Nelfinavir and Lamivudine pharmacokinetics during the first two weeks of life

Lamivudine dosing for preterm infants exposed to HIV: a population pharmacokinetic modelling and simulation study

OBJECTIVES

To develop a pragmatic twice daily lamivudine dosing strategy for preterm infants from 24 to 37 completed weeks of gestation.

METHODS

Data were combined from eight pharmacokinetic studies in neonates and infants receiving lamivudine oral solution. A population pharmacokinetic model was developed using non-linear mixed effects regression. Different lamivudine dosing strategies, stratified by gestational age at birth (GA) bands, were simulated in a virtual population of preterm infants, aimed at maintaining lamivudine drug exposures (AUC0-12) within a reference target range of 2.95 to 13.25 µg·h/mL, prior to switching to WHO-weight band doses when ≥4 weeks of age and weighing ≥3 kg.

RESULTS

A total of 154 infants (59% female) contributed 858 lamivudine plasma concentrations. Median (range) GA at birth was 38 (27-41) weeks. At the time of first pharmacokinetic sampling infants were older with median postnatal age (PNA) of 6.3 (0.52-26.6) weeks. Lamivudine concentrations were described by a one-compartment model, with CL/F and V/F allometrically scaled to weight. Maturation of CL/F was described using an Emax model based on PNA. CL/F was also adjusted on GA to allow extrapolation for extreme prematurity. Simulations predicted an optimal lamivudine dosing for infants GA ≥24 to <30 weeks of 2 mg/kg twice daily from birth until weighing 3 kg; and for GA ≥30 to <37 weeks, 2 mg/kg twice daily for the first 4 weeks of life, followed by 4 mg/kg twice daily until weighing 3 kg.

CONCLUSIONS

Model-based predictions support twice daily pragmatic GA band dosing of lamivudine for preterm infants, but clinical validation is warranted.

Preventive and therapeutic benefits of nelfinavir in rhesus macaques and human beings infected with SARS-CoV-2

Effective drugs with broad spectrum safety profile to all people are highly expected to combat COVID-19 caused by SARS-CoV-2. Here we report that nelfinavir, an FDA approved drug for the treatment of HIV infection, is effective against SARS-CoV-2 and COVID-19. Preincubation of nelfinavir could inhibit the activity of the main protease of the SARS-CoV-2 (IC50 = 8.26 μM), while its antiviral activity in Vero E6 cells against a clinical isolate of SARS-CoV-2 was determined to be 2.93 μM (EC50). In comparison with vehicle-treated animals, rhesus macaque prophylactically treated with nelfinavir had significantly lower temperature and significantly reduced virus loads in the nasal and anal swabs of the animals. At necropsy, nelfinavir-treated animals had a significant reduction of the viral replication in the lungs by nearly three orders of magnitude. A prospective clinic study with 37 enrolled treatment-naive patients at Shanghai Public Health Clinical Center, which were randomized (1:1) to nelfinavir and control groups, showed that the nelfinavir treatment could shorten the duration of viral shedding by 5.5 days (9.0 vs. 14.5 days, P = 0.055) and the duration of fever time by 3.8 days (2.8 vs. 6.6 days, P = 0.014) in mild/moderate COVID-19 patients. The antiviral efficiency and clinical benefits in rhesus macaque model and in COVID-19 patients, together with its well-established good safety profile in almost all ages and during pregnancy, indicated that nelfinavir is a highly promising medication with the potential of preventative effect for the treatment of COVID-19.

Safety and Efficacy of Starting Antiretroviral Therapy in the First Week of Life

Background

Early antiretroviral therapy (ART) is recommended for infants with human immunodeficiency virus (HIV) infection. However, few antiretroviral options are available for neonates.

Methods

The Early Infant Treatment Study in Botswana tested HIV-exposed infants within 96 hours of birth, and HIV-infected infants started nevirapine (NVP) 6 mg/kg twice daily, zidovudine (ZDV), and lamivudine (3TC) at age < 7 days. NVP trough concentrations were tested at 1 and 2 weeks. NVP was switched to ritonavir-boosted lopinavir (LPV/r) at week 2, 3, 4, or 5 according to delivery gestational age.

