PENTA guidelines for the use of antiretroviral therapy, 2004

Genetic variants in CYP2B6 and CYP2A6 explain interindividual variation in efavirenz plasma concentrations of HIV-infected children with diverse ethnic origin

Background

Approximately 2.6 million children live with HIV globally, and efavirenz (EFV) is one of the most widely used antiretroviral agents for HIV treatment in children and adults. There are concerns about the appropriateness of current EFV dosing and it has been discussed whether EFV dosing should be adapted according to genotype in children as suggested for adults.

Aim

To investigate if pediatric EFV dosing should be guided by genetic variation in drug metabolizing enzymes rather than by body weight.

Method

EFV plasma concentrations measured for clinical purposes from all children less than 18 years old at Karolinska University Hospital, Stockholm, Sweden, treated with EFV were collected retrospectively. They were genotyped for eleven polymorphisms in genes coding for drug-metabolizing enzymes and P-glycoprotein, of potential importance for EFV disposition. Data on country of origin, sex, age, weight, HIV RNA, viral resistance patterns, CD4 cells, adherence to treatment, subjective health status and adverse events were collected from their medical records.

Results

Thirty-six patients and 182 (mean 5 samples/patient) EFV plasma concentration measurements from children of African, Asian and Latin American origin were included. EFV plasma concentration varied 21-fold between measurements (n = 182) (0.85–19.3 mg/L) and 9-fold measured as mean EFV plasma concentration across the subjects (1.55–13.4 mg/L). A multivariate mixed-effects restricted maximum likelihood regression model, including multiple gene polymorphisms, identified CYP2B6*6 T/T (p < 0.0005), CYP2B6*11 G/G (p < 0.0005), CYP2A6*9 A/C (p = 0.001) genotypes, age at treatment initiation (p = 0.002) and time from treatment initiation (p < 0.0005) as independent factors significantly related to log_e concentration/(dose/weight). The contribution of the model to the intra- and interindividual variation were 6 and 75%, respectively (Bryk/Raudenbush R-squared level).

Conclusion

Genetic polymorphisms in CYP2B6 and CYP2A6 explained a significant proportion of variability in EFV plasma concentration in HIV-infected children in a multi-ethnic outpatient clinic. Knowledge about individual variants in key drug metabolizing enzyme genes could improve clinical safety and genotype directed dosing could achieve more predictable EFV plasma concentrations in HIV-infected children.

Dose evaluation of lamivudine in human immunodeficiency virus-infected children aged 5 months to 18 years based on a population pharmacokinetic analysis

AIM

The objectives of this study were to characterize age-related changes in lamivudine pharmacokinetics in children and evaluate lamivudine exposure, followed by dose recommendations for subgroups in which target steady state area under the daily plasma concentration-time curve (AUC_0-24h ) is not reached.

METHODS

Population pharmacokinetic modelling was performed in NONMEM using data from two model-building datasets and two external datasets [n = 180 (age 0.4-18 years, body weight 3.4-60.5 kg); 2061 samples (median 12 per child); daily oral dose 60-300 mg (3.9-17.6 mg kg^-1 )]. Steady state AUC_0-24h was calculated per individual (adult target 8.9 mg·h l^-1 ).

RESULTS

A two-compartment model with sequential zero order and first order absorption best described the data. Apparent clearance and central volume of distribution (% RSE) were 13.2 l h^-1 (4.2%) and 38.9 l (7.0%) for a median individual of 16.6 kg, respectively. Bodyweight was identified as covariate on apparent clearance and volume of distribution using power functions (exponents 0.506 (20.2%) and 0.489 (32.3%), respectively). The external evaluation supported the predictive ability of the final model. In 94.5% and 35.8% of the children with a body weight >14 kg and <14 kg, respectively, the target AUC_0-24h was reached.

CONCLUSION

Bodyweight best predicted the developmental changes in apparent lamivudine clearance and volume of distribution. For children aged 5 months-18 years with a body weight <14 kg, the dose should be increased from 8 to 10 mg kg^-1  day^-1 if the adult target for AUC_0-24h is aimed for. In order to identify whether bodyweight influences bioavailability, clearance and/or volume of distribution, future analysis including data on intravenously administered lamivudine is needed.

Rilpivirine as a Treatment for HIV-infected Antiretroviral-naïve Adolescents: Week 48 Safety, Efficacy, Virology and Pharmacokinetics

BACKGROUND

Rilpivirine 25 mg qd yields similar exposure in adolescents and adults (Pediatric study in Adolescents Investigating a New NNRTI TMC278 [PAINT] Cohort 1, Part 1). We report rilpivirine safety, efficacy, virology and pharmacokinetics in adolescents during 48 weeks of treatment (Cohort 1, Part 2).

METHODS

PAINT (NCT00799864) is a phase II, ongoing, open-label, single-arm trial of rilpivirine plus 2 investigator-selected nucleoside/nucleotide reverse-transcriptase inhibitors. Cohort 1 of PAINT includes treatment-naïve HIV-1-infected adolescents (≥12 to <18 years). Following approval in adults and after Part 1a in Cohort 1, enrollment was restricted to screening viral load (VL) ≤100,000 copies/mL.

RESULTS

Overall, 20 (56%) of 36 patients were women, 18 (50%) were aged ≥12 to <15 years, 32 (89%) were Black or African American, mostly from South Africa or Uganda, and 28 (78%) had baseline VL ≤100,000 copies/mL. At week 48, adverse events considered possibly related to treatment occurred in 13 (36%) patients, mostly (excluding investigations) somnolence (n = 5, 14%) and nausea (n = 2, 6%). Most adverse events were grade 1 or 2, and 7 (19%) patients had grade 3 or 4 adverse events. Week 48 virologic response (VL <50 copies/mL, time-to-loss-of-virologic-response) was achieved in 26 of the 36 (72%) patients: 22 of the 28 (79%) with baseline VL ≤100,000 copies/mL and 4 of the 8 (50%) with baseline VL >100,000 copies/mL. Median (range) CD4 count increased by 184 (-135 to 740) cells/mm at week 48. Eight patients experienced virologic failure, including 5 who developed rilpivirine resistance-associated mutations, mostly E138K, K101E and M230L. Mean (standard deviation) rilpivirine area-under-the-concentration-time curve from 0 to 24 hours (AUC24h and C0h) were 2391 (991) ng·h/mL and 83.5 (38.7) ng/mL, respectively.

CONCLUSIONS

Rilpivirine safety, virologic and pharmacokinetic profiles were similar in treatment-naïve HIV-1-infected adolescents and adults, supporting use of rilpivirine 25 mg qd, plus other antiretrovirals, in treatment-naïve adolescents with VL ≤100,000 copies/mL at treatment initiation.

Safety of darunavir and atazanavir in HIV-infected children in Europe and Thailand

BACKGROUND

Surveillance for mid- and long-term antiretroviral therapy (ART) toxicity in children is important for informing treatment guidelines. We assessed the safety of darunavir (DRV) and atazanavir (ATV), commonly used as second-line protease inhibitors following lopinavir/ritonavir, in Europe and Thailand.

METHODS

Cohorts contributed individual patient data on adverse events (AE) in those aged <18 years taking DRV and ATV, respectively, to 02/2014. Rates of Division of AIDS (DAIDS) grade ≥3 laboratory AEs were calculated.

