Unexpected interactions between dolutegravir and folate: randomized trial evidence from South Africa

Effect of 2 Forms of Tenofovir on Duodenal Enterocytes-A Hypothesis for Different Effect of Tenofovir Disoproxil Fumarate and Tenofovir Alafenamide on Body Weight and Plasma Lipids

BACKGROUND

Tenofovir disoproxil fumarate (TDF), compared to tenofovir alafenamide (TAF), leads to lower body weight and plasma lipids by an unknown mechanism. We hypothesize that TDF, when absorbed, may damage enterocytes of the proximal duodenum, leading to reduced absorption of nutrients.

METHODS

People with human immunodeficiency virus, without significant gastrointestinal symptoms, receiving a regimen containing TDF (n = 12) or TAF (n = 12), underwent esophagogastroduodenoscopies. Plasma/serum concentrations of nutrients absorbed from proximal duodenum and serum intestinal fatty acid-binding protein (I-FABP), a marker of enterocyte damage, were measured. Cytochrome c oxidase/succinate dehydrogenase (COX/SDH) staining and electron microscopy (EM) were conducted to evaluate mitochondria.

RESULTS

Five patients in the TDF group (1 celiac disease [excluded from further analyses], 1 Helicobacter gastritis, and 3 esophagitis) and 2 in the TAF group (2 esophagitis) had a pathological finding in esophagogastroduodenoscopy. Villi were flatter (337 [59] vs 397 [42] μm; P = .016), crypts nonsignificantly deeper (200 [46] vs 176 [27] μm; P = .2), and villus-to-crypt ratio lower (1.5 [0.42] vs 2.5 [0.51]; P = .009) in the TDF versus TAF group (mean [standard deviation]). I-FABP concentration was higher in the TDF versus TAF group (3.0 [1.07] vs 1.8 [0.53] ng/mL; P = .003). The TDF group had numerically but not statistically significantly lower concentrations of folate and vitamins A, B1, D, and E. COX/SDH staining and EM showed similar mitochondrial damage in both groups.

CONCLUSIONS

Duodenal villous alterations may explain TDF-associated decrease in body weight and plasma lipids. Larger studies are needed to evaluate concentrations of nutrients absorbed from duodenum among TDF users..

CLINICAL TRIALS REGISTRATION

NCT05326971; EudraCT 2022-000849.

Dolutegravir- Versus Efavirenz-Based Treatment in Pregnancy: Impact on Red Blood Cell Folate Concentrations in Pregnant Women and Their Infants

BACKGROUND

In the International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) 2010/VESTED study, pregnant women were randomized to initiate dolutegravir (DTG) + emtricitabine (FTC)/tenofovir alafenamide (TAF), DTG + FTC/tenofovir disoproxil fumarate (TDF), or efavirenz (EFV)/FTC/TDF.

METHODS

We assessed red blood cell (RBC) folate concentrations at maternal study entry and delivery, and infant birth. RBC folate outcomes were (1) maternal change entry to delivery (trajectory), (2) infant, and (3) ratio of infant-to-maternal delivery. Generalized estimating equation models for each log(folate) outcome were fit to estimate adjusted geometric mean ratio (Adj-GMR)/GMR trajectories (Adj-GMRTs) of each arm comparison in 340 mothers and 310 infants.

RESULTS

Overall, 90% of mothers received folic acid supplements and 78% lived in Africa. At entry, median maternal age was 25 years, gestational age was 22 weeks, CD4 count was 482 cells/μL, and log10 HIV RNA was 3 copies/mL. Entry RBC folate was similar across arms. Adj-GMRT of maternal folate was 3% higher in the DTG + FTC/TAF versus EFV/FTC/TDF arm (1.03 [95% confidence interval {CI}, 1.00-1.06]). The DTG + FTC/TAF arm had an 8% lower infant-maternal folate ratio (0.92 [95% CI, .78-1.09]) versus EFV/FTC/TDF.

CONCLUSIONS

Results are consistent, with no clinically meaningful differences between arms for all RBC folate outcomes, and they suggest that cellular uptake of folate and folate transport to the infant do not differ in pregnant women starting DTG- versus EFV-based antiretroviral therapy.

CLINICAL TRIALS REGISTRATION

NCT03048422.

Risk of Congenital Anomalies with Dolutegravir-Based Anti-retroviral Regimens: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Dolutegravir has been used as a first-line anti-human immunodeficiency virus drug because of its better efficacy compared with other counterpart medicines. However, making a unanimous decision on its use during pregnancy has become difficult for stakeholders following congenital anomalies reported with its use. The objective of this systematic review and meta-analysis was to study the risk of congenital anomalies in newborns exposed to dolutegravir-based-regimens compared with those exposed to non-dolutegravir-based regimens during the antenatal period.