Results

Forty HIV-infected infants started ART at median age 2 days (range, 1–5 days). NVP trough concentrations were highly variable and below therapeutic target (3000 ng/mL) for 50% of 2-week measurements; concentrations did not correlate with viral decline at weeks 2, 4, or 12. Two deaths unrelated to ART occurred through 24 weeks. Only 1 unscheduled treatment modification was required. Within 4 weeks of transition to LPV/r, 9 (22.5%) had transient HIV RNA increases, likely due to poor LPV/r palatability. At 12 weeks, 22 (55%) of 40 were <40 copies/mL (93% <400 copies/mL); by 24 weeks, 27 of 38 (71%) were < 40 copies/mL (84% < 400 copies/mL). HIV-1 RNA response at 12 and 24 weeks did not differ by baseline HIV RNA or other factors.

Conclusions

NVP/ZDV/3TC started in the first week of life was safe and effective, even when trough NVP levels were below target. Transient viral increases occurred following transition to LPV/r, but by 12 and 24 weeks most children achieved and maintained viral suppression.

Clinical Trials Registration

NCT02369406.

Pharmacokinetics and safety of maraviroc in neonates

OBJECTIVE

The aim of this study was to evaluate safety and pharmacokinetics of maraviroc administered with standard antiretroviral prophylaxis to HIV-1 exposed infants and to determine the appropriate dose of maraviroc during the first 6 weeks of life.

DESIGN

A phase I, multicentre, open-label study enrolling two sequential cohorts.

METHODS

IMPAACT 2007 participants enrolled by day 3 of life and were stratified by exposure to maternal efavirenz. Cohort 1 participants received two single 8 mg/kg maraviroc doses 1 week apart with pharmacokinetic sampling after each dose. Cohort 2 participants received 8 mg/kg maraviroc twice daily through 6 weeks of life with pharmacokinetic sampling at weeks 1 and 4. Maraviroc exposure target was Cavg at least 75 ng/ml. Laboratory and clinical evaluations assessed safety.

RESULTS

Fifteen Cohort 1 and 32 Cohort 2 HIV-exposed neonates were enrolled (median gestational age 39 weeks, 51% male). All 13 evaluable Cohort 1 infants met the pharmacokinetic target. Median exposure for the 25 evaluable Cohort 2 infants met the pharmacokinetic target but variability was high, with 17-33% of infants below target at Weeks 1 and 4. Pharmacokinetic target achievement was similar between efavirenz exposure strata. No Grade 3+ toxicities, early study or treatment discontinuations due to maraviroc occurred.

CONCLUSION

Median maraviroc exposure met the Cavg target in neonates receiving 8 mg/kg twice daily, although exposures were variable. Maternal efavirenz use did not impact maraviroc exposure and no discontinuations were due to maraviroc toxicity/intolerance. No infants acquired HIV-1 infection during follow-up. Maraviroc 8 mg/kg twice daily appears well tolerated during the first 6 weeks of life.

Pediatric Antiretroviral Therapy

Human immunodeficiency virus (HIV) is one of the most serious pediatric infectious diseases, affecting around 3 million children and adolescents worldwide. Lifelong antiretroviral treatment (ART) provides multiple benefits including sustained virologic suppression, restoration and preservation of immune function, decreased morbidity and mortality, and improved quality of life. However, access to ART, particularly among neonates and young infants, continues to be challenging due to limited number of suitable formulations and limited access to pediatric ARV drug. Moreover, children and adolescents living with HIV may experience long-term HIV- and ART-associated comorbidities including cardiovascular, renal, neurological, and metabolic complications. We provide an overview of currently available formulations, dosing, and safety considerations for pediatric antiretroviral drugs by drug classes and according to the three age groups including neonates, children, and adolescents.

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.

Prevention of perinatal transmission of zidovudine- and nevirapine-resistant HIV

PURPOSE

The use of a three-drug regimen for the prevention of perinatal transmission of zidovudine- and nevirapine-resistant HIV is described.

SUMMARY

A 17-year-old Hispanic woman infected with HIV arrived at our clinic for the management of her first pregnancy. The patient was in her second trimester of her pregnancy, had not previously been treated with antiretroviral therapy, and was only taking daily prenatal vitamins at the time of her first clinic visit. Her HIV RNA viral load was 240 copies/mL, and the virus was resistant to both zidovudine and nevirapine. Nelfinavir (compounded suspension), lamivudine, and zidovudine were prescribed for the mother, though she was generally nonadherent to therapy. Nelfinavir, lamivudine, and zidovudine were initiated for the newborn within eight hours of delivery. Six months later, the patient returned to the clinic in the first trimester of her second pregnancy. At this visit, her HIV RNA viral load was 120 copies/mL. After the birth of her second child, the infant received the same regimen received by her firstborn: zidovudine 4 mg/kg orally twice daily for six weeks, lamivudine 2 mg/kg orally twice daily for two weeks, and nelfinavir 55 mg/kg orally twice daily for two weeks. At four months of age, each infant was found to be HIV-negative.

