Thirteen-year viral suppression and immunologic recovery of LPV/r-based regimens in pediatric HIV treatment: a multicenter cohort study in resource-constrained settings of China

Background

Antiretroviral Therapy (ART) in children remains challenging due to resource-constrained settings. We conducted a 13-year, prospective, multicenter cohort study on the effectiveness and safety of LPV/r-based regimens in ART-naive and ART-experienced children.

Methods

From January 2008 to May 2021, children living with HIV-1 were recruited with LPV/r-based regimens from 8 clinical research sites in 6 provinces in China. Effectiveness outcomes were virologic failure (defined as at least two consecutive measurements of VL > 200 copies/mL after 6 months of ART) and immune response (defined as CD4% recovered to more than 25% after 12 months of treatment). The safety outcomes were treatment-related grade 2-4 adverse events and abnormal laboratory test results.

Results

A total of 345 ART-naïve children and 113 ART-experienced children were included in this cohort study. The median follow-up time was 7.3 (IQR 5.5-10.5) years. The incidence density of virologic failure was 4.1 (95% CI 3.3-4.9) per 100 person-years in ART-naïve children and 5.0 (95% CI 3.5-6.5) per 100 person-years in ART-experienced children. Kaplan Meyer (KM) curve analysis showed children with ART experience were at a higher risk of virologic failure (p < 0.05). The risk factors of virologic failure in ART-naïve children were clinic setting in rural hospitals (aHR = 2.251, 1.108-4.575), annual missed dose times >5 days of LPV intake (aHR = 1.889, 1.004-3.554); The risk factor of virologic failure in ART-experienced children was missed dose times >5 days (aHR = 2.689, 1.299-5.604) and mother as caregivers for ART administration (aHR = 0.475, 0.238-0.948). However, during long-term treatment, viral suppression rates between ART-naïve and ART-experienced children remained similar. No significant differences were observed in the immune response, treatment-related grade 2-4 events, and abnormal laboratory test results between ART-naïve children and ART-experienced children.

Conclusion

Our research underscores that with consistent, long-term treatment of LPV/r-based regimens, ART-experienced children can achieve therapeutic outcomes comparable to ART-naïve children. It provides crucial insights on LPV/r-based regimens in pediatric HIV treatment, especially in resource-limited settings where high-cost Integrase Strand Transfer Inhibitors (INSTs) are inaccessible. This evidence-based understanding provides an essential addition to the global therapeutic strategies for pediatric HIV treatment.

Potent Synergistic Interactions between Lopinavir and Azole Antifungal Drugs against Emerging Multidrug-Resistant Candida auris

The limited therapeutic options and the recent emergence of multidrug-resistant Candida species present a significant challenge to human medicine and underscore the need for novel therapeutic approaches. Drug repurposing appears as a promising tool to augment the activity of current azole antifungals, especially against multidrug-resistant Candida auris In this study, we evaluated the fluconazole chemosensitization activities of 1,547 FDA-approved drugs and clinical molecules against azole-resistant C. auris This led to the discovery that lopinavir, an HIV protease inhibitor, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration, lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole against C. auris (fractional inhibitory concentration index [ΣFICI] ranged from 0.04 to 0.09). Additionally, the lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (P < 0.05) relative to that of the untreated control. Furthermore, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species, including C. albicans, C. tropicalis, C. krusei, and C. parapsilosis Comparative transcriptomic profiling and mechanistic studies revealed that lopinavir was able to significantly interfere with the glucose permeation and ATP synthesis. This compromised the efflux ability of C. auris and consequently enhanced the susceptibility to azole drugs, as demonstrated by Nile red efflux assays. Altogether, these findings present lopinavir as a novel, potent, and broad-spectrum azole-chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.

Optimizing Pediatric Dosing Recommendations and Treatment Management of Antiretroviral Drugs Using Therapeutic Drug Monitoring Data in Children Living With HIV

Supplemental Digital Content is Available in the Text.

Introduction:

This review summarizes the current dosing recommendations for antiretroviral (ARV) drugs in the international pediatric guidelines of the World Health Organization (WHO), US Department of Health and Human Services (DHHS), and Pediatric European Network for Treatment of AIDS (PENTA), and evaluates the research that informed these approaches. We further explore the role of data generated through therapeutic drug monitoring in optimizing the dosing of ARVs in children.