METHODS

An extensive literature search was performed in MEDLINE (through PubMed), EMBASE, Cochrane Database of Systematic Reviews, Google Scholar, and ClinicalTrials.gov until 30 November, 2023. Studies reporting data on congenital anomalies following antenatal use of dolutegravir were included. Risk of bias for randomized controlled trials, non-randomized controlled trials, and observational studies was assessed using RoB2, ROBINS-I, and ROBINS-E tools, respectively. A meta-analysis was performed in 'RevMan 5.4.1' using a random-effects model. Heterogeneity was assessed by the 'Q' statistic and I2 value. A sensitivity analysis was performed for higher heterogeneity/high-risk studies. The study protocol was registered in PROSPERO [CRD42023446374] a priori.

RESULTS

Of 26 eligible studies, 12 (six randomized controlled trials and six observational studies with a pooled sample of 32,617) were included in a meta-analysis and 14 in a qualitative synthesis only. The meta-analysis does not show a statistically significant difference in the risk of congenital anomalies between newborns exposed antenatally to dolutegravir-based regimen(s) and those exposed to non-dolutegravir-based regimens [risk ratio 1.10; 95% confidence interval 0.79-1.53; p = 0.59]. Heterogeneity was moderate (I2 = 47%). Pooled results for randomized controlled trials and observational studies separately and the sensitivity analysis for heterogeneity provided similar results.

CONCLUSIONS

The risk of congenital anomalies was not significantly different between dolutegravir-based regimens and non-dolutegravir-based-regimens in newborns exposed during their antenatal period.

Dolutegravir-induced neural tube defects in mice are folate responsive

OBJECTIVES

In 2018, the Botswana Tsepamo Study reported a nine-fold increased risk of neural tube defects in infants whose mothers were treated with dolutegravir (DTG) from the time of conception. As maternal folate supplementation and status is a well known modifier of neural tube defect (NTD) risk, we sought to evaluate birth outcomes in mice fed normal and low folic acid diets treated with DTG during pregnancy.

DESIGN

DTG was evaluated for developmental toxicity using pregnant mice fed normal or low folic acid diet.

METHODS

CD-1 mice were provided diet with normal (3 mg/kg) or low (0.3 mg/kg) folic acid. They were treated with water, a human therapeutic-equivalent dose, or supratherapeutic dose of DTG from mouse embryonic day E6.5 to E12.5. Pregnant dams were sacrificed at term (E18.5) and fetuses were inspected for gross, internal, and skeletal defects.

RESULTS

Fetuses with exencephaly, an NTD, were present in both therapeutic human equivalent and supratherapeutic exposures in dams fed low folic acid diet. Cleft palates were also found under both folate conditions.

CONCLUSIONS

Recommended dietary folic acid levels during mouse pregnancy ameliorate developmental defects that arise from DTG exposure. Since low folate status in mice exposed to DTG increases the risk for NTDs, it is possible that DTG exposures in people living with HIV with low folate status during pregnancy may explain, at least in part, the elevated NTD risk signal observed in Botswana. Based on these results, future studies should consider folate status as a modifier for DTG-associated NTD risk.

Metabolic implications and safety of dolutegravir use in pregnancy

Dolutegravir is recommended for all people living with HIV because of its efficacy, high barrier to resistance, favourable safety and tolerability profile, and affordability. Dolutegravir has the highest rates of viral suppression in pregnancy, therefore preventing perinatal HIV transmission. In view of these benefits, particularly for pregnant women, an important question is if dolutegravir is safe in pregnancy. Dolutegravir has been associated with metabolic complications, including weight gain and rare events of hyperglycaemia, that could affect maternal, fetal, and postnatal health. We review the current clinically and experimentally based literature on the implications of dolutegravir use for pregnant women and for developing embryos and fetuses. Possible effects on folate status, energy metabolism, adipogenesis, and oxidative stress are considered. In many instances, insufficient data are available, pointing to the need for additional research in this important area of HIV treatment.

Folate deficiency increases the incidence of dolutegravir-associated foetal defects in a mouse pregnancy model

BACKGROUND

Dolutegravir (DTG) is a recommended first-line regimen for all people with Human Immunodeficiency Virus (HIV) infection. Initial findings from Botswana, a country with no folate fortification program, showed an elevated prevalence of neural tube defects (NTDs) with peri-conceptional exposure to DTG. Here we explore whether a low folate diet influences the risk of DTG-associated foetal anomalies in a mouse model.

