Protease inhibitor therapy in children with perinatally acquired HIV infection

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.

The unanswered question: when to initiate antiretroviral therapy in children with HIV infection

PURPOSE OF REVIEW

The question of when to initiate antiretroviral treatment for children is perhaps the most critical unanswered question in pediatric HIV therapeutics. With large numbers of children throughout the world acquiring HIV infection and with improved global access to HIV treatment it is particularly timely to consider the optimal time to initiate antiretroviral therapy in infants, children and adolescents.

RECENT FINDINGS

Early treatment can result in suppression of HIV viremia, immune preservation and prevention of disease progression. This must be balanced by the challenges of maintaining adherence to multidrug regimens, the risks of selecting drug-resistant virus, and long and short-term toxicities of medications.

SUMMARY

This review provides a framework within which to consider when to initiate children on antiretroviral treatment. A child's age and developmental status, where they live, and the goals and expectations for treatment provide a context for balancing the risks of disease progression with the risks of drug-related toxicities and viral resistance.

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.

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.

HAART-related nephropathies in HIV-infected patients

There is no doubt that highly active antiretroviral therapy (HAART) has been the most important progress in the therapy of human immunodeficiency virus (HIV)-infected patients in the last decade. A growing number of observations suggest that the beneficial effects of HAART also include improvement of HIV-related renal complications. Consequently, the cohort of HIV-infected patients requiring HAART has increased and includes patients with preexisting nephropathies, whether related or unrelated to HIV infection. However, some antiretroviral drugs may have renal- and life-threatening side-effects, especially if underlying renal abnormalities exist. In this review, we focus on those aspects that require particular attention in preventing new health complications in HIV-infected patients.

Triple nucleoside reverse transcriptase inhibitor therapy in children

Much of the success attributed to HIV therapy in the last few years has resulted from improved ways of using existing drugs in combination therapy regimens. The availability of new, more potent drugs such as protease inhibitors and more accurate viral load tests to aid decisions to start or change treatment has also contributed to the success. Published recommendations for pediatric HIV therapy, generated by a panel of experts and specialists, are readily available and regularly updated. Preferred regimens of 'potent' therapy (referred to as highly active antiretroviral therapy, or HAART) currently consist of two nucleoside reverse transcriptase inhibitors (NRTIs) combined with either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor. More intense four-drug regimens using an NNRTI or a second protease inhibitor as a fourth drug are being evaluated. Problems with HAART include: unpalatable drug formulations and adverse effects, coupled with lack of data on the pharmacokinetics, efficacy, and safety of various drug combinations. Adherence is a major factor influencing the efficacy and outcome of antiretroviral therapy. Many children cannot adhere to complex multidrug regimens, which cause virologic failure, despite excellent CD4+ cell count responses. This means a rapid progression through the limited number of treatment regimens available. Simpler regimens such as those containing three NRTIs have been proposed as a method of treatment that will allow suppression of the virus, yet circumvent many of the problems previously mentioned. An additional benefit would be the preservation of antiretroviral drugs from other classes for future treatment options if required. The major advantages of triple NRTI regimens are the simplicity of the regimen, good tolerability, few drug-drug interactions, and infrequent adverse effects coupled with a low pill burden. However, abacavir hypersensitivity remains a major problem. Up to 3% of patients may develop an early idiosyncratic hypersensitivity reaction - fever, malaise, and mucositis with or without rash, which can progress to more advanced stages of shock and death. A major concern is the apparently inferior virologic control of triple NRTI therapy as demonstrated in the AIDS Clinical Trials Group A5095 study with zidovudine/lamivudine/abacavir (Trizivir) combination in adults. Such a combination should only be considered in special situations. Examples cited include informed patient choice based on anticipated poor adherence on other treatment regimens, or if concomitant drugs such as tuberculosis medication are prescribed. The low pill burden of triple NRTI regimens (especially if combined in a single pill such as Trizivir), offers hope that regimen simplification may still be possible in the future.

Positive virological outcome after lopinavir/ritonavir salvage therapy in protease inhibitor-experienced HIV-1-infected children: a prospective cohort study

BACKGROUND

Lopinavir/ritonavir has demonstrated antiviral activity in the HIV-infected patient.

OBJECTIVE

To analyse virological response to lopinavir/ritonavir therapy in previously protease inhibitor (PI)-experienced HIV-1-infected children.

MATERIALS AND METHODS

Sixty-seven HIV-1-children on lopinavir/ritonavir were studied in a multicentre prospective cohort observational study. The outcome variables were undetectable viral load (uVL; VL < or =400 copies/mL) and virological failure after uVL with a rebound of VL >400 copies/mL. VL and genotype of HIV-1-isolates were measured using standard assays.

RESULTS

83.5% of children had a 1 log10 VL decrease including 65.6% who reached uVL. Children with >2 changes of antiretroviral therapy (ART) or >5 drugs needed a median time of 3-4 months higher than children with < or =2 changes of ART or < or =5 drugs previous to lopinavir/ritonavir, to reach those values, and the relative proportions (RP) were 2.2 (P =0.038) and 1.9 (P=0.050), respectively. Children with CD4+>15% (P=0.122), VL < or =30,000 (P < 0.001) copies/mL, and age >12 years (P=0.096) achieved an earlier control of VL during the follow-up. The children with virological failure or rebound of VL had higher baseline VL and lower CD4+ T-lymphocytes/mm3 and had taken a greater number of drugs previous to lopinavir/ritonavir. HIV-children with a new nucleoside reverse transcriptase inhibitor (NRTI), or protease inhibitor (PI) or PI plus non-nucleoside reverse transcriptase inhibitors (NNRTI) in the current regimen had a better virological response than children without these new drugs. Also, children with <6 protease mutations had an RP of 2.31 of achieving uVL.

CONCLUSIONS

Highly active antiretroviral therapy (HAART) including lopinavir/ritonavir induces beneficial effects in terms of virological outcome responses, and it is an effective option for salvage therapy in PI-experienced HIV-1-infected children.

Salvage lopinavir-ritonavir therapy in human immunodeficiency virus-infected children

OBJECTIVE

To study the control of viral replication in human immunodeficiency virus (HIV)-infected children on different salvage therapies.