RESULTS

Of 431 patients on DRV and 372 on ATV, 317 (74%) and 301 (81%), respectively, had weight and dose data available, of whom 56 (18%) and 33 (9%) took the drugs at a non-approved age or dose. Median age at DRV and ATV start was 14.8 years (IQR 12.8-16.1) and 13.5 years (11.4-15.2); 43% and 26% had received ≥8 ART drugs previously. Overall rates of grade ≥3 AEs for absolute neutrophils, total cholesterol, triglycerides, pancreatic amylase, lipase and alanine aminotransferase (ALT) were ≤3/100 person-years (PY) on approved doses of both drugs, but 66/100 PY (95% CI 52, 84) for bilirubin after <12 months on ATV declining to 32/100 PY (95% CI 23, 44) after >24 months. Five serious drug-related clinical AEs were reported in four patients on ATV (one discontinued) and three in three patients on DRV (all discontinued), and did not substantially differ in those on approved compared to non-approved doses. Proportions on the drugs at last follow-up were 89% (383/431) for DRV and 81% (301/372) for ATV (including 73/92 with grade ≥3 hyperbilirubinaemia).

CONCLUSIONS

AEs were few in number and comparable for the two drugs, with the exception of high rates of hyperbilirubinaemia for ATV; few patients discontinued due to toxicity.

Rapid viral rebound after 4 years of suppressive therapy in a seronegative HIV-1 infected infant treated from birth

Attention has focused on the possibility of cure for HIV infected infants if treated promptly after delivery. The "Mississippi baby," who had very prolonged remission after antiretroviral discontinuation, may represent a unique situation. We report an infant treated from birth, who seroreverted, remained virologically suppressed, and had undetectable HIV-1 RNA and DNA at 4 years of age, yet experienced virologic rebound within days of discontinuation of antiretroviral therapy.

Plasma lopinavir concentrations predict virological failure in a cohort of South African children initiating a protease-inhibitor-based regimen

BACKGROUND

Poor adherence to antiretroviral therapy contributes to pharmacokinetic variability and is the major determinant of virological failure. However, measuring treatment adherence is difficult, especially in children. We investigated the relationship between plasma lopinavir concentrations, pretreatment characteristics and viral load >400 copies/ml.

METHODS

A total of 237 HIV-infected children aged 4-42 months on lopinavir/ritonavir oral solution were studied prospectively and followed for up to 52 weeks. Viral load and lopinavir concentration were measured at clinic visits 12, 24, 36 and 52 weeks after starting treatment. Cox multiple failure events models were used to estimate the crude and adjusted effect of lopinavir concentrations on the hazard of viral load >400 copies/ml.

RESULTS

The median (IQR) pretreatment CD4(+) T-lymphocyte percentage was 18.80% (12.70-25.35) and 53% of children had a pretreatment viral load >750,000 copies/ml. The median (IQR) weight-for-age and height-for-age z-scores were -2.17 (-3.35--2.84) and -3.34 (-4.57--3.41), respectively. Median (IQR) lopinavir concentrations were 8.00 mg/l (4.11-12.42) at median (IQR) 3.50 h (2.67-4.25) after the dose. The hazard of viral load >400 copies/ml was increased with lopinavir concentrations <1 mg/l versus ≥1 mg/l (adjusted hazard ratio 2.3 [95% CI 1.63, 3.26]) and lower height-for-age z-scores.

CONCLUSIONS

Low lopinavir concentrations (<1 mg/l) are associated with viraemia in children. This measure could be used as a proxy for adherence and to determine which children are more likely to fail.

Incidence and risk factors for first line anti retroviral treatment failure among Ugandan children attending an urban HIV clinic

Background

Early recognition of antiretroviral therapy (ART) failure in resource limited settings is a challenge given the limited laboratory facilities and trained personnel. This study aimed at describing the incidence, risk factors and the resistance associated mutations (RAMs) of first line treatment failure among HIV-1-infected children attending the Joint Clinical Research Centre (JCRC), Kampala, Uganda.

Methods

A retrospective cohort of 701 children who had been initiated on ART between January 2004 and September 2009 at the JCRC was studied. Data of children aged 6 months up to 18 years who had been started on ART for at least 6 months was extracted from the clinic charts. The children who failed the first-line ART were taken as cases and those who did not fail as the controls. Data was analysed using STATA version10.

Results

Of 701 children, 240(34%) failed on first line ART (cases) and 461(66%) did not fail (controls). The overall median time (IQR) to first line ART failure was 26.4 (18.9 – 39.1) months. The factors associated with treatment failure were poor adherence [(OR = 10, 95 CI: 6.4 – 16.7) p < 0.001], exposure to single dose nevirapine (sdNVP) [(OR = 4.2, 95% CI:1.8-9.4), p = 0.005] and a NVP containing regimen [(OR = 2.2,95% CI:1.4-3.6), p < 0.001]. Of 109 genotypic resistance profiles analyzed, the commonest non nucleoside reverse transcriptase inhibitor (NNRTI) resistance associated mutations (RAM) were: K103N (59; 54%)), Y181C (36; 27%)) and G190A (26; 24%)) while the commonest nucleoside reverse transcriptase inhibitor (NRTI) RAM was the M184V (89; 81%). Thymidine analogue- mutations (TAMs) were detected in 20% of patients.

Conclusions

One in three children on first-line ART are likely to develop virological treatment failure after the first 24 months of therapy. Poor adherence to ART, a NVP based first-line regimen, prior exposure to sdNVP were associated with treatment failure.

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.

Paediatric HIV--trends & challenges

With the availability of antiretroviral therapy (ART), HIV infection, which was once considered a progressively fatal illness, has now become a chronic treatable condition in children, as in adults. However, the challenges these children are forced to face are far more daunting. The most significant shortcoming in the response to paediatric HIV remains the woefully inadequate prevention of mother-to-child transmission (PMTCT), allowing a large number of children to be born with HIV in the first place, in spite of it being largely preventable. In the west, mother-to-child transmission has been virtually eliminated; however, in resource-limited settings where >95 per cent of all vertical transmissions take place, still an infected infants continue to be born. There are several barriers to efficient management: delayed infant diagnosis, lack of appropriate paediatric formulations, lack of skilled health personnel, etc. Poorly developed immunity allows greater dissemination throughout various organs. There is an increased frequency of malnutrition and infections that may be more persistent, severe and less responsive to treatment. In addition, these growing children are left with inescapable challenges of facing not only lifelong adherence with complex treatment regimens, but also enormous psychosocial, mental and neuro-cognitive issues. These unique challenges must be recognized and understood in order to provide appropriate holistic management enabling them to become productive citizens of tomorrow. To address these multi-factorial issues, there is an urgent need for a concerted, sustainable and multi-pronged national and global response.

Poor health-related quality of life and abnormal psychosocial adjustment in Italian children with perinatal HIV infection receiving highly active antiretroviral treatment

To evaluate health-related quality of life (HRQL), social competence, and behavioral problems in children with perinatal HIV infection receiving highly active antiretroviral therapy (HAART), a cross-sectional study was performed at the Department of Pediatrics, University of Brescia. We evaluated HRQL, social competence, and behavioral problems in 27 HIV-infected children compared with age and sex-matched control subjects using the Pediatric Quality of Life Inventory (PedsQL) and the Child Behavior Checklist (CBCL), respectively. On the PedsQL 4.0 Generic Core Scale, HIV-infected subjects displayed significantly reduced physical (p=0.043) and psychosocial health (p=0.021) functioning, particularly at school (p=0.000), compared with healthy subjects, resulting in a significantly reduced total score (p=0.013). Assessment of social competence and the behavioral features of HIV-infected children by means of the CBCL revealed severe limitations of functioning in HIV-infected children who had impaired social ability. Children with HIV-RNA above the threshold level of 50 had higher scores on the CBCL delinquent behavior (p=0.021) and school competence (p=0.025) subsets. Although the introduction of HAART regimens has prolonged the survival of HIV-infected children, other factors, including disease morbidity and familial and environmental conditions, negatively affect their quality of life, thereby contributing to increased risk for behavioral problems.

Risk of triple-class virological failure in children with HIV: a retrospective cohort study

BACKGROUND

In adults with HIV treated with antiretroviral drug regimens from within the three original drug classes (nucleoside or nucleotide reverse transcriptase inhibitors [NRTIs], non-NRTIs [NNRTIs], and protease inhibitors), virological failure occurs slowly, suggesting that long-term virological suppression can be achieved in most people, even in areas where access is restricted to drugs from these classes. It is unclear whether this is the case for children, the group who will need to maintain viral suppression for longest. We aimed to determine the rate and predictors of triple-class virological failure to the three original drugs classes in children.