Methods:

A PubMed search was conducted for the literature on ARV dosing published in English. In addition, the registration documentation of European Medicines Agency and the US Food and Drug Administration for currently used ARVs and studies referenced by the WHO, DHHS, and EMA guidelines were screened. Resulting publications were screened for papers containing data on the area under the concentration–time curve, trough concentration, and peak concentration. Studies with enrolled participants with a median or mean age of ≥18 years were excluded. No restriction on publishing date was applied.

Discussion and conclusion:

Pediatric ARV dosing is frequently based on data obtained from small studies and is often simplified to facilitate dosing in the context of a public health approach. Pharmacokinetic parameters of pediatric ARVs are subject to high interpatient variation and this leads to a potential risk of underdosing or overdosing when drugs are used in real life. To ensure optimal use of ARVs and validate dosing recommendations for children, it is essential to monitor ARV dosing more thoroughly with larger sample sizes and to include diverse subpopulations. Therapeutic drug monitoring data generated in children, where available and affordable, have the potential to enhance our understanding of the appropriateness of simplified pediatric dosing strategies recommended using a public health approach and to uncover suboptimal dosing or other unanticipated issues postmarketing, further facilitating the ultimate goal of optimizing pediatric ARV treatment.

Prediction of area under the concentration-time curve for lopinavir from peak or trough lopinavir concentrations in patients receiving lopinavir-ritonavir therapy

PURPOSE

A "single time point" strategy for predicting the area under the concentration-time curve (AUC) for lopinavir in patients receiving ritonavir-boosted lopinavir therapy was investigated.

METHODS

Linear regression equations describing the relationships of lopinavir peak and trough concentrations to lopinavir AUC values were established using pharmacokinetic data from published studies of patients or healthy subjects receiving lopinavir and ritonavir at standard dosages. The resulting "trough-AUC model" and "peak-AUC model" were used to predict lopinavir AUC values in the evaluated study populations (total n = 479); those values were then compared with reported AUC values.

RESULTS

Lopinavir peak or trough concentrations were strongly correlated with lopinavir AUC values (r = 0.9947 and r = 0.9541, respectively). For about 94% of calculations using the peak-AUC model and 87% of calculations using the trough-AUC model, differences between predicted and observed AUC values were in the range of 0.76-1.5 fold; the associated r values were 0.9514 (p < 0.001) and 0.9345 (p < 0.001), respectively. The mean absolute predictive error was less than 6% with the use of either the peak-AUC model or the trough-AUC model, with corresponding values for root-mean-square error of 17.6% and 23.5%, respectively.

CONCLUSION

Equations incorporating lopinavir peak and trough concentrations were found to satisfactorily predict lopinavir AUC values in data sets describing patients receiving lopinavir with ritonavir boosting. Variability in predictions was higher with use of the trough-AUC model.

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.

The Global Health Impact Index: Promoting Global Health

Millions of people cannot access essential medicines they need for deadly diseases like malaria, tuberculosis (TB) and HIV/AIDS. There is good information on the need for drugs for these diseases but until now, no global estimate of the impact drugs are having on this burden. This paper presents a model measuring companies' key malaria, TB and HIV/AIDS drugs' consequences for global health (global-health-impact.org). It aggregates drugs' impacts in several ways-by disease, country and originator-company. The methodology can be extended across diseases as well as drugs to provide a more extensive picture of the impact companies' drugs are having on the global burden of disease. The study suggests that key malaria, TB and HIV/AIDS drugs are, together, ameliorating about 37% of the global burden of these diseases and Sanofi, Novartis, and Pfizer's drugs are having the largest effect on this burden. Moreover, drug impacts vary widely across countries. This index provides important information for policy makers, pharmaceutical companies, countries, and other stake-holders that can help increase access to essential medicines.

Pharmacokinetics of atazanavir/ritonavir among HIV-infected Thai children concomitantly taking tenofovir disoproxil fumarate

BACKGROUND

Atazanavir/ritonavir (ATV/r) is a recommended once-daily protease inhibitor. Tenofovir disoproxil fumarate (TDF) can reduce ATV exposure. The authors studied ATV pharmacokinetic (PK) parameters among children who received atazanavir/ritonavir co-administered with TDF.

METHODS

HIV-infected children aged 6-18 years with a body weight of 25-50 kg were eligible. Branded ATV 200 mg/capsule was taken with generic ritonavir 100 mg/tablet once daily plus TDF and lamivudine. A 24-hour PK study was performed at week 4 at t = 0 (pre-dose), 2, 4, 6, 8, 10, 12 and 24 hours. PK parameters were calculated using non-compartmental methods with WinNonlin software. Targeted ATV AUC 0-24 was 15 mg h/L and C trough was 0.15 mg/L. Comparisons of geometric means of ATV PK parameters between different weight bands were made using regression models.

