, 15-24%, and >25%; p<0.0001). After adjustment for pre-PI CD4%, the mean increase was largest among the youngest participants (9.2%, 8.0%, and 4.3% for ages <5 years, 5-9 years, and >10 years; p=0.001). However, only a minority of significantly immunocompromised participants (33%, 26%, and 49% of those with pre-PI CD4% of <5%, 5-14%, or 15-24%) achieved CD4% values above 25%, whereas 84% of those with pre-PI values above 25% maintained such values.

INTERPRETATION

Although PI-based therapy was associated with substantial improvements in CD4%, initiation before severe immunosuppression and at younger ages may be more effective for recovery or maintenance of normal CD4%. Randomised investigation of when to start combination therapy in children, particularly infants, is needed.

Impact of highly active antiretroviral therapy on the morbidity and mortality in Spanish human immunodeficiency virus-infected children

BACKGROUND

Highly active antiretroviral therapy (HAART) slows the progression of HIV disease and lowers mortality and morbidity in adults. The impact on the disease course in children has not been still completely elucidated. Furthermore the effect of HAART on organ-specific complications of HIV is unknown.

OBJECTIVES

To assess the effect of HAART on the progression of HIV infection, mortality, organ-specific complications, number of infections and hospitalizations in HIV-1-infected children.

PATIENTS AND METHODS

Records of HIV-1-infected children were reviewed in a large referral pediatric hospital. Patients were divided into three groups: children who did not receive antiretroviral therapy (Group 1); children who received mono- or bitherapy (Group 2); and patients who received HAART (Group 3). Endpoints analyzed were progression to AIDS and mortality among AIDS patients and overall.

RESULTS

One hundred seven children have been evaluated. Actuarial survival at 5 years of age was 33% in Groups 1 and 2 compared with 100% in Group 3 (P < 0.01). At 5 years of age, the proportion of children progressing to AIDS was 76% in Groups 1 and 2, compared with 26% in Group 3 (P < 0.01). At 5 years of follow-up, there were 45 cases of organ-specific complications in patients without HAART. No children without organ-specific complications when HAART was started have developed them after 5 years (P < 0.01). In patients without HAART there were 9 cases of lymphoid interstitial pneumonia, and there was none in Group 3 (P < 0.01). The incidence rates of infections and hospitalizations were 2.83 and 0.52 per patient-year, respectively, in children who did not receive HAART and 0.75 and 0.17 when they were managed with HAART (relative risk, 0.26 and 0.32).

CONCLUSIONS

HAART is associated with a marked decline in the progression to AIDS, improved survival in HIV-1-infected children, reduced incidence of infections and hospitalizations and decreased incidence of some organ-specific complications of HIV.

Pharmacology considerations for antiretroviral therapy in human immunodeficiency virus (HIV)-infected children

The contemporary treatment of the child infected with human immunodeficiency virus (HIV) unavoidably requires combination therapy with antiretroviral agents and may include additional drugs for the prevention and treatment of opportunistic infections or other disease states. The current guidelines for the treatment of the HIV-infected child recommend that the same principles of treatment for adults should apply to children. However, the pharmacokinetic and pharmacodynamic characteristics of many agents and regimens used in adults have not been defined adequately in children, and large-scale clinical trials to establish safety and show efficacy have not been completed. Therefore, the clinician will be required to use agents with incomplete knowledge about their pharmacologic properties. The purpose of this article is to provide an overview of the pediatric pharmacologic principles, a review of the pharmacologic characteristics of selected antiretroviral agents in children, and a prospectus on the design of drug dosing regimens in children.

Tolerabilities of antiretrovirals in paediatric HIV infection

Data on the efficacy and tolerability of antiretrovirals in children are limited as, in contrast to adult studies, large paediatric cohort studies are lacking. Thus, data pertaining to adults are often extrapolated to children despite the acknowledgement that children are not little adults. This review summarises information gathered from existing reports and focuses on the tolerabilities of antiretrovirals in children infected with HIV-1. The efficacy of antiretrovirals is not included in the scope of the discussion. Taste of antiretrovirals should be an important factor when considering the tolerability of antiretrovirals in children. However, antiretroviral options are often limited in young children as only some of the antiretrovirals are available as paediatric formulations. All antiretrovirals have been associated with toxicities in children, but in general, they are relatively well tolerated. The gastrointestinal system including hepatic system is most prone to being affected by these drugs. Skin rashes and hypersensitivity reactions are also associated with antiretroviral use, particularly with the non-nucleoside reverse transcriptase inhibitors. Mitochondrial toxicities that lead to impairment of liver function, pancreatic function and lactic acidosis are associated with most of the nucleoside analogues. Haematological toxicity is often a dose limiting adverse effect especially of the nucleoside analogues, in particular zidovudine. The protease inhibitors are associated with gastrointestinal intolerance (diarrhoea) and metabolic derangements that can lead to hypercholesterolaemia and hypertriglyceridaemia, which in turn and can lead to changes in body habitus. The renal system is also affected by several drugs, the most important of which is indinavir, which has been associated with renal stones and damage to the renal tubules. Fortunately, with lower incidence of major toxicity and with the range of drugs now available for paediatric use, toxicities are usually not a barrier to effect antiretroviral therapy in children.

Nutritional aspects of HIV-infected children receiving highly active antiretroviral therapy

The presentation of the nutritional problems of HIV-infected children is changing over time with improved antiretroviral regimens. Early reports of HIV infection in the 1980s, included such problems as malnutrition and wasting. However, as treatment and prophylactic regimens improve, the current nutritional problems of HIV-infected children in developed countries include truncal obesity and insulin resistance in addition to malnutrition. Background data on the wasting syndrome, etiology of malnutrition, nutritional effects of highly active antiretroviral therapies, and nutritional intervention strategies for HIV-infected children will be presented.