METHODS

In the Collaboration of Observational HIV Epidemiological Research Europe, the rate of triple-class virological failure was studied in children infected perinatally with HIV who were aged less than 16 years, starting antiretroviral therapy (ART) with three or more drugs, between 1998 and 2008. We used Kaplan-Meier and Cox regression methods to investigate the risk and predictors of triple-class virological failure after ART initiation.

FINDINGS

Of 1007 children followed up for a median of 4·2 (IQR 2·4-6·5) years, 237 (24%) were triple-class exposed and 105 (10%) had triple-class virological failure, of whom 29 never had a viral-load measurement less than 500 copies per mL. Incidence of triple-class virological failure after ART initiation increased with time, and risk by 5 years after ART initiation was 12·0% (95% CI 9·4-14·6). In multivariate analysis, older age at ART initiation was associated with increased risk of failure (p=0·02). Of 686 children starting ART with NRTIs and either a NNRTI or ritonavir-boosted protease inhibitor, the rate of failure was higher than in adults with heterosexually transmitted HIV (hazard ratio 2·2 [95% CI 1·6-3·0, p<0·0001]).

INTERPRETATION

Findings highlight the challenges of attaining long-term viral suppression in children who will be taking life-long ART. Early identification of children not responding to ART, adherence support, particularly for children and adolescents aged 13 years or older starting ART, and ART simplification strategies are all needed to attain and sustain virological suppression.

FUNDING

UK Medical Research Council award G0700832.

Dysfunctional B-cell responses during HIV-1 infection: implication for influenza vaccination and highly active antiretroviral therapy

Although HIV-1 infection does not directly target B cells, B-cell numbers are reduced and their function is impaired during HIV infection. Antibody titres against antigens previously encountered through vaccination or natural infection are low in patients with HIV. Intrinsic B-cell defects might be involved in the impairment of humoral immunity during early HIV infection. Abnormal T-cell activation and the altered expression of molecules involved in the B-cell homing process cause dysfunctional interaction between T and B cells in the germinal centres of lymphoid tissues, which might impair B-cell responses during HIV infection. Class-switch recombination is also impaired in individuals with HIV. Protective immune responses against T-cell-dependent antigens, including influenza antigens, rely on the production of neutralising antibodies. Impaired B-cell responses during HIV infection could therefore hamper the effectiveness of vaccinations against seasonal influenza or the new pandemic influenza A H1N1 vaccines in individuals with HIV. By maintaining B-cell responses, highly active antiretroviral therapy might improve the efficacy of influenza vaccines in individuals with HIV.

Boosted protease inhibitors as a therapeutic option in the treatment of HIV-infected children

OBJECTIVE

Paediatric HIV treatment must address various special considerations. Administration of pharmacokinetically enhanced protease inhibitors (PIs) can improve paediatric therapeutic outcomes. The objective of this study was to review the use of boosted PI regimens in children.

METHODS

Systematic literature searches of published manuscripts and conference databases using generic drug names and specific keywords were performed to ensure thorough and balanced reporting of available data.

RESULTS

Boosted PI regimens offer multiple options across a range of ages and are efficacious in naïve and experienced children; safety and tolerability are similar to those observed in adults. Novel boosted PI simplification approaches may foster adherence and diminish resistance.

CONCLUSIONS

Boosted PIs are key components of first- and second-line treatments in children. Identifying factors associated with the response to highly active antiretroviral therapy in children may ultimately permit individualized therapies.

PENTA 2009 guidelines for the use of antiretroviral therapy in paediatric HIV-1 infection

PENTA Guidelines aim to provide practical recommendations for treating children with HIV infection in Europe. Changes to guidance since 2004 have been informed by new evidence and by expectations of better outcomes following the ongoing success of antiretroviral therapy (ART). Participation in PENTA trials of simplifying treatment is encouraged. The main changes are in the following sections: 'When to start ART': Treatment is recommended for all infants, and at higher CD4 cell counts and percentages in older children, in line with changes to adult guidelines. The number of age bands has been reduced to simplify and harmonize with other paediatric guidelines. Greater emphasis is placed on CD4 cell count in children over 5 years, and guidance is provided where CD4% and CD4 criteria differ. 'What to start with': A three-drug regimen of two nucleoside reverse transcriptase inhibitors (NRTIs) with either a nonnucleoside reverse transcriptase inhibitor (NNRTI) or a boosted protease inhibitor (PI) remains the first choice combination. Lamivudine and abacavir are the NRTI backbone of choice for most children, based on long-term follow-up in the PENTA 5 trial. Stavudine is no longer recommended. Whether to start with an NNRTI or PI remains unclear, but PENPACT 1 trial results in 2009 may help to inform this. All PIs should be ritonavir boosted. Recommendations on use of resistance testing, therapeutic drug monitoring and HLA testing draw from data in adults and from European paediatric cohort studies. Recently updated US and WHO paediatric guidelines provide more detailed review of the evidence base. Differences between guidelines are highlighted and explained.

Italian consensus statement on paediatric HIV infection

The objective of this document is to identify and reinforce current recommendations concerning the management of HIV infection in infants and children in the context of good resource availability. All recommendations were graded according to the strength and quality of the evidence and were voted on by the 57 participants attending the first Italian Consensus on Paediatric HIV, held in Siracusa in 2008. Paediatricians and HIV/AIDS care specialists were requested to agree on different statements summarizing key issues in the management of paediatric HIV. The comprehensive approach on preventing mother-to-child transmission (PMTCT) has clearly reduced the number of children acquiring the infection in Italy. Although further reduction of MTCT should be attempted, efforts to personalize intervention to specific cases are now required in order to optimise the treatment and care of HIV-infected children. The prompt initiation of treatment and careful selection of first-line regimen, taking into consideration potency and tolerance, remain central. In addition, opportunistic infection prevention, adherence to treatment, and long-term psychosocial consequences are becoming increasingly relevant in the era of effective antiretroviral combination therapies (ART). The increasing proportion of infected children achieving adulthood highlights the need for multidisciplinary strategies to facilitate transition to adult care and maintain strategies specific to perinatally acquired HIV infection.

Novel strategies in the use of lopinavir/ritonavir for the treatment of HIV infection in children

Lopinavir/ritonavir (LPV/r) is considered by many as the first choice protease inhibitor (PI) for children. This co-formulation avoids the need for children to take ritonavir separately to “boost” the levels of lopinavir. LPV/r has high virologic potency, an excellent toxicity profile and a high barrier to the development of viral resistance. However, LPV/r has poor tolerability of the oral suspension (due to the poor taste of ritonavir), difficult dosing requirements and metabolic side effects, especially hyperlipidemia. The new tablet low-dose formulation (100/25 mg) may allow more convenient antiretroviral treatment in children. Novel strategies of LPV/r in childhood could maximize its advantages. For example, infants infected with HIV despite single dose Nevirapine after birth need effective combination antiretroviral treatment. This can be given using a higher dose of LPV/r with therapeutic drug monitoring. Other novel uses include once daily LPV/r regimens in older children and adolescents and lower doses of LPV/r in certain populations, which may decrease hyperlipidemia. Heavily pre-treated children might benefit from a double PI/r regimen which includes LPV/r. The high potency of LPV/r needs to be balanced with convenient regimens, to enhance adherence and decrease toxicity whenever possible. The aim of this review is to discuss the rationale behind these novel strategies of LPV/r use in pediatric antiretroviral treatment as well as their results and limitations.

