Fetal and maternal outcome after administration of tenofovir to gravid rhesus monkeys (Macaca mulatta)

Safety of tenofovir during pregnancy: early growth outcomes and hematologic side effects in HIV-exposed uninfected infants

Intrauterine exposure to zidovudine-based combination antiretroviral therapy (cART) can cause severe anemia within the first weeks of life. Tenofovir disoproxil fumarate (TDF)-based regimens may have less hematologic side effects but may affect growth parameters. This study aimed to assess the safety of TDF for prevention of mother-to-child transmission (PMTCT) in HIV-exposed uninfected infants regarding early growth outcomes and hematologic side effects. Our retrospective observational cohort study included children born (n = 232) to HIV-infected mothers (n = 228) on cART. Blood counts were compared at birth, 4-6 weeks, and 3, 12 and 18 months of age. Growth parameters were measured at birth and 12 and 18 months of age. Data were analyzed according to treatment group (TDF and non-TDF cART regimes). The median hemoglobin (Hgb) was significantly lower in the non-TDF-based group at birth (15.4 g/dl vs. 16.9 g/dl; **p = 0.002) and at 4-6 weeks of age (9.9 g/dl vs. 10.4 g/dl; **p = 0.004). The mean corpuscular volume was higher in the non-TDF-based group (109 fl vs. 105 fl; ***p < 0.001) as well at 4-6 weeks (102 fl vs. 95 fl; ***p < 0.001). In the TDF-based group, a higher proportion of neutropenia (grade 2 and higher) compared to the non-TDF-group (21.4% vs. 11%; *p = 0.015) was observed at three months of age. This effect was transient. There was no difference in growth.Conclusions: TDF appears to have no major side effects in our cohort. Transient anemia was observed more commonly with non-TDF regimens. However, our research suggests a potential delayed effect of TDF on neutrophils at 3 months of age.What is Known:• TDF is suspected to affect the growth of HIV-exposed uninfected infants.• Non-TDF-based cART regimes for prevention of mother-to-child transmission of HIV often result in transient anemia in the infant.What is New:• TDF appears to have no major side effects regarding the growth of HIV-exposed uninfected infants.• Our research suggests a potential delayed effect of TDF on neutrophils at 3 months of age in these infants.

Safety of Tenofovir Disoproxil Fumarate-Based Antiretroviral Therapy Regimens in Pregnancy for HIV-Infected Women and Their Infants: A Systematic Review and Meta-Analysis

Supplemental Digital Content is Available in the Text.

Background:

There are limited data on adverse effects of tenofovir disoproxil fumarate (TDF)-based antiretroviral therapy (ART) on pregnant women and their infants.

Methods:

We conducted a systematic review of studies published between January 1980 and January 2017 that compared adverse outcomes in HIV-infected women receiving TDF- vs. non–TDF-based ART during pregnancy. The risk ratio (RR) for associations was pooled using a fixed-effects model.

Results:

Seventeen studies met the study inclusion criteria. We found that the rate of preterm (<37 weeks gestation) delivery (RR = 0.90, 95% confidence interval [CI]: 0.81 to 0.99, I² = 59%) and stillbirth (RR = 0.60, 95% CI: 0.43 to 0.84, I² = 72.0%) were significantly lower in women exposed (vs. not) to TDF-based ART regimen. We found no increased risk in maternal severe (grade 3) or potentially life-threatening (grade 4) adverse events (RR = 0.62; 95% CI: 0.30 to 1.29), miscarriage (RR = 1.09; 95% CI: 0.80 to 1.48), very preterm (<34 weeks gestation) delivery (RR = 1.08, 95% CI: 0.72 to 1.62), small for gestational age (RR = 0.87, 95% CI: 0.67 to 1.13), low birth weight (RR = 0.91; 95% CI: 0.80 to 1.04), very low birth weight (RR = 3.18; 95% CI: 0.65 to 15.63), congenital anomalies (RR = 1.03; 95% CI: 0.83 to 1.28), infant adverse outcomes or infant mortality (age >14 days) (RR = 0.65; 95% CI: 0.23 to 1.85), but increased neonatal mortality (age <14 days) risk (RR = 5.64, 95% CI: 1.70 to 18.79) with TDR-based ART exposure. No differences were found for anthropomorphic parameters at birth; one study reported minor differences in z-scores for length and head circumference at age 1 year.

Conclusions:

TDF-based ART in pregnancy seems generally safe for women and their infants. However, data remain limited and further studies are needed, particularly to assess neonatal mortality and infant growth/bone effects.

Bone Age and Mineral Density Assessments Using Plain Roentgenograms in Tenofovir-exposed Infants in Malawi and Brazil Enrolled in HIV Prevention Trials Network 057

BACKGROUND

Tenofovir disoproxil fumarate (TDF) use during pregnancy has been increasing, and studies linking bone toxicity with exposure to TDF have raised concern for its use in infants.

METHODS

Hand/wrist and spine radiographs were obtained at 3 days and 12 weeks of age in infants born to HIV-infected pregnant women enrolled in the HIV Prevention Trials Network 057 pharmacokinetic study of TDF conducted in Malawi and Brazil assigned to 3 TDF dosing cohorts. In cohort 1, mothers received 600 mg of TDF during labor. In cohort 2, infants received 4 mg/kg dose on days 0, 3 and 5. In cohort 3, a 900 mg maternal dose was given during labor, followed by a 6 mg/kg infant dose on days 0, 3 and 5 of life.

RESULTS

Across all 3 cohorts, 89 infants had radiographs performed at either time point, and 85 had radiographs performed at both time points. Metaphyseal lucency was present in 1 case in Brazil and 2 in Malawi. Fifteen percent of infants from Brazil and 9% of infants from Malawi presented bone age discrepancies. No other abnormalities were identified in Brazil, whereas in Malawi, there were 7 more cases of wrist osteopenia, 2 of spine osteopenia and 3 other abnormalities.

CONCLUSION

Bone abnormalities were not uncommon in the overall cohort of HIV-exposed infants. Because of very limited study drug exposure at the time of birth, it is unlikely that TDF was associated with these findings. Untreated maternal HIV disease and/or maternal nutritional status could potentially be related to fetal bone development. This association should be explored in future cohort studies.

Bone health in HIV-infected children and adolescents

PURPOSE OF REVIEW

Chronic HIV infection and exposure to antiretroviral therapy compromises bone health in children and adolescents, potentially impacting their long-term quality of life. Thus, the purpose of this article is to review the most recent literature on this topic in HIV-infected children and adolescents.

RECENT FINDINGS

Recent studies continue to demonstrate bone abnormalities in HIV-infected children and adolescents, whether HIV is acquired perinatally or during adolescence. Researchers have employed new modalities, both high tech and those that can be utilized in resource-limited settings, to better assess bone health. New data suggest that this population may also be experiencing an increase incidence of fractures, and they may not acquire the same peak bone mass as their HIV-uninfected counterparts. Reassuringly, however, in-utero tenofovir exposure does not appear to have a significant impact on bone health in HIV-exposed, uninfected infants.

SUMMARY

HIV-infected children and adolescents are exposed to HIV and antiretroviral therapy for many decades starting early in life and during the most critical time for skeletal growth and bone mass accrual. Recent findings underscore the need for further research on bone in this population. Longitudinal studies are especially needed to evaluate long-term risk of osteoporosis and fracture.

