Safety of Tenofovir Disoproxil Fumarate Among Breastfeeding Infants of Patients With Chronic Hepatitis B: A Systematic Review

An integral component to achieving worldwide chronic hepatitis B (CHB) elimination is addressing vertical transmission. Guidelines differ in their recommendations for breastfeeding while on tenofovir disoproxil fumarate (TDF). To conduct a systematic review of published studies analysing the concentration of tenofovir (TFV) in the breast milk of mothers receiving TDF and determining infant exposure from breastfeeding. We conducted a systematic literature search of studies evaluating infant safety from the breast milk of breastfeeding mothers receiving TDF for any indication that reported a TFV breast milk concentration. Daily infant exposure was used to calculate the relative dose of TFV in infants. Other pertinent information collected was the concentration of TFV in maternal and infant plasma, the duration of therapy of TDF and the indication for TDF. We identified 10 studies including 443 patients-266 of whom were mothers, and the remaining were infants-that reported the TFV concentration of breast milk in breastfeeding mothers receiving TDF. A total of 654 breast milk samples were included. The mean TFV concentration from all the studies that reported a median concentration of TFV was 4.8 ng/mL (95% CI [3.8, 5.8]). The mean infant exposure of TFV from breast milk was 0.56 μg/kg/day (95% CI [0.44, 0.68]). The mean relative dose was determined to be 0.01% of the weight-based recommended infant dose. Infant plasma levels of TFV were also collected. This was undetectable in a majority of the studies that reported it. Based on the negligible infant exposure of TFV while breastfeeding, from a pharmacologic and toxicity standpoint, maternal dosing of TDF appears safe for breastfeeding infants.

Phosphaturia in HIV-Exposed Uninfected Neonates Associated with Maternal Use of Tenofovir Disoproxil Fumarate in Late Pregnancy

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is often used in treating pregnant women living with HIV. Third-trimester TDF exposure is associated with a 12% reduction in bone mineral content in HIV-exposed uninfected (HEU) neonates. The potential mechanisms underlying this observation are unknown.

METHODS

The TDF study enrolled newborns of gestational age ≥36 weeks from the Surveillance Monitoring for Antiretroviral Therapy and Toxicities study based on in utero TDF exposure (TDF use ≥8 weeks in the third trimester vs none). Blood and urine samples were collected cross-sectionally within 30 days of birth to assess renal function (serum creatinine, serum phosphate, eGFR, percent tubular reabsorption of phosphate [PTRP]), and bone turnover (serum parathyroid hormone, 25-OH vitamin D [25(OH)D], and urinary cross-linked N-telopeptide of type 1 collagen). For each biomarker, a LOESS plot was fit using values at age at specimen collection; regression lines over age were fit among samples collected from 4 to 30 days, to compare slopes by TDF exposure.

RESULTS

Among 141 neonates, 77 were TDF-exposed and 64 TDF-unexposed. Between age 4 and 30 days, PTRP decreased more rapidly in the TDF-exposed compared to the unexposed group with slopes of -0.58 vs -0.08/day (difference -0.50/day [95% CI -0.88, -0.11]). Slopes for 25(OH)D were similar in both groups, but serum levels were lower in TDF-exposed neonates (median [IQR]: 22 [19, 29] vs 26 [22, 37] ng/mL). No differences were observed for other biomarkers.

CONCLUSIONS

Third-trimester in utero exposure to TDF is associated with increased urinary loss of phosphate and lower serum concentrations of 25(OH)D in HEU neonates.

Safety review of tenofovir disoproxil fumarate/emtricitabine pre-exposure prophylaxis for pregnant women at risk of HIV infection

Introduction: Pregnancy is a period of elevated HIV risk in high-burden settings, motivating the need for prevention tools that are both safe for use and effective during pregnancy. Oral pre-exposure prophylaxis (PrEP) containing tenofovir disoproxil fumarate (TDF) is recommended by the World Health Organization, including for pregnant and postpartum women at substantial risk of HIV infection. Although TDF use during pregnancy appears generally safe, data on PrEP use during pregnancy remain limited.Areas covered: We provide an overview of the clinical pharmacology and efficacy of daily TDF-based PrEP and summarize current evidence on the safety of PrEP use by pregnant HIV-uninfected women. We synthesize relevant studies assessing pregnancy outcomes among pregnant women who are living with HIV (WLHIV) and using TDF-based therapy. Finally, we make comparison to the safety profiles of other emerging HIV prevention options.Expert opinion: The current evidence indicates that TDF/FTC PrEP use is not associated with increased risk of adverse pregnancy and early infant growth outcomes. While safety data are generally reassuring, there is need for continued accrual of data on growth and pregnancy outcomes in PrEP research, implementation projects, and controlled pharmacokinetic studies to support current evidence and to understand concentration-efficacy relationship in pregnant women.

Differences in Growth of HIV-exposed Uninfected Infants in Ethiopia According to Timing of In-utero Antiretroviral Therapy Exposure

BACKGROUND

There are concerns about the adverse effect of in-utero exposure to antiretroviral therapy (ART) on the growth of HIV exposed-uninfected (HEU) infants. We compared growth of HEU-infants according to the timing and type of ART exposure.

METHODS

A retrospective cohort study was conducted by abstracting clinical data from HIV-infected mothers and HEU-infants in Addis Ababa, Ethiopia between February 2013 and October 2016. Mixed-effects linear models were used to compare changes in weight and length and cox proportional hazard models were used to evaluate stunting (length-for-age z score <-2.0) and underweight (weight-for-age z score <-2.0).