[Complete immune and clinical recovery after highly active antiretroviral therapy in advanced vertically HIV-1 infected children]

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the ability of long-term highly active antiretroviral therapy (HAART) to fully reconstitute the immune system in children with severe AIDS.

PATIENT AND METHOD

Lymphoproliferative responses (LPR) were evaluated by incorporation of [3H]-thymidine. Cytokine production in culture (IFN- gamma, IL-5) was quantified using commercially available specific ELISA assays. T-cells subsets were determined by 3-color flow cytometry and thymic production of T-cells was assessed by quantification of TCR rearrangement excision circles (TRECs).

RESULTS

We present a vertically HIV-1-infected child at clinical category C, with long-standing CD4+ T-cells below 50/l, who was monitored during 3-years after starting HAART by quantifying the viral load (VL), naïve, memory, and activated T-cell subsets, and thymical function as well as clinical events. VL was suppressed to undetectable levels since the beginning of HAART with d4T, 3TC, nelfinavir, and efavirenz resulting in a dramatic immune reconstitution, achieving normal CD4+ T-cells counts after 6 months (25%, 597 CD4+ T-cells/l) and perdurable undetectable VL levels. Naïve CD4 and CD8 T-cells increased in parallel to TCR rearrangement excision circles (TRECs) levels, with a concomitant decrease in T-cell activation markers. Interestingly, the patient showed an increase in the lymphoproliferative responses to PHA; the IFN-gamma production by PBMCs increased with HAART while the production of IL-5 diminished, thus indicating a switch of type 2 to type 1 response. He recovered clinically and immunologically (up to normal levels) and remains asymptomatic at present.

CONCLUSION

This report demonstrates that at least in these children, an immune and clinical recovery from an advanced stage of HIV-disease can be possible throught HAART.

Neurologic aspects of HIV infection in infants and children: therapeutic approaches and outcome

Central nervous system (CNS) HIV-related disorders frequently have devastating consequences. Significant progress has been made in the early diagnosis and treatment of the HIV-infected patient. As a result, the prevalence and natural history of neurologic illnesses have changed. This paper reviews the epidemiology, clinical manifestations, and neuropathogenesis of HIV-related CNS disorders. Advances in antiretroviral therapy, neuroprophylaxis, and neuroprotective strategies are also discussed.

Hepatitis C virus infection in children coinfected with HIV: epidemiology and management

Mothers with hepatitis C virus (HCV) and HIV coinfection are the major source of HCV/HIV coinfection in infancy and childhood. There is no known intervention capable of interrupting HCV spread from mother to child, while the majority of infant HIV infections occurring in the developed world can be prevented by antiretroviral prophylaxis in the mother and child, elective caesarean section, and formula-feeding. In the era preceding treatment of HIV infection with highly active antiretroviral therapy, HCV coinfection was of little concern because the short-term survival of patients with HIV infection prevented the slowly developing consequences of chronic hepatitis C. As the life expectancy of patients with HIV infection increased with therapy, HCV has emerged as a significant pathogen. Several lines of evidence in adult patients suggest that liver disease may be more severe in patients coinfected with HIV and that progression of HIV disease may be accelerated by HCV coinfection. Whether coinfected children may share these clinical patterns remains a matter of speculation. Chronic hepatitis C in otherwise healthy children is usually a mild disease; liver damage may be sustained and fibrosis may increase over the years, suggesting slow progression of the disease. Interferon-alpha has been the only drug used in the past decade to treat hepatitis C in children and adolescents, with average response rates of 20%. Preliminary results of treatment with interferon-alpha and ribavirin suggest that the efficacy would be greater with combined therapy. These treatment protocols have not yet been applied to children coinfected with HIV, but the increasing number of long-term survivors will probably prompt further investigation in the near future. At present, treating HIV disease and monitoring HCV infection and hepatotoxicity induced by antiretroviral drugs seem to be the more reasonable approach to HCV/HIV coinfection in childhood.

The role of protease inhibitor therapy in children with HIV infection

In comparison with HIV infection in adults, higher HIV RNA levels in children with perinatal HIV infection, differences in the natural history of HIV disease progression, and the presence of a relatively immature immune system contribute to the more complex and problematic nature of pediatric antiretroviral therapy. Current US treatment guidelines for pediatric HIV infection advocate aggressive therapy with potent combination antiretroviral regimens, to achieve profound and durable suppression of viral replication and preservation of immune function. The combination of a protease inhibitor (PI) and dual nucleoside reverse transcriptase inhibitors (NRTIs) is the most commonly recommended form of highly active antiretroviral treatment (HAART). However, use of PI therapy in pediatrics has been constrained by the lack of suitable drug formulations, a paucity of pharmacokinetic and safety data, and drug intolerance. Pharmacokinetic studies of PIs demonstrate frequent differences between children and adults, and greater variability among children, which has led to subtherapeutic dosage regimens and the development of viral resistance. The optimal dosage of many PIs in younger children is not yet known. A therapeutically important drug interaction associated with PIs is that occurring between the various PIs themselves, which allows lower doses of PI at less frequent intervals. Dual PI regimens will probably become more common, as they permit a simpler antiretroviral regimen, lower pill/medication burden, fewer adverse effects and improved adherence. Poor adherence to antiretroviral therapy remains the greatest barrier to overall success in the treatment of HIV-infected children. The key to improving adherence in HIV-infected children is to find treatment regimens that are better suited to their normal life. With improvements in existing PIs and the development of newer ones, simplification of current antiretroviral therapy to once-daily regimens without loss of potency should be achievable. PI-containing HAART has transformed HIV infection into a chronic illness, and HIV-infected children now live longer.