CONCLUSION

A prophylactic regimen that included nelfinavir, lamivudine, and zidovudine was used to prevent perinatal transmission of HIV in two neonates. The regimen was well tolerated, and both infants were determined to be HIV-negative at four months of age.

The last and first frontier--emerging challenges for HIV treatment and prevention in the first week of life with emphasis on premature and low birth weight infants

Introduction

There is new emphasis on identifying and treating HIV in the first days of life and also an appreciation that low birth weight (LBW) and preterm delivery (PTD) frequently accompany HIV-related pregnancy. Even in the absence of HIV, PTD and LBW contribute substantially to neonatal and infant mortality. HIV-exposed and -infected infants with these characteristics have received little attention thus far. As HIV programs expand to meet the 90-90-90 target for ending the HIV pandemic, attention should focus on newborn infants, including those delivered preterm or of LBW.

Discussion

In high prevalence settings, infant diagnosis of HIV is usually undertaken after the neonatal period. However, as in utero infection may be diagnosed at birth, earlier initiation of therapy may limit viral replication and prevent early damage. Globally, there is growing awareness that preterm and LBW infants constitute a substantial proportion of births each year. Preterm infants are at high risk for vertical transmission. Feeding difficulties, apnoea of prematurity and vulnerability to sepsis occur commonly. Feeding intolerance, a frequent occurrence, may compromise oral administration of medications. Although there is growing experience with post-exposure prophylaxis for HIV-exposed term newborn infants, there is less experience with preterm and LBW infants. For treatment, there are even fewer options for preterm infants. Only zidovudine has adequate dosing recommendations for treating term and preterm infants and has an intravenous formulation, essential if feeding intolerance occurs. Nevirapine dosing for prevention, but not treatment, is well established for both term and preterm infants.

HIV diagnosis at birth is likely to be extremely stressful for new parents, more so if caring for preterm or LBW infants. Programs need to adapt to support the medical and emotional needs of young infants and their parents, where interventions may be lifesaving.

Conclusions

New focus is required for the newborn baby, including those born preterm, with LBW or small for gestational age to consolidate gains already made in early diagnosis and treatment of young children.

Pharmacokinetic considerations in the use of antivirals in neonates

INTRODUCTION

Neonatal patients, because of the inability of their immune system to properly respond to microbial challenge, are highly susceptible to viral infections. Immunoglobulins, monoclonal antibody and antiviral drugs are used for prophylaxis and treatment of viral diseases in neonates. Neonates and, especially, preterm infants differ in drug absorption, distribution, metabolism and excretion from adults and older children.

AREAS COVERED

This review will evaluate deficiencies of neonatal immune responses to microbial challenge that predispose newborns to viral infections, clinical manifestations and the treatment of viral diseases in neonates. We focus on published studies describing antiviral drug pharmacokinetics in neonates and make recommendations on the dosing of these drugs, allowing achievement of maximal clinical benefits in neonates.

EXPERT OPINION

While some efforts were undertaken to study pharmacokinetics and pharmacodynamics of antiviral drugs, much more needs to be done. Current data indicate that the pharmacokinetics of antiviral drugs may vary significantly depending on gestational age, maturation processes of drug-metabolizing enzymes and renal clearance. Specifics of pharmacokinetics of antiviral drugs need to be taken into consideration when they are prescribed to neonates and infants.

Serious adverse events are uncommon with combination neonatal antiretroviral prophylaxis: a retrospective case review