RESULTS

A total of 624 HEU-infants were included in the analyses. Infants exposed to ART from conception had a lower rate of change in length [β = -0.54, 95% confidence interval (CI): -1.00 to -0.08] the first 3 months of life, as compared with infants exposed from late pregnancy. Risk of stunting was 51.9 per 100 person-years and risk of underweight was 26.7 per 100 person-years. Exposure to ART from conception was associated with a higher rate of stunting as compared with exposure from late pregnancy (adjusted hazard ratio = 1.95, 95% CI: 1.27-2.99). Infants born to mothers with advanced disease had a higher incidence of underweight compared with infants born to mothers with early-stage disease adjusted hazard ratio = 1.99, 95% CI: 1.32-3.03).

CONCLUSIONS

In HEU-infants, exposure to ART from conception was associated with decrease growth during early infancy and higher incidence of stunting compared with treatment exposure later in pregnancy. Close monitoring of HEU-infants' growth and prompt nutritional intervention is essential.

Long-term growth and bone development in children of HBV-infected mothers with and without fetal exposure to tenofovir disoproxil fumarate

BACKGROUND & AIMS

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent maternal transmission of HBV, owing to its efficacy and safety. However, data are lacking on the long-term safety outcomes in children following fetal exposure to TDF.

METHODS

Children participating in a prospective, multisite trial of maternal TDF treatment during late pregnancy were recruited for follow-up visits once a year. Growth parameters, serum biochemistry, HBV serology, and bone mineral density (BMD) by dual-energy x-ray absorptiometery scan were measured.

RESULTS

One hundred and twenty-eight children, 71 in the TDF and 57 in the control group, completed 255 follow-up visits at the age of 2 to 7 (median, 4.08) years. No differences in z-scores for weight-for-age (0.26 ± 0.90 vs. 0.22 ± 0.99, p = 0.481), z-scores for height-for-age (0.20 ± 1.02 vs. 0.25 ± 0.98, p = 0.812), and estimated glomerular filtration rate (169.12 ± 50.48 vs. 169.06 ± 34.46 ml/min/1.73m², p = 0.479) were detected. After adjustment for age, sex and HBV status by multiple linear regression, children in the TDF and control group had comparable levels of serum calcium, phosphorus, bone-specific alkaline phosphatase, calcidiol and BMD of lumbar spines (0.55 ± 0.01 vs. 0.57 ± 0.01 g/cm², p = 0.159) and left hip (0.56 ± 0.01 vs. 0.56 ± 0.01 g/cm², p = 0.926).

CONCLUSIONS

Children of HBV-infected mothers who did or did not receive tenofovir disoproxil fumarate treatment during late pregnancy had comparable long-term growth, renal function, and bone development up to 6-7 years after delivery.

CLINICAL TRIAL NUMBER

NCT01312012 (ClinicalTrials.gov) LAY SUMMARY: Currently there are insufficient long-term safety data in children born to mothers who took antiviral agents during pregnancy to prevent mother-to-infant transmission of hepatitis B virus (HBV). In this study, we found that children of HBV-infected mothers who did or did not receive tenofovir disoproxil fumarate treatment during late pregnancy had comparable long-term growth, renal function, and bone development up to 6-7 years after delivery.

PrEP uptake preferences among men who have sex with men in China: results from a National Internet Survey

INTRODUCTION

HIV incidence among men who have sex with men (MSM) is high in China. Pre-exposure prophylaxis (PrEP) is a promising mean to prevent HIV transmission but it is not widely available in China. We conducted a large Internet-based online survey to assess the willingness of Chinese MSM to take PrEP and associated factors to their uptake preferences.

METHODS

Between 19 January and 6 February, 2017, 4581 MSM aged over 15 years were recruited via a social networking app to take an online PrEP survey. HIV status at the time of the survey being conducted was not one of recruitment criteria. Participants were asked if they had heard of PrEP, if they had concerns about PrEP, and if they would be ready to uptake PrEP should it be provided. When asked if participants were willing to take PrEP, they were asked to select from the following responses: "definitely not," "probably not," "not sure," "probably yes," and "definitely yes." In the final analysis, we grouped these five-level Likert scale responses into three-level responses as "definitely yes," "probably yes," and "no (definitely not/probably not/not sure)." Descriptive analysis and multinomial logistic regressions were conducted to assess the associations of PrEP adoption readiness and uptake concerns with HIV risk behaviours and demographic characteristics.

RESULTS

MSM from 33 geographical regions of China participated in the survey. The majority were younger than 25 (65.2%) and had attended college (68.6%). HIV prevalence was high (6.8%) and 43.3% reported a history of unprotected anal sex. Only 22.4% of participants had heard of PrEP. When asked if they would uptake PrEP, 26.0% said "definitely yes," 49.6% were "probably yes," and 24.4% said "no." PrEP adoption readiness was associated with having previously heard of PrEP and expressing concerns about accessibility and cost. Worries about side effects, low perceived HIV risk, preference for condoms, and never having received HIV testing were negatively associated with PrEP uptake willingness.

CONCLUSION

Young and well-educated Chinese MSM reported a low willingness to uptake PrEP despite being high-risk for HIV. Effective education, especially through online mediums, will be critical to optimize this group's PrEP uptake.

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.