DESIGN AND SETTING

A retrospective observational study in 120 HIV-infected children was conducted. The children were divided into 3 groups according to their salvage therapies: (1) children receiving first line highly active antiretroviral therapy (HAART); (2) protease inhibitor-experienced children receiving second line HAART; (3) protease inhibitor-experienced children receiving HAART including lopinavir-ritonavir (LPV/r). The outcome variables examined were time to achieve viral load (VL) < or =400 copies/mL, success in achieving VL < or =400 copies/mL and time to virologic failure (VL >400 copies/mL).

METHODS

VL (HIV-RNA copies/mL) was quantified with reverse transcription-polymerase chain reaction molecular assay. For each protocol, survival analyses were conducted to determine the probability of achieving VL < or =400 copies/mL and rebound of VL.

RESULTS

VL < or =400 copies/mL was achieved by 52.4% of children receiving first line HAART, 48.3% receiving second line HAART and 71.5% receiving HAART including LPV/r. Children receiving HAART including LPV/r reached VL < or =400 copies/mL in a shorter time than children receiving second line HAART (P = 0.017), but quite similar to children receiving first line HAART. In terms of adjusted relative risk, children receiving HAART including LPV/r were 3.36 [95% confidence interval (95% CI), 1.59, 7.07] more likely to achieve VL < or =400 copies/mL than children receiving a different second line HAART. VL rebound occurred in 68.2% children receiving first line HAART, 73.4% receiving second line HAART and 32.4% receiving HAART including LPV/r. Children receiving HAART that includes LPV/r has less incidence of VL rebound (P=0.013) and 3.29 (95% CI 1.04, 10.3) times less risk to achieve a VL rebound than children receiving a different second line HAART.

CONCLUSIONS

HAART that includes LPV/r is able to control HIV replication more efficiently than other classic salvage antiretroviral therapies.

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.

Virological phenotype switches under salvage therapy with lopinavir-ritonavir in heavily pretreated HIV-1 vertically infected children

OBJECTIVE

To investigate the effects of salvage therapy with lopinavir-ritonavir on HIV-1 phenotype in heavily antiretroviral experienced HIV-infected children.

DESIGN

Twenty antiretroviral experienced HIV-infected children were studied during a mean of time of 16.1 months from initiation of the treatment with lopinavir-ritonavir.

METHODS

Besides CD4 T cells, viral load and clinical status, we analyzed 91 serial viral isolates to study the phenotype, and biological clones derived from co-cultivation techniques.

RESULTS

We observed an increase in CD4 T cells, a statistically significant decrease in viral load and clinical benefits from 3 months after treatment. Ninety per cent of children had SI/X4 bulk isolates in peripheral blood mononuclear cells at study entry. The viral phenotype changed to non syncitium-inducing (NSI)/R5 in 94% of the children after a mean of 5.7 months (95% confidence interval, 2.1-9.3 months) of salvage therapy. The remaining 10% of children had NSI/R5 isolates at entry and at all follow-up study. Similar results were found at the clonal level. Thus, at study entry in PBMC of three children with bulk syncitium-inducing (SI) phenotype, we recovered 65 biologic clones, 56 being SI and nine NSI. After salvage therapy bulk isolates changed to NSI and of 40 biologic clones recovered only five were SI and the rest were NSI.

CONCLUSIONS

Our data suggest that lopinavir-ritonavir salvage therapy led not only to a viral load decrease but also to a phenotypic change. X4 virus appeared to be preferentially suppressed. Shifts in co-receptor usage may thereby contribute to the clinical efficacy of anti-HIV drugs in vertically infected infants.

CD38 expression in CD8+ T cells predicts virological failure in HIV type 1-infected children receiving antiretroviral therapy

An observational study of children vertically infected with human immunodeficiency virus type 1 (HIV-1) was performed to determine the role of CD38 expression in CD8(+) T cells as prognostic marker of virological failure in children receiving HAART. We studied 42 children who were receiving antiretroviral therapy and who had an undetectable virus load (uVL), and we found a negative correlation between CD38 expression in CD8(+) T cells and the duration of uVL. We selected 17 HIV-1-infected children with CD38 values close to the baseline level (i.e., the first uVL achieved), and we distributed the children into 2 groups on the basis of median CD38 value in CD8(+) T cells. Children with CD38 values in CD8(+) T cells that were higher than the median had a higher incidence and relative risk of virological failure than did those with values lower than the median. In conclusion, we demonstrate for the first time that CD8(+)CD38(+) T cell count is a good prognostic marker of therapeutic failure in HIV-1-infected children.

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.

Characterizing the immune system after long-term undetectable viral load in HIV-1-infected children

Thirty two HIV-infected children, on highly active antiretroviral therapy (HAART) and > 500 CD4+ T cells/mm3, were rated according to the time-course of viral load (VL) during the whole follow-up period (> 18 months) in a longitudinal retrospective study. (a) uVL group: 15 children with VL below 400 copies/mL; (b) dVL group: 17 children with higher VL. The uVL group showed higher memory (CD4+CD45RO+) T cells than did dVL group, and higher number of memory activated CD4+CD45RO+HLA-DR+ than did control group (healthy age-matched uninfected children), whereas CD4+CD45RA(hi)+CD62L+ was similar. However, TCR rearrangement excision circles (TRECs) were higher in uVL group than in dVL group. uVL Group showed CD8+CD45RO+ and CD8+CD45RO+CD38- higher number than the control group, but lower than the dVL group. The percentage of CD8+CD45RA(hi)+CD62L+, CD8+CD45RA+, CD8+CD62L-, and CD8+CD28+ was higher in uVL group than in dVL group, and lower than in control group. The uVL group showed higher number of activated (HLA-DR+CD38+, HLA-DR+, HLA-DR+CD38-) CD4+ T cells and lower percentages of CD4+HLA-DR-CD38+ than dVL group. In activated CD8- T cell, the uVL group had lower CD8+HLA-DR+CD38+, CD8+HLA-DR+, and CD8+CD38+ than the dVL group. Preeffector (CD8+CD57-CD28- and CD8+CD45RA-CD62L-) T cells were lower in the uVL group than in dVL group. In the effector (CD8+CD57+, CD8+CD57+CD28-, and CD8+CD45RA+CD62L-) T cells, HIV-infected-children had higher values than control group. HIV-infected-children who respond to HAART had TRECs reconstitution, decreased immune activation, and lower effector CD8+ T cells. Moreover, successful HAART allow the increment of activated CD4+ T cells.

Recovery of T-cell subsets after antiretroviral therapy in HIV-infected children

BACKGROUND

Variation of percentageCD4+ T cells may accurately reflects the kinetics of a comprehensive immune recovery independently of the antiretroviral (ART) regimen. To test this we have investigated the relationship among peripheral blood T-cell subsets with the variation of percentageCD4+ T cells during follow up in 49 HIV-infected children.

