Toward a universal antiretroviral regimen: special considerations of pregnancy and breast feeding

Lower birth weight-for-age and length-for-age z-scores in infants with in-utero HIV and ART exposure: a prospective study in Cape Town, South Africa

Background

Successful scale-up of antiretroviral therapy (ART) during pregnancy has minimized infant HIV acquisition, and over 1 million infants are born HIV-exposed but uninfected (HEU), with an increasing proportion also exposed in utero to maternal ART. While benefits of ART in pregnancy outweigh risks, some studies have reported associations between in utero ART exposure and impaired fetal growth, highlighting the need to identify the safest ART regimens for use in pregnancy.

Methods

We compared birth anthropometrics of infants who were HEU with those HIV-unexposed (HU) in Cape Town, South Africa. Pregnant women had gestational age assessed by ultrasound at enrolment. Women living with HIV were on ART (predominately tenofovir-emtricitabine-efavirenz) either prior to conception or initiated during pregnancy. Birth weights and lengths were converted to weight-for-age (WAZ) and length-for-age (LAZ) z-scores using Intergrowth-21st software. Linear regression was used to compare mean z-scores adjusting for maternal and pregnancy characteristics.

Results

Among 888 infants, 49% (n = 431) were HEU and 51% (n = 457) HU. Of 431 HEU infants, 62% (n = 268) were exposed to HIV and antiretrovirals (ARVs) from conception and 38% (n = 163) were exposed to ARVs during gestation but after conception (median fetal ARV exposure of 21 weeks [IQR; 17–26]). In univariable analysis, infants who were HEU had lower mean WAZ compared with HU [β = − 0.15 (95% Confidence Interval (CI): − 0.28, − 0.020)]. After adjustment for maternal age, gravidity, alcohol use, marital and employment status the effect remained [adjusted β − 0.14 (95%CI: − 0.28, − 0.01]. Similar differences were noted for mean LAZ in univariable [β − 0.20 (95%CI: − 0.42, − 0.01] but not multivariable analyses [adjusted β − 0.18 (95%CI: − 0.41, + 0.04] after adjusting for the same variables. Mean WAZ and LAZ did not vary by in utero ARV exposure duration among infants who were HEU.

Conclusion

In a cohort with high prevalence of ART exposure in pregnancy, infants who were HEU had lower birth WAZ compared with those HU. Studies designed to identify the mechanisms and clinical significance of these disparities, and to establish the safest ART for use in pregnancy are urgently needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03836-z.

Darunavir Pharmacokinetics With an Increased Dose During Pregnancy

BACKGROUND

This study aims to evaluate the pharmacokinetics of an increased dose of darunavir (800 mg twice daily) with 100 mg ritonavir during pregnancy and postpartum.

METHODS

Darunavir (DRV) and ritonavir (RTV; r) intensive pharmacokinetic evaluations were performed at steady state during the second and third trimesters of pregnancy (DRV/r 800/100 mg bid) and 2-3 weeks postpartum (DRV/r 600/100 mg twice daily). Plasma concentrations of darunavir and ritonavir were measured using high-performance liquid chromatography. Target darunavir area under the concentration time curve (AUC) was >70% (43.6 μg × h/mL) of median AUC (62.3 μg × h/mL) in nonpregnant adults on twice daily darunavir-ritonavir 600/100 mg.

RESULTS

Twenty-four women were included in the analysis. Darunavir AUC0-12 was lower with the increased dose during the second {[geometric mean ratio (GMR) of 0.62 (IQR 0.44-0.88); P = 0.055]} and third trimesters [GMR 0.64 (IQR 0.55-0.73); P = <0.001] compared with postpartum. Darunavir apparent clearance was higher during the second [GMR 1.77 (IQR 1.24-2.51); P = 0.039] and third trimesters [GMR 2.01 (IQR 1.17-2.35); P = <0.001] compared with postpartum. Similarly, ritonavir AUC0-12 was lower during the third trimester [GMR 0.65 (IQR 0.52-0.82); P = 0.007] compared with postpartum, whereas its apparent clearance was higher during the third trimester [GMR 1.53 (IQR 1.22-1.92); P = 0.008] compared with postpartum. No major drug-related safety concerns were noted.

CONCLUSIONS

Increasing darunavir dose to 800 mg BID failed to significantly increase darunavir exposure compared with 600 mg BID. Other strategies, such as increasing the ritonavir dose should be investigated.