RESULTS

Eighteen HIV-infected children with a median (IQR) age of 13 (11-14) years were enrolled. Median (range) body weight and body surface area were 35 (25-42) kg and 1.21 (0.96-1.35) m2, respectively. Median (IQR) CD4 cell count was 735 (540-1233) cells/mm3. Median (range) of ATV was 164 (145-209) mg/m2. Geometric mean (SD) ATV AUC 0-24 was 35.05 (1.06) mg h/L, and ATV C trough was 0.31 (1.13) mg/L. No child had ATV AUC 0-24 or C trough below target levels. There were no significant differences in PK parameters among weight bands.

CONCLUSION

Atazanavir/ritonavir 200/100 mg dosing provided adequate ATV AUC 0-24 when used with TDF in HIV-infected Thai children weighing between 25 and 50 kg.

Pharmacokinetics of pediatric lopinavir/ritonavir tablets in children when administered twice daily according to FDA weight bands

BACKGROUND

Lopinavir/ritonavir (LPV/r) pediatric tablets (100/25 mg) are approved by the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) as part of combination antiretroviral therapy. Dosing is based on body weight bands or body surface area under FDA approval and only body surface area by the EMA. This can lead to a different recommended dose. In addition, weight band-based dosing has not been formally studied in the target population. We evaluated the pharmacokinetics (PK) of LPV/r in children, administered twice daily according to the FDA weight bands, using pediatric tablets.

METHODS

Fifty-three HIV-infected children were included in the PK substudy of the Paediatric European Network for the Treatment of AIDS 18 trial (KONCERT). In this study, children were randomized to receive LPV/r twice or once daily, according to FDA weight bands. A PK assessment was performed in 17, 16 and 20 children in the 15-25 kg, ≥ 25-35 kg and >35 kg weight band, respectively, while children took the tablets twice daily. Rich sampling was performed, and PK parameters were calculated by noncompartmental analysis. Given the high percentage of Asian children, it was also tested whether there was a difference in PK parameters between Asian and non-Asian children.

RESULTS

For the total group, LPV geometric mean AUC0-12, Cmax and C12 were 106.9 h × mg/L, 12.0 mg/L and 4.9 mg/L, respectively. There were no significant differences in LPV PK parameters between the weight bands. In addition, weight was not found to be associated with variability in Cmax, C12 or AUC0-12 for the LPV PK parameters.

CONCLUSIONS

FDA weight band-based dosing recommendations provide adequate exposure to LPV when using LPV/r pediatric tablets.

Second-line protease inhibitor-based HAART after failing non-nucleoside reverse transcriptase inhibitor-based regimens in Asian HIV-infected children

BACKGROUND

The World Health Organization (WHO) recommends boosted protease inhibitor (bPI)-based HAART after failing non-nucleoside reverse transcriptase inhibitor (NNRTI) treatment. We examined outcomes of this regimen in Asian HIV-infected children.

METHODS

Children from five Asian countries in the TREAT Asia Pediatric HIV Observational Database (TApHOD) with ≥ 24 weeks of NNRTI-based HAART followed by ≥ 24 weeks of bPI-based HAART were eligible. Primary outcomes were the proportions with virological suppression (HIV RNA < 400 copies/ml) and immune recovery (CD4+ T-cell percentage [CD4%]≥ 25% if age < 5 years and CD4+ T-cell count ≥ 500 cells/mm3 if age ≥ 5 years) at 48 and 96 weeks.

RESULTS

Of 3,422 children, 153 were eligible; 52% were female. At switch, median age was 10 years, 26% were in WHO stage 4. Median weight-for-age z-score (WAZ) was -1.9 (n = 121), CD4% was 12.5% (n = 106), CD4+ T-cell count was 237 cells/mm3 (n = 112), and HIV RNA was 4.6 log10 copies/ml (n = 61). The most common bPI was lopinavir/ritonavir (83%). At 48 weeks, 61% (79/129) had immune recovery, 60% (26/43) had undetectable HIV RNA and 73% (58/79) had fasting triglycerides ≥ 130 mg/dl. By 96 weeks, 70% (57/82) achieved immune recovery, 65% (17/26) had virological suppression, and hypertriglyceridaemia occurred in 66% (33/50). Predictors for virological suppression at week 48 were longer duration of NNRTI-based HAART (P = 0.006), younger age (P = 0.007), higher WAZ (P = 0.020) and HIV RNA at switch < 10,000 copies/ml (P = 0.049).