Frequencies of ex vivo-activated human immunodeficiency virus type 1-specific gamma-interferon-producing CD8+ T cells in infected children correlate positively with plasma viral load

HIV-specific CD8+ T cells are critical in controlling human immunodeficiency virus (HIV) replication. We present the evaluation of a gamma-interferon (IFN-gamma)-based enzyme linked immunospot (ELISPOT) assay for the quantification of HIV-specific CD8+ T cells from HIV-infected children. We studied 20 HLA-A*0201-positive HIV-infected children. The IFN-gamma production in response to stimulation with two HLA-A*0201-restricted immunodominant CD8 epitopes (SLYNTVATL [SL9] in Gag and ILKEPVHGV [IV9] in Pol) was tested using the ELISPOT assay. The results were compared to labeling with the corresponding tetramers. Among the 20 children, 18 had detectable responses against the SL9 and/or the IV9 epitope using the ELISPOT assay (medians, 351 and 134 spot-forming cells/10(6) peripheral blood mononuclear cells, respectively). Comparison of results from the tetramer and ELISPOT assays suggests that only a fraction of HIV-specific CD8+ T cells were able to produce IFN-gamma. Most importantly, we found that the frequencies of IFN-gamma-producing CD8+ T cells were positively correlated with the viral load whereas the frequencies of tetramer-binding CD8+ T cells were not. The high sensitivity of the ELISPOT assay and the fact that this functional assay provided information different from that of tetramer labeling support its use for measurement of HIV-specific CD8+ T cells. In conclusion, our results show that the ex vivo-activated IFN-gamma-producing HIV-specific CD8+ T-cell subset is dependent upon continuous antigenic stimulation.

Persistent sterile leukocyturia is associated with impaired renal function in human immunodeficiency virus type 1-infected children treated with indinavir

BACKGROUND

Prolonged administration of indinavir is associated with the occurrence of a variety of renal complications in adults. These well-documented side effects have restricted the use of this potent protease inhibitor in children.

DESIGN

A prospective study to monitor indinavir-related nephrotoxicity in a cohort of 30 human immunodeficiency virus type 1-infected children treated with indinavir.

METHODS

Urinary pH, albumin, creatinine, the presence of erythrocytes, leukocytes, bacteria and crystals, and culture were analyzed every 3 months for 96 weeks. Serum creatinine levels were routinely determined at the same time points. Steady-state pharmacokinetics of indinavir were done at week 4 after the initiation of indinavir.

RESULTS

The cumulative incidence of persistent sterile leukocyturia (> or =75 cells/ micro L in at least 2 consecutive visits) after 96 weeks was 53%. Persistent sterile leukocyturia was frequently associated with a mild increase in the urine albumin/creatinine ratio and by microscopic hematuria. The cumulative incidence of serum creatinine levels >50% above normal was 33% after 96 weeks. Children with persistent sterile leukocyturia more frequently had serum creatinine levels of 50% above normal than those children without persistent sterile leukocyturia. In children younger than 5.6 years, persistent sterile leukocyturia was significantly more frequent than in older children. A higher cumulative incidence of persistent leukocyturia was found in children with an area under the curve >19 mg/L x h or a peak serum level of indinavir >12 mg/L. In 4 children, indinavir was discontinued because of nephrotoxicity. Subsequently, the serum creatinine levels decreased, the urine albumin/creatinine ratios returned to zero, and the leukocyturia disappeared within 3 months.

CONCLUSIONS

Children treated with indinavir have a high cumulative incidence of persistent sterile leukocyturia. Children with persistent sterile leukocyturia more frequently had an increase in serum creatinine levels of >50% above normal. Younger children have an additional risk for renal complications. The impairment of the renal function in these children occurred in the absence of clinical symptoms of nephrolithiasis. Indinavir-associated nephrotoxicity must be monitored closely, especially in children with risk factors such as persistent sterile leukocyturia, age <5.6 years, an area under the curve of indinavir >19 mg/L x h, and a C(max) >12 mg/L.

Sarcoidosis and interstitial nephritis in a child with acquired immunodeficiency syndrome: implications of immune reconstitution syndrome with an indinavir-based regimen

A child with perinatally acquired AIDS and profound immunodeficiency was treated with zidovudine, lamivudine and indinavir and had excellent immunologic and virologic response. His subsequent clinical course was complicated by multisystem sarcoidosis characterized by granulomatous hepatitis, nephritis, duodenitis and a CD4+ lymphocytic alveolitis as part of the immune reconstitution syndrome.

Esophageal candidiasis in human immunodeficiency virus-infected pediatric patients after the introduction of highly active antiretroviral therapy

OBJECTIVE

To investigate epidemiologic trends, clinical features and outcome of esophageal candidiasis in the era of highly active antiretroviral therapy in a prospectively monitored population of HIV-infected children and adolescents followed at the National Cancer Institute.

PATIENTS AND METHODS

The records of all HIV-infected pediatric patients (n = 266) followed between 1995 and 2000 were reviewed for a history of esophageal candidiasis. Proven esophageal candidiasis was defined as clinical plus radiographic and/or endoscopic findings of esophageal candidiasis. Probable esophageal candidiasis was defined as esophageal symptoms that responded promptly to appropriate antifungal therapy. The medical records of all patients fulfilling these criteria were reviewed for demographic, clinical and laboratory features at presentation, as well as therapeutic interventions and outcome.

RESULTS

Of the 266 patients 9 (3.4%) had 18 documented episodes of proven (n = 16) or probable (n = 2) esophageal candidiasis. A history of prior mucosal candidiasis was present in 94% of all episodes. The median CD4+ count at the time of diagnosis was 7/microl (range, 0 to 550), and the median viral load was 98000 copies/ml (range, 22916 to 1278933). Concurrent oropharyngeal candidiasis was the most common clinical presentation (72%) followed by fever (55%), odynophagia (50%) and nausea or vomiting (39%). Treatment consisted of antifungal triazoles (61%) or amphotericin B (39%). Clinical cure was achieved in 15 cases, including all patients receiving triazoles.