Short communication: evaluation of the effect of enfuvirtide in 11 HIV-1 vertically infected pediatric patients outside clinical trials

The effect of enfuvirtide (ENF) in 11 HIV-1 heavily antiretroviral-experienced children and adolescents enrolled in the HIV-1 Paediatric Spanish cohort was further investigated. Patients who received ENF with novel drugs (etravirine, darunavir, and/or tipranavir) reached and maintained undetectable plasma HIV-1 RNA levels and showed immunological recovery within the first 3 months of therapy that was maintained during the follow-up. Viremia was not fully suppressed in patients who did not combine ENF with novel drugs but interestingly, immunological benefit was observed in half of these patients. Therefore, ENF showed a greater and more stable efficacy when administrated with novel drugs.

Otolaryngologic manifestations of pediatric immunodeficiency

Many adults and children with an underlying immunodeficiency can frequently present to ear, nose and throat (ENT) surgeons. This work deals with the presentation, investigation and management of immuno-compromised children in ENT practise. Both primary immunodeficiencies (PID) and secondary or acquired immunodeficiencies such as human immunodeficiency virus (HIV) infection are here discussed. The aim of this work is to give a complete and exhaustive description of ENT manifestations in immunodeficiency, and to outline basic principles to guide clinical practice.

Pharmacokinetics of nevirapine in HIV-infected children with and without malnutrition receiving divided adult fixed-dose combination tablets

OBJECTIVES

To determine the relationship between nutritional status and nevirapine exposure by comparing the pharmacokinetics of nevirapine in HIV-infected children of different ages with and without malnutrition receiving divided tablets of Triomune 30 (stavudine + lamivudine + nevirapine) in accordance with Malawi National Guidelines.

METHODS

Children were recruited in weight-based dosage bands and nutritional status classified according to weight for height. Total and unbound plasma nevirapine concentrations were measured over a full dosing interval. Multivariate linear and logistic regression analyses were performed to determine the effects of malnutrition, age, dose and other factors on nevirapine exposure and likelihood of achieving therapeutic nevirapine trough concentrations.

RESULTS

Forty-three children were recruited (37 included for analysis). Mild to moderate malnutrition was present in 12 (32%) children; 25 (68%) were of normal nutritional status. There was no effect of malnutrition on any measure of total drug exposure or on the unbound fraction of nevirapine. Nevirapine exposure was strongly related to dose administered (P = 0.039) and to age (for every yearly increase in age there was an approximately 88% increase in the odds of achieving a therapeutic nevirapine concentration; P = 0.056, 95% confidence interval 0.983-3.585).

CONCLUSIONS

Use of divided adult Triomune 30 tablets in treating young children results in significant underdosing. No independent effect of malnutrition on total and unbound nevirapine exposures was observed. These data support the use of bespoke paediatric antiretroviral formulations.

Pediatric HIV: new opportunities to treat children

BACKGROUND

Treating HIV-infected children remains a challenge due to a lack of treatment options, appropriate drug formulations and, in countries with limited resources, insufficient access to diagnostic tests and treatment.

OBJECTIVE

To summarize current data concerning new opportunities to improve the treatment of HIV-infected children.

METHODS

This review includes data from the most recently published peer-reviewed publications, guidelines or presentations at international meetings concerning new ways to treat HIV-infected children.

RESULTS/CONCLUSIONS

New WHO guidelines recommend starting combination antiretroviral treatment in all infants aged < 1 year. Although this is common practice in some high-income countries, implementation of these recommendations in countries with limited resources is still a challenge. There is still an important gap between the availability of licensed drugs in children compared with adults. There remains a need for further pharmacokinetic studies, and for more pediatric formulations of antiretroviral drugs with improved palatability.

The impact of AIDS diagnoses on long-term neurocognitive and psychiatric outcomes of surviving adolescents with perinatally acquired HIV

OBJECTIVE

To explore the association between previous severe HIV disease, defined as past Centers for Disease Control and Prevention class C diagnosis, and neurocognitive and psychiatric outcomes in long-term survivors of perinatally acquired HIV.

DESIGN

A retrospective cohort study of perinatally HIV-infected adolescents receiving outpatient care at a single site.

METHODS

Comparisons were made between those with and without class C diagnoses.

RESULTS

Eighty-one patients formed the study group, 47% were females and 72% were African-American. Median patient age was 15 years (interquartile range 13-17). Of the study group, 47% had a past class C diagnosis. The median age at class C diagnosis was 3.1 years (interquartile range 0.9-8.1). There were no significant differences between the groups with respect to most recent CD4(+) cell percentage or plasma viral RNA level. Class C patients were more likely to have a history of psychiatric diagnosis [odds ratio 2.6; 95% confidence interval (CI) 1.1-6.3], psychiatric hospitalization (odds ratio 4.8; 95% CI 1.2-17.4), or learning disability (odds ratio 4.5; 95% CI 1.7-11.4). There was a significant difference in full-scale intelligence quotient between the groups (adjusted linear regression coefficient -11.7; 95% CI -17.9 to 5.5). After adjusting for age at antiretroviral therapy initiation, the associations between class C diagnosis and lower full-scale intelligence quotient, learning disorders, and psychiatric diagnoses remained significant.

CONCLUSION

A distant history of AIDS diagnosis was associated with an increased risk of neurocognitive and psychiatric impairment in adolescents with perinatally acquired HIV. Further research should help delineate if early treatment, possibly soon after birth and definitely prior to AIDS diagnosis, might lead to improved outcomes.

Policies and practices for the clinical management of HIV/HCV coinfected children in Europe: an epidemiological survey

The antenatal prevalence of HIV/HCV coinfection ranges from 12% to 28% with mother-to-child transmission rates ranging from 3.6% to 9.5%. There are no guidelines detailing the most appropriate clinical management and treatment of coinfected children. We used a semi-structured questionnaire to investigate current European practices for the management and follow-up of HIV/HCV coinfected children among clinical centres contributing to the European Collaborative Study or the European Paediatric HCV Network. Clinicians from 16 out of 24 clinical centres responded and were caring for a total of 44 HIV/HCV coinfected children. We found that, although there was a high level of concordance regarding testing for HIV and/or HCV infection, monitoring practices in these European centres varied widely. Few clinicians stated they would administer HIV and HCV treatment concurrently. Limited experience in the clinical management of this group and the lack of an evidence base to guide policy may be a barrier to achieving optimal care and treatment.

Antiretroviral treatment of HIV infection: Swedish recommendations 2007

On 3 previous occasions, in 2002, 2003 and 2005, the Swedish Medical Products Agency (Läkemedelsverket) and the Swedish Reference Group for Antiviral Therapy (RAV) have jointly published recommendations for the treatment of HIV infection. An expert group, under the guidance of RAV, has now revised the text again. Since the publication of the previous treatment recommendations, 1 new drug for the treatment of HIV has been approved - the protease inhibitor (PI) darunavir (Prezista). Furthermore, 3 new drugs have become available: the integrase inhibitor raltegravir (MK-0518), the CCR5-inhibitor maraviroc (Celsentri), both of which have novel mechanisms of action, and the non-nucleoside reverse transcriptase inhibitor (NNRTI) etravirine (TMC-125). The new guidelines differ from the previous ones in several respects. The most important of these are that abacavir is now preferred to tenofovir and zidovudine, as a first line drug in treatment-naïve patients, and that initiation of antiretroviral treatment is now recommended before the CD4 cell count falls below 250/microl, rather than 200/microl. Furthermore, recommendations on the treatment of HIV infection in children have been added to the document. As in the case of the previous publication, recommendations are evidence-graded in accordance with the Oxford Centre for Evidence Based Medicine, 2001 (see http://www.cebm.net/levels_of_evidence.asp#levels).