Six weeks of zidovudine (ZDV) is recommended for postnatal prophylaxis of HIV-exposed infants, but combination antiretrovirals are indicated if HIV transmission risk is increased. We investigated the frequency and severity of adverse events (AE) in infants receiving multiple drug prophylaxis compared to ZDV alone. In this retrospective review of 148 HIV-exposed uninfected infants born between 1997–2009, we determined clinical and laboratory AE that occurred between days of life 8–42. Thirty-six infants received combination prophylaxis; among those, a three-drug regimen containing ZDV, lamivudine, and nevirapine was most common (53%). Rates of laboratory AE grade ≥1 were as follows for the combination prophylaxis and ZDV alone groups, respectively: neutropenia 55% and 39%; anemia 50% and 39%; thrombocytopenia 0 and 3%; elevated aspartate aminotransferase 3% and 3%; elevated alanine aminotransferase 0 and 1%; hyperbilirubinemia 19% and 42%. Anemia occurred more frequently in infants who received three-drug prophylaxis compared to infants who received ZDV alone (63% vs. 39%, p = 0.04); all anemia AE were grade 1 or 2 in the three-drug prophylaxis group. Overall, 75% of infants on combination prophylaxis and 66% of infants on ZDV alone developed grade ≥1 AE (p = 0.32), and 17% of infants in either group developed grade ≥3 AE. Stavudine was substituted for ZDV in 23 infants due to anemia or neutropenia. After this antiretroviral change, 50% of evaluable infants demonstrated improvement in AE grade, and 25% had no change. In conclusion, low grade anemia, neutropenia, and hyperbilirubinemia occurred frequently regardless of the prophylactic regimen, but serious AE were uncommon. Although most AE were typical of ZDV toxicity, the combination of ZDV with lamivudine and nevirapine resulted in an increased frequency of low-grade anemia. Further studies are needed to identify prophylactic regimens with less toxicity for infants born to HIV-infected mothers.

Translation of biomedical prevention strategies for HIV: prospects and pitfalls

Early achievements in biomedical approaches for HIV prevention included physical barriers (condoms), clean injection equipment (both for medical use and for injection drug users), blood and blood product safety, and prevention of mother-to-child transmission. In recent years, antiretroviral drugs to reduce the risk of transmission (when the infected person takes the medicines; treatment as prevention) or reduce the risk of acquisition (when the seronegative person takes them; preexposure prophylaxis) have proven to be efficacious. Circumcision of men has also been a major tool relevant for higher prevalence regions such as sub-Saharan Africa. Well-established prevention strategies in the control of sexually transmitted diseases and tuberculosis are highly relevant for HIV (ie, screening, linkage to care, early treatment, and contact tracing). Unfortunately, only slow progress is being made in some available HIV-prevention strategies such as family planning for HIV-infected women who do not want more children and prevention of mother-to-child HIV transmission. Current studies seek to integrate strategies into approaches that combine biomedical, behavioral, and structural methods to achieve prevention synergies. This review identifies the major biomedical approaches demonstrated to be efficacious that are now available. We also highlight the need for behavioral risk reduction and adherence as essential components of any biomedical approach.

Use of combination neonatal prophylaxis for the prevention of mother-to-child transmission of HIV infection in European high-risk infants

OBJECTIVES

To evaluate use of combination neonatal prophylaxis (CNP) in infants at high risk for mother-to-child transmission (MTCT) of HIV in Europe and investigate whether CNP is more effective in preventing MTCT than single drug neonatal prophylaxis (SNP).

DESIGN

Individual patient-data meta-analysis across eight observational studies.

METHODS

Factors associated with CNP receipt and with MTCT were explored by logistic regression using data from nonbreastfed infants, born between 1996 and 2010 and at high risk for MTCT.

RESULTS

In 5285 mother-infant pairs, 1463 (27.7%) had no antenatal or intrapartum antiretroviral prophylaxis, 915 (17.3%) had only intrapartum prophylaxis and 2907 (55.0%) mothers had detectable delivery viral load despite receiving antenatal antiretroviral therapy. Any neonatal prophylaxis was administered to 4623 (87.5%) infants altogether; 1105 (23.9%) received CNP. Factors significantly associated with the receipt of CNP were later calendar birth year, no elective caesarean section, maternal CD4 cell count less than 200 cells/μl, maternal delivery viral load more than 1000 copies/ml, no antenatal antiretroviral therapy, receipt of intrapartum single-dose nevirapine and cohort. After adjustment, absence of neonatal prophylaxis was associated with higher risk of MTCT compared to neonatal prophylaxis [adjusted odds ratio (aOR) 2.29; 95% confidence interval (95% CI) 1.46-2.59; P < 0.0001]. Further, there was no association between CNP and MTCT compared to SNP (aOR 1.41; 95% CI 0.97-2.5; P = 0.07).

CONCLUSION

In this European population, CNP use is increasing and associated with presence of MTCT risk factors. The finding of no observed difference in MTCT risk between one drug and CNP may reflect residual confounding or the fact that CNP may be effective only in a subgroup of infants rather than the whole population of high-risk infants.

Pharmacotherapy of pediatric HIV infection

The delivery of safe and effective antiretroviral therapy to children and adolescents is crucial to save the lives of millions of children worldwide. The immunologic response to human immunodeficiency infection is closely related to a child's development and creates age-specific parameters for the evaluation of therapeutic response to antiretroviral therapy. Similarly, the development and maturation of organ systems involved in drug absorption, distribution, metabolism, and elimination determines significant changes in the pharmacokinetics of antiretroviral drugs throughout childhood. The authors review the evolution in treatment of pediatric HIV from infancy through adolescence.

