Comparison of two antiretroviral triple combinations including the protease inhibitor indinavir in children infected with human immunodeficiency virus

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.

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.

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.

Therapeutic drug monitoring in children with HIV/AIDS

In this paper we present an overview on the use of TDM in the treatment of HIV-1-infected children. The processes of growth and development have a significant impact on drug metabolism. The use of TDM makes it possible to optimize plasma drug concentrations of antiretroviral drugs. This is important when one considers that the levels of viral suppression and drug toxicity in adults and children are associated with the plasma concentration of PIs and NNRTIs. Indeed, in clinical practice the use of TDM in the treatment of HIV-1-infected children has favorable results. However, there is a serious shortage of population reference values of antiretroviral medication in children. Targeting plasma drug levels in children to adult reference values may be insufficient because of the unique features of HIV infection in children. Apart from its primary function for dose optimization, TDM can also be used as a tool to assess adherence to antiviral medication. One should, however, be cautious to base assumptions on plasma levels alone because aberrant plasma levels may also be the result of other factors such as changes in nutritional habits, drug-drug interactions, or changing gastric motility. We conclude that TDM is a useful tool in the treatment of HIV-1-infected children. Additional data are needed to establish child-specific reference values and to assess the optimal method of TDM.

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.

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.

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.

[Responses to antiretroviral treatments in vertically HIV-1-infected children]

BACKGROUND AND OBJECTIVE

Our goal was to determine the probability of achieving a fall-off of viral load (VL) and an increase of CD4+T-lymphocytes by 36 months from the initiation of antiretroviral therapy (ART) in a cohort of HIV-infected children according to their baseline data.

PATIENTS AND METHOD

This was retrospective multicenter observational study of virologic and immunologic markers in 128 HIV-1-vertically infected children on ART: 55 HIV-infected children on combination therapy (CT), and 73 HIV-infected children on highly active antiretroviral therapy (HAART). Viral load (VL) was quantified using a standard molecular assay. CD4+ and CD8+ T-cells subsets were determined by flow cytometry.

RESULTS

The median time for a 10% rise of CD4+ T-lymphocytes was 35.7 months (95% confidence interval [95% CI], 15.5-55.9) after starting CT, and 11 months (95% CI, 7,7-14.3) after starting HAART. The median time for a VL fall to < 400 copies/ml was 29.6 months (95% CI, 9.4-49.7) after starting CT, and the median time for a VL fall to < 400 copies/ml was 10.9 months (95% CI, 0-21.9) after starting HAART. A 10% increase of CD4+ T-cells over baseline was associated with HAART, low CD4+ T-cells and high VL. On the other hand, a VL fall lower than 400 copies/ml was associated with HAART and low baseline VL.

CONCLUSIONS

Our data indicate that HAART was better than CT in the control of VL and CD4+ T-cell increase. Also, baseline CD4+ T-cell and VL values helped to determine the response to ART in HIV-1 infected children.

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.

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.

Therapeutic immune reconstitution in HIV-1-infected children is independent of their age and pretreatment immune status

OBJECTIVE

To evaluate long-term immune reconstitution of children treated with highly active antiretroviral therapy (HAART).

METHODS

The long-term immunological response to HAART was studied in 71 HIV-1-infected children (aged 1 month to 18 years) in two prospective, open, uncontrolled national multicentre studies. Blood samples were taken before and after HAART was initiated, with a follow-up of 96 weeks, and peripheral CD4 and CD8 T cells plus naive and memory subsets were identified in whole blood samples. Relative cell counts were calculated in relation to the median of the age-specific reference.

RESULTS

The absolute CD4 cell count and percentage and the CD4 cell count as a percentage of normal increased significantly (P < 0.001) to medians of 939 x 106 cells/l (range, 10-3520), 32% (range, 1-50) and 84% (range, 1-161), respectively, after 48 weeks. This increase was predominantly owing to naive CD4 T cells. There was a correlation between the increase of absolute naive CD4 T cell counts and age. However, when CD4 T cell restoration was studied as percentage of normal values, the inverse correlation between the increase of naive CD4 T cell count and age was not observed. In addition, no difference in immunological reconstitution was observed at any time point between virological responders and non-responders.