Disclosing in utero HIV/ARV exposure to the HIV-exposed uninfected adolescent: is it necessary?

Introduction

The tremendous success of antiretroviral therapy has resulted in a diminishing population of perinatally HIV-infected children on the one hand and a mounting number of HIV-exposed uninfected (HEU) children on the other. As the oldest of these HEU children are reaching adolescence, questions have emerged surrounding the implications of HEU status disclosure to these adolescents. This article outlines the arguments for and against disclosure of a child's HEU status.

Discussion

Disclosure of a child's HEU status, by definition, requires disclosure of maternal HIV status. It is necessary to weigh the benefits and harms which could occur with disclosure in each of the following domains: psychosocial impact, long-term physical health of the HEU individual and the public health impact. Does disclosure improve or worsen the psychological health of the HEU individual and extended family unit? Do present data on the long-term safety of in utero HIV/ARV exposure reveal potential health risks which merit disclosure to the HEU adolescent? What research and public health programmes or systems need to be in place to afford monitoring of HEU individuals and which, if any, of these require disclosure?

Conclusions

At present, it is not clear that there is sufficient evidence on whether long-term adverse effects are associated with in utero HIV/ARV exposures, making it difficult to mandate universal disclosure. However, as more countries adopt electronic medical record systems, the HEU status of an individual should be an important piece of the health record which follows the infant not only through childhood and adolescence but also adulthood. Clinicians and researchers should continue to approach the dialogue around mother–child disclosure with sensitivity and a cogent consideration of the evolving risks and benefits as new information becomes available while also working to maintain documentation of an individual's perinatal HIV/ARV exposures as a vital part of his/her medical records. As more long-term adult safety data on in utero HIV/ARV exposures become available these decisions may become clearer, but at this time, they remain complex and multi-faceted.

The PHACS SMARTT Study: Assessment of the Safety of In Utero Exposure to Antiretroviral Drugs

The Surveillance Monitoring for ART Toxicities (SMARTT) cohort of the Pediatric HIV/AIDS Cohort Study includes over 3,500 HIV-exposed but uninfected infants and children at 22 sites in the US, including Puerto Rico. The goal of the study is to determine the safety of in utero exposure to antiretrovirals (ARVs) and to estimate the incidence of adverse events. Domains being assessed include metabolic, growth and development, cardiac, neurological, neurodevelopmental (ND), behavior, language, and hearing. SMARTT employs an innovative trigger-based design as an efficient means to identify and evaluate adverse events. Participants who met a predefined clinical or laboratory threshold (trigger) undergo additional evaluations to define their case status. After adjusting for birth cohort and other factors, there was no significant increase in the likelihood of meeting overall case status (case in any domain) with exposure to combination ARVs (cARVs), any ARV class, or any specific ARV. However, several individual ARVs were significantly associated with case status in individual domains, including zidovudine for a metabolic case, first trimester stavudine for a language case, and didanosine plus stavudine for a ND case. We found an increased rate of preterm birth with first trimester exposure to protease inhibitor-based cARV. Although there was no overall increase in congenital anomalies with first trimester cARV, a significant increase was seen with exposure to atazanavir, ritonavir, and didanosine plus stavudine. Tenofovir exposure was associated with significantly lower mean whole-body bone mineral content in the newborn period and a lower length and head circumference at 1 year of age. With ND testing at 1 year of age, specific ARVs (atazanavir, ritonavir-boosted lopinavir, nelfinavir, and tenofovir) were associated with lower performance, although all groups were within the normal range. No ARVs or classes were associated with lower performance between 5 and 13 years of age. Atazanavir and saquinavir exposure were associated with late language emergence at 1 year, but not at 2 years of age. The results of the SMARTT study are generally reassuring, with little evidence for serious adverse events resulting from in utero ARV exposure. However, several findings of concern warrant further evaluation, and new ARVs used in pregnancy need to be evaluated.

In Utero Tenofovir Exposure Is not Associated With Fetal Long Bone Growth

BACKGROUND

Despite widespread use of tenofovir disoproxil fumarate (TDF) in pregnant and breastfeeding women, few data exist on fetal bone development after in utero TDF exposure. We evaluated fetal long bone growth in human immunodeficiency virus (HIV)-infected pregnant woman/fetus dyads in Cape Town, South Africa.

METHODS

Women were recruited from primary care antenatal services and underwent ultrasonography to determine femur (FLZ) and humerus (HLZ) length z scores. The duration of in utero TDF exposure was calculated in weeks. Linear regression models were applied to assess the associations between the duration of in utero TDF exposure and change in FLZ and HLZ.

RESULTS

A total of 646 woman/fetus dyads contributed 1376 ultrasonographic scans to this analysis: 132 dyads with ≥25 weeks, 326 with 10-24 weeks, and 188 with <10 weeks of TDF exposure. Women receiving TDF for ≥25 weeks were older than those receiving TDF for 10-24 or <10 weeks (median age, 31 vs 28 and 28 years, respectively; P < .01), and had lower HIV RNA levels (median log10 HIV RNA level, 1.59 vs 4.08 and 3.83, respectively; P < .01). Throughout gestation, overall median FLZ and HLZ were 0.30 (interquartile range, -0.03 to 0.63) and 0.22 (-0.26 to 0.59) respectively. In multivariate analysis, there was no association between duration of in utero TDF exposure per 1-week increment and change in FLZ (ß = .00; P = .51) or change in HLZ (ß = .00; P = .40). Results were similar using mixed-effects models.

CONCLUSIONS

Although longer follow-up is needed, these in utero data are reassuring and support the continued use of TDF in pregnancy.

Long-term administration of tenofovir or emtricitabine to pregnant rats; effect on Abcb1a, Abcb1b and Abcg2 expression in the placenta and in maternal and fetal organs

OBJECTIVES

Tenofovir and emtricitabine are very effective and well-tolerated antiretrovirals representing current backbone of the antiretroviral combination regimens for the prevention of perinatal HIV transmission. The aim of our study was to determine whether tenofovir or emtricitabine administered in long-term fashion affect expression of two widely described pharmacokinetic determinants, P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2), in maternal or fetal biological tissues.

METHODS

For this purpose, pregnant Wistar rats were administered tenofovir (2.25 mg/kg/day), emtricitabine (3.5 mg/kg/day) or saline i.m. for 10 days (from the 12th to 21st gestation day). On the 22nd day, the placenta and maternal/fetal intestine, brain, kidneys and liver were sampled and analysed for Abcb1a, Abcb1b and Abcg2 expression; placental and newborns' weights were also monitored.

KEY FINDINGS

We found that long-term application of tenofovir or emtricitabine did not significantly affect expression of Abcb1a, Abcb1b and Abcg2 in either maternal or fetal organs. However, tenofovir administration significantly increased placenta-to-birthweight ratio, a strong indicator of various diseases occurring later in life.

CONCLUSIONS

Our data broaden current knowledge on safety profile of tenofovir and emtricitabine use in pregnancy. Nevertheless, further research in other mammal species, including humans, is important to fully elucidate this issue.