CONCLUSION

Esophageal candidiasis persists in the subgroup of patients not responding to highly active antiretroviral therapy and in that setting may present without concomitant oropharyngeal candidiasis or typical clinical symptoms, thus underscoring the need for a high index of suspicion in children with very low CD4+ counts.

Results of 2 years of treatment with protease-inhibitor--containing antiretroviral therapy in dutch children infected with human immunodeficiency virus type 1

Clinical, virologic, and immunologic responses to treatment that contained either indinavir or nelfinavir (both regimens included zidovudine and lamivudine) were determined in 32 children infected with human immunodeficiency virus type 1 (HIV-1) who participated for >/= 96 weeks in a prospective, open, uncontrolled multicenter trial. The pharmacokinetics of indinavir and of nelfinavir were determined and showed large interindividual differences. After 96 weeks of therapy, 69% and 50% of the patients had an HIV-1 RNA load that was below the HIV assays' detection limits of 500 and 40 copies/mL, respectively. Virologic failure was associated with poor compliance and younger age (independent of baseline virus load and receipt of pretreatment). Relative CD4 cell counts increased significantly in relation to the median of the age-specific reference value, from a median of 44% at baseline to 94% after 96 weeks. In a high percentage of the children, clinical, virologic, and immunologic response rates to combination therapy were optimal during the initial 2 years of therapy.

Efficacy of highly active antiretroviral therapy in HIV-1 infected children

Although the reduction in HIV-1-related deaths with highly active antiretroviral therapy (HAART) is similar in adults and children, the extent of the changes in two important surrogate markers HIV-1 RNA levels and CD4+ T cell counts, differs widely. In most paediatric studies virological response rates to HAART are inferior to those in adults. This review provides an overview of the paediatric clinical studies using HAART and seeks to improve the understanding of factors that may contribute to success or failure of HAART in children. An overview of all current articles on paediatric clinical trials using HAART is provided. 23 papers were available. HIV-1 RNA loads and CD4+ T cell counts were used as primary outcome measures. Virological response rates were highly variable, both among the different antiretroviral drugs but also among different studies using the same medication. Four studies in which dosages of the administrated protease inhibitor (PI) were adjusted after pharmacokinetic evaluation had superior virological response rates compared with those in which fixed dosages were used. Immunological response rates were more uniform than virological responses. In almost all studies increases of CD4+ T cell counts are reported independent of the extent of the virological response. Side-effects of HAART were generally mild, transient, and of gastrointestinal origin. Significant percentages of patients with serum lipid abnormalities were reported in three paediatric studies. However, signs of clinical lipodystrophy were not observed. The inferior virological response rates, which have been reported in HIV-1 infected children treated with HAART form a reflection of the challenges that are encountered in the treatment of these children. Difficulties with adherence and with the pharmacokinetics of PIs in children require an intensive, child-adjusted approach. A practical approach to therapy in institutions without tertiary care facilities may be induction therapy with a lopinavir containing regimen (lacking a need for therapeutic drug monitoring), to reduce high viral load levels followed by an easily tolerated maintenance regimen, for example containing abacavir or nevirapine.

Correlation between reduction in plasma HIV-1 RNA concentration 1 week after start of antiretroviral treatment and longer-term efficacy

BACKGROUND

Early assessment of antiretroviral drug efficacy is important for prevention of the emergence of drug-resistant virus and unnecessary exposure to ineffective drug regimens. Current US guidelines for changing therapy are based on measurements of plasma HIV-1 RNA concentrations 4 or 8 weeks after the start of treatment with cut-off points of 0.75 or 1.00 log, respectively. We investigated the possibility of assessing drug efficacy from measurements of plasma HIV-1 concentrations made during the first week on therapy.

METHODS

The kinetics of virus decay in plasma during the first 12 weeks of treatment was analysed for 124 HIV-1-infected patients being treated for the first time with a protease inhibitor. Patients with a continuous decline of HIV-1 concentrations and in whom HIV-1 was either undetectable or declined by more than 1.5 log at 12 weeks were defined as good responders; the rest were poor responders.

FINDINGS

The individual virus decay rate constants (k) at day 6 correlated significantly (r>0.66, p<0.0001) with changes in HIV-1 concentrations at 4, 8, and 12 weeks, and correctly predicted 84% of the responses with a cut-off value of k=0.21 per day (in log scale). Reduction in plasma HIV-1 of less than 0.72 log by day 6 after initiation of therapy predicted poor long-term responses in more than 99% of patients.

INTERPRETATION

These results suggest that changes in HIV-1 concentration at day 6 after treatment initiation are major correlates of longer-term virological responses. They offer a very early measure of individual long-term responses, suggesting that treatment could be optimised after only a few days of therapy.

Effect of combination therapy including protease inhibitors on mortality among children and adolescents infected with HIV-1

BACKGROUND

Combination therapy including protease inhibitors has been shown to be effective in treating adults infected with human immunodeficiency virus type 1 (HIV-1), but there are only limited data regarding the treatment of children and adolescents.

METHODS

A cohort of 1028 HIV-1-infected children and adolescents, from birth through 20 years of age, who were enrolled in research clinics in the United States before 1996 was followed prospectively through 1999. We used proportional-hazards regression models to estimate the effect on mortality of combination therapy including protease inhibitors.