Long-term effectiveness of highly active antiretroviral therapy (HAART) in perinatally HIV-infected children in Denmark

The long-term impact of highly active antiretroviral therapy (HAART) on HIV-1 infected children is not well known. The Danish Paediatric HIV Cohort Study includes all patients <16 y of age with HIV-1 infection in Denmark. We report the complete follow-up from 1996 to 2005 of 49 perinatally infected children treated with HAART. Initial HAART included 2 nucleoside reverse-transcriptase inhibitors in combination with either a protease inhibitor (n =38) or a non-nucleoside reverse-transcriptase inhibitor (n =12). 19 (39%) patients were previously treated with mono- or dual therapy. Baseline characteristics were median CD4 percentage 14% and HIV-RNA viral load 4.9 log(10). Within the first 12 weeks of therapy approximately 60% achieved HIV-RNA viral load <500 copies/ml, and this remained stable for up to 8 y, although many children changed the components of HAART. The proportion of children with CD4 percentage >25% increased to 60-70% over the y of treatment. For the total cohort, 245 patient-y of observation were available with only 1 death. During our observation period there were no signs of a waning impact. The challenge remains to maintain a high adherence to therapy as the children grow into adolescence and develop more independence from family and health care staff.

Early treatment of HIV: implications for resource-limited settings

PURPOSE OF REVIEW

We review the current literature supporting adoption of higher CD4 thresholds for initiation of antiretroviral treatment and survey progress in adoption of early treatment policies in resource-limited settings. We highlight some of the challenges and opportunities implementation of early treatment will bring.

RECENT FINDINGS

The initial success of combination antiretroviral treatment resulted in the recommendation to treat early all individuals with HIV. However, the gradual realization that antiretroviral treatment was associated with toxicity led to a more tempered approach. Recent cohort studies and some clinical trials have shown that delaying treatment is associated with increased morbidity and mortality.

SUMMARY

Early treatment is routinely practiced in developed countries. Now, early treatment is being adopted as a strategy in many resource-limited settings. The implications of this policy shift are not known, but we predict early treatment will have important consequences for the health system, the individual, and the community. Whereas these consequences will bring significant challenges, the increased numbers of HIV-infected individuals on treatment will result in many new opportunities - antiretroviral treatment will become less expensive, systems to deliver chronic care will be strengthened, and the policy shift will focus greater attention on pregnant women and children. Finally, some authors postulate that early treatment may impact HIV transmission.

Management of paediatric HIV-1 resistance

PURPOSE OF REVIEW

Children have higher rates of virological failure than adults, often associated with more extensive resistance and limited second-line options. In order to maintain clinical benefits of highly active antiretroviral therapy (HAART) into adulthood, particularly for children starting at a young age, strategies are needed to limit the emergence of resistance and to offer highly effective subsequent lines of therapy. Similarly, well resourced settings face challenges regarding extensive resistance accumulated over the past decade or more, particularly resulting from suboptimal therapies.

RECENT FINDINGS

Rates of resistance at failure of nonnucleoside reverse-transcriptase inhibitor based HAART are higher in developing countries than in well resourced settings. In the latter, second-generation protease inhibitors tipranavir and darunavir are promising, with tipranavir now licensed for those above 2 years and darunavir showing good trial results in children above 6 years. However, combination with new classes such as integrase inhibitors (currently in phase I trials) and CCR5 antagonists (no paediatric data yet) will probably be necessary to gain maximal long-term benefits.

SUMMARY

Common goals in paediatric HIV for both resource-rich and resource-limited settings are to limit vertical transmission, minimize emergence of resistant viruses in both mother and child where prevention of mother-to-child transmission fails, and limit resistance in children starting HAART. Optimal sequencing of regimens in the absence of resistance testing is a priority research area. Paediatric studies using newer classes of agents are of paramount importance, as well as expanding access to existing antiretrovirals.

Timing of HAART defines the integrity of memory B cells and the longevity of humoral responses in HIV-1 vertically-infected children

HIV-1 infection induces a progressive disruption of the B cell compartment impairing long-term immune responses to routine immunizations. Depletion of specific memory B cell pools occurs during the 1st stages of the infection and cannot be reestablished by antiretroviral treatment. We reasoned that an early control of viral replication through treatment could preserve the normal development of the memory B cell compartment and responses to routine childhood vaccines. Accordingly, we evaluated the effects of different highly-active antiretroviral therapy (HAART) schedules in 70 HIV-1 vertically-infected pediatric subjects by B cell phenotypic analyses, antigen-specific B cell enzyme-linked immunosorbent spot (ELISpot) and ELISA for common vaccination and HIV-1 antigens. Initiation of HAART within the 1st year of life permits the normal development and maintenance of the memory B cell compartment. On the contrary, memory B cells from patients treated later in time are remarkably reduced and their function is compromised regardless of viral control. A cause for concern is that both late-treated HIV-1 controllers and noncontrollers loose protective antibody titers against common vaccination antigens. Timing of HAART initiation is the major factor predicting the longevity of B cell responses in vaccinated HIV-1-infected children.

Effect of early antiretroviral therapy on the risk of AIDS/death in HIV-infected infants

OBJECTIVE

In the absence of treatment, rapid progression to AIDS occurs in approximately 20% of HIV-1-infected infants over the first year of life. The prognosis of these children has considerably improved with highly active antiretroviral therapy. As data from well resourced countries are lacking, the objective of this collaborative study was to evaluate the impact of early treatment in vertically infected infants.

DESIGN

Children born to HIV-infected mothers between 1 September 1996 and 31 December 2004, who were diagnosed with HIV and free of AIDS before 3 months, were eligible. Demographics and pregnancy data, details of antiretroviral therapy, and clinical outcome were collected from 11 European countries.

METHODS

The risk of AIDS or death, by whether or not an infant started treatment before 3 months of age, was estimated by Kaplan-Meier survival analysis and Cox proportional hazards models.

RESULTS

Among 210 children, 21 developed AIDS and three died. Baseline characteristics of the 124 infants treated before 3 months were similar to those of the 86 infants treated later. The risk of developing AIDS/death at 1 year was 1.6 and 11.7% in the two groups, respectively (P < 0.001). Deferring treatment was associated with increased risk of progression [crude hazard ratio 5.0; 95% confidence interval (CI) 2.0-12.6; P = 0.001] that persisted after adjusting for cohort in multivariate models (adjusted hazard ratio 3.0; 95% CI 1.2-7.9; P = 0.021).

CONCLUSION

In HIV-1 vertically infected infants, starting antiretroviral therapy before the age of 3 months is associated with a significant reduction in progression to AIDS and death.

Tenofovir use in human immunodeficiency virus-1-infected children in the United kingdom and Ireland

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is neither licensed for use nor extensively studied in HIV-infected children. The only available formulation is an adult tablet, introducing the possibility of dosing errors in children. TDF interacts with other antiretrovirals and has been associated with decline in renal function and CD4 count. We describe the use of TDF in a cohort of HIV-1-infected children in the United Kingdom and Ireland.

METHODS

Children ever prescribed TDF and followed in the Collaborative HIV Pediatric Study cohort since 2001 were included in analyses of dosing, adverse events, and virologic and immunologic response. Suspected adverse drug reactions to TDF reported to the Medicines and Healthcare products Regulatory Agency during the same time were also reviewed.

RESULTS

One hundred fifty-nine of 1253 children had taken TDF. They were older and had clinically more advanced disease than the rest of the cohort. Eighteen percent received >120% and 37% received <80% of the suggested pediatric dose (8 mg/kg). Thirty-seven percent of new TDF regimens contained didanosine (ddI), though few since 2005. Twelve of 159 (7.5%) children experienced serious adverse events and stopped TDF permanently, 11 taking concurrent lopinavir-ritonavir, and 10 ddI; 5 had renal toxicity. Viral load suppressed to < or =50 copies/mL at 12 months in 38% of those starting TDF. Median increase in CD4 count at 12 months was +110 cells/mL (interquartile range, 9-270), but only 3 cells/mL in those taking concurrent ddI.