Maternal Tenofovir Disoproxil Fumarate Use in Pregnancy and Growth Outcomes among HIV-Exposed Uninfected Infants in Kenya

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is commonly used in antiretroviral treatment (ART) and preexposure prophylaxis regimens. We evaluated the relationship of prenatal TDF use and growth outcomes among Kenyan HIV-exposed uninfected (HEU) infants.

MATERIALS AND METHODS

We included PCR-confirmed HEU infants enrolled in a cross-sectional survey of mother-infant pairs conducted between July and December 2013 in Kenya. Maternal ART regimen during pregnancy was determined by self-report and clinic records. Six-week and 9-month z-scores for weight-for-age (WAZ), weight-for-length (WLZ), length-for-age (LAZ), and head circumference-for-age (HCAZ) were compared among HEU infants with and without TDF exposure using t-tests and multivariate linear regression models.

RESULTS

Among 277 mothers who received ART during pregnancy, 63% initiated ART before pregnancy, of which 89 (32%) used TDF. No differences in birth weight (3.0 kg versus 3.1 kg, p = 0.21) or gestational age (38 weeks versus 38 weeks, p = 0.16) were detected between TDF-exposed and TDF-unexposed infants. At 6 weeks, unadjusted mean WAZ was lower among TDF-exposed infants (-0.8 versus -0.4, p = 0.03), with a trend towards association in adjusted analyses (p = 0.06). There were no associations between prenatal TDF use and WLZ, LAZ, and HCAZ in 6-week or 9-month infant cohorts.

CONCLUSION

Maternal TDF use did not adversely affect infant growth compared to other regimens.

Lower Newborn Bone Mineral Content Associated With Maternal Use of Tenofovir Disoproxil Fumarate During Pregnancy

BACKGROUND

Fetal bone effects of maternal tenofovir use have not been well studied. We sought to compare whole-body bone mineral content (BMC) of newborns exposed vs not exposed to tenofovir in utero.

METHODS

We enrolled participants from April 2011 to June 2013 at 14 US clinical sites. Singleton infants of women with human immunodeficiency virus (HIV) infection who took tenofovir in late pregnancy (tenofovir-exposed) or no tenofovir during pregnancy (tenofovir-unexposed) were enrolled during late pregnancy or within 72 hours of birth. Infants born before 36 weeks gestation or with confirmed HIV infection were excluded. Whole-body BMC was measured in the first month of life and compared with that of the tenofovir-exposed and tenofovir-unexposed newborns, unadjusted and adjusted for covariates.

RESULTS

Seventy-four tenofovir-exposed and 69 tenofovir-unexposed infants had evaluable BMC measurements. Tenofovir-exposed mothers were more likely to be married (31% vs 22%; P = .04) and to use boosted protease inhibitors (84% vs 62%; P = .004). Tenofovir-exposed newborns did not differ from unexposed newborns on mean gestational age (38.2 vs 38.1 weeks) or mean length (-0.41 vs -0.18) or weight (-0.71 vs -0.48) Z-scores. The mean (standard deviation) BMC of tenofovir-exposed infants was 12% lower than for unexposed infants (56.0 [11.8] vs 63.8 [16.6] g; P = .002). The adjusted mean bone mineral content was 5.3 g lower (95% confidence interval, -9.5, -1.2; P = .013) in the tenofovir-exposed infants.

CONCLUSIONS

Maternal tenofovir use is associated with significantly lower neonatal BMC. The duration and clinical significance of this finding should be evaluated in longitudinal studies.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov NCT01310023.

Meconium Tenofovir Concentrations and Growth and Bone Outcomes in Prenatally Tenofovir Exposed HIV-Uninfected Children

BACKGROUND

Maternal tenofovir disoproxil fumarate (TDF) treatment among HIV-infected pregnant women results in fetal tenofovir (TFV) exposure. Fetal TFV toxicity was demonstrated in animals, but most clinical investigations have not observed toxicity in humans.

METHODS

We evaluated HIV-exposed, uninfected infants in the Surveillance Monitoring for Antiretroviral Therapy Toxicities cohort of the Pediatric HIV/AIDS Cohort Study whose mothers were prescribed TDF for ≥ 8 third trimester weeks. Infant dual-energy X-ray absorptiometry scans were obtained at 0-4 weeks to measure whole body bone mineral content. Meconium TFV concentrations were quantified by liquid chromatography-tandem mass spectrometry.

RESULTS

Fifty-eight TFV-exposed infants had meconium TFV quantified. Detectable concentrations were 11-48,100 ng/g; 3 infants had undetectable concentrations. Maternal TDF prescription duration ranged from 8 to 41 gestational weeks; infant gestational ages were 36-41 weeks. Meconium TFV concentrations were not correlated with TFV exposure duration or timing and did not vary by concomitant prescription of protease inhibitors. Increased meconium TFV concentrations were associated with greater gestational ages (ρ = 0.29, P = 0.03) and lower maternal plasma HIV RNA before delivery (ρ = -0.29, P = 0.04). Meconium TFV concentrations were not associated with infant weight, length (n = 58) or bone mineral content (n = 49).

CONCLUSIONS

For the first time, we explored associations between meconium TFV concentrations and infant growth and bone measurements; we did not observe a meconium concentration-dependent relationship for these infant outcomes. These findings support other clinical research failing to show dose-response relationships for growth and bone outcomes among intrauterine TFV-exposed infants. High meconium TFV concentrations correlated with low maternal viral load, suggesting maternal TDF adherence significantly contributes to meconium TFV concentrations.

Tolerance of the newborn to antiretroviral drug exposure in utero

INTRODUCTION

The prevention of mother-to-child HIV-1 transmission by antiretroviral drug treatment is remarkably effective. The risk of transmission to the child is now almost zero for women optimally treated during pregnancy. The rapid expansion of this prophylactic treatment has led the World Health Organization to aspire to the virtual elimination of mother-to-child transmission and pediatric AIDS over the next few years. In 2014, more than 900,000 women worldwide were treated with antiretroviral drugs during pregnancy. The issue of fetal and neonatal antiretroviral drug tolerance is therefore extremely important.

AREAS COVERED

This review focuses on the possible impact of in utero exposure to antiretroviral drug on newborn health. To restrict analysis to this period is justified by the specificities of transplacental drug exposure and fetal vulnerability. Relevant data are available from trials and observational cohorts. The significance of various bio-markers detectable at birth is still unresolved, but merits a careful evaluation. Long-term assessment is associated with various logistical difficulties.

EXPERT OPINION

The health of 'exposed but not infected' children poses no major problem in the immense majority of cases, but a series of biological, clinical and imaging-based warning signs have emerged indicating the need for careful attention to be paid to this issue. Some effects that are straightforward to manage in industrialized countries may have more severe consequences in countries in which access to effective healthcare is limited. Nucleoside/nucleotide analogs are potentially genotoxic to mitochondrial and nuclear DNA, and the principal question to be addressed concerns their potential long-term effects.

Tenofovir during pregnancy in rats: a novel pathway for programmed hypertension in the offspring

OBJECTIVES

To evaluate the occurrence of systemic and renal abnormalities in the offspring of Wistar rats exposed to tenofovir disoproxil fumarate (DF) during pregnancy.