METHODS

Children were divided into two groups according to the sign of slope percentageCD4+ T cell during follow up: Ps-group (positive slope) and Ns-group (negative percentageCD4 slope) indicative of immunological recovery or not, respectively. CD4+ and CD8+ T-cell subset percentages were examined by three-colour flow cytometry.

RESULTS

We found higher memory CD4+ and CD8+ T-cell percentages in the Ns-group than in the Ps-group, and inversely, higher naive CD4+ and CD8+ T cells in the Ps-group than in the Ns-group. CD4+ and CD8+ subsets in the Ps-group expressed higher levels of CD38+ and lower levels of HLA-DR+ compared with the Ns-group. We found a very strong positive correlation among the slope of percentageCD4+, CD4+ CD38+, whereas a negative correlation among the slope of percentageCD4+, the CD8+ CD28+ CD57+ and CD8+ CD57+ T-cell subsets.

CONCLUSION

Recovery of the CD4+ T-cell percentage induced by ART reflects a reduction in the chronic immune activation and a measurable reconstitution of the immune system and depends on naive CD4+ T cells.

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.

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.

Zidovudine: a review of its use in the management of vertically-acquired pediatric HIV infection

Zidovudine is a thymidine analog that, after intracellular phosphorylation to zidovudine triphosphate metabolite, inhibits HIV-specific reverse transcriptase and terminates proviral DNA. Zidovudine administered to mildly symptomatic women with HIV infection in the antepartum (100mg orally 5 times/day), intrapartum (2 mg/kg intravenously over 1 hour then 1 mg/kg/h) and then to the neonate for 6 weeks (2 mg/kg), significantly reduced the rate of vertical HIV transmission by about two thirds, in the absence of breast-feeding (The Pediatric AIDS Clinical Trials Group 076 trial, standard protocol). Shorter zidovudine regimens, reduced the risk of transmission of HIV by 50% in a non-breast-feeding population and by about 37% in breast-feeding populations. Zidovudine (standard protocol) in combination with lamivudine was superior to zidovudine alone. A short oral zidovudine regimen was not as effective as a two-dose oral nevirapine regime, although the combination of short-course zidovudine plus lamivudine was as effective. Suppression of viral replication in neonates, infants and children has been achieved with zidovudine when used in triple-therapy regimens that include other antiviral drugs. Results from a trial of treatment-naive children indicate that the antiviral efficacy of combinations of zidovudine and lamivudine or abacavir, given with the protease inhibitor nelfinavir, is superior to treatment with this combination minus nelfinavir. When zidovudine was used in other highly active antiretroviral therapy regimens significant improvements in surrogate markers were consistently seen. Changing to ritonavir-containing regimens was superior to changing to treatment with two new nucleoside reverse transcriptase inhibitors. Short- and long-term (up to 5.6 years) outcomes from clinical trials showed that prenatal and neonatal exposure to zidovudine was generally well tolerated with the exception of mild anemia that resolved spontaneously after treatment cessation. Zidovudine was generally well tolerated as monotherapy in clinical trials of pediatric patients with HIV infection, and adverse events were similar to those reported in adults, with anemia and neutropenia being the most common.

CONCLUSION

Zidovudine, as monotherapy or in combination with other antiretroviral agents, remains a first-choice therapy for the prophylaxis of mother-to-child HIV transmission as shown by substantial reductions in transmission rates. Where feasible, the optimal strategy to prevent vertical transmission is to combine drug therapy with Cesarean section delivery and no breast-feeding. In addition, zidovudine in combination with another nucleoside analogue and a protease inhibitor is a first- or second-choice therapy for the treatment of pediatric HIV infection as significant and sustained reductions in viral load have been shown in both plasma and cerebrospinal fluid.

Characterizing immune reconstitution after long-term highly active antiretroviral therapy in pediatric AIDS

In this study, we sought to characterize the T lymphocyte recovery in vertically HIV-1-infected children who respond to long-term highly active antiretroviral therapy (HAART). A 3-year longitudinal retrospective study was used to perform a cross-sectional study of 32 children rated according to the time course of CD4(+) T cell percentages in response to antiretroviral therapy and CDC clinical classification: (1) long-term asymptomatic (LTA group): 8 children in A1 during the whole follow-up period; (2) responsive to HAART (Rec group): 13 children in C3 before HAART who achieved CD4(+) T cell counts of > 500 cells/mm(3) after 3 years of HAART; and (3) nonresponsive to HAART (Non-Rec group): 11 children in C3 during the whole follow-up period despite 3 years of HAART. We also studied 17 healthy age-matched uninfected children as controls. Lymphoproliferative responses (LPRs) were evaluated by incorporation of [(3)H]thymidine, identification of T cell subsets by three-color flow cytometry, and determination of thymic production of T cells by quantification of T cell receptor rearrangement excision circles (TRECs). Interestingly, the Rec group showed an increase in percentage of CD4(+) T cells and a decrease in viral load, and recovered LPRs to mitogens and recall antigens, with values similar to those of the LTA group. Moreover, the Rec group produced similar percentages and absolute counts of naive (CD45RA(+)CD62L(+)) CD4(+) and CD8(+) T cells, and TRECs similar to those of the LTA group. In particular, the Rec group produced similar percentages of CD8(+)CD28(-)CD57(+) and CD8(+)CD28(-)CD57(-) T cell subsets compared with controls. Our data indicate that among children who have already progressed to AIDS and severe immunodeficiency but who respond to HAART, the immune system can recover and resemble those of nonprogressors or even uninfected children, in quantitative as well as in functional terms.

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.

Aging cohort of perinatally human immunodeficiency virus-infected children in New York City. New York City Pediatric Surveillance of Disease Consortium

BACKGROUND

New York City (NYC) pediatricians are now caring for fewer HIV-infected infants and more school age children and adolescents than earlier in the epidemic.

METHODS

Clinical, laboratory and demographic data were abstracted from medical records at 10 NYC centers participating in the CDC Pediatric Spectrum of HIV Disease project. Pediatric AIDS cases and HIV-related deaths reported to the NYC Department of Health were examined.