CONCLUSIONS

TDF seems to be an effective antiretroviral drug in this pediatric cohort, although considerable underdosing and overdosing occurs. A small number of children experienced serious adverse events while taking TDF; half were renal toxicity, most associated with concurrent ddI and lopinavir-ritonavir use.

Immunological recovery and metabolic disorders in severe immunodeficiency HIV type 1-infected children on highly active antiretroviral therapy

Little is known about immunologic reconstitution in children on highly active antiretroviral treatment (HAART) during very long-term periods. A retrospective study was carried out to assess the effectiveness and development of metabolic disorders after very long-term periods on HAART in HIV-infected children with severe immunodeficiency. We included 55 children who were stratified into three groups according to %CD4(+) pre-HAART and rate of immunologic recovery: (1) S1-Rec: CD4(+) < or =5% at baseline and slow immunologic recovery; (2) S2-Rec: CD4(+) 5-15% at baseline and slow immunologic recovery; (3) R-Rec: CD4(+) < or =15% at baseline and rapid immunologic recovery (reference group). An adequate immune recovery after 8 years on HAART was achieved by only 25% of children. S1-Rec never achieved a mean of CD4(+) > or =25% after 8 years on HAART. All children had a significant increase in plasma cholesterol levels during the first 2 years. Afterward, cholesterol levels reached a plateau and remained stable until year 8 of follow-up. Higher rates of lipodystrophy were found in the R-Rec group [14 (100%)] than in the S1-Rec group [9/19 (47.4%)] or the S2-Rec group [13/20 (65%)] at the end of the study (p = 0.006). Overall, having a low nadir of CD4(+) hindered immune reconstitution; however, children with rapid immunologic recovery showed a higher prevalence of the lipodystrophy syndrome.

Early antiretroviral therapy and mortality among HIV-infected infants

BACKGROUND

In countries with a high seroprevalence of human immunodeficiency virus type 1 (HIV-1), HIV infection contributes significantly to infant mortality. We investigated antiretroviral-treatment strategies in the Children with HIV Early Antiretroviral Therapy (CHER) trial.

METHODS

HIV-infected infants 6 to 12 weeks of age with a CD4 lymphocyte percentage (the CD4 percentage) of 25% or more were randomly assigned to receive antiretroviral therapy (lopinavir-ritonavir, zidovudine, and lamivudine) when the CD4 percentage decreased to less than 20% (or 25% if the child was younger than 1 year) or clinical criteria were met (the deferred antiretroviral-therapy group) or to immediate initiation of limited antiretroviral therapy until 1 year of age or 2 years of age (the early antiretroviral-therapy groups). We report the early outcomes for infants who received deferred antiretroviral therapy as compared with early antiretroviral therapy.

RESULTS

At a median age of 7.4 weeks (interquartile range, 6.6 to 8.9) and a CD4 percentage of 35.2% (interquartile range, 29.1 to 41.2), 125 infants were randomly assigned to receive deferred therapy, and 252 infants were randomly assigned to receive early therapy. After a median follow-up of 40 weeks (interquartile range, 24 to 58), antiretroviral therapy was initiated in 66% of infants in the deferred-therapy group. Twenty infants in the deferred-therapy group (16%) died versus 10 infants in the early-therapy groups (4%) (hazard ratio for death, 0.24; 95% confidence interval [CI], 0.11 to 0.51; P<0.001). In 32 infants in the deferred-therapy group (26%) versus 16 infants in the early-therapy groups (6%), disease progressed to Centers for Disease Control and Prevention stage C or severe stage B (hazard ratio for disease progression, 0.25; 95% CI, 0.15 to 0.41; P<0.001). Stavudine was substituted for zidovudine in four infants in the early-therapy groups because of neutropenia in three infants and anemia in one infant; no drugs were permanently discontinued. After a review by the data and safety monitoring board, the deferred-therapy group was modified, and infants in this group were all reassessed for initiation of antiretroviral therapy.

CONCLUSIONS

Early HIV diagnosis and early antiretroviral therapy reduced early infant mortality by 76% and HIV progression by 75%. (ClinicalTrials.gov number, NCT00102960.)

A feasibility study of immediate versus deferred antiretroviral therapy in children with HIV infection

OBJECTIVE

To evaluate the feasibility of a large immediate versus deferred antiretroviral therapy (ART) study in children.

METHODS

We conducted an open-label pilot randomized clinical trial study in 43 Thai children with CD4 15 to 24% of starting generic AZT/3TC/NVP immediately (Arm 1) or deferring until CD4 < 15% or CDC C (Arm 2). Primary endpoints were recruitment rate, adherence to randomized treatment and retention in trial. Secondary endpoints were % with CDC C or CD4 < 15%. Children were in the trial until the last child reached 108 weeks. Intention to treat and on treatment analyses were performed.

RESULTS

Recruitment took 15 months. Twenty-six of 69 (37.7%) were not eligible due mainly to low CD4%. Twenty four and 19 were randomized to arms 1 and 2 respectively. All accepted the randomized arm; however, 3 in arm 1 stopped ART and 1 in arm 2 refused to start ART. Ten/19 (53%) in arm 2 started ART. At baseline, median age was 4.8 yrs, CDC A:B were 36:7, median CD4 was 19% and viral load was 4.8 log. All in arm 1 and 17/19 in arm 2 completed the study (median of 134 weeks). No one had AIDS or death. Four in immediate arm had tuberculosis. Once started on ART, deferred arm children achieved similar CD4 and viral load response as the immediate arm. Adverse events were similar between arms. The deferred arm had a 26% ART saving.

CONCLUSION

Almost 40% of children were not eligible due mainly to low CD4% but adherence to randomized treatment and retention in trial were excellent. A larger study to evaluate when to start ART is feasible.

Spatial pattern of HIV-1 mother-to-child-transmission in Madrid (Spain) from 1980 till now: demographic and socioeconomic factors

OBJECTIVE

To evaluate any possible association between indicators of social inequalities and the geographical distribution of HIV-1 mother-to-child transmission (MTCT) cases in Madrid.

METHODS

We carried out an observational survey of 224 HIV-1 vertically infected children born in 1980-2006 living in Madrid. We elaborated maps representing the prevalence of HIV-1 MTCT cases. We assessed the association between indicators of social inequalities and the spatial distribution of MTCT cases. Poisson univariate and multivariate analysis of risk factors for MTCT were performed.

RESULTS

We identified core areas of transmission mainly in southern Madrid until 2006. The prevalence of MTCT cases was significantly correlated to the percentage of immigrants, illiterates, unemployed women and the income in 1996 and 2000/2001. The risk of MTCT increased in the periods up to 1996 compared with the calendar period 1980-1989, whereas the risk decreased in 1999-2006 [relative risk, 0.08; 95% confidence interval (CI), 0.03-0.18; P < 0.001]. The risk was especially high in the districts of Usera (absolute relative risk, 11.4; 95% CI, 2.6-49.5; P = 0.001), Puente de Vallecas (absolute relative risk, 14.0; 95% CI, 3.4-57.9; P < 0.001) and San Blas (absolute relative risk, 12.5; 95% CI, 2.9-53.6; P = 0.001). The percentage of illiterates was the indicator that explained the risk of MTCT (absolute relative risk, 1.07; 95% CI, 1.05-1.10; P = 0.001).

CONCLUSION

We observed a geographic heterogeneity of the HIV-1 vertical transmission with the highest prevalence in disadvantaged districts. What is described in the present review is the HIV-1 vertical transmission within a social context; this approach could be relevant in analysing the pattern of HIV-1 transmission in other Western cities or highlighting the distribution of other infectious diseases.