METHODS

C57BL/6 mice fed a folate-deficient diet for 2 weeks, were mated and then randomly allocated to control (water), or 1xDTG (2.5 mg/kg), or 5xDTG (12.5 mg/kg) both administered orally with 50 mg/kg tenofovir disoproxil fumarate 33.3 mg/kg emtricitabine. Treatment was administered once daily from gestational day (GD) 0.5 to sacrifice (GD15.5). Foetuses were assessed for gross anomalies. Maternal and foetal folate levels were quantified.

FINDINGS

313 litters (103 control, 106 1xDTG, 104 5xDTG) were assessed. Viability, placental weight, and foetal weight did not differ between groups. NTDs were only observed in the DTG groups (litter rate: 0% control; 1.0% 1xDTG; 1.3% 5xDTG). Tail, abdominal wall, limb, craniofacial, and bleeding defects all occurred at higher rates in the DTG groups versus control. Compared with our previous findings on DTG usage in folate-replete mouse pregnancies, folate deficiency was associated with higher rates of several defects, including NTDs, but in the DTG groups only. We observed a severe left-right asymmetry phenotype that was more frequent in DTG groups than controls.

INTERPRETATION

Maternal folate deficiency may increase the risk for DTG-associated foetal defects. Periconceptional folic acid supplementation could be considered for women with HIV taking DTG during pregnancy, particularly in countries lacking folate fortification programs.

FUNDING

This project has been funded by Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN275201800001I and award #R01HD104553. LS is supported by a Tier 1 Canada Research Chair in Maternal-Child Health and HIV. HM is supported by a Junior Investigator award from the Ontario HIV Treatment Network.

Effect of dolutegravir on folate, vitamin B12 and mean corpuscular volume levels among children and adolescents with HIV: a sub-study of the ODYSSEY randomized controlled trial

INTRODUCTION

Dolutegravir-based antiretroviral therapy (ART) is the preferred antiretroviral treatment for children and adolescents living with HIV. A large surveillance study in Botswana previously raised concerns about an association between pre-conception dolutegravir and neural tube defects. Before these concerns were subsequently resolved, we set up a sub-study to look at the effect of dolutegravir on levels of folate and vitamin B12 in children and adolescents within the randomized ODYSSEY trial, as folate and vitamin B12 are known to play a crucial role in neural tube development.

METHODS

We conducted the sub-study among Ugandan ODYSSEY participants and compared folate and vitamin B12 between children randomized to dolutegravir-based ART (DTG) and non-dolutegravir-based standard-of-care treatment (SOC). Plasma folate was measured at enrolment and week 4 on stored samples; in addition, plasma and red blood cell (RBC) folate and vitamin B12 were assayed at week ≥96 in prospectively collected samples. RBC mean corpuscular volume (MCV) was measured 24-weekly in all ODYSSEY participants. Samples analysed in the sub-study were collected between September 2016 and October 2020.

RESULTS

A total of 229 children aged ≥6 years were included in the sub-study with median age at trial enrolment of 12.3 (interquartile range [IQR] 9.0, 14.7) years, and CD4 count of 501 (IQR 228, 695); 112 (49%) children were male. Most participants (225/229, 98%) had plasma folate results at enrolment and 214 (93%) children had results available for RBC folate, vitamin B12 and plasma folate at week ≥96. MCV results were analysed on 679 children aged ≥6 years enrolled in ODYSSEY. At week 4, mean plasma folate was significantly higher in the dolutegravir arm than in SOC (difference [DTG-SOC] 1.6 ng/ml, 95% CI 0.8, 2.3; p<0.001), and this difference persisted to week ≥96 (2.7 ng/ml, 95% CI 1.7, 3.7; p<0.001). Mean RBC folate at ≥96 weeks was also higher in the DTG arm (difference 73 ng/ml, 95% CI 3, 143; p = 0.041). There was no difference in the treatment arms for vitamin B12 levels at ≥96 weeks or change in MCV through trial follow-up.

CONCLUSIONS

Plasma and RBC folate levels were higher in children and adolescents receiving dolutegravir-based ART than on other ART regimens. Further studies are needed to clarify the mechanisms of these interactions and the clinical implications of increased blood folate levels.