CONCLUSIONS

In this regional cohort of Asian children on bPI-based second-line HAART, 60% of children tested had immune recovery by 1 year, and two-thirds had hyperlipidaemia, highlighting difficulties in optimizing second-line HAART with limited drug options.

Effectiveness and safety of protease inhibitor-based regimens in HIV-infected Thai children failing first-line treatment

OBJECTIVES

Virological failure on first-line nonnucleoside reverse transcriptase inhibitor (NNRTI)-based treatment regimens has become a problem in HIV-infected children on long-term antiretroviral therapy (ART). Protease inhibitor (PI)-based regimens are therefore often given to children failing NNRTI-based regimens. The aim of the study was to assess the 48-week effectiveness, safety and predictive factors for viral suppression of PI-based regimens in HIV-infected Thai children who had failed NNRTI-based regimens.

METHODS

This study assessed 41 HIV-infected children who had failed first-line NNRTI-based regimens and were switched to PI-based regimens for at least 48 weeks. We assessed their CD4 cell counts, plasma HIV RNA levels, weight-for-age and height-for-age z-scores, and adverse events.

RESULTS

The children's median age was 9.5 years (range 1.5-15.8 years). At baseline, their median CD4 cell count was 276 cells/μL [interquartile range (IQR) 160-749 cells/μL], and their median plasma HIV RNA level was 4.5 log10 HIV-1 RNA copies/mL (IQR 3.9-4.8 log10 copies/mL). After 48 weeks of PI-based therapy, their CD4 cell counts increased to a median of 572 cells/μL (IQR 343-845 cells/μL) and in 73.2% plasma HIV RNA levels decreased to < 50 copies/mL. Their median weight-for-age and height-for-age z-scores were stable over the period of the study. Diarrhoea occurred in 29.3% of patients. Triglyceride levels were significantly higher at weeks 24 and 48 in comparison to baseline measurements.

CONCLUSIONS

PI-based regimens are safe and effective for HIV-infected Thai children who have failed first-line NNRTI-based regimens. However, long-term follow-up is warranted in order to ascertain the feasibility and sustainability of these new regimens.

Pharmacokinetics of darunavir/ritonavir in Asian HIV-1-infected children aged ≥7 years

BACKGROUND

The Asian population, in general, has higher antiretroviral concentrations than those who are not Asian, but there are limited pharmacokinetic data for darunavir/ritonavir in Asian children.

METHODS

Thai children aged ≥7 years and with body weight (BW)≥20 kg who were on darunavir/ritonavir for ≥2 weeks underwent 12-h pharmacokinetics with blood sampling before and at 1, 2, 4, 6, 8, 10 and 12 h post-dosing. Darunavir/ritonavir doses were 375/100 mg twice daily (BW 20 to <30 kg, n=12), 450/100 mg twice daily (BW 30 to <40 kg, n=2) or 600/100 mg twice daily (BW ≥40 kg, n=5). Ritonavir 100 mg soft gel capsules were used instead of solution.

RESULTS

Of the 19 children, 8 were female, median age was 13 years (range 7-16) and median BW was 29.4 kg. The median duration of darunavir/ritonavir treatment was 11 months. The geometric mean values for darunavir were 60.3 h×mg/l for the area under the concentration-time curve at 0-12 h (AUC(0-12)), 8.3 mg/l for the maximum concentration (C(max)) and 3.1 for the concentration prior to the next dose (C(12)) with no differences between dosing groups. All had C(12) above the protein binding adjusted 50% effective concentration (EC(50)) of protease inhibitor-resistant virus (0.55 mg/l). The darunavir pharmacokinetic parameters were similar to those in non-Asian individuals from the DELPHI study, in which 13 of 20 with BW<40 kg used 50 or 60 mg ritonavir boosting.

CONCLUSIONS

Thai children aged ≥7 years who were on standard darunavir dosing with 100 mg ritonavir boosting had adequate and comparable darunavir AUC(0-12), C(max) and C(12) to non-Asian children who mainly used lower doses of ritonavir boosting. A ritonavir boosting dose of 100 mg can be used for children weighing ≥20 kg, particularly when lower dose formulations are unavailable or if intolerant to the solution.