Current and future antiretroviral treatment options in paediatric HIV infection

Because of a lack of prevention policies or problems in implementing prevention of mother-to-child transmission (P-MTCT), most of the 1500 daily new HIV infections in children aged<15 years are caused by MTCT. Fifteen percent of all HIV-infected individuals are children, but the vast majority lack access to highly active antiretroviral therapy (HAART), which can drastically reduce morbidity and mortality. There are 22 antiretroviral drugs currently approved by the US FDA for use in the treatment of HIV-infected adults and adolescents, but only 12 of these drugs are approved for use in children. Antiretroviral drugs belong to four major classes: nucleoside and nucleotide analogue reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors and fusion inhibitors. According to international guidelines developed by organizations including WHO, the Paediatric European Network for Treatment of AIDS (PENTA) and the US National Institutes of Health (US-NIH), the treatment of choice for HIV-infected children and adults is a combination of two NRTIs (backbone treatment) plus a third potent agent from a different class, either an NNRTI or a ritonavir-boosted protease inhibitor. There are specific challenges in treating HIV-infected children, including uncertainty about the best time to start treatment, the need for more paediatric formulations, the lack of pharmacokinetic studies for new drugs, and incomplete dosing guidelines. Furthermore, the most appropriate regimen for an individual child depends on a variety of factors, including the age of the child; the availability of appropriate drug formulations; the potency, complexity and toxicity of the drug regimen; the home situation; the child and caregiver's ability to adhere to the regimen; and the child's antiretroviral treatment history. In addition, antiretroviral drugs are not licensed for all age groups and the drugs are often not affordable. This review describes NNRTI and protease inhibitors as key components of first- and second-line antiretroviral therapy (ART), focusing on the rationale for choosing an NNRTI- versus protease inhibitor-based regimen based on the results of available phase II and III studies. Some of the new agents available for children as second-line and salvage therapy both on- and off-label are also discussed. The drug regimens described in this review are relevant to clinicians in developed and developing countries. The availability of new, potent compounds with different resistance and toxicity profiles may represent an alternative option to interclass switching and could redefine ART strategy, including the option of first-line NRTI-sparing regimens.

Type I interferon-dependent gene MxA in perinatal HIV-infected patients under antiretroviral therapy as marker for therapy failure and blood plasmacytoid dendritic cells depletion

Background

To determine the role of interferon-alpha in controlling HIV infection we phenotypically and functionally analyzed circulating plasmacytoid dendritic cells (pDC), which are known to be the highest interferon-alpha producing cells, in 33 perinatally infected HIV⁺ patients undergoing standard antiretroviral therapy.

Methods

Circulating pDC were identified by flow cytometry using anti-BDCA-2 monoclonal antibody and by measuring BDCA-2 mRNA by real-time PCR, while tissue-resident pDC were identified by immunohistochemistry. mRNA for interferon-alpha and MxA, a gene that is specifically induced by interferon-alpha, was quantified in peripheral blood cells by real-time PCR, while serum interferon-alpha protein was measured by ELISA.

Results

While median values of pDC, both in terms of percentage and absolute number, were not statistically different from age-matched controls, interferon-alpha mRNA was increased in HIV-infected patients. However, in a group of patients with long disease duration, having a low number of both pDC and CD4⁺ lymphocytes and a significant increase of serum interferon-alpha, MxA mRNA was produced at high level and its expression directly correlated with HIV RNA copy numbers. Furthermore in patients displaying a low CD4⁺ blood cell count, a severe depletion of pDC in the tonsils could be documented.

Conclusion

HIV replication unresponsive to antiretroviral treatment in perinatal-infected patients with advanced disease and pDC depletion may lead to interferon-alpha expression and subsequent induction of MxA mRNA. Thus, the latter measurement may represent a valuable marker to monitor the clinical response to therapy in HIV patients.

Response to combination antiretroviral therapy: variation by age

OBJECTIVE

To provide information on responses to combination antiretroviral therapy in children, adolescents and older HIV-infected persons.

DESIGN AND SETTING

Multicohort collaboration of 33 European cohorts.

SUBJECTS

: Forty-nine thousand nine hundred and twenty-one antiretroviral-naive individuals starting combination antiretroviral therapy from 1998 to 2006.

OUTCOME MEASURES

Time from combination antiretroviral therapy initiation to HIV RNA less than 50 copies/ml (virological response), CD4 increase of more than 100 cells/microl (immunological response) and new AIDS/death were analysed using survival methods. Ten age strata were chosen: less than 2, 2-5, 6-12, 13-17, 18-29, 30-39 (reference group), 40-49, 50-54, 55-59 and 60 years or older; those aged 6 years or more were included in multivariable analyses.

RESULTS

The four youngest age groups had 223, 184, 219 and 201 individuals and the three oldest age groups had 2693, 1656 and 1613 individuals. Precombination antiretroviral therapy CD4 cell counts were highest in young children and declined with age. By 12 months, 53.7% (95% confidence interval: 53.2-54.1%) and 59.2% (58.7-59.6%) had experienced a virological and immunological response. The probability of virological response was lower in those aged 6-12 (adjusted hazard ratio: 0.87) and 13-17 (0.78) years, but was higher in those aged 50-54 (1.24), 55-59 (1.24) and at least 60 (1.18) years. The probability of immunological response was higher in children and younger adults and reduced in those 60 years or older. Those aged 55-59 and 60 years or older had poorer clinical outcomes after adjusting for the latest CD4 cell count.

CONCLUSION

Better virological responses but poorer immunological responses in older individuals, together with low precombination antiretroviral therapy CD4 cell counts, may place this group at increased clinical risk. The poorer virological responses in children may increase the likelihood of emergence of resistance.

Vertically acquired paediatric HIV infection: the challenges of providing comprehensive packages of care in resource-limited settings

The successes achieved in paediatric disease management in well-resourced countries in recent years highlight the vast divide between the care options, and ultimately survival, between developed and developing areas of the world. Using an extensive literature review, we quantify recent achievements in terms of improved survival and quality of life, and examine current evidence of the effects of treatment on the survival and morbidity of HIV-infected children in developing countries. When provided with the same care as their counterparts in developed countries, children in developing countries show similar improvements in survival and general health, with 1-year survival rates exceeding 90% in many African settings. Despite the challenges of providing comprehensive packages of care in resource-limited settings, there is an urgent need to scale up prevention and treatment of HIV infections in children, focussing on strengthening Prevention of Mother-to-Child Transmission programmes in order to reduce the numbers of infants who are infected in addition to reducing morbidity and mortality among their mothers.

Double boosted protease inhibitors, saquinavir, and lopinavir/ritonavir, in nucleoside pretreated children at 48 weeks

OBJECTIVES

To assess the 48-week efficacy, safety, pharmacokinetics, and resistance of double boosted protease inhibitors (PI), saquinavir (SQV), and lopinavir/ritonavir (LPV/r), in children who have failed nucleoside reverse transcription inhibitors /non-nucleoside reverse transcription inhibitors-based regimens.

METHODS

Fifty children at 2 sites in Thailand were treated with standard dosing of SQV and LPV/r. CD4, HIV-RNA viral load (VL), plasma drug concentrations and safety laboratory evaluations were monitored. Virologic failure was defined as having 2 consecutive VL >400 copies/mL after week 12 of therapy. Intention to treat analysis was performed.

RESULTS

Baseline data were a median age of 9.3 years (interquartile range [IQR]: 7.1-11.2), Center for Disease Control and Prevention (CDC) classification N:A:B:C 4%:14%:68%:14%, VL 4.8 log10 (IQR: 4.5-5.1), CD4 7% (IQR: 3-9.5). At 48 weeks, 3 had died of bacterial infection but no cases had progressed CDC classification. Median CD4% rise was 9 (IQR: 5-16) and median HIV RNA reduction was -2.8 log10 (IQR: -3.2 to -1.4), both P < 0.001. Thirty-nine (78%) and 32 (64%) children had VL <400 and <50 with significant differences between the 2 sites. Five children (10%) had VL failure as a result of poor adherence to the drug regimen but no one had major PI mutations. Median serum cholesterol and triglyceride increased significantly (+35 mg/dL, +37 mg/dL, respectively, both P < 0.001). Mean minimum plasma concentrations (Cmin) of LPV and SQV were 4.6 and 1.24 mg/L, respectively.