CONCLUSIONS

Normalization of the CD4 cell counts in children treated with HAART is independent of age, indicating that children of all age groups can meet their CD4 T cell production demands. In general, it appears that children restore their CD4 T cell counts better and more rapidly than adults, even in a late stage of HIV-1 infection.

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.

Saliva as a specimen for monitoring compliance but not for predicting plasma concentrations in patients with HIV treated with indinavir

The presence of the HIV-protease inhibitor indinavir in saliva was analyzed to investigate whether salivary indinavir concentrations are applicable to monitor compliance and/or predict plasma indinavir levels. Fourteen HIV-infected outpatients treated with indinavir and 24 healthy volunteers who ingested a single dose of indinavir were included. Paired plasma and citric-acid-stimulated saliva samples were analyzed by high-performance liquid chromatography (HPLC). Stimulated salivary indinavir concentrations showed a high correlation (r = 0.85, p < 0.01) with corresponding plasma levels. The median saliva/plasma ratio was 65% (P25 50%; P75 94%). The ratios were independent of the plasma concentration; however, a relation with time after ingestion was seen. The unbound fraction of indinavir in plasma was not significantly correlated with the saliva/plasma ratio after stimulated saliva collection, in contrast with a subset of nonstimulated saliva from healthy volunteers, where we did find a significant correlation. Although stimulated salivary indinavir concentrations are highly correlated with plasma concentrations, it is not possible to predict plasma indinavir levels by the salivary concentrations for purposes of therapeutic drug monitoring, due to large interindividual and intraindividual variation. Nevertheless, monitoring compliance by measuring the presence of indinavir in saliva is possible: ingestion of indinavir can be assessed with a sensitivity of 84.8% in the whole dosing interval or with 98.8% between 1 and 6 hours after the last dose, which is comparable with plasma.

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.

Comparison of ritonavir plus saquinavir- and nelfinavir plus saquinavir-containing regimens as salvage therapy in children with human immunodeficiency type 1 infection

BACKGROUND

In this retrospective study we compared the antiretroviral effect of regimens consisting of simultaneous administration of two protease inhibitors (PI) with at least one nucleoside reverse transcriptase inhibitor on plasma viral load (VL) and CD4 cell count in HIV-infected children intensively pretreated with nucleoside reverse transcriptase inhibitors and PIs.

METHODS

Eleven HIV-infected children were changed to antiretroviral combination regimens including two PIs and followed for a median time of 24 weeks. Group A comprised six patients who were given ritonavir + saquinavir (SQV) and Group B consists of five patients who were changed to nelfinavir + SQV. Patients were treated with these combinations with 2 PIs because of treatment failure (increasing viral load) of prior PI therapy or clinical signs of disease progression.

OUTCOME MEASURES

Serial determinations of plasma viral load (Amplicor, Roche) and CD4 cells were performed every 4 to 8 weeks. The detection limit of the Amplicor-reverse transcriptase-PCR assay was 50 copies/ml (1.7 log10).

RESULTS

In Group A the median VL reduction was 1.1 log10 after 3 months and 1.4 log10 after 6 months. In Group B median VL decreased 0.1 and 0.2 log10 after 3 and 6 months. In both groups during the study period none of the patients reached undetectable VL. The relative changes of CD4 cells above baseline in Group A showed a median increase of 7% after 3 months and 23% after 6 months. In Group B after 3 months CD4 cells did not increase, and after 6 months the median relative increase was only 7%. Both combination therapies were well tolerated, not necessitating any drug interruption during study period.