RESULTS

Seven percent of the subjects were receiving combination therapy including protease inhibitors in 1996; by 1999, 73 percent were receiving such therapy. In univariate analyses, a higher base-line percentage of lymphocytes that were CD4-positive, a higher weight for age, a higher height for age, black race, Hispanic ethnic background, younger age, and perinatally acquired infection were associated with a longer median time to the initiation of this type of therapy (P<0.001). After adjustment for covariates, the differences among racial and ethnic groups in the time to initiation were not statistically significant. Mortality declined from 5.3 percent in 1996 to 2.1 percent in 1997, 0.9 percent in 1998, and 0.7 percent in 1999 (P for trend <0.001). There were reductions in mortality in all subgroups defined according to age, sex, percentage of CD4+ lymphocytes, educational level of the parent or guardian, and race or ethnic background. In adjusted analyses, the initiation of combination therapy including protease inhibitors was independently associated with reduced mortality (hazard ratio for death, 0.33; 95 percent confidence interval, 0.19 to 0.58; P<0.001).

CONCLUSIONS

The use of combination therapy including protease inhibitors has markedly reduced mortality among children and adolescents infected with HIV-1.

Impact of protease inhibitor-containing combination antiretroviral therapies on height and weight growth in HIV-infected children

OBJECTIVE

To examine beneficial or detrimental effects of protease inhibitor (PI)-containing antiretroviral regimens on height and weight growth in children with human immunodeficiency virus (HIV) infection.

METHODS

A prospective cohort study was conducted of 906 HIV-infected children, from pediatric research clinics in the United States, who were between 3 months and 18 years of age and who had height and weight assessed in 1995 (before introduction of PIs in this population) and at least once more through 1999. Changes in age- and gender-adjusted height and weight growth associated with PI use were assessed.

RESULTS

Compared with a healthy reference population, children were more affected in height (mean z score: -0.90 [18th percentile]) than in weight (mean z score: -0.42 [34th percentile]) at baseline (1995). Two thirds of children received at least 1 PI during 1996 to 1999. In the multivariate mixed effects regression models adjusted for baseline log(10) CD4 cell count, baseline age, gender, and race/ethnicity, the use of PIs was associated with per-year gains of 0.13 z scores in height and 0.05 z scores in weight relative to the expected growth with non-PI-containing regimens (eg, after 1 year of PI use, a representative 6-year-old boy in our study would be approximately 0.7 cm taller and 0.1 kg heavier than if he had not received PIs). No significant differential effects of PIs on height or weight growth according to specific agents or children's sociodemographic or clinical characteristics were found.

CONCLUSIONS

Although the use of PI-containing regimens was not associated with growth retardation, it was associated with only small annual increments in height and weight growth in HIV-infected children.

Protective effect of CCR5 delta 32 heterozygosity is restricted by SDF-1 genotype in children with HIV-1 infection

OBJECTIVE

To determine the influences on pediatric AIDS of a heterozygous 32 base pair deletion in the CC-chemokine receptor 5 gene (CCR5 wt/Delta 32) and a common polymorphism in the 3' untranslated region of stromal cell-derived factor-1 beta gene transcript (SDF1-3'A).

DESIGN

The rate of HIV-1 disease progression and viral burden were compared according to the CCR5 and SDF-1 genotypes in 127 (58 Caucasians, 60 African-Americans and nine Hispanics) perinatally HIV-1-infected children.

RESULTS

Regardless of ethnic background, the CCR5 wt/Delta 32 genotype was associated with a delayed onset of AIDS-defining infectious complications during the first 5 years of infection [relative hazard (RH) = 0.22; 95% confidence interval (CI), 0.012--1.02; P = 0.053]. Similarly, CCR5 wt/Delta 32 conferred an early protection against severe immune suppression and HIV-1 encephalopathy, but only in those without SDF1-3'A (RH = 0; 95% CI, 0--0.70; P = 0.020, and RH = 0; 95% CI, 0--0.71; P = 0.021, respectively). When examined before 5 years of age (n = 81), the children with CCR5 wt/Delta 32 had significantly lower levels of cell-associated HIV-1 DNA than wild-type homozygotes (P = 0.016, adjusted by race), while SDF1-3'A carriers had relatively higher levels (P = 0.047, adjusted by race). Although the disease-retarding effect of CCR5 wt/Delta 32 subsequently disappeared, time to death was still significantly delayed in the CCR5 Delta 32 heterozygotes without SDF1-3'A (RH = 0; 95% CI, 0--0.53; P = 0.008).

CONCLUSION

In pediatric AIDS, the protective effect of CCR5 wt/Delta 32 is more pronounced in early years of infection and appears to be abrogated by the SDF1-3'A genotype.

Antiretroviral drugs in pediatrics

The advent of potent drugs to treat HIV and the development of increasingly effective treatment strategies have resulted in dramatic improvements in the prognosis and quality of life for HIV-infected children. The purpose of this article is to provide the primary care physicians with practical information on antiretroviral drugs that are currently used for the treatment of pediatric HIV infection.

The effect of protease inhibitor therapy on growth and body composition in human immunodeficiency virus type 1-infected children

OBJECTIVE

To determine the effect of protease inhibitors (PIs) on growth and body composition in children with human immunodeficiency virus type 1 (HIV-1) infection.

BACKGROUND

HIV-1-infected children have chronic problems with both linear growth and weight gain. Viral load may directly influence growth and nutritional status of HIV-1-infected children with reduction of viral load improving the nutritional condition.

DESIGN/METHODS

Data from 67 patients who initiated PI therapy between 1996 and 1999 and who were enrolled in a prospective, longitudinal study of growth and nutrition in HIV-1-infected children were analyzed. Outcomes included pre-PI versus post-PI measures of height, weight, weight-for-height, triceps skinfold thickness, and arm muscle circumference. Predictor covariates included age, race, gender, Tanner stage, CD4 z score, Centers for Disease Control and Prevention stage, route of infection, plasma HIV-1 RNA, other antiretroviral therapy, recommended daily allowances for calories, treatment with megestrol acetate, and PI therapy.