RESULTS

Median age of HIV-infected children in care increased from 3 years in 1989 to 1991 to 6 years in 1995 to 1998. The number of HIV-infected women giving birth in NYC declined 50% from 1990 to 1997 (1630 to 831); increasing numbers were identified prenatally (14% in 1989; 78% after 1995); and most received prenatal zidovudine prophylaxis (73% in 1997). Estimated perinatal transmission decreased to 10% by 1997. Improved identification of seropositive status in infants was associated with an increased proportion of infected infants receiving Pneumocystis carinii pneumonia (PCP) prophylaxis, 84% in 1997. AIDS free survival was longer for children born 1995 to 1998 than for those born before 1995, P = 0.004. In 1998 among children with advanced immunosuppression (CDC category 3), 66% were prescribed 3 or more antiretroviral medicines and 88% received PCP prophylaxis. Citywide AIDS cases and HIV-related deaths fell precipitously beginning in 1996.

CONCLUSIONS

Based on the observations of this study, the cohort of NYC HIV-infected children in care is aging, associated with a decline in new HIV infections, high rates of PCP prophylaxis and increased time to AIDS. Falling HIV-related deaths citywide support these observations.

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.

Gastrostomy tube placement in nonadherent HIV-infected children

OBJECTIVE

To determine the benefits of gastrostomy tube (G-tube) placement in HIV-infected children receiving highly active antiretroviral therapy (HAART).

METHODS

Children who had a G-tube placed due to medication adminsitration difficulties were followed to determine changes in medication adherence and changes in laboratory parameters. Medication adherence and laboratory parameters were reviewed for three months prior to G-tube placement and then were followed for six months after G-tube placement. Viral RNA and CD4+ counts were assessed between the two time periods. Medication adherence was followed by review of pharmacy refill records and pill counts. Parents were surveyed about their opinion regarding the G-tube placement and medication administration in their children.

RESULTS

Six children had G-tubes placed due to medication administration difficulties. The G-tube was tolerated in all six cases, although one child developed a staphylococcal infection 13 months after G-tube placement. Before G-tube placement, the medication adherence to HAART averaged 47% +/- 20% SD, with a range of 15-90%. After G-tube placement, medication adherence improved to 90-100%. All parents were satisfied with the G-tube and all reported shorter medication administration times and fewer behavioral problems. Five of six patients had at least a 2-log10 decrease in viral load, and CD4+ percentages improved by an average of 6.4%.

CONCLUSIONS

G-tubes were well tolerated by HIV-infected children. Although G-tube placement is not needed in most children with HIV, it may provide an option for parents and children where administration of antiretroviral medication poses extreme difficulty and all other avenues have been exhausted.

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.

Symptomatic crystalluria associated with indinavir

OBJECTIVE

To report a case of severe and recurrent crystalluria resulting from the use of indinavir and to review the literature describing this adverse effect.

CASE SUMMARY

A 26-year-old HIV-positive white woman had recurrent episodes of left-sided flank pain accompanied by dilation of the left renal collecting system while undergoing treatment with a triple-drug regimen including indinavir 1200 mg every 12 hours (full dosage). Typical indinavir crystalluria was observed, with no evidence of stones. Acute episodes were treated with intravenous fluids, diclofenac, and ciprofloxacin. Crystalluria and clinical symptoms eventually resolved with withdrawal of indinavir and substitution with a different protease inhibitor. Renal function remained normal.

DISCUSSION

A wide spectrum of disorders of the urinary tract can occur in subjects taking indinavir, with potentially severe complications caused by crystalluria and stones. Indinavir is excreted in the urine; the low solubility of those crystals is the critical factor accounting for the risk of stone formation. An elevated pH with a reduced excretion of citric acid contributes to the low urinary solubility of indinavir. Pharmacokinetic interactions with other drugs, leading to elevated plasma concentrations of indinavir, and dehydration could also increase the risk of stone formation. The impact on renal function can be unfavorable over the long-term period. Cornerstones of treatment and prevention are increased fluid intake and possibly urinary acidification. Emergency drainage may be required for patients with severe obstruction. Reducing the dosage of indinavir has been proposed, but this carries the risk of viral mutations with development of resistance.

CONCLUSIONS

Treatment with indinavir can result in crystalluria with potentially severe obstruction. All patients taking indinavir, not only those with documented crystalluria or renal effects from the drug, should greatly increase their fluid intake and have renal function checked at baseline and then monitored regularly. Urinalysis also should be performed regularly for appropriate monitoring and prevention.

Relationship between efficacy, tolerance, and plasma drug concentration of ritonavir in children with advanced HIV infection

The relationship between ritonavir plasma concentration, efficacy, and tolerance was evaluated in 31 children with advanced HIV infection who were receiving a triple therapy with ritonavir as protease inhibitor. Median CD4+ lymphocyte count and median viral load before the initiation of ritonavir-containing combination therapy were 1320 cells/mL and 5 log10 copies/mL, respectively. Ritonavir was given at a dose ranging from 300 to 450 mg/m2 twice daily. The median follow-up of triple therapy was 19 months. Response was defined as a drop of viremia of more than 1 log. Plasma drug levels were determined twice during the observation period: after at least 4 weeks and after 3 months of combined treatment. Samples were collected before (residual) and 2 hours (T2) after drug intake. Cholesterol, triglycerides, alanine transaminase, aspartate transaminase, and gamma-glutamyl transpeptidase were assessed at the same time. The median values of ritonavir residual and T2 levels were 1.64 mg/L and 5.9 mg/L at observation 1 and 3.35 mg/L and 6.29 mg/L at observation 2, respectively. According to virologic response, median residual concentrations of ritonavir were 3.17, 2.52, and 1.04 mg/L for the complete, the partial, and the no-response groups. The authors observed a wide intersubject variability of ritonavir concentrations with an increase in residual levels between the two observation periods. Residual levels were correlated with virologic response whereas there was no direct association between T2 levels and long-term response. Patients with complete or partial response displayed statistically significantly higher residual concentrations than the no-response group. No correlation could be demonstrated between elevated plasma drug concentrations and abnormal cholesterol or triglycerides values. These results emphasize the importance of a sustained high ritonavir concentration to achieve optimal treatment efficacy. Furthermore, these results prove the clinical benefit of therapeutic drug monitoring and could potentially improve patient evaluation in terms of treatment efficacy, compliance, and viral resistance.