CONCLUSIONS

Double boosted SQV/LPV/r resulted in significant CD4 rise and VL decline at 48 weeks. Hyperlipidemia was common. Cmin of both PIs exceeded therapeutic concentrations. Poor adherence caused failure in 10%. No major PI mutations were found.

Long-term safety and effectiveness of ritonavir, nelfinavir, and lopinavir/ritonavir in antiretroviral-experienced HIV-infected children

AIM

To evaluate the long-term safety and effectiveness of ritonavir, nelfinavir, and lopinavir/ritonavir in antiretroviral-experienced, initially protease inhibitor (PI)-naive, human immunodeficiency virus (HIV)-1-infected children.

METHODS

HIV-1-infected children enrolled in the Swiss Mother and Child HIV Cohort Study were eligible for this observational cohort study if they received at least 1 PI of interest between March 1996 and October 2003: ritonavir, nelfinavir, or lopinavir/ritonavir. Data regarding demographics, clinical disease and antiretroviral treatment history, HIV-1 RNA copies/mL, CD4 T-cell counts [absolute (cells/microL) and percentages (%)], adverse events, clinical laboratory values, reasons for discontinuation of PIs, and concomitant medications were extracted from the database for PI-naive (first-line) and PI-experienced (second- or higher-line) PI use.

RESULTS

The total duration of ritonavir, nelfinavir, and lopinavir/ritonavir use for 133 HIV-1-infected children was 163.8, 235.0, and 46.1 patient-years, respectively. In an on-treatment analysis, first-line therapy with any of the PIs significantly reduced HIV-1 concentrations and increased CD4 T-cell counts and percentages from baseline throughout the 288-week study (P <or= 0.05) for ritonavir and nelfinavir and throughout 84 weeks of use for lopinavir/ritonavir, which was introduced into treatment more recently. All PIs investigated were most effective in PI-naive children. Thirteen PI-associated toxicities occurred requiring treatment changes or interruptions (neurologic symptoms, n = 2; pancreatitis, n = 1; allergic reactions, n = 4; visual symptoms, n = 3; and hyperlipidemia, n = 3).

CONCLUSIONS

Long-term PI-based therapy seems to be safe and to result in durable virologic and immunologic effectiveness in HIV-1-infected antiretroviral-experienced children.

Delayed early antiretroviral treatment is associated with an HIV-specific long-term cellular response in HIV-1 vertically infected infants

Antiviral T-cell immune responses appear to be crucial to control HIV replication. Infants treated before the third month of life with highly active antiretroviral treatment (HAART) did not develop a persistent HIV-specific immune response. We evaluated how delayed initiation of HAART after 3 months of age influences the development of HIV-1-specific T-cell responses during long-term follow-up in 9 HIV-1 vertically infected infants. These data suggest that a longer antigenic stimulation, due to a larger window for therapeutic intervention with HAART, is associated with the establishment of a persistent specific HIV immune response resulting in a long-term viral control of vertically infected infants.

Current CD4 cell count and the short-term risk of AIDS and death before the availability of effective antiretroviral therapy in HIV-infected children and adults

BACKGROUND

Currently, there are no comparable estimates of the short-term risk of disease progression in the absence of effective antiretroviral therapy for human immunodeficiency virus (HIV)-infected adults and children.

METHODS

A joint analysis of 2 large studies of children with vertically acquired HIV infection (the HIV Paediatric Prognostic Markers Collaborative Study) and adults with seroconversion (the CASCADE [Concerted Action on Sero-Conversion to AIDS and Death in Europe] collaboration) was conducted. Follow-up was censored at the end of 1995, before the introduction of combination antiretroviral therapy. The incidence rates of death and AIDS or death (AIDS/death) were estimated on the basis of age and current CD4 cell count.

RESULTS

A total of 1260 deaths (over 20,500 person-years of follow-up) and 1894 initial AIDS events (over 17,200 person-years of follow-up) were observed among 6741 patients (3244 children [i.e., patients < or =15 years of age] and 3497 adults). Young children (age, <5 years) experienced high morbidity and mortality rates. After adjustment for the CD4 cell count, the effect of age on disease progression was not significant among older children, whereas the risk increased markedly in association with increasing age among adults. Death rates were similar among older children and adults aged approximately 20 years, as were the rates of progression to AIDS/death when cases of serious recurrent bacterial infection, which has a more restrictive case definition in adults, were excluded.

CONCLUSIONS

Similar CD4 cell count criteria for initiation of antiretroviral therapy can be applied to adults and children > or = 5 years of age.

When should children with HIV infection be started on antiretroviral therapy?

BACKGROUND TO THE DEBATE

The advent of highly active antiretroviral therapy (HAART) dramatically improved the prognosis for both adults and children infected with HIV who had access to treatment. However, the optimal timing for initiating treatment remains controversial, particularly in children. This debate lays out the case for deferred treatment against the case for early initiation of HAART in children.

Serum leptin concentrations and fat redistribution in HIV-1-infected children on highly active antiretroviral therapy

OBJECTIVES

HIV-related lipodystrophy is a syndrome of adipose tissue redistribution, dyslipidaemia and insulin resistance. Combination antiretroviral therapy (CART) is a key risk factor. We hypothesized that fat redistribution in HIV-infected children is related to altered endocrine function of adipose tissue, namely leptin secretion.

METHODS

Serum leptin and fat redistribution were measured in 104 HIV-infected children in a prospective observational study from 2003 to 2004. Fat redistribution was defined by clinical observation. Body fatness was estimated using body mass index and four skinfold measurements. Serum leptin was determined using an enzyme-linked immunosorbent assay (Quantikine; R&D Systems, Abingdon, UK). Linear analogue models were used to adjust the leptin concentration for body fatness.

RESULTS

There was no significant difference in serum leptin among children treated with protease inhibitors (PIs), children on non-PI CART and children not treated with CART (P>0.05). When leptin concentrations were adjusted for body fatness, there was again no difference among PI-treated, non-PI-treated and untreated children. Categorization of CART exposure as never, current or past did not change these results.

CONCLUSIONS

There is no evidence that leptin plays any role in lipodystrophy other than reflecting body fatness.

Early Therapy in HIV-1-Infected Children: Effect on HIV-1 Dynamics and HIV-1-Specific Immune Response

Background

Perinatal HIV-1 infection is acquired in the milieu of a developing immune system, leading to high levels of uncontrolled viral replication. Few data have been reported that address the viral dynamics and immunological response in infants who initiated aggressive antiretroviral therapy (ART) shortly after birth.

Methods

Six HIV-1-infected infants who started ART within 3 months of age were studied. The median follow-up was 61 months. Plasma HIV-1 RNA, cell-associated HIV-1 DNA, unspliced and multiply spliced HIV-1 mRNAs, HIV-1 antibodies, and CD4+ and CD8+ T-cell subsets were assessed in sequential peripheral blood samples. HIV-1 cellular immune response was measured by EliSpot assay.

Results

All children showed a decline in plasma viraemia to undetectable levels. HIV-1 DNA persisted in four children, but only two of these had detectable HIV-1 mRNA. All viral parameters remained persistently negative in two children. Only two children produced HIV-1 antibodies, while the others, after having lost maternal antibodies, remained seronegative. No HIV-1 cellular immune response was observed in any child. Therapy interruption was performed in two children: one HIV-1-seropositive and one HIV-1-seronegative with persistently undetectable levels of all viral parameters. Rebound of HIV-1 plasma viraemia in the seronegative child was more rapid and higher than that observed in the seropositive child.

Conclusions

Early ART treatment in infants modifies the natural course of infection by controlling HIV-1 replication and reducing viral load to below the threshold levels required for onset of HIV-1 immune response, but does not prevent the establishment of a reservoir of latently infected cells that precludes virus eradication.