Safety of in-utero antiretroviral exposure: neurologic outcomes in children who are HIV-exposed but uninfected

OBJECTIVE

To evaluate whether there is an increased risk of neurologic diagnoses in children who are HIV-exposed but uninfected (CHEU) exposed in utero to specific antiretroviral medications.

DESIGN

Prospective cohort study of CHEU enrolled from 2007 to 2017.

METHODS

We evaluated children for neurologic case status, including microcephaly, febrile seizures, seizure disorders, ophthalmologic disorders, and other neurologic disorders. Adjusted relative risks (aRRs) were estimated for the association between in-utero antiretroviral exposure and neurologic case using log-binomial regression, accounting for potential confounders. Sensitivity analyses were conducted to evaluate robustness of findings.

RESULTS

Among 3747 eligible CHEU, 231 (6.2%) met neurologic case criteria (95% CI 5.4--7%). Most eligible children (86%) were exposed in utero to combination antiretroviral regimens. In adjusted models, children exposed to efavirenz at any time during pregnancy had higher risk of neurologic case status (aRR = 1.53, 95% CI 0.94--2.51). This association was stronger when comparing efavirenz exposure at conception to no exposure during pregnancy (aRR = 1.92, 95% CI 1.09--3.36) and considering follow-up and case diagnosis only through age 2 (aRR = 2.14, 95% CI 1.11--4.12). Children exposed to didanosine at conception and during the first trimester had increased risk of neurologic case status (aRR = 2.28, 95% CI 1.07--4.87 and aRR = 2.02, 95% CI 1.01--4.04, respectively), compared with didanosine-unexposed children. Children with dolutegravir exposure had some suggestion of increased risk of neurologic case (aRR = 2.43, 95% CI 0.75--7.84), which was observed consistently across several sensitivity analyses.

CONCLUSION

Efavirenz and didanosine exposure during pregnancy were associated with higher risk of neurologic abnormalities in CHEU, and dolutegravir exposure showed some suggestive associations, which warrant further monitoring.

Inclusion of pregnant women in antiretroviral drug research: what is needed to move forwards?

INTRODUCTION

To adequately ascertain drug safety and efficacy, drug trials need to include participants from all groups likely to receive the medication following approval. Pregnant women, however, are mostly excluded from trials, and women participating are often required to use highly effective contraception and taken off study product (even off study) if they conceive. There is little commercial incentive for including pregnant women in clinical trials, even when preclinical animal and human pharmacokinetic and safety data appear reassuring. With this conservative approach, large numbers of pregnant women are exposed to drug postlicensing with little known about drug safety and efficacy, and little done to systematically monitor outcomes of pregnancy exposure.

DISCUSSION

The article focuses on antiretrovirals for treating and preventing HIV, and presents potential approaches which could extend to other therapeutic areas, to obtaining adequate and timely data to inform use of these drugs in this population. Most importantly the pregnancy risk profile of investigational agents can be systematically stratified from low to high risk, based on guidelines from regulatory bodies. This stratification can determine the progress through preclinical work with animals and non-pregnant women to opportunistic studies among women who become pregnant on a clinical trial or within routine clinical treatment. Stratification can include pregnant women in clinical trials, concurrent with Phase II/III trials in non-pregnant adults, and ultimately to postmarketing surveillance for outcomes in pregnant women and their infants. Each step can be enabled by clear criteria from international and local regulatory bodies on progression through study phases, standardized protocols for collecting relevant data, collaborative data sharing, pregnancy outcomes surveillance systems supported by committed funding for these endeavours.

CONCLUSIONS

A formalized step-wise approach to including pregnant women in antiretroviral drug research should become the new norm. Systematic implementation of this approach would yield more timely and higher quality pregnancy dosing, safety and efficacy data. Through more vigorous action, regulatory bodies could responsibly overcome reluctance to include pregnant women in drug trials. Funders, researchers and programme implementers need to be galvanized to progressively include pregnant women in research - the use of newer, more effective drugs in women is at stake (349).

Placental transfer and tissue accumulation of dolutegravir in the ex vivo human cotyledon perfusion model

OBJECTIVE

To determine the transplacental pharmacokinetics of the HIV integrase inhibitor dolutegravir.