Gastrostomy tube insertion for improvement of adherence to highly active antiretroviral therapy in pediatric patients with human immunodeficiency virus

OBJECTIVES

Newer combination antiretroviral therapies used to treat human immunodeficiency virus (HIV)-infected individuals have resulted in dramatic delays in HIV progression, with reduction in mortality and morbidity. However, adherence to highly active antiretroviral therapy (HAART) may be problematic, particularly in HIV-infected children. Reasons for nonadherence include refusal, drug tolerability, and adverse reactions. We assess: 1) the potential benefits of gastrostomy tube (GT) for the improvement of adherence to HAART in HIV-infected children, and 2) the factors that may result in improved viral suppression after GT placement.

METHODS

The medical records of 17 pediatric HIV-infected patients, in whom GT was used to improve HAART adherence, were retrospectively reviewed for clinical and laboratory parameters. Each record was reviewed for the period of 1 year before and after GT insertion. The main outcome parameters were virologic (plasma HIV RNA polymerase chain reaction quantification) and immunologic (CD4 cell counts). Documentation of adherence to medications in medical records was also assessed during the study. Parental questionnaires were used to determine GT satisfaction and medication administration times. The Wilcoxon rank sum test was used to assess change in viral load (VL) and CD4 cell percentages.

RESULTS

GT was well-tolerated with minor complications, such as local site tenderness, reported by 4 patients (23%). Before GT insertion, only 6 patients (35%) were documented as being adherent, compared with all patients after GT insertion. Ten patients (58%) had >/=2 log(10) VL decline after GT insertion (median: 3.2 log(10)), compared with 7 patients (42%) who had </=2 log(10) VL decline (median: 1.27 log(10)). Both groups of patients (responders and nonresponders) did not differ significantly in baseline parameters, such as VL, CD4 cell percentages, or previous drug therapy. However, in all 10 patients with >/=2 log(10) VL decline, therapy was changed at the time of or soon after GT insertion (median:.8 months; range: 0-6 months), compared with 7 patients with <2 log(10) VL decline who had therapy changed before GT insertion (median: 3.2 months; range: 1-8 months). Parental questionnaires reported significantly shorter medication administration times after GT insertion, with 70% of patients taking >5 minutes before GT, compared with 0% after GT. Questionnaires indicated satisfaction with GT, with perceived benefits being reduced medication administration time and improved behavior surrounding taking medications.

CONCLUSIONS

GT is well-tolerated in pediatric HIV-infected patients and should be considered for selected patients to overcome difficulties with medication administration and to improve adherence. For maximal virologic response, combination therapy should be changed at the time of GT insertion.

Oral manifestations and dental status in paediatric HIV infection

OBJECTIVE

To describe the incidence and prevalence of oral manifestations of HIV infection in a population of perinatally infected children.

DESIGN

Retrospective and prospective study of a cohort of perinatally HIV-infected children.

SETTING

Community hospital and community-based paediatric clinic.

SAMPLE AND METHODS

Forty perinatally HIV-infected children with a median age of 12 months were eligible and selected for the study, which included a medical chart review from birth and prospective follow-up. Each child was examined quarterly for oral manifestations, tooth eruption, and for 27 children, caries and periodontal status.

RESULTS

The incidence of pseudomembranous candidiasis was 43% (95% CI, 27-58%) within 6 months of birth. Oral candidiasis (defined as pseudomembranous or erythematous) was positively associated with low CD4 counts and the occurrence of plaque. Children with low CD4 counts were also found to have fewer teeth than children with high CD4 counts, after adjusting for age.

CONCLUSIONS

Oral manifestations are common in paediatric HIV infection and are possible predictors of HIV disease progression. Primary care of HIV-infected children should include periodic oral examinations to monitor their HIV disease progression and to alleviate symptoms associated with oral opportunistic infections.

Indinavir pharmacokinetics and parmacodynamics in children with human immunodeficiency virus infection

The indinavir dosage regimen currently used for human immunodeficiency virus (HIV)-infected children is not based on pharmacokinetic data obtained in the target patient population. The purpose of our study was to characterize indinavir pharmacokinetics and pharmacodynamics in HIV-infected children. Eleven children (age range, 9.0 to 13.6 years; weight range, 21.7 to 56.0 kg) receiving indinavir (500 mg/m(2) every 8 h) in combination with lamivudine and stavudine were studied. The correlation of indinavir pharmacokinetic parameters and demographic parameters was evaluated. Also, the pharmacodynamic relationship between parameters of indinavir exposure and parameters of renal toxicity and immunologic recovery was studied. The area under the indinavir concentration-time curve (AUC) and patient body surface area (BSA) showed a significant negative correlation (r = 0.73; P = 0.012). Patients with smaller BSA had excessive indinavir AUC compared to adults. On the other hand, the median minimum drug concentration in plasma (C(min)) was lower than that reported for adults. The maximum indinavir concentration in serum was higher in patients with renal toxicity (5 out of 11 children), but the difference was not statistically significant (15.3 +/- 8.2 versus 9.8 +/- 4.4 mg/liter; P = 0.19). There was a trend toward higher immunologic efficacy in patients with greater indinavir exposure: the time-averaged AUC of the percentage of CD4(+) lymphocytes over the baseline value for patients with indinavir C(min) > 95% inhibitory concentration (IC(95)) was higher than in patients with C(min) < IC(95) (P = 0. 068). Our study suggests that a dose reduction may be appropriate for children with small BSA and that a 6-h dosage regimen may be indicated for a substantial percentage of patients. Due to the low number of patients enrolled in this study, our results should be confirmed by a larger study.

Opportunistic infections and other clinical manifestations of HIV disease in children

As the decade draws to a close, physicians can be cautiously optimistic about the prevention and treatment of opportunistic infections in children with HIV disease. As more children receive therapy with powerful antiretroviral regimens, fewer are likely to be at risk for opportunistic pathogens. The widespread use of protease inhibitor combination therapies has already resulted in a dramatic decrease in morbidity and mortality in the population of HIV-infected adults. The same effect has been seen at pediatric care centers throughout the United States. Clinicians caring for HIV-infected children are now considering the safety of discontinuing prophylactic therapies for children with sustained immunologic improvement on antiretroviral therapy. For children who remain at risk, prophylactic regimens for PCP and MAC have been shown to decrease the risk for these infections. Preventive regimens for several other opportunistic infections are also available. The understanding of the pathogenesis of HIV and many of the opportunistic pathogens has led to the development of a variety of efficacious therapies for these infections. Despite these advances, physicians can anticipate that HIV-infected children will continue to develop opportunistic infections and other related complications. Some children fail to respond to antiretroviral therapies, whereas others are unable to tolerate the complex medication regimens. Prophylactic therapies are not 100% protective and, despite improved treatments, few opportunistic infections are cured. Most require lifelong maintenance therapy in the absence of immune reconstitution. Drug interactions, complex dosing schedules, adverse side effects, and high costs further limit the efficacy of these therapies. The prophylaxis, diagnosis, and treatment of opportunistic infections are likely to remain integral components of HIV care for the near and distant future.