RESULTS

Sixty-seven children were followed for a median of 2.4 years with a total of 362 visits (median: 5 visits; range: 1-12). During follow-up, they received PIs for a median of 5 months. Fifty-one percent were girls, 54% black, 15% Hispanic, and 25% white. The mean age at first visit was 6.8 years. In a univariate analysis, weight z score (-0.67 to -0.35) and weight/height z score (0.25-0.76) improved on PI therapy. Using repeated-measures regression analysis, controlling for the above named covariates, PI treatment showed a significant effect on weight z score (increase in z score by 0.46), weight/height z score (increase in z score by 0.49), and arm muscle circumference (increase in percentile by 11.5). A borderline effect was found for height z score (increase in z score by 0.17) and no effect was found for triceps skinfold thickness. In a separate analysis, PI therapy increased CD4 counts twofold and reduced plasma HIV-1 RNA copies by 79%.

CONCLUSION

In addition to a significant reduction in viral load, PI therapy in children has a positive effect on several growth parameters, including weight, weight/height, and muscle mass.

Pharmacokinetics of the protease inhibitor indinavir in human immunodeficiency virus type 1-infected children

The objective of this study was to evaluate the pharmacokinetics of indinavir in human immunodeficiency virus-infected children as part of a prospective, open, uncontrolled, multicenter study in The Netherlands. Human immunodeficiency virus type 1-infected children were monitored over 6 months of treatment with zidovudine (120 mg/m(2) every 8 h [q8h]), lamivudine (4 mg/kg of body weight q12h), and indinavir (33mg/kg of metabolic weight [MW] q8h). Four weeks after the start of treatment, the steady-state pharmacokinetics of indinavir were determined by high-pressure liquid chromatography. If patients had an indinavir area under the concentration-time curve (AUC) of below 10 or above 30 mg/liter. h, a dose increase or a dose reduction was made and pharmacokinetic measurements were repeated 4 weeks later. Nineteen patients started with the dose of 33 mg/kg of MW q8h. The median AUC (range) was 10.5 (2.8 to 51.0) mg/liter. h. The median AUC (range) in 17 children treated with 50 mg/kg of MW q8h was 20.6 (4.1 to 38.7) mg/liter. h. Finally, five patients had a dose increase to 67 mg/kg of MW q8h, resulting in a median AUC (range) of 36.6 (27.2 to 80.0) mg/liter. h. After 6 months of treatment, there were 11 children with an AUC of below 20 mg/liter. h, of whom 5 (45%) had a detectable viral load, while this was the case in none of the 11 children with an AUC of higher than 20 mg/liter. h. We conclude that the optimal dose of indinavir in children to obtain drug exposure similar to that observed in adult patients is 50 mg/kg of MW q8h, which approximates 600 mg/m(2) q8h. It would even be better to adjust the indinavir dose based on an AUC of greater than 20 mg/liter. h.

The safety and antiviral effect of protease inhibitors in children

STUDY OBJECTIVE

To determine the safety and antiviral effect of protease inhibitors (PIs) over 36 months in pediatric patients infected with the human immunodeficiency virus (HIV).

DESIGN

Observational study

SETTING

Pediatric immunodeficiency clinic.

PATIENTS

Twenty-one children.

INTERVENTION

Demographics, dosage regimens, genotype data, viral RNA and CD4+ lymphocyte counts, adverse drug events (ADEs), laboratory tests, and compliance were evaluated over 3 years. Data were analyzed by chi2, repeated measures analysis of variance, and paired t tests.

MEASUREMENTS AND MAIN RESULTS

Twenty-one pediatric patients (aged 3 mo-15 yrs) received PIs over the study period. Average daily doses were ritonavir 26 mg/kg in 12 patients, nelfinavir 94 mg/kg in 16, indinavir 49 mg/kg in 5, and saquinavir 43 mg/kg in 4. Five patients developed resistance to an existing PI. Overall compliance was 70%. Baseline HIV-1 RNA plasma concentrations were significantly higher than average follow-up concentrations during 3-36 months in patients taking ritonavir (p<0.001) and nelfinavir (p<0.001). Sample size was insufficient for indinavir or saquinavir. Sixty ADEs occurred, diarrhea being most common. Of patients with ADEs, 55% required increased monitoring and 43% treatment. Ritonavir was associated with the most ADEs (28), followed by nelfinavir (16), indinavir (11), and saquinavir (5). Significant increases between baseline and follow-up cholesterol levels were found with ritonavir (p=0.02) and nelfinavir (p=0.001), and for serum creatinine (p=0.02) and triglycerides (p=0.02) with ritonavir. Follow-up triglycerides were significantly higher than baseline for indinavir (p=0.003).

CONCLUSION

Nelfinavir and ritonavir were effective in decreasing HIV-1 viral loads and improving CD4+ lymphocyte counts. Ritonavir was associated with more ADEs than other PIs. Changes in cholesterol, serum creatinine, and triglycerides were noted with some PIs.

A randomized, double-blind study of triple nucleoside therapy of abacavir, lamivudine, and zidovudine versus lamivudine and zidovudine in previously treated human immunodeficiency virus type 1-infected children. The CNAA3006 Study Team

OBJECTIVES

Abacavir (ABC) is a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We compared the efficacy, safety, and tolerability of combination therapy with ABC, lamivudine (3TC), and zidovudine (ZDV) versus 3TC and ZDV in antiretroviral experienced HIV-1-infected children over 48 weeks.

METHODS

Two hundred five HIV-1-infected children who had received previous antiretroviral therapy and had CD4(+) cell counts >/=100 cells/mm(3) were stratified by age and by previous treatment. Participants were randomly assigned to receive ABC (8 mg/kg twice daily [BID]) plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2) BID; ABC/3TC/ZDV group) or ABC placebo plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2); 3TC/ZDV group). Participants who met a protocol-defined switch criteria (plasma HIV-1 RNA >0.5 log(10) copies/mL above baseline at week 8 or >10 000 copies/mL after week 16) had the option to switch to open-label ABC plus any antiretroviral combination or continue randomized therapy or withdraw from the study.