CONCLUSIONS

In children with intensive prior antiretroviral treatment, a salvage therapy including two PIs demonstrated antiretroviral efficacy in some patients. In this study the reduction of the VL as well as the increase of CD4 cells was more pronounced with ritonavir + SQV than with nelfinavir + SQV. With both combinations complete suppression of HIV replication was not achieved. Therefore the long term effect of these combinations may be limited by the emergence of resistant HIV strains.

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.

Correlation of clinical parameters and immunological function with human immunodeficiency virus plasma viremia in children

Studies of immune function in human immunodeficiency virus (HIV)-infected children are important, because functional abnormalities can precede CD4+ T-cell loss and are associated with the development of opportunistic and bacterial infections. We sought to correlate clinical parameters and immunological function with HIV RNA plasma levels in 20 children. HIV RNA levels were measured by a polymerase chain reaction assay. We analyzed T-cell responses to mitogens (phytohemagglutinin, concanavalin A, and pokeweed [PWM]) and antigens (tetanus toxoid and Candida albicans); T-cell suppressor activity; and humoral immunity to Haemophilus influenzae, hepatitis B, tetanus, and diphtheria vaccines. The median age of the children was 6 years. Eight children had HIV RNA levels less than 200 to 9621 copies per milliliter (group I). Four children had 37,970 to 82,630 copies per milliliter (group II). Eight children had 102,100 to 191,200 copies per milliliter (group III). There were no differences in the HIV-related complications between group I and II children. Group I/II children had significantly higher CD4+ T-cell counts (P = 0.02), less symptomatic HIV disease (P = 0.005), and more detectable protective vaccine immunity (P = 0.014) compared with group III children. Responses to mitogens were conserved in most children. Group I children tended to have higher responses to tetanus toxoid than group II children and significantly higher responses than group III children (P = 0.01). Group I had significantly higher responses to C. albicans than groups II (P = 0.016) and III (P = 0.001). Group I/II children tended to have lower suppressor activity compared with group III children (median, 0 vs 64%). We demonstrated that humoral and cellular immune dysfunction exists at all stages of disease in HIV-infected children but was most severe in children with greater than or equal to 100,000 HIV RNA copies per milliliter. Function was the most intact in children with less than 10,000 copies per milliliter.

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.

Combination antiretroviral therapy including ritonavir in children infected with human immunodeficiency

OBJECTIVE

To assess the efficacy of combination therapy that includes ritonavir in HIV-1 infected children.

DESIGN

A monocentric retrospective study.

PATIENTS AND METHODS

Twenty-two children with a minimum follow-up of 6 months under triple therapy including ritonavir were analysed for treatment efficacy. At entry, all the patients were protease inhibitor naive and all but two had received previous antiretroviral therapy during a median period of 5 years. Their initial median CD4+ lymphocyte count and viral load were 121 x 10(6)/l and 5.08 log10 copies/ml, respectively. Clinical and biological evaluation included clinical assessment every 6 weeks and determination of CD4 cell count and HIV-RNA concentration every 3 months.

RESULTS

Median length of follow-up on triple therapy was 15 months (range: 7-21 months). Neither progression in the CDC classification nor death occurred. No significant change in mean weight SD scores was noted when baseline values were compared with values obtained after 1 year of triple therapy. Median CD4 count increases were of 210 x 10(6)/l, 415 x 10(6)/l, and 472 x 10(6)/l cells at 6, 12, and 18 months, respectively. Among the patients baseline characteristics, neither age nor initial CD4 cells count influenced the magnitude of immunologic improvement. There were median decreases of 1.14, 0.95, and 1.5 log10 per ml of plasma in the concentration of viral RNA at 6, 12, and 18 months respectively. Seven patients maintained an undetectable viral load when under treatment. The introduction of at least one new reverse transcriptase inhibitor at the initiation of triple therapy correlated significantly with a greater viral suppression.

CONCLUSION

Despite variable viral response, antiretroviral-experienced HIV-infected children demonstrated a substantial CD4 cell increase during a median period of 15 months of ritonavir containing combination therapy.