Use and cost of hospital and community service provision for children with HIV infection at an English HIV referral centre

OBJECTIVE

To describe the use of hospital and community services for children infected with HIV and estimate the cost per patient-year by stage of HIV infection during the era of antiretroviral monotherapy.

DESIGN

Data on the use of hospital services were collected from case notes; the use of statutory and nonstatutory community services was recorded through diaries and interviews. Total cost estimates were calculated from unit costs from relevant hospital departments and community organisations.

SETTING

Children managed at St. Mary's Hospital (London, England) between 1 January 1986 and 31 December 1994, some of whom used statutory and nonstatutory community services in South East England between 1 November 1994 and 31 May 1996.

PATIENTS AND PARTICIPANTS

118 children with positive HIV antibody status.

MAIN OUTCOME MEASURES AND RESULTS

Mean inpatient days, outpatient visits, tests and procedures performed, drugs prescribed, community services used, associated unit costs and average cost estimates per patient-year by stage of HIV infection (1995/1996 values), and lifetime costs. Service provision during the study period was predominantly hospital-based. The use of services increased for different stages of HIV infection and increased with increasing severity of HIV infection. A shift from an inpatient-based to an outpatient-based service was seen between the periods 1986 to 1991 and 1992 to 1994. As symptoms evolved, children used more hospital inpatient services, with an accompanying shift in the use of community services from general services, such as schooling, to increased use of nurses, social care and home help. The estimated total cost of hospital and community care was 18,600 Pounds per symptomatic non-AIDS patient per year and 46,600 Pounds per AIDS patient per year. Similar estimates for children with indeterminate HIV infection and asymptomatic infection amounted to 8300 Pounds and 4800 Pounds per patient-year, respectively. Nondiscounted lifetime costs for hospital care amounted to 152,400 Pounds (44,300 Pounds to 266,800 Pounds) compared with discounted lifetime costs of 122,700 Pounds (42,000 Pounds to 182,200 Pounds); nondiscounted lifetime costs for community care amounted to 24,300 Pounds (7900 Pounds to 41,600 Pounds) compared with discounted lifetime costs of 21,000 Pounds (6800 Pounds to 32,000 Pounds).

CONCLUSIONS

The continued emphasis on the use of hospital services may be due to the small number of children infected with HIV, most of whom lived in the London metropolitan area where specialist care was concentrated in a few centres. A shift from an inpatient- to an outpatient-based service was observed over time; the advent of the use of combination antiretroviral therapy in this population may further facilitate a shift in service provision and promote shared care between specialist centres, local hospital and community-based services.

Immunologic and virologic responses to HAART in severely immunocompromised HIV-1-infected children

OBJECTIVE

To determine the long-term immunologic and virologic effects of highly active antiretroviral therapy (HAART) in children with AIDS.

DESIGN

A prospective observational study.

SETTING

Two pediatric HIV clinics.

PARTICIPANTS

Twenty-five protease-inhibitor naive HIV-infected children (aged 2-18 years) with advanced disease (CD4 < or =6%).

INTERVENTION

HAART (one protease inhibitor and one or more nucleoside analogs). Diphtheria and tetanus immunization in six patients after 18 months of therapy.

MAIN OUTCOME MEASURES

Changes in percentage of CD4 cells and plasma HIV-1 RNA levels; post-treatment assays of lymphoproliferative responses to recall antigens; CD4 cell memory phenotype.

RESULTS

Median duration of follow-up was 18.8 months (range, 7.5-28 months). At baseline the CD4 cell percentage was 2% (range, 0-6%), this increased significantly to 16% (range, 3-48%) above baseline at 12 months (P = 0.002). The mean maximum CD4 cell increase was 20.7% (range 4-48%) which corresponds to 657x10(6) cells/l (range, 30-2240x10(6) cells/l) above baseline. By contrast, the median viral load was not significantly lower at 12 months than at baseline (P = 0.34), and only 25% of the patients had sustained undetectable viral load. Of the reconstituted CD4 cells 70% were naive, and none of the subjects had lymphoproliferative responses to tetanus and diphtheria although 40% did develop responses to Candida, an environmental antigen. A single immunization with diphtheria and tetanus toxoid produced lymphoproliferative responses to tetanus in three out of six patients.

CONCLUSIONS

HAART was associated with sustained increases in CD4 cell counts, despite a high incidence of 'virologic failure'. CD4 counts and the proportion of naive cells were higher than have been reported in adults, which may be a reflection of greater thymic activity in children. Memory cell clones for antigens encountered in the past which are not prevalent before therapy could not be expanded without additional antigenic exposure.

Combination therapy with efavirenz, nelfinavir, and nucleoside reverse-transcriptase inhibitors in children infected with human immunodeficiency virus type 1. Pediatric AIDS Clinical Trials Group 382 Team

BACKGROUND

Consistent long-term viral suppression has been difficult to achieve in children with human immunodeficiency virus type 1 (HIV-1) infection. We tested the safety and antiviral efficacy of a novel combination consisting of efavirenz, nelfinavir, and one or more nucleoside reverse-transcriptase inhibitors in 57 children previously treated with only nucleoside reverse-transcriptase inhibitors.

METHODS

The children were monitored for 48 weeks after the initiation of therapy. We assessed plasma concentrations of efavirenz and nelfinavir, plasma HIV-1 RNA levels, and lymphocyte subpopulations.

RESULTS

At base line, the 57 HIV-1-infected children (age range, 3.8 to 16.8 years) had a median of 699 CD4 cells per cubic millimeter and 10,000 copies of HIV-1 RNA per milliliter of plasma. The most common treatment-related effects of at least moderate severity were rash (in 30 percent of children), diarrhea (in 18 percent), neutropenia (in 12 percent), and biochemical abnormalities (in 12 percent). Serious side effects were uncommon. The mean values for the area under the curve for efavirenz and nelfinavir corresponded to expected values. In an intention-to-treat analysis, 76 percent of children had plasma HIV-1 RNA levels of less than 400 copies per milliliter after 48 weeks of therapy and 63 percent had levels of less than 50 copies per milliliter. A high plasma HIV-1 RNA level at base line significantly decreased the likelihood that plasma levels of HIV-1 RNA would become undetectable during treatment.