METHODS

Female Wistar rats received a standard diet, with or without addition of tenofovir DF (100 mg/kg diet), 1 week before mating and during pregnancy. Offspring from the tenofovir DF group were placed with an untreated foster mother during breastfeeding and compared with offspring from rats maintained on a standard diet during mating and pregnancy (control). Control and tenofovir DF were followed up at 3 and 6 months of age. Monthly body weight and systolic blood pressure (SBP), glomerular counts, renal function, biochemical parameters, angiotensin II, renal renin angiotensin aldosterone system (RAAS) and renal sodium transporters were analysed.

RESULTS

Tenofovir DF offspring showed lower birth weight compared with the control group. After the third month, growth among the tenofovir DF group experienced a rapid catch-up. SBP increased progressively after the second month of age in the tenofovir DF group. Nephron number did not differ between the groups; however, the tenofovir DF group showed glomerular structural changes. Plasma aldosterone was higher in the tenofovir DF group, associated with a significant increase in renal expression of RAAS. The tenofovir DF rats showed up-regulation of renal sodium transporters and consequently lower urinary sodium excretion.

CONCLUSIONS

This is the first demonstration using an experimental model that maternal exposure to tenofovir DF during gestation results in overactivation of RAAS, up-regulation of renal sodium transporters and hypertension in the offspring.

Pre-exposure prophylaxis of HIV: A right way to go or a long way to go?

Antiretroviral drugs are being tried as candidates for the pre-exposure prophylaxis (PrEP) against HIV for a considerable period, due to their potential for immediate inhibition of viral replication. Discrepancies in the findings called for a critical review of the relevant efforts and their outcomes. A systematic literature search identified 143 eligible articles of which only 5 reported complete findings while another 11 were still on-going. Observed moderate efficacy and good safety profile seemed to identify PrEP as a promising step for minimizing the spread of HIV to relatively unaffected population and controlling the epidemic among high risk population groups. But the duration of this efficacy was found to depend heavily on the availability, adherence and other related issues like cost, political commitment, ethical consideration etc. To prevent potential cultural and behavioral modifications, proper pre-administration counseling also seemed critical for the success of PrEP as a cost-effective intervention with adequate coverage.

Metabolic complications of in utero maternal HIV and antiretroviral exposure in HIV-exposed infants

BACKGROUND

Despite a wide body of literature supporting the use of antenatal antiretrovirals (ARV) for the prevention of mother-to-child transmission, there remains a need for continued monitoring as the intrauterine interval is a critical period during which fetal programming influences the future health and development of the child.

METHODS

We conducted a systematic review of the current literature addressing potential metabolic complications of in utero HIV and ARV exposure. We describe studies evaluating metabolic outcomes such as intrauterine and early postnatal growth, bone health and mitochondrial toxicity.

RESULTS

Overall, infants exposed to HIV/ARV do not appear to exhibit vastly compromised intrauterine or early postnatal growth. However, some studies on the effect of combination antiretroviral therapy on small for gestational age and low birth weight outcomes in low-middle income countries show a risk for small for gestational age/low birth weight while those in the United States do not. Postnatal growth to 1 year does not appear to be affected by intrauterine tenofovir exposure in African studies, but a US study found statistically significant differences in length for age z scores (LAZ) at 1 year. Little data exists on long-term bone health. Mitochondrial toxicity including abnormal mitochondrial morphology and DNA content, as well as neurologic deficits and death, have been demonstrated in HIV/ARV-exposed infants.

CONCLUSION

Although gross measures of metabolic well-being appear to be reassuring, careful vigilance of even small risks for potential serious adverse effects to infants exposed to intrauterine HIV/ARVs is warranted as intrauterine fetal metabolic programming may substantially impact the future health of the child.

Age- and gender-associated changes in the concentrations of serum TGF-1β, DHEA-S and IGF-1 in healthy captive baboons (Papio hamadryas anubis)

Age-related changes in the concentration of factors like TGF-1β, DHEA-S and IGF-1 may increase the risk of disease and illnesses in advanced life. A better understanding of these changes would aid in the development of more appropriate treatments and/or preventative care for many conditions associated with age. Due to their similar immune system and vulnerability to pathogens, baboons are an ideal model for humans. However, little research has been done examining the general effects of age in baboons. Therefore, we wanted to further examine the effects of aging in baboons by determining the age-dependent changes in serum TGF-1β, DHEA-S and IGF-1 concentrations. Blood samples were collected during routine health checks in 113-118 captive baboons. In addition, longitudinal samples from 23 to 27 adult individuals were collected an average of 10.7years apart. Both age and gender influenced the concentrations of serum TGF-1β and IGF-1. When both genders were analyzed together, TGF-1β increased 16.1% as adults, compared to younger and older animals, but male and female baboons showed a slightly different temporal pattern of change. IGF-1 decreased with increasing age and males had a 30% greater concentration of IGF-1 than did females. While there was no effect of gender among our population, serum DHEA-S was negatively correlated with age, decreasing by 51.6% in the oldest animals. There were no effects of age or gender on serum IGFBP-3. In longitudinal samples collected from the same individuals, the concentrations of TGF-1β, DHEA-S and IGF-1 were reduced with age. The results presented herein provide additional knowledge of the aging process in baboons and further validate the use of this species as an appropriate model for aging in humans.

Infant growth outcomes after maternal tenofovir disoproxil fumarate use during pregnancy

OBJECTIVE

To determine whether maternal use of tenofovir disoproxil fumarate for treatment of HIV in pregnancy predicts fetal and infant growth.

METHODS

The study population included HIV-uninfected live-born singleton infants of mothers enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group protocol P1025 (born 2002-2011) in the United States and exposed in utero to a combined (triple or more) antiretroviral regimen. Infant weight at birth and 6 months was compared between infants exposed and unexposed to tenofovir in utero using 2-sample t test, χ test, and multivariable linear and logistic regression models, including demographic and maternal characteristics.

RESULTS

Among 2025 infants with measured birth weight, there was no difference between those exposed (N = 630, 31%) versus unexposed to tenofovir in mean birth weight (2.75 vs. 2.77 kg, P = 0.64) or mean gestational age- and sex-adjusted birth weight z-score (WASZ) (0.14 vs. 0.14, P = 0.90). Among 1496 infants followed for 6 months, there was no difference in mean weight at 6 months between tenofovir-exposed (N = 457, 31%) and tenofovir-unexposed infants (7.64 vs. 7.59 kg, P = 0.52) or in mean WASZ (0.29 vs. 0.26, P = 0.61). Tenofovir exposure during the second/third trimester, relative to no exposure, significantly predicted underweight (WASZ < 5%) at age 6 months [odds ratio (95% confidence interval): 2.06 (1.01 to 3.95), P = 0.04]. Duration of tenofovir exposure did not predict neonatal or infant growth.

CONCLUSIONS

By most measures, in utero exposure to tenofovir did not significantly predict infant birth weight or growth through 6 months of age.