Inhibition of matrix metalloproteinases by HIV-1 integrase strand transfer inhibitors

More than fifteen million women with the human immunodeficiency virus type-1 (HIV-1) infection are of childbearing age world-wide. Due to improved and affordable access to antiretroviral therapy (ART), the number of in utero antiretroviral drug (ARV)-exposed children has exceeded a million and continues to grow. While most recommended ART taken during pregnancy suppresses mother to child viral transmission, the knowledge of drug safety linked to fetal neurodevelopment remains an area of active investigation. For example, few studies have suggested that ARV use can be associated with neural tube defects (NTDs) and most notably with the integrase strand transfer inhibitor (INSTI) dolutegravir (DTG). After risk benefit assessments, the World Health Organization (WHO) made recommendations for DTG usage as a first and second-line preferred treatment for infected populations including pregnant women and those of childbearing age. Nonetheless, long-term safety concerns remain for fetal health. This has led to a number of recent studies underscoring the need for biomarkers to elucidate potential mechanisms underlying long-term neurodevelopmental adverse events. With this goal in mind, we now report the inhibition of matrix metalloproteinases (MMPs) activities by INSTIs as an ARV class effect. Balanced MMPs activities play a crucial role in fetal neurodevelopment. Inhibition of MMPs activities by INSTIs during neurodevelopment could be a potential mechanism for adverse events. Thus, comprehensive molecular docking testing of the INSTIs, DTG, bictegravir (BIC), and cabotegravir (CAB), against twenty-three human MMPs showed broad-spectrum inhibition. With a metal chelating chemical property, each of the INSTI were shown to bind Zn++ at the MMP's catalytic domain leading to MMP inhibition but to variable binding energies. These results were validated in myeloid cell culture experiments demonstrating MMP-2 and 9 inhibitions by DTG, BIC and CAB and even at higher degree than doxycycline (DOX). Altogether, these data provide a potential mechanism for how INSTIs could affect fetal neurodevelopment.

HIV-1 Integrase Strand Transfer Inhibitors and Neurodevelopment

Children born to mothers, with or at risk, of human immunodeficiency virus type-1 (HIV-1) infection are on the rise due to affordable access of antiretroviral therapy (ART) to pregnant women or those of childbearing age. Each year, up to 1.3 million HIV-1-infected women on ART have given birth with recorded mother-to-child HIV-1 transmission rates of less than 1%. Despite this benefit, the outcomes of children exposed to antiretroviral drugs during pregnancy, especially pre- and post- natal neurodevelopment remain incompletely understood. This is due, in part, to the fact that pregnant women are underrepresented in clinical trials. This is underscored by any potential risks of neural tube defects (NTDs) linked, in measure, to periconceptional usage of dolutegravir (DTG). A potential association between DTG and NTDs was first described in Botswana in 2018. Incidence studies of neurodevelopmental outcomes associated with DTG, and other integrase strand transfer inhibitors (INSTIs) are limited as widespread use of INSTIs has begun only recently in pregnant women. Therefore, any associations between INSTI use during pregnancy, and neurodevelopmental abnormalities remain to be explored. Herein, United States Food and Drug Administration approved ARVs and their use during pregnancy are discussed. We provide updates on INSTI pharmacokinetics and adverse events during pregnancy together with underlying mechanisms which could affect fetal neurodevelopment. Overall, this review seeks to educate both clinical and basic scientists on potential consequences of INSTIs on fetal outcomes as a foundation for future scientific investigations.

Transporters in drug development: International transporter consortium update on emerging transporters of clinical importance

During its 4^th transporter workshop in 2021, the International Transporter Consortium (ITC) provided updates on emerging clinically relevant transporters for drug development. Previously highlighted and new transporters were considered based on up-to-date clinical evidence of their importance in drug-drug interactions and potential for altered drug efficacy and safety, including drug-nutrient interactions leading to nutrient deficiencies. For the first time, folate transport pathways (PCFT, RFC, and FRα) were examined in-depth as a potential mechanism of drug-induced folate deficiency and related toxicities (e.g., neural tube defects, megaloblastic anemia). However, routine toxicology studies conducted in support of drug development appear sufficient to flag such folate deficiency toxicities, while prospective prediction from in vitro folate metabolism and transport inhibition is not well enough established to inform drug development. Previous suggestion of retrospective study of intestinal OATP2B1 inhibition to explain unexpected decreases in drug exposure were updated. Furthermore, when the absorption of a new molecular entity is more rapid and extensive than can be explained by passive permeability, evaluation of OATP2B1 transport may be considered. Emerging research on hepatic and renal OAT2 is summarized, but current understanding of the importance of OAT2 was deemed insufficient to justify specific consideration for drug development. Hepatic, renal, and intestinal MRPs (MRP2, MRP3, MRP4) were revisited. MRPs may be considered when they are suspected to be the major determinant of drug disposition (e.g., direct glucuronide conjugates); MRP2 inhibition as a mechanistic explanation for drug-induced hyperbilirubinemia remains justified. There were no major changes in recommendations from previous ITC whitepapers.