CONCLUSIONS

In HIV-1-infected children who were previously treated with nucleoside reverse-transcriptase inhibitors, the combination of efavirenz, nelfinavir, and nucleoside reverse-transcriptase inhibitors was generally well tolerated and had a potent and sustained antiviral effect.

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.

Preliminary experiences with triple therapy including nelfinavir and two reverse transcriptase inhibitors in previously untreated HIV-infected children

OBJECTIVE

In an intent-to-treat study increase in CD4 cell count, reduction of viral load, clinical benefit and adverse reactions were examined in HIV-infected previously treatment-naive children taking triple therapy.

METHODS

sixteen HIV-infected children in category A or B on antiretroviral triple therapy were followed-up for a period of 12 months. In group I eight patients received zidovudine, lamivudine and nelfinavir; in group II eight patients received stavudine, didanosine and nelfinavir. Viral load and CD4 cell count were measured every 4-8 weeks. Plasma nelfinavir levels were assessed once in all patients at baseline and monitored in patients with increasing viral load.

RESULTS

No significant differences were observed between treatment groups in terms of CD4 cell counts and viral load. A median viral load reduction of 2.8 log10 (range, 1.4-4.2 log10) was achieved over a period of 12 months in both groups. Viral load < 500 copies/ml was found in 69% of patients and viral load < 50 copies/ml in 44% of patients after 12 months. Median CD4 cell count increased from 656 x 10(6) to 850 x 10(6) cells/l after 3 months and was maintained at 813 x 10(6) cells/l after 12 months of treatment. Main side-effects were diarrhoea, rash and hyperlipidaemia. Except for application problems, both regimens were well tolerated. Appropriate formula and individual counselling must be performed during the first weeks of treatment in order to achieve good compliance in paediatric patients.

CONCLUSION

Triple antiretroviral therapy shows a stronger and more sustained reduction of viral load in HIV-infected children compared with studies combining two nucleoside analogues.

Efficacy of and adherence to highly active antiretroviral therapy in children infected with human immunodeficiency virus type 1

BACKGROUND

Clinical trials in adults have demonstrated the efficacy of highly active antiretroviral therapy (HAART) to suppress replication of HIV-1 to nondetectable levels, but lower success rates have been observed in practice. We sought to determine the efficacy of HAART in our population of HIV-1-infected children and to identify determinants of efficacy, especially the role of adherence to prescribed antiretrovirals.

METHODS

The viral load and CD4+ T cell responses of 72 children with perinatally acquired HIV-1 treated with HAART including a protease inhibitor for at least 90 days were examined retrospectively in relation to adherence, as measured by pharmacy records for the first 180 days of HAART.

RESULTS

Patients were defined as adherent if > or =75% of protease inhibitors and > or =75% of all antiretroviral prescriptions were filled. Of the 42 patients (58%) who were adherent, nondetectable viral loads were achieved and maintained in 22 (52%). A Kaplan-Meier plot showed a drop-off in patients maintaining a nondetectable viral load after 200 days. Higher initial viral load was the only pretreatment factor that identified adherent patients at risk for treatment failure. Only 3 (10%) nonadherent patients maintained a viral load of <400 copies/ml. The adherent group had a prompt and sustained increase in CD4+ T cell counts.

CONCLUSIONS

HAART can achieve control of viral replication in HIV-1-infected children who adhere to therapy. However, treatment failure is likely unless there is a high level of adherence. Nonadherence to therapy is common and might be the major impediment to successful treatment of children infected with HIV-1.

Anti-retroviral therapy for HIV-infected children--toward maximal effectiveness

Viral suppression may be more difficult to achieve in children compared to adults. However, appropriate regimens at adequate dosages combined with monitoring of adherence and virologic response should allow children with HIV infection to realize a sustained benefit from combination anti-retroviral therapy.

Ritonavir combination therapy restores intestinal function in children with advanced HIV disease

OBJECTIVES

To investigate the intestinal absorptive processes in children with HIV infection before and after treatment with combination therapy that includes ritonavir. To test the hypothesis that combination therapy improves intestinal function.

DESIGN

Intestinal function tests were performed in 10 children with advanced HIV disease at the enrollment and after 3 and 6 months of therapy with ritonavir combined with two HIV reverse transcriptase inhibitors. HIV viral load and CD4 cell counts were also determined; body weight was monitored.

METHODS

The D-xylose absorption test, the steatocrit and the determination of fecal alpha1-antitrypsin concentration were used to evaluate carbohydrate and fat absorption, as well as fecal protein loss. Serum iron levels were measured to indirectly evaluate iron absorption. HIV-1 RNA-polymerase chain reaction (PCR) and immunofluorescence imaging were used to evaluate virologic and immunologic responses.

RESULTS

In all, 9 children had carbohydrate malabsorption, 3 steatorrhea, 2 protein loss, and 7 iron deficiency. Most tests produced normal results after 3 months of therapy, and all abnormalities were abolished 6 months after institution of combination therapy. Mean results of each of four absorption tests were significantly changed on combination therapy. Viral load was progressively reduced and CD4 count was increased, with an inverse relationship. An evident shift of body weight pattern toward catch-up growth was observed in all children.

CONCLUSIONS

Ritonavir combination therapy results in prompt and sustained restoration of intestinal function, which is associated with reduction in viral load, increase in CD4 counts, and gain in body weight.

Determination of indinavir, a HIV-1 protease inhibitor, in human plasma using ion-pair reversed-phase high-performance liquid chromatography

Indinavir is widely prescribed as a component of potent antiretroviral therapy for the treatment of HIV-1 infection. Because virologic failure of therapy can result from subtherapeutic drug levels, monitoring of indinavir levels may be important in clinical management. We have developed a simple, accurate, and precise high-performance liquid chromatographic (HPLC) assay for measurement of indinavir concentration in human plasma. In our method, indinavir was extracted from plasma with dichloromethane at pH 10.4, which resulted in quantitative recovery of indinavir and the internal standard (IS), methyl-indinavir (86% and 80%-97%, respectively). Chromatographic separation was accomplished using a Luna C18 (2) (Phenomenex) analytic column with a mobile phase composed of acetonitrile:phosphate buffer (25 mM) and 0.2% triethylamine pH 7.0 (34.5:65.5, v/v). Ion-paired reagent triethylamine was necessary to ensure an appropriate retention time for indinavir and differentiate it from other protease inhibitors that were coextracted. Quantification was performed at 210 nm. The standard curves were linear (r2>0.999) over the concentration range 25-5,000 ng/mL, when 1-mL aliquots of plasma were extracted. Inter- and intraday coefficients of variation were acceptable. The assay was used to determine trough and peak levels of in plasma from 12 subjects who received indinavir 1200 mg every 12 hours, 1000 mg every 12 hours, or 800 mg every 8 hours. The concentrations of indinavir found in this study (trough 26-768 ng/mL; peak at 1 hr 3,309-17,568 ng/mL) has a wider range than defined previously (trough 50-300 ng/mL; peak 6,000-12,000 ng/mL). This study illustrates three potential uses of indinavir monitoring: to assess individual dosing regimen, to assess patient compliance, and to monitor unusual indinavir levels caused by changed drug clearance.

