Dolutegravir in pregnant mice is associated with increased rates of fetal defects at therapeutic but not at supratherapeutic levels.

Haneesha Mohan,Paul Delgado-Olguín,Evelyn Y Laurette,Lindsay S Cahill,Nicholas D.E Greene,Tanvi Sanghvi,Monica Guzman Lenis,John G Sled,Lena Serghides,Andrew J Copp,Kit-Yi Leung,Oscar Tejada

doi:10.1016/j.ebiom.2020.103167

Abstract

BackgroundDolutegravir (DTG) is a preferred regimen for all people with HIV including pregnant women, but its effects on the fetus are not fully understood. Periconceptional exposure to DTG has been associated with increased rates of neural tube defects (NTDs), although it is unknown whether this is a causal relationship. This has led to uncertainty around the use of DTG in women of reproductive potential.MethodsPregnant C57BL/6J mice were randomly allocated to control (water), 1x-DTG (2.5 mg/kg-peak plasma concentration ~3000 ng/ml – therapeutic level), or 5x-DTG (12.5 mg/kg-peak plasma concentration ~12,000 ng/ml – supratherapeutic level), once daily from gestational day 0.5 until sacrifice. DTG was administered with 50 mg/kg tenofovir+33.3 mg/kg emtricitabine. Fetal phenotypes were determined, and maternal and fetal folate levels were quantified by mass-spectrometry.Findings352 litters (91 control, 150 1x-DTG, 111 5x-DTG) yielding 2776 fetuses (747 control, 1174 1x-DTG, 855 5x-DTG) were assessed. Litter size and viability rates were similar between groups. Fetal and placenta weights were lower in the 1x-DTG vs. control. Placental weight was higher in the 5x-DTG vs. control. Five NTDs were observed, all in the 1x-DTG group. Fetal defects, including microphthalmia, severe edema, and vascular/bleeding defects were more frequent in the 1x-DTG group. In contrast, defect rates in the 5x-DTG were similar to control. Fetal folate levels were similar between control and 1x-DTG, but were significantly higher in the 5x-DTG group.InterpretationOur findings support a causal relationship of DTG at therapeutic doses with increased risk for fetal defects, including NTDs at a rate that is similar that reported in the Tsepamo study for women exposed to DTG-based ART from conception. The non-monotonic dose-response relationship between DTG and fetal anomalies could explain the previous lack of fetal toxicity findings from pre-clinical DTG studies. The fetal folate levels suggest that DTG is unlikely to be an inhibitor of folate uptake.FundingThis project has been funded with 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.

Highlights

Dolutegravir (DTG), an integrase strand transfer inhibitor, is an efficacious, well-tolerated drug with a high barrier to resistance [1]
To determine if maternal exposure to DTG led to a higher frequency of other fetal defects besides neural tube defects (NTDs), we examined all fetuses for gross anomalies and calculated odds ratio (OR) compared to control for each fetal anomaly with more than 10 occurrences, adjusting for litter effects
We observe a 2-fold increased risk of fetal anomalies, as well as lower fetal and placenta weights, in mice exposed to a dose of DTG that yields therapeutic plasma levels, administered with a dual nucleoside reverse transcriptase inhibitor (NRTI) backbone consisting of TDF/FTC (1xDTG)

Summary

Introduction

Dolutegravir (DTG), an integrase strand transfer inhibitor, is an efficacious, well-tolerated drug with a high barrier to resistance [1]. In a study by the Botswana Ministry of Health, NTD prevalence was 0.65% with DTG-based ART at conception compared to 0% with non-DTG ART at conception and 0.09% in HIV-negative women [6]. Periconceptional exposure to DTG has been associated with increased rates of neural tube defects (NTDs), it is unknown whether this is a causal relationship. This has led to uncertainty around the use of DTG in women of reproductive potential. Interpretation: Our findings support a causal relationship of DTG at therapeutic doses with increased risk for fetal defects, including NTDs at a rate that is similar that reported in the Tsepamo study for women exposed to DTG-based ART from conception.

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