RESULTS

The Kaplan-Meier estimates (95% confidence interval) of the proportion of participants who maintained HIV-1 RNA levels </=10 000 copies/mL for 48 weeks or more was significantly better in the ABC/3TC/ZDV group compared with the 3TC/ZDV group: 33% (23%-42%) versus 21% (13%-29%). At week 48, the proportions of participants with HIV-1 RNA </=10 000 copies/mL were 36% versus 26% for the ABC/3TC/ZDV and 3TC/ZDV groups, respectively, by intent-to-treat analysis. For the subgroup of participants with baseline HIV-1 RNA >10 000 copies/mL, a significantly higher proportion of participants in the ABC/3TC/ZDV group had HIV-1 RNA </=10 000 copies/mL compared with the 3TC/ZDV group (29% vs 12%) but no difference was observed in the subgroup of participants with baseline HIV-1 RNA </=10 000 copies/mL (78% vs 72%). The median changes from baseline in CD4(+) cell counts were greater in the ABC/3TC/ZDV group than in the 3TC/ZDV group. Few participants (3%) experienced abacavir-related hypersensitivity reaction.

CONCLUSIONS

ABC, in combination with 3TC and ZDV, provides additional antiretroviral activity over 48 weeks, compared with combination therapy with 3TC and ZDV in antiretroviral experienced HIV-1-infected children. ABC was safe and generally well-tolerated and should be considered an active component of combination antiretroviral therapy in this pediatric population.

Effects of negative life events on immune suppression in children and youth infected with human immunodeficiency virus type 1

OBJECTIVES

To evaluate the association of negative stressful life events experienced over 12 months and the risk of moderate to severe immune suppression among children and youth infected with human immunodeficiency virus type 1 (HIV-1).

METHODS

Longitudinal study of 618 HIV-1-infected children, baseline ages 1 to 20 years (mean age: 6.4 years), who completed 52 weeks of participation in the Pediatric Late Outcomes Study (Pediatric AIDS Clinical Trials Group Protocol 219). Severity of immune suppression was indicated by the Centers for Disease Control and Prevention Pediatric HIV Disease Classification System, based on CD4 percentages. The total number of negative life events-categorized as none, 1, or >1 life event reported as having occurred in the previous 12 months (previous 6 months for children <3 years of age)-was the predictor variable. Multiple logistic regressions were estimated to assess the relationship of negative life events and immune suppression at outcome, controlling for baseline measures of immune suppression, continuous CD4%, negative life events, age, race/ethnicity, gender, primary caretaker, education level of caretaker, and acquired immunodeficiency syndrome status.

RESULTS

At week 52, 379 subjects (61% of total study population) had moderate to severe immune suppression. Of 275 children with normal immune function at baseline, 68 (24.7%) subsequently developed moderate to severe suppression levels by week 52 of follow-up. Of 343 children with immune suppression at baseline, 32 (9.2%) had recovered to normal CD4% levels by week 52. More than 1 negative life event was associated with an increased risk (prevalence) of immune suppression (odds ratio [OR]: 2.76; 95% confidence interval [CI]: 1.44,5.31), controlling for baseline CD4%, total life events, and other covariates. Children without immune suppression at baseline who experienced >1 negative life event had an increased incidence of immune suppression (OR: 2.93; 95% CI: 1.34,6.39), controlling for baseline covariates.

CONCLUSIONS

Results indicate that negative stressful life events increase the risk of children with HIV-1 infection having impaired immune function. Further research is needed to identify potential mechanisms of the relationship between stressful life events and impaired immune function. These mechanisms include psychoneuroendocrinologic response and difficulties in adherence to therapy after exposure of a child to major negative life events.

Pharmacologic characteristics of indinavir, didanosine, and stavudine in human immunodeficiency virus-infected children receiving combination therapy

The use of human immunodeficiency virus (HIV) protease inhibitors in children has lagged behind that in adults because of the lack of suitable pediatric formulations and information on safe and effective dosing regimens. This study was designed to obtain pharmacokinetic information on indinavir, administered to HIV-infected children also receiving therapy with two nucleoside agents, and to explore relationships between pharmacokinetic parameters and anti-HIV effect. Indinavir was initiated at a dose of 500 mg/m(2) every 8 h. Plasma indinavir concentrations were measured every 4 weeks; the dose or dosing interval was adjusted to maintain trough concentrations of > or =0.1 mg/liter. All children were evaluated clinically at baseline and every 4 weeks. Plasma HIV RNA was quantitated at baseline and at weeks 4, 12, and 24. Eighteen children participated in this study. The average daily dose of indinavir was 2,043 mg/m(2); nine children received indinavir at 6-h intervals. Pharmacokinetic characteristics of indinavir (mean +/- standard deviation) were the following: oral clearance, 1.4 +/- 0.5 liters/h/kg; half-life, 1.1 +/- 0.43 h; and trough concentration, 0. 29 +/- 0.32 mg/liter. In nine children that completed 24 weeks of therapy, the baseline-to-week-24 change in HIV RNA level was related to indinavir trough concentration and didanosine area under the curve. This study illustrates the ability to obtain pharmacokinetic information from children during routine clinic visits and to use this information to provide a safeguard against underdosing. The incorporation of pharmacologic knowledge with virologic, immunologic, and behavioral considerations should result in improved clinical outcomes for children infected with HIV.