Safety of tenofovir during pregnancy for the mother and fetus: a systematic review

Tenofovir disoproxil fumarate (TDF) safety during pregnancy has important public health implications. This review summarizes TDF safety during pregnancy, focusing on pregnancy outcomes, congenital anomaly risk, and other potential toxicities on neonates. Although information is limited, TDF appears to be safe during pregnancy. In 6 studies of human immunodeficiency virus type 1 (and/or hepatitis B virus)-infected women receiving TDF during pregnancy, adverse events were mild to moderate; none were considered to be TDF-related. Five studies that followed in utero TDF-exposed infants showed no increased risk of growth or bone abnormalities. One study showed slightly lower infant height at age 1 year, but the significance is unclear. The Antiretroviral Pregnancy Registry database, with 1800 pregnancies exposed to TDF in the first trimester, does not indicate increased congenital anomaly risk with TDF exposure. More evidence collected prospectively, ideally with bone density measurements and randomized trial design, will be optimal to determine the effects of antenatal TDF exposure on children's health.

The pharmacokinetics, safety and efficacy of tenofovir and emtricitabine in HIV-1-infected pregnant women

OBJECTIVE

To describe the pharmacokinetics of tenofovir and emtricitabine in the third trimester of pregnant HIV-infected women and at postpartum.

DESIGN

A nonrandomized, open-label, multicentre phase IV study in HIV-infected pregnant women recruited from HIV treatment centres in Europe.

METHODS

HIV-infected pregnant women treated with the nucleotide/nucleoside analogue reverse transcriptase inhibitors (NRTIs) tenofovir disoproxil fumarate (TDF 300 mg; equivalent to 245 mg tenofovir disoproxil) and/or emtricitabine (FTC 200 mg) were included in the study. Twenty-four-hour pharmacokinetic curves were recorded in the third trimester (preferably week 33) and postpartum (preferably week 4-6). Collection of a cord blood sample and maternal sample at delivery was optional. Pharmacokinetic parameters were calculated using WinNonlin software version 5.3. Statistical analysis was conducted using SPSS version 16.0.

RESULTS

Thirty-four women were included in the analysis. Geometric mean ratios of third trimester vs. postpartum [90% confidence interval (CI)] were 0.77 (0.71-0.83) for TDF area under the curve (AUC0-24 h); 0.81 (0.68-0.96) for TDF Cmax and 0.79 (0.70-0.90) for TDF C24 h and 0.75 (0.68-0.82) for FTC AUC0-24 h; and 0.87 (0.77-0.99) for FTC Cmax and 0.77 (0.52-1.12) for FTC C24 h. The viral load close to delivery was less than 200  copies/ml in all but one patient, the average gestational age at delivery was 38 weeks. All children were tested HIV-negative and no congenital abnormalities were reported.

CONCLUSION

Although pharmacokinetic exposure of the NRTIs TDF and FTC during pregnancy is approximately 25% lower, this was not associated with virological failure in this study and did not result in mother-to-child transmission.

Chronic hepatitis B virus infection and pregnancy

Planning of pregnancy and management of chronic hepatitis B virus during pregnancy includes recognition of maternal virological status, assessment of liver disease severity and minimization of risk for mother to infant transmission of infection. Decisions regarding the use of antivirals during pregnancy need to be individualized. Monitoring for infection and immunization in newborns is also important. For mothers on antiviral therapy, breastfeeding is not recommended.

Reduced bone mineral density among HIV-infected patients in Taiwan: prevalence and associated factors

BACKGROUND

Reduced bone mineral density (BMD) is an emerging threat to the successful long-term management of human immunodeficiency virus (HIV) infection among patients with access to combination antiretroviral therapy (cART). Data on the prevalence and associated factors of reduced BMD in Asian populations remain scarce.

METHODS

From March 2002 to April 2006, a cross-sectional survey was conducted among HIV-infected patients aged ≥ 20 years at the National Taiwan University Hospital. BMD of the lumbar spine was measured with the use of dual-energy X-ray absorptiometry. Osteopenia was defined as a BMD T-score between -1.0 and -2.5, and osteoporosis was defined as a BMD T-score ≤ -2.5. Linear and ordinal logistic regression analyses were performed.

RESULTS

Among 320 patients with a median age of 37.3 years, body mass index (BMI) of 21.4kg/m(2) and 94.4% on cART, osteopenia and osteoporosis were diagnosed in 35.6% and 3.8%, respectively. On multivariate linear analysis, factors associated with reduced BMD were increasing age (p=0.006), longer duration on antiretroviral therapy (p=0.007), and a decreasing BMI (p=0.002). Using ordinal logistic regression, being underweight with a body mass index (BMI)<18.5kg/m(2) was independently associated with reduced BMD (proportional odds ratio, 4.12; 95% confidence interval, 1.93-8.82).

CONCLUSION

Reduced BMD was prevalent among HIV-infected Taiwanese adults on cART. Increased age, lower BMI, and exposure to antiretroviral therapy were significantly associated with decrease of BMD.

Hepatitis B in pregnancy

Chronic hepatitis B virus (HBV) infection affects about 350 million individuals worldwide. Management of HBV infection in pregnancy is difficult because of several peculiar and somewhat controversial aspects. The aim of the present review is to provide a tool that may help physicians to correctly manage HBV infection in pregnancy. This review focuses on (1) the effect of pregnancy on HBV infection and of HBV infection on pregnancy; (2) the potential viral transmission from mother to newborn despite at-birth prophylaxis with immunoglobulin and vaccine; (3) possible prevention of mother-to-child transmission through antiviral drugs, the type of antiviral drug to use considering their efficacy and potential teratogenic effect, and the timing of their administration and discontinuation; and (4) the evidence for the use of elective caesarean section vs vaginal delivery and the possibility of breastfeeding.

Tenofovir disoproxil fumarate for prevention of vertical transmission of hepatitis B virus infection by highly viremic pregnant women: a case series

BACKGROUND

Despite appropriate immunoprophylaxis, up to 10 % of infants born to highly viremic hepatitis B virus (HBV-DNA ≥ 7 log IU/mL) mothers are infected with HBV. Use of TDF to prevent vertical transmission (VT) by such mothers has not been evaluated.

PURPOSE

To evaluate the efficacy and safety of TDF in preventing VT from highly viremic HBV-infected mothers.

METHODS

Data were collected retrospectively from HBV mono-infected, hepatitis B e antigen (HBeAg) positive, pregnant women between 6/2008 and 11/2010. Cases enrolled were HBV mono-infected mothers who received TDF (300 mg orally once a day) in the third trimester. Those with pregnancy complications or an abnormal fetus on sonography were excluded from use of TDF. All infants received hepatitis B immunoglobulin and vaccination at birth and subsequently.

RESULTS

Eleven Asian mothers received TDF at the median gestational age of 29 (28-32) weeks and the median duration of TDF use before delivery was 10 (7-12) weeks. A significant reduction in serum HBV-DNA was achieved at delivery compared with baseline (mean 5.25 ± 1.79 vs. 8.87 ± 0.45 log(10) copies/mL, respectively; p < 0.01). Three had serum ALT levels more than 1.5 times the upper limit of normal and two of these normalized before delivery. The 11 infants were born with no obstetric complication or birth defects. Five infants were breastfed. All infants were hepatitis B surface antigen negative 28-36 weeks after birth.

CONCLUSION

Our preliminary data suggest that TDF use in the third trimester is safe, and effectively prevents VT of HBV from high viremic HBeAg-positive mothers.

Safety of tenofovir use during pregnancy: early growth outcomes in HIV-exposed uninfected infants

OBJECTIVE

To evaluate the association of tenofovir disoproxil fumarate (TDF) use during pregnancy with early growth parameters in HIV-exposed, uninfected (HEU) infants.