Three postpartum antiretroviral regimens to prevent intrapartum HIV infection

BACKGROUND

The safety and efficacy of adding antiretroviral drugs to standard zidovudine prophylaxis in infants of mothers with human immunodeficiency virus (HIV) infection who did not receive antenatal antiretroviral therapy (ART) because of late identification are unclear. We evaluated three ART regimens in such infants.

METHODS

Within 48 hours after their birth, we randomly assigned formula-fed infants born to women with a peripartum diagnosis of HIV type 1 (HIV-1) infection to one of three regimens: zidovudine for 6 weeks (zidovudine-alone group), zidovudine for 6 weeks plus three doses of nevirapine during the first 8 days of life (two-drug group), or zidovudine for 6 weeks plus nelfinavir and lamivudine for 2 weeks (three-drug group). The primary outcome was HIV-1 infection at 3 months in infants uninfected at birth.

RESULTS

A total of 1684 infants were enrolled in the Americas and South Africa (566 in the zidovudine-alone group, 562 in the two-drug group, and 556 in the three-drug group). The overall rate of in utero transmission of HIV-1 on the basis of Kaplan-Meier estimates was 5.7% (93 infants), with no significant differences among the groups. Intrapartum transmission occurred in 24 infants in the zidovudine-alone group (4.8%; 95% confidence interval [CI], 3.2 to 7.1), as compared with 11 infants in the two-drug group (2.2%; 95% CI, 1.2 to 3.9; P=0.046) and 12 in the three-drug group (2.4%; 95% CI, 1.4 to 4.3; P=0.046). The overall transmission rate was 8.5% (140 infants), with an increased rate in the zidovudine-alone group (P=0.03 for the comparisons with the two- and three-drug groups). On multivariate analysis, zidovudine monotherapy, a higher maternal viral load, and maternal use of illegal substances were significantly associated with transmission. The rate of neutropenia was significantly increased in the three-drug group (P<0.001 for both comparisons with the other groups).

CONCLUSIONS

In neonates whose mothers did not receive ART during pregnancy, prophylaxis with a two- or three-drug ART regimen is superior to zidovudine alone for the prevention of intrapartum HIV transmission; the two-drug regimen has less toxicity than the three-drug regimen. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development [NICHD] and others; ClinicalTrials.gov number, NCT00099359.).

Experience in international clinical research: the HIV Prevention Trials Network

The HIV Prevention Trials Network (HPTN) is supported by the NIH to conduct randomized clinical trials to assess the efficacy of HIV prevention strategies and technologies to reduce HIV transmission between adults. A special focus of attention is on the use of antiretroviral drugs to prevent HIV transmission, both by reducing infectiousness among HIV-infected persons taking combination antiretroviral therapy (cART) and also by reducing susceptibility among HIV-uninfected persons taking antiretrovirals for pre-exposure prophylaxis. Studies may be developmental in nature to assess novel ideas for interventions or for assessing trial feasibility. However, pivotal efficacy trials to test HIV-specific prevention strategies and technologies are the main HPTN priority. Examples include a major protocol investigating the impact of expanded testing and linkage to care on HIV surveillance indicators in the USA (HPTN 065). Another protocol is addressing similar issues while also investigating how combinations of prevention approaches are best deployed to make a community-level impact in southern Africa (HPTN 071). HPTN 068 is evaluating a novel conditional cash transfer structural intervention to increase school completion rates in young girls and thereby reduce their HIV risk. Studies outside the US address the epidemic in most at-risk populations and include an assessment of opiate agonist therapy to reduce risk of HIV seroconversion among injection drug users (HTPN 058), methods to increase HIV testing rates (HTPN 043), as well as methods for reducing high-risk behaviors, and increasing adherence to cART in HIV-infected individuals (HPTN 062 and HPTN 063, respectively). The recent HPTN 052 study demonstrated that a 96% reduction in HIV transmission could be achieved between serodiscordant sexual partners by providing the infected partners with cART at a CD4(+) cell count (350-550/µl) above the level that would usually qualify them for therapy in low- and middle-income countries. The immediate relevance to public health policy showcased in these trials is a paradigm for the HPTN: design and conduct of clinical trials using available licensed tools that can be rapidly translated for implementation ('Prevention NOW!').