Antiretroviral therapy of HIV infection in children

Much progress has been made in the therapy of pediatric HIV infection, which has been transformed from a usually fatal disease into that of a chronic disease model. Early, aggressive therapy with the goal of complete suppression of viral replication (undetectable plasma virus) should be the therapeutic goal, but this new, more hopeful environment has been created at the cost of complexity and compromises in quality of life. The rapid pace of new developments and therapeutic complexities argue strongly for care in specialized centers or, at least, frequent consultation. Efforts are ongoing to develop simpler, more effective therapeutic regimens that suppress and ultimately eradicate infection and that stimulate immune reconstitution.

Indinavir: a review of its use in the management of HIV infection

Indinavir is a protease inhibitor used in the treatment of patients with HIV infection. Combination antiretroviral therapy with indinavir plus 2 nucleoside reverse transcriptase inhibitors (NRTIs) is associated with greater reductions in viral load, greater increases in CD4+ cell counts, and reduced morbidity and mortality when compared with 2 NRTIs alone. In the landmark clinical trial ACTG 320, the rate of progression to AIDS or death (primary end-point) among zidovudine-experienced patients treated with indinavir, zidovudine and lamivudine was approximately half that of patients who received only zidovudine plus lamivudine (6 vs 11%; p < 0.001). The durability of an indinavir-containing regimen was demonstrated in Merck protocol 035, an ongoing trial in which a significant proportion of patients had sustained viral suppression for up to 3 years. Merck protocol 039, also an ongoing trial, showed a greater effect on surrogate markers of HIV disease progression with indinavir-based triple therapy than with zidovudine plus lamivudine or indinavir monotherapy in patients with advanced disease (median baseline CD4+ count 15 cells/microL). Numerous additional clinical trials have established the beneficial antiviral and immunological effects of indinavir in both antiretroviral-naive and -experienced patients with HIV infection. Indinavir is associated with various drug class-related adverse events, including gastrointestinal disturbances (e.g. nausea, diarrhoea), headache and asthenia/fatigue. A lipodystrophy syndrome has been commonly reported with indinavir and other protease inhibitors combined with NRTIs, but it has also been reported in many protease inhibitor-naive patients, and a definitive causal link has not been established between the syndrome and protease inhibitors. Nephrolithiasis may develop in about 9% of patients receiving indinavir but does not appear to be associated with other protease inhibitors; <0.5% of patients receiving indinavir discontinue the drug because of nephrolithiasis, which may be the extreme end of a continuum of crystal-related renal syndromes. Additional renal problems (e.g. nephropathy) have been reported in small numbers of patients receiving indinavir. In summary, indinavir is a protease inhibitor with well documented efficacy when used as part of combined therapy in patients with HIV infection. Both US and UK treatment guidelines continue to recommend protease inhibitor-based regimens including indinavir as a first-line option. Indinavir is being studied as a twice daily and once daily regimen with a low dosage of ritonavir as a way to alleviate tolerability, drug interaction and patient compliance/adherence issues. Indinavir-containing triple therapy has demonstrated positive effects not only on surrogate markers of disease progression, but also on clinical end-points of mortality and morbidity in patients with HIV disease. Protease inhibitors are a significant advance in the care of patients with HIV infection, and, in an era of evidence-based medicine, indinavir represents an important component of antiretroviral treatment strategies.

Primary HIV infection of infants: the effects of somatic growth on lymphocyte and virus dynamics

Acute HIV infection is characterized by the appearance of high concentrations of virus in the peripheral blood. In adults, this high-level viremia spontaneously abates after several weeks. In contrast, after perinatal infection of infants, blood virus levels remain high for many months, during which the concentration of circulating CD4+ lymphocytes remains well above normal values for adults. Here we suggest an explanation for these differences, based on developmental factors including somatic growth and immunological ontogeny. Flow cytometric analysis revealed that at birth the thymus contains elevated levels of mature T lymphocytes, compared to the thymus after 3 months of age. A mathematical model is proposed incorporating immunological and virological data from longitudinally evaluated infants who acquired infection at the time of birth. This model explains the pattern of high-level viremia in infants as resulting from the replication of HIV within the progressively expanding lymphoid cell mass.

Protease inhibitor and triple-drug therapy: cellular immune parameters are not restored in pediatric AIDS patients after 6 months of treatment

OBJECTIVE

To assess whether treatment of HIV-positive children by antiretroviral drugs for a 6-month period would improve immune function significantly.

DESIGN AND METHODS

Immunological assessment of 89 HIV-positive children who received protease inhibitor monotherapy for 12-16 weeks as part of phase I/II studies, followed by triple antiretroviral therapy for an additional 12 weeks, was conducted. Immunological parameters were assessed in vitro at four time points (at enrollment, at weeks 2-4, at weeks 12-16, and at weeks 24-28). Assessments included: cytokine production by monocytes, T-cell proliferation to mitogen or recall antigens (including an HIV antigen) and apoptotic cell death. Plasma levels of tumor necrosis factor (TNF)-alpha and soluble TNF receptor (sTNF-R) were also measured, in addition to CD4+ T-lymphocyte counts and viral load. In addition, limited analyses were performed on samples from 17 children after 120 weeks of therapy, including 104 weeks of triple therapy.

RESULTS

At enrollment, the 89 children exhibited severe immune defects. Antiretroviral therapy raised CD4+ T-lymphocyte counts significantly and decreased viral loads. In contrast, the in vitro immune parameters studied were not improved, except for plasma levels of sTNF-RII which decreased in parallel with the decrease in viral load. In addition, there was a trend towards increased skin test reactivity for the ritonavir-treated children. No differences were seen in the immune parameters whether the patients were treated with mono- or triple therapy. Results obtained after 120 weeks of therapy demonstrated that defective interleukin-12 production was not restored by long-term therapy.

CONCLUSIONS

After 6 months of therapy, with the exception of decreased sTNF-RII levels, and a trend towards increased skin test reactivity, restoration of several defective cellular immune responses did not occur despite significantly decreased viral loads and increased CD4+ T-lymphocyte counts.