DESIGN

US-based prospective cohort study of HEU children to examine potential adverse effects of prenatal TDF exposure.

METHODS

We evaluated the association of maternal TDF use during pregnancy with small for gestational age (SGA); low birth weight (LBW, <2.5 kg); weight-for-age z-scores (WAZ), length-for-age z-scores (LAZ), and head circumference-for-age (HCAZ) z-scores at newborn visit; and LAZ, HCAZ, and WAZ at age 1 year. Logistic regression models for LBW and SGA were fit, adjusting for maternal and sociodemographic factors. Adjusted linear regression models were used to evaluate LAZ, WAZ, and HCAZ by TDF exposure.

RESULTS

Of 2029 enrolled children with maternal antiretroviral information, TDF was used by 449 (21%) HIV-infected mothers, increasing from 14% in 2003 to 43% in 2010. There was no difference between those exposed to combination regimens with vs. without TDF for SGA, LBW, and newborn LAZ and HCAZ. However, at age 1 year, infants exposed to combination regimens with TDF had significantly lower adjusted mean LAZ and HCAZ than those without TDF (LAZ: -0.17 vs. -0.03, P=0.04; HCAZ: 0.17 vs. 0.42, P=0.02).

CONCLUSION

TDF use during pregnancy was not associated with increased risk for LBW or SGA. The slightly lower mean LAZ and HCAZ observed at age 1 year in TDF-exposed infants are of uncertain significance but underscore the need for additional studies of growth outcomes after TDF use during pregnancy.

Pregnancy and infant outcomes among HIV-infected women taking long-term ART with and without tenofovir in the DART trial

BACKGROUND

Few data have described long-term outcomes for infants born to HIV-infected African women taking antiretroviral therapy (ART) in pregnancy. This is particularly true for World Health Organization (WHO)-recommended tenofovir-containing first-line regimens, which are increasingly used and known to cause renal and bone toxicities; concerns have been raised about potential toxicity in babies due to in utero tenofovir exposure.

METHODS AND FINDINGS

Pregnancy outcome and maternal/infant ART were collected in Ugandan/Zimbabwean HIV-infected women initiating ART during The Development of AntiRetroviral Therapy in Africa (DART) trial, which compared routine laboratory monitoring (CD4; toxicity) versus clinically driven monitoring. Women were followed 15 January 2003 to 28 September 2009. Infant feeding, clinical status, and biochemistry/haematology results were collected in a separate infant study. Effect of in utero ART exposure on infant growth was analysed using random effects models. 382 pregnancies occurred in 302/1,867 (16%) women (4.4/100 woman-years [95% CI 4.0-4.9]). 226/390 (58%) outcomes were live-births, 27 (7%) stillbirths (≥22 wk), and 137 (35%) terminations/miscarriages (<22 wk). Of 226 live-births, seven (3%) infants died <2 wk from perinatal causes and there were seven (3%) congenital abnormalities, with no effect of in utero tenofovir exposure (p>0.4). Of 219 surviving infants, 182 (83%) enrolled in the follow-up study; median (interquartile range [IQR]) age at last visit was 25 (12-38) months. From mothers' ART, 62/9/111 infants had no/20%-89%/≥90% in utero tenofovir exposure; most were also zidovudine/lamivudine exposed. All 172 infants tested were HIV-negative (ten untested). Only 73/182(40%) infants were breast-fed for median 94 (IQR 75-212) days. Overall, 14 infants died at median (IQR) age 9 (3-23) months, giving 5% 12-month mortality; six of 14 were HIV-uninfected; eight untested infants died of respiratory infection (three), sepsis (two), burns (one), measles (one), unknown (one). During follow-up, no bone fractures were reported to have occurred; 12/368 creatinines and seven out of 305 phosphates were grade one (16) or two (three) in 14 children with no effect of in utero tenofovir (p>0.1). There was no evidence that in utero tenofovir affected growth after 2 years (p = 0.38). Attained height- and weight for age were similar to general (HIV-uninfected) Ugandan populations. Study limitations included relatively small size and lack of randomisation to maternal ART regimens.

CONCLUSIONS

Overall 1-year 5% infant mortality was similar to the 2%-4% post-neonatal mortality observed in this region. No increase in congenital, renal, or growth abnormalities was observed with in utero tenofovir exposure. Although some infants died untested, absence of recorded HIV infection with combination ART in pregnancy is encouraging. Detailed safety of tenofovir for pre-exposure prophylaxis will need confirmation from longer term follow-up of larger numbers of exposed children.

TRIAL REGISTRATION

www.controlled-trials.com ISRCTN13968779

In utero exposure to tenofovir disoproxil fumarate does not impair growth and bone health in HIV-uninfected children born to HIV-infected mothers

BACKGROUND

Growth impairment and bone toxicity due to tenofovir disoproxil fumarate (TDF) fetal exposure has been described mainly in animals. We evaluated growth pattern and bone health in TDF-exposed HIV-uninfected children born to HIV-infected mothers, defined as seroreverters (SR).

METHODS

This was a multicentre observational cross-sectional cohort study enrolling 68 SR who were in utero exposed to an antiretroviral regimen including (TDF+) or not including (TDF-) tenofovir. Neonatal data and duration of antiretroviral exposure were recorded. At enrolment, anthropometric measures, tibial speed of sound (SOS) by quantitative ultrasound and several parameters of bone metabolism were assessed.

RESULTS

Gestational age and median in utero antiretroviral exposure were similar in subjects exposed to TDF (n=33) and those non-exposed (n =35). Age at enrolment was comparable in the two groups (TDF-exposed range 11.8-76.2 months and TDF non-exposed range 11.8-77.9 months). The incidence of low weight and length measurements (<10th percentiles) at birth was similar in TDF-exposed and TDF non-exposed. Normal growth development was found in both groups of subjects at enrolment. The median (0.6; range -2.4-2.6) SOS z-score of TDF-exposed was similar to the median (0.8; range -2.2-4.4) SOS z-score of TDF non-exposed (Student's t=0.84; P=0.40). Parameters of bone metabolism were similar in the two groups.

CONCLUSIONS

Exposure to TDF during pregnancy does not impair growth patterns, bone health and markers of bone metabolism in SR infants and young children born to HIV-infected women.

Antiviral therapy for hepatitis B infection during pregnancy and breastfeeding

It is estimated there are 350-400 million people worldwide chronically infected with HBV. Many of these are women and of reproductive age. As such, they may face therapeutic decisions regarding antiviral therapy and the implication this may have on future or current pregnancies. This article reviews the data of all antivirals licensed for use against hepatitis B infection regarding teratogenicity, carcinogenicity, clinical experience during pregnancy, placental transfer and excretion in breast milk.