Interaction between dolutegravir and folate transporters and receptor in human and rodent placenta

Background

Due to the critical role of folates in neurodevelopment, it is important to understand potential interactions between anti-HIV drugs used during pregnancy, and folate delivery pathways in the placenta. This study investigates the effect of dolutegravir (DTG) exposure on the functional expression of the reduced folate carrier (RFC), proton-coupled folate transporter (PCFT), and folate receptor-α (FRα) in the placenta.

Methods

Human placental cell lines, human placental explants, and a pregnant mouse model treated with clinically relevant concentrations of DTG were used. Gene and protein expression were assessed by qPCR, immunoblot and immunohistochemical assays. Folate transport function was measured by applying radioisotope-based transport assays.

Findings

In placental cells, clinically relevant DTG exposure for 3h or 6h was associated with a modest but significant reduction in the expression of RFC and PCFT both at the mRNA and protein levels, as well as decreased uptake of RFC and PCFT substrates [³H]-methotrexate and [³H]-folic acid, respectively. In pregnant mice, DTG administration was associated with an increase in both placental RFC and PCFT mRNA expression, accompanied by a decrease in placental FRα mRNA under folate-deficient dietary conditions.

Interpretation

These findings demonstrate a potential interaction between DTG and folate transport pathways in the placenta, particularly in vivo, under folate deficient conditions, potentially impacting folate delivery to the foetus in the context of DTG-based ART during pregnancy.

Funding

Funded by Ontario HIV Treatment Network, grant #506657; and Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health, award #R01HD104553.

Dolutegravir impairs stem cell-based 3D morphogenesis models in a manner dependent on dose and timing of exposure: an implication for its developmental toxicity

Dolutegravir is an anti-retroviral drug of the integrase strand transfer inhibitor class used to treat HIV infection. It is the recommended first-line regimen for most people, including women of childbearing age. However, some human and animal studies have suggested that dolutegravir causes birth defects, although its developmental toxicity remains controversial. Here, we investigated the adverse effects of dolutegravir using pluripotent stem cell-based in vitro morphogenesis models that have previously been validated as effective tools to assess the developmental toxicity of various chemicals. Dolutegravir diminished the growth and axial elongation of the morphogenesis model of mouse pluripotent stem cells at exposures of 2 μM and above in a concentration-dependent manner. Concomitantly, dolutegravir altered the expression profiles of developmental regulator genes involved in embryonic patterning. The adverse effects were observed when the morphogenesis model was exposed to dolutegravir at early stages of development, but not at later stages. The potency and molecular impact of dolutegravir on the morphogenesis model were distinct from other integrase strand transfer inhibitors. Lastly, dolutegravir altered the growth and gene expression profiles of the morphogenesis model of human embryonic stem cells at 1 μM and above. These studies demonstrate that dolutegravir impairs morphological and molecular aspects of the in vitro morphogenesis models in a manner dependent on dose and timing of exposure through mechanisms that are unrelated to its action as an integrase strand transfer inhibitor. This finding will be useful for interpreting the conflicting outcomes regarding the developmental toxicity of dolutegravir in human and animal studies.

Dolutegravir Inhibition of Matrix Metalloproteinases Affects Mouse Neurodevelopment

Dolutegravir (DTG) is a first-line antiretroviral drug (ARV) used in combination therapy for the treatment of human immunodeficiency virus type-1 (HIV-1) infection. The drug is effective, safe, and well tolerated. Nonetheless, concerns have recently emerged for its usage in pregnant women or those of child-bearing age. Notably, DTG-based ARV regimens have been linked to birth defects seen as a consequence of periconceptional usages. To this end, uncovering an underlying mechanism for DTG-associated adverse fetal development outcomes has gained clinical and basic research interest. We now report that DTG inhibits matrix metalloproteinases (MMPs) activities that could affect fetal neurodevelopment. DTG is a broad-spectrum MMPs inhibitor and binds to Zn⁺⁺ at the enzyme’s catalytic domain. Studies performed in pregnant mice show that DTG readily reaches the fetal central nervous system during gestation and inhibits MMP activity. Postnatal screenings of brain health in mice pups identified neuroinflammation and neuronal impairment. These abnormalities persist as a consequence of in utero DTG exposure. We conclude that DTG inhibition of MMPs activities during gestation has the potential to affect prenatal and postnatal neurodevelopment.