Administration of 9-[2-(R)-(phosphonomethoxy)propyl]adenine (PMPA) to gravid and infant rhesus macaques (Macaca mulatta): safety and efficacy studies

9-[2-(R)-(phosphonomethoxy)propyl]adenine (PMPA) significantly inhibits viral reverse transcription and has been reported to sustain low virus load in SIV-infected rhesus monkeys. Based on these findings, studies were conducted to assess the safety, efficacy, and placental transfer of PMPA when administered once daily subcutaneously to gravid rhesus monkeys during the second and third trimesters and their offspring (30 mg/kg/day). Fetuses (SIV-infected, N = 6; noninfected, N = 6) were monitored sonographically, and maternal/fetal blood samples were collected at select time points for hematologic, clinical chemical, virologic, immunologic, and pharmacologic assessments. Newborns were delivered by cesarean section at term and nursery reared for postnatal studies. Infants were administered PMPA once daily beginning on day 2 of life until 9 months postnatal age. Results of these studies have shown significant placental transport of PMPA, with peak fetal levels at 1 to 3 hours post-maternal administration; a significant and sustained reduction in viral load in SIV-infected fetuses and infants; and marked improvements in outcome (e.g., survival, growth, health) in SIV-infected offspring. However, decreased infant body weights and alterations of select serum biochemical parameters (e.g., decreased phosphorus levels, elevated alkaline phosphatase) have been shown to occur in approximately 67% of PMPA-treated infants, with severe growth restriction and bone-related toxicity in approximately 25% of animals studied. These data suggest that although PMPA holds great promise for HIV-infected patients, there is the potential for bone-related toxicity at chronic, high dosages, particularly in infants.

Preliminary experiences with ritonavir in children with advanced HIV infection

The aim of this study was to obtain information on the feasibility (tolerance, safety) of antiretroviral combination therapy, including ritonavir, in children. In eight children (median age 8.9 years; range 3 to 13 years) with advanced HIV disease (median CD4+ lymphocyte count at baseline, 80 cells/microliter; range 0 to 280 cells/ microliter), drug combinations including ritonavir (approximately 300 mg/m2 b.i.d.) were administered. In seven children, previous therapy using a combination of at least two nucleoside reverse transcriptase inhibitors (NRTI) had failed. Four patients had ritonavir added to an already existing regimen of two NRTI; two patients had one NRTI replaced by a new one; and in two patients two new NRTI were initiated. The number of CD4 T cells, plasma HIV RNA concentration, CBC and blood chemistry profile were monitored. Medication had to be discontinued in two children because of severe nausea and vomiting. In the remaining six children, ritonavir was tolerated and treatment was maintained for at least 6 months. The number of CD4 cells increased in five of six patients. The median number of CD4 cells increased from 66 +/- 110 cells/microliter at baseline to 92 +/- 99 cells/microliter, 161 +/- 88 cells/microliter, and 252 +/- 25 cells/microliter after 1, 3 and 6 months of therapy, respectively. The plasma HIV RNA concentration decreased below the detection limit of 500 copies/ml in three children. In the remaining children a maximum reduction of 0.8, 1.0 and 1.8 log10 was observed. In one child the HIV RNA concentration reincreased after 6 months by 0.7 log10 above the nadir. Antiretroviral combinations including ritonavir were tolerated by six of eight children and produced substantial benefits with respect to increased numbers of CD4 cells and a decline in plasma viral RNA concentration. It can be concluded that the administration of ritonavir is possible in a significant proportion of HIV-infected children, and leads to improvement of the CD4 cell count and viral load.

Serum HIV-1 p24 antibody, HIV-1 RNA copy number and CD4 lymphocyte percentage are independently associated with risk of mortality in HIV-1-infected children. National Institute of Child Health and Human Development Intravenous Immunoglobulin Clinical Trial Study Group

OBJECTIVE

The role of HIV-1 antibody in modulating disease progression must be assessed in the context of other immune and viral load markers. We evaluated the association between HIV-1 p24 antibody, HIV-1 RNA, immune complex-dissociated (ICD) p24 antigen, CD4 cell percentage, and mortality in a cohort of 218 HIV-infected children enrolled in a trial of intravenous immunoglobulin prophylaxis of bacterial infections.

METHODS

CD4 cell percentage was measured and sera collected and stored at baseline and every 3 months on study (1988-1991). Stored sera were assayed for HIV-1 p24 antibody, HIV-1 RNA, and ICD p24 antigen. Mortality was recorded during the trial and updated through 1996 (mean total follow-up, 6.3 years).

RESULTS

Eighty-one (37%) children died; probability of mortality for children with baseline HIV-1 p24 antibody concentrations of undetectable (< 1), 1-4, 5-124, and > or = 125 reciprocal titer units (RTU) was 61, 50, 24, and 10%, respectively. A 3.5-fold increase in the relative risk (RR) of death [95% confidence interval (CI), 2.2-5.5] was observed among children with baseline HIV-1 p24 antibody concentration < 5 RTU compared with > or = 5 RTU. In multivariate analyses, p24 antibody, HIV-1 RNA, and CD4 cell percentage but not ICD p24 antigen were independently associated with mortality; the RR of death increased by 1.7 (95% CI, 1.3-2.1) for each log10 decrement in baseline HIV-1 p24 antibody.

CONCLUSIONS

HIV-1 p24 antibody, HIV-1 RNA and CD4 cell percentage independently predict mortality amongst infected children. Whereas CD4 cell percentage provides an estimate of the general degree of immune suppression, HIV-1 p24 antibody could provide an easily obtained, inexpensive assessment of CD4 cell function and could augment prognostic information provided by CD4 cell count and viral load for clinical management of infected children.