Exposure to antiretroviral agents during pregnancy does not alter bone status in infants

The use of combined antiretroviral agents during pregnancy is important to prevent mother-to-child transmission of human immunodeficiency virus (HIV). Antiretroviral treatment (ARV) is associated with reduced bone mass and altered bone metabolism in HIV-infected patients. There are no data regarding the effect of ARV exposure during pregnancy on newborns and infants. We therefore studied 38 subjects born from HIV-infected mothers, and we measured the speed-of-sound (SOS) at the tibia by quantitative ultrasonography (QUS) just after birth. QUS measurements at mid-tibia is easily performed in infants with the appropriate probe. Nevertheless, at this skeletal site only cortical bone is present, and therefore QUS measurements reflect the status of only one kind of bone tissue. We also measured bone alkaline phosphatase (BAP) and C-terminal telopeptide of type I collagen (CTX) in the cord blood as bone formation and resorption markers, respectively. SOS measurements were repeated at 4 and 12 months of age. As a control group we studied 94 subjects born from HIV-negative mothers. At birth the median (range) SOS of ARV-exposed neonates was 3006 (2870-3168) m/s, while that of control subjects was 3007 (2757-3311) m/s. The difference was not significant. BAP concentration of ARV-exposed was 103.6 (31.6-182.8) U/L, not different from that of control subjects (104.4 [43.2-227.2] U/L). CTX concentrations were 1.07 (0.26-2.8) ng/mL, and 1.38 (0.34-4.2) ng/mL in ARV-exposed and control subjects, respectively. SOS measurements at 4 months and 12 months of age were available for 17 ARV-exposed subjects and for 57 control subjects. SOS values changed significantly over time in both groups (F=6.1; P<0.0001). No differences were present between ARV-exposed and control subjects at 4 and 12 months. Our study suggests that ARV exposure during intrauterine life does not affect negatively bone metabolism and bone development, and that the changes occurring in bone QUS measurements during the first year of life in ARV-exposed subjects are similar to those occurring in healthy control infants.

Use of zidovudine-sparing HAART in pregnant HIV-infected women in Europe: 2000-2009

BACKGROUND

Increasing numbers of women in resource-rich settings are prescribed zidovudine (ZDV)-sparing highly active antiretroviral therapy (HAART) in pregnancy. We compare ZDV-sparing with ZDV-containing HAART in relation to maternal viral load at delivery, mother-to-child transmission (MTCT) of HIV, and congenital abnormality.

METHODS

This is an analysis of data from the National Study of HIV in Pregnancy and Childhood and the European Collaborative Study. Data on 7573 singleton births to diagnosed HIV-infected women between January 2000 and June 2009 were analyzed. Logistic regression models were fitted to estimate adjusted odds ratios (AORs).

RESULTS

Overall, 15.8% (1199 of 7573) of women received ZDV-sparing HAART, with increasing use between 2000 and 2009 (P < 0.001). Nearly a fifth (18.4%) of women receiving ZDV-sparing HAART in pregnancy had a detectable viral load at delivery compared with 28.6% of women on ZDV-containing HAART [AOR 0.90; 95% confidence interval (CI): 0.72 to 1.14, P = 0.4]. MTCT rates were 0.8% and 0.9% in the ZDV-sparing and ZDV-containing groups, respectively (AOR 1.81; 95% CI: 0.77 to 4.26, P = 0.2). The congenital abnormality rate was the same in both groups (2.7%, AOR 0.98; 95% CI: 0.66 to 1.45, P = 0.9), with no significant difference between the groups in a subanalysis of pregnancies with first trimester HAART exposure (AOR 0.79; 95% CI: 0.48 to 1.30, P = 0.4).

CONCLUSIONS

We found no difference in risk of detectable viral load at delivery, MTCT, or congenital abnormality when comparing ZDV-sparing with ZDV-containing HAART. With increasing use of ZDV-sparing HAART, continued monitoring of pregnancy outcomes and long-term consequences of in utero exposure to these drugs is required.

In utero and postnatal exposure to antiretrovirals among HIV-exposed but uninfected children in the United States

An increasing number of antiretroviral agents (ARVs) are approved for use, but their use during pregnancy in the United States has not been completely described. We used data from the Pediatric HIV/AIDS Cohort Study (PHACS) Surveillance Monitoring for ART Toxicities (SMARTT) study, a United States-based prospective cohort study of HIV-exposed but uninfected children, to assess temporal trends and maternal characteristics associated with the use of ARVs during pregnancy. The proportion of children exposed in utero to ARVs was calculated over time. A multivariable logistic regression model was used to estimate associations of maternal characteristics with use of highly active antiretroviral therapy (HAART) during pregnancy. We studied 1768 HIV-exposed but uninfected children born between 1995 and 2009 and enrolled in SMARTT. Prenatal HAART exposure increased from 19% in 1997 to 88% in 2009. Of children born in 2009, 99% had prenatal exposure to NRTIs (including zidovudine, 73%; lamivudine, 72%; tenofovir, 39%; and emtricitabine, 37%). Exposure to protease inhibitors increased from 15% in 1997 to 86% in 2009, while exposure to non-nucleoside reverse transcriptase inhibitors (NNRTIs) declined from 33% in 2003 to 11% in 2009. Higher maternal HIV RNA viral load (VL) concentration, lower maternal CD4 count, and earlier timing of the first maternal CD4 or VL measurement during pregnancy were associated with increased odds of HAART exposure. Prenatal HAART exposure has increased but is not universal. As ARV use during pregnancy continues to evolve, follow-up of children is needed to assess long-term effects of ARV exposures.

Antiretroviral pharmacology: special issues regarding pregnant women and neonates

Antiretrovirals may be used in pregnant women infected with the HIV and their newborns both for treatment of maternal HIV disease and for prevention of mother-to-child transmission of HIV. More than 25 antiretroviral agents in 5 classes have been approved, with new drugs and classes in development. This article reviews current knowledge of the pharmacology of these drugs during pregnancy and in the newborn period, highlighting those pharmacologic issues critical to the safe and effective use of antiretrovirals in these populations.

Periconception pre-exposure prophylaxis to prevent HIV transmission: benefits, risks, and challenges to implementation

HIV-serodiscordant couples face complicated choices between fulfilling reproductive desire and risking HIV transmission to their partners and children. Sexual HIV transmission can be dramatically reduced through artificial insemination and sperm washing; however, most couples cannot access these resources. We propose that periconception pre-exposure prophylaxis (PrEP) could offer an important, complementary therapy to harm reduction counseling programs that aim to decrease HIV transmission for couples who choose to conceive. In this paper, we describe the potential benefits of periconception PrEP and define critical points of clarification prior to implementation of PrEP as part of a reproductive health program. We consider sexual transmission risk, current risk reduction options, PrEP efficacy, cost, adherence, resistance, fetal toxicity, and impact of PrEP counseling on entry into health services. We address PrEP in the context of other periconception HIV-prevention strategies, including antiretroviral treatment of the HIV-infected partner. We conclude that, should PrEP prove safe and efficacious in ongoing trials, periconception PrEP may offer a useful approach to minimize risk of HIV transmission for individuals of reproductive age in HIV-endemic countries.

A review of nucleoside reverse transcriptase inhibitor use to prevent perinatal transmission of HIV

Worldwide, women comprise > 50% of all people living with HIV and the vast majority of these women are of childbearing age. In fact, a significant proportion of these women are identified as HIV-infected during pregnancy. Preventing perinatal transmission has been one of the greatest prevention successes of the HIV epidemic with < 2% of live births resulting in an HIV-infected infant. The strategic use of combination antiretroviral therapy has been a critical component of this reduction. With more antiretroviral agents available for HIV, the appropriate selection of therapy is often based on provider familiarity with the various agents. Although benefits of antiretroviral use in pregnancy tremendously outweigh the risks, concerns regarding short- and long-term toxicity in mothers and their children, in addition to the risk of the development of HIV resistance, remain subjects of discussion. The choice of antiretroviral 'backbone' is supported by extensive data showing efficacy in the prevention of HIV vertical transmission. Co-formulated zidovudine/lamivudine is the most commonly used combination in pregnancy. Long-term consequences of in utero exposure to antiretroviral agents are not fully understood. In this article, we review the data regarding nucleoside reverse transcriptase inhibitors with a focus on tenofovir.