STUDY DESIGN

Maternal-to-fetal transfer across the term human placenta was investigated with the ex-vivo dually perfused cotyledon model, in 5 closed-circuit, recirculating experiments. Dolutegravir was added to a maternal perfusate containing antipyrine, a marker to validate the cotyledon's viability, and 2 g/liter of human albumin.

RESULTS

After 3h of recirculating perfusion, the mean (± SD) DTG concentrations in the maternal and in the fetal compartments were respectively 2450 ± 286 ng/mL and 715 ± 369 ng/mL, with a fetal-to-maternal ratio of 34% ± 18% and a clearance index (in comparison with antipyrine transfer) of 79% ± 23%. The mean cotyledon accumulation index was 153% ± 25%.

CONCLUSION

Fetal transplacental exposure to dolutegravir was considerable as well as accumulation in placental tissue. Whether this may lead to risks for the exposed fetus requires more investigation.

Propelling the Pediatric HIV Therapeutic Agenda With Science, Innovation, and Collaboration

BACKGROUND

A number of well-described obstacles to the pediatric therapeutic agenda have resulted in substantial delays in the introduction of new medications, formulations, strategies, and approaches to treat infants, children, and adolescents living with HIV.

SETTING

Global landscape.

METHODS

The authors will provide a summary of current and emerging initiatives to accelerate the pediatric therapeutic agenda including illustrative case studies of innovations and scientific discovery in diagnosis and treatment of very young children with HIV infection.

RESULTS

The challenges posed by rapid physiologic and developmental changes that characterize the trajectory of childhood as well as the complex regulatory and fiscal milieu of HIV therapeutics have hampered pediatric HIV therapeutic research. Recent efforts to accelerate this agenda include prioritizing agents and formulations, defining dosing by weight bands, applying innovative study designs, synergizing work across research networks to achieve common goals, and the establishment of a global prioritized research agenda. A case study of initiatives to diagnose and effectively treat newborns and infants will illustrate the critical role of basic science research and novel approaches to study design and implementation that are informing global efforts to end AIDS.

CONCLUSIONS

A pediatric therapeutic agenda informed by basic science and achieved through innovation and global cooperation is essential to achieve an AIDS-free generation.

Dolutegravir for first-line antiretroviral therapy in low-income and middle-income countries: uncertainties and opportunities for implementation and research

A new first-line antiretroviral therapy (ART) regimen containing dolutegravir is being rolled out in low-income and middle-income countries (LMICs). In studies from predominantly high-income settings, dolutegravir-based regimens had superior efficacy, tolerability, and durability compared with existing first-line regimens. However, several questions remain about the roll out of dolutegravir in LMICs, where most people with HIV are women of reproductive age, tuberculosis prevalence can be high, and access to viral load and HIV drug resistance testing is limited. Findings from cohort studies suggest that dolutegravir is safe when initiated in pregnancy, but more data are needed to determine the risk of adverse birth outcomes when dolutegravir-based regimens are initiated before conception. Increasing access to viral load testing to monitor the effectiveness of dolutegravir remains crucial, but the best strategy to manage patients with viraemia is unclear. Furthermore, evidence to support the effectiveness of dolutegravir when given with tuberculosis treatment is scarce, particularly in programmatic settings in LMICs. Lastly, whether nucleoside reverse transcriptase inhibitor resistance will affect the long-term efficacy of dolutegravir-based regimens in first-line, and potentially second-line, ART is unknown. Clinical trials, cohorts, and surveillance of HIV drug resistance will be necessary to answer these questions and to maximise the benefits of this new regimen.

HIV treatment in pregnancy

Almost 25 years since antiretroviral therapy (ART) was first shown to prevent mother-to-child transmission of HIV, 76% of pregnant women living with HIV (over 1 million women) receive ART annually. This number is the result of successes in universal ART scale-up in low-income and middle-income countries. Despite unprecedented ART-related benefits to maternal and child health, challenges remain related to ART adherence, retention in care, and unequal access to ART. Implementation research is ongoing to understand and to address obstacles that lead to loss to follow-up. The biological mechanisms that underlie observed associations between antenatal ART and adverse outcomes in pregnancy and birth are not completely understood, with further research needed as well as strengthening of the systems to assess safety of antiretroviral drugs for the mother and HIV-exposed child. In the treat-all era, as duration of treatment and options for ART expand, pregnant women will remain a priority population for treatment optimisation to promote their health and that of their ART-exposed children.