Drug resistance profiles among HIV-1-infected children experiencing delayed switch and 12-month efficacy after using second-line antiretroviral therapy: an observational cohort study in rural China

OBJECTIVE

To analyze the genotypic resistance profiles of HIV-infected children from rural China who were experiencing virologic failure to first-line antiretroviral therapy regimens and to evaluate 1-year regimen efficacy after switching to second-line therapy.

METHODS

A prospective cohort study was performed. Seventy-six children from the first rural pilot program with HIV viral load >1000 copies per milliliter on 2 consecutive occasions were studied. We analyzed genotype results and observed second-line therapy efficacy to 12 months.

RESULTS

After 33.1 (23.3, 41.1) months on first-line treatment after enrollment into national program, 98.7% of genotyped patients developed high-level resistance to nevirapine and 81.6% of patients had high-level resistance to efavirenz. High-level resistance to lamivudine was observed in 82.9%, followed by 57.9% for stavudine and 52.6% for zidovudine. In the nonnucleoside reverse transcriptase inhibitor class, the most common mutations were K103N/S at 50% and Y181C/I at 48.7%. M184V/I was the most common nucleoside reverse transcriptase inhibitor resistance mutation at 77.6%, the mutation rate for ≥3 thymidine analogue mutations, Q151M, and K65R were 33%, 12%, and 9%, respectively. After 12 months of boosted protease inhibitor-based second-line therapy, CD4 counts had on average increased 256 cells per cubic millimeter compared with switch baseline and 83.1% of patients had undetectable viral loads (<50 copies/mL).

CONCLUSIONS

HIV-1-infected children who continued their first-line regimen regardless of virologic failure harbored multiple resistance mutations. Although the extent of resistance to nucleoside reverse transcriptase inhibitor class drugs would be expected to limit subsequent treatment options, the current second-line regimen remained effective during a 1-year observational period.

Monoboosted lopinavir/ritonavir as simplified second-line maintenance therapy in virologically suppressed children

BACKGROUND

Monoboosted protease inhibitor is being evaluated as a strategy to simplify therapy in virologically suppressed patients who are on complex regimens.

METHODS

Children with two consecutive HIV-RNA below 50 copies/ml at least 3 months apart while on double boosted protease inhibitor (dPI) were switched to monoboosted lopinavir/r (mLPV/r). The previous dPI regimen was resumed within 4 weeks in children who experienced virological failure defined as two HIV-RNA at least 500 or three HIV-RNA at least 50 copies/ml. Primary endpoint was the proportion of children still on mLPV/r and having HIV-RNA less than 50 copies/ml at week 48.

RESULTS

Forty children on LPV/r + saquinavir (90%) or LPV/r + indinavir (10%) were enrolled, 50% were female, median [interquartile range (IQR)] age was 11.7 (10.2-13.5) years, and body weight was 29.4 (24.1-40.2 kg). The median (IQR) CD4% was 27 (23.5-29.5%). At 48 weeks, none had died or had HIV disease progression. Thirty-one children were on mLPV/r and 29 (72.5%) had HIV-RNA less than 50 copies/ml. Nine resumed dPI due to mLPV/r failure with four achieving undetectable HIV-RNA. Overall, 31 children (82.5%) had HIV-RNA suppression. Predicting factor for failing mLPV/r was baseline HIV-RNA at least 50 copies/ml. No major protease mutations were found.

CONCLUSION

By simplifying second-line treatment from dPI to mLPV/r, the majority of children had sustained viral suppression at 48 weeks. Randomized study of simplified mono protease inhibitor therapy in children is warranted.

Generic and low dose antiretroviral therapy in adults and children: implication for scaling up treatment in resource limited settings

Although access to antiretroviral therapy (ART) for the treatment of HIV has increased during the last decade, many patients are still in need of treatment. With limited funds to provide ART to millions of patients worldwide, there is a need for alternative ways to scale up ART in resource limited settings. This review provides an overview of pharmacokinetic, safety and efficacy studies of generic and reduced dose ART. The production of generic ART has greatly influenced the decline in drug prices and the increased in ART access. Generic ART has good pharmacokinetic profile, safety and efficacy. Toxicity is however the main cause for ART discontinuation. Several dose reduction studies have shown adequate pharmacokinetic parameters and short term efficacy with reduced dose ART. Ethnicity may affect drug metabolism; several pharmacokinetic studies have confirmed higher plasma ART concentration in Asians. Randomized efficacy trial of reduced versus standard ART is warranted.

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.