Tenofovir disoproxil fumarate in pregnancy and prevention of mother-to-child transmission of HIV-1: is it time to move on from zidovudine?

OBJECTIVES

Zidovudine (ZDV) has been the cornerstone of antiretroviral (ARV) therapy for pregnant women infected with HIV-1 in the prevention of mother-to-child transmission (MTCT) and remains the only licensed ARV for use in pregnancy. We explored the current and future roles of tenofovir disoproxil fumarate (TDF) in the prevention of MTCT of HIV-1.

METHODS

We reviewed the published literature by conducting database searches of in vitro, animal and clinical studies, reported in journals and at conferences, using the search terms Tenofovir/gs4331/viread, pregnant/pregnancy, lactate, lactation, natal, reproduce/reproduction, placenta/placental, malformation, and teratogenicity/teratogenic.

RESULTS

In a macaque model, perinatal exposure to very high dose tenofovir resulted in bone toxicity in some offspring. However, perinatal use of TDF, both single dose and as part of highly active antiretroviral therapy in women, has been well tolerated in the short term by mothers and their infants. Further, the addition of single-dose TDF to single-dose nevirapine (SD-NVP) during delivery following maternal ZDV use during pregnancy significantly reduces the frequency of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance.

CONCLUSIONS

The addition of TDF to SD-NVP reduces NNRTI resistance. The role of TDF in this setting and during pregnancy for reducing rates of MTCT requires investigation. While short-term toxicity data are encouraging, long-term follow-up of exposed mothers and infants is required.

Pharmacologic and nonpharmacologic options for the management of HIV infection during pregnancy

Over the past decade, significant advances have been made in the treatment of HIV-1 infection using both pharmacologic and nonpharmacologic strategies to prevent mother-to-child transmission (MTCT). Optimal prevention of the MTCT of HIV requires antiretroviral drugs (ARV) during pregnancy, during labor, and to the infant. ARVs reduce viral replication, lowering maternal plasma viral load and thus the likelihood of MTCT. Postexposure prophylaxis of ARV agents in newborns protect against infection following potential exposure to maternal HIV during birth. In general, the choice of an ARV for treatment of HIV-infected women during pregnancy is complicated by the need to consider the effectiveness of the therapy for the maternal disease as well as the teratogenic or teratotoxic potential of these drugs. Clinicians managing HIV in pregnancy need to discuss the potential risks and benefits of available therapy options so that mothers can make informed decisions in choosing the best treatment regimen for themselves and for their children.

Adverse effects of tenofovir use in HIV-infected pregnant women and their infants

BACKGROUND

Data regarding use of tenofovir disoproxil fumarate in HIV-infected pregnant women are limited.

OBJECTIVE

To identify adverse effects of tenofovir use during pregnancy in HIV-infected women and their infants.

METHODS

In a retrospective case series, the charts of 127 pregnant HIV-infected women who received highly active antiretroviral therapy (HAART) between 2001 and 2005 were reviewed. Those who received tenofovir during pregnancy were selected for this study. Each woman's chart was reviewed for clinical data and adverse events during the pregnancy; each infant's chart was reviewed for growth parameters from birth to 12 months.

RESULTS

Fifteen HIV-infected women with limited treatment options were prescribed HAART containing tenofovir during 16 pregnancies. In utero tenofovir exposure was a median of 127 days (range 6-259). Tenofovir was well tolerated by all women throughout pregnancy. There were 15 successful deliveries occurring at a median (range) of 36 weeks (30-40), with a median birth weight of 3255 g (1135-3610). Complications, including 1 spontaneous abortion, occurred in 9 pregnancies and were not attributed to tenofovir. Eleven (73%) women had abnormal laboratory results, including 6 who experienced grade 1 hemoglobin abnormalities; 4 of these women had preexisting anemia. Calculated glomerular filtration rate (calculated by Modification of Diet in Renal Disease equation) remained above 90 mL/min/1.73 m(2) in all women, except one who had a transient decline. Fourteen infants demonstrated normal growth and development for weight and height at birth, as well as during the 12-month follow-up period; no congenital malformations were documented. Mother-to-child transmission of HIV was not observed in this cohort.

CONCLUSIONS

Tenofovir was found to be a well-tolerated component of HAART in this small cohort. Longer-term assessment of tenofovir effects on childhood growth and larger prospective studies of tenofovir use in pregnant women are warranted.

Chronic administration of tenofovir to rhesus macaques from infancy through adulthood and pregnancy: summary of pharmacokinetics and biological and virological effects

The reverse transcriptase (RT) inhibitor tenofovir (TFV) is highly effective in the simian immunodeficiency virus (SIV) macaque model of human immunodeficiency virus infection. The current report describes extended safety and efficacy data on 32 animals that received prolonged (>or=1- to 13-year) daily subcutaneous TFV regimens. The likelihood of renal toxicity (proximal renal tubular dysfunction [PRTD]) correlated with plasma drug concentrations, which depended on the dosage regimen and age-related changes in drug clearance. Below a threshold area under the concentration-time curve for TFV in plasma of approximately 10 microg x h/ml, an exposure severalfold higher than that observed in humans treated orally with 300 mg TFV disoproxil fumarate (TDF), prolonged TFV administration was not associated with PRTD based on urinalysis, serum chemistry analyses, bone mineral density, and clinical observations. At low-dose maintenance regimens, plasma TFV concentrations and intracellular TFV diphosphate concentrations were similar to or slightly higher than those observed in TDF-treated humans. No new toxicities were identified. The available evidence does not suggest teratogenic effects of prolonged low-dose TFV treatment; by the age of 10 years, one macaque, on TFV treatment since birth, had produced three offspring that were healthy by all criteria up to the age of 5 years. Despite the presence of viral variants with a lysine-to-arginine substitution at codon 65 (K65R) of RT in all 28 SIV-infected animals, 6 animals suppressed viremia to undetectable levels for as long as 12 years of TFV monotherapy. In conclusion, these findings illustrate the safety and sustained benefits of prolonged TFV-containing regimens throughout development from infancy to adulthood, including pregnancy.

Tenofovir disoproxil fumarate for the treatment of HIV infection

Tenofovir disoproxil fumarate is a nucleotide analogue reverse transcriptase inhibitor approved by the FDA for the treatment of HIV infection. It is a potent agent with a long intracellular half-life that allows for once-daily dosing. It has been well tolerated in clinical trials, without evidence of the mitochondrial toxicity that has been associated with long-term treatment of some of the nucleoside analogue reverse transcriptase inhibitors. Because of its demonstrated efficacy and favourable safety profile, tenofovir disoproxil fumarate has quickly become a favoured nucleoside component of antiretroviral regimens for both treatment-naive and -experienced patients.