Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to STRIBILD during pregnancy. Healthcare providers are encouraged to register patients on the worldwide Antiretroviral Pregnancy Registry (APR) at www.apregistry.com/.

Risk Summary

STRIBILD is not recommended during pregnancy [see Dosage and Administration (2.5)]. A literature report evaluating the pharmacokinetics (PK) of antiretrovirals during pregnancy demonstrated substantially lower exposures of elvitegravir and cobicistat in the second and third trimesters (see Data).

Prospective pregnancy data from the APR are not sufficient to adequately assess the risk of birth defects or miscarriage. However, elvitegravir, cobicistat, emtricitabine, and TDF use during pregnancy have been evaluated in a limited number of individuals as reported to the APR. Available data from the APR show no increase in the overall risk of major birth defects for cobicistat, emtricitabine or TDF compared with the background rate for major birth defects of 2.7% in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). The number of exposures to elvitegravir is insufficient to make a risk assessment compared to a reference population (see Data). The rate of miscarriage is not reported in the APR. In the U.S. general population, the estimated background risk of miscarriage in clinically recognized pregnancies is 15–20%.

In animal studies, no adverse developmental effects were observed when the components of STRIBILD were administered separately during the period of organogenesis at exposures up to 23 and 0.2 times (rats and rabbits, respectively, elvitegravir), 1.8 and 4.3 times (rats and rabbits, respectively, cobicistat), and 60 and 120 times (mice and rabbits, respectively, emtricitabine) the exposure at the recommended daily dose of these components in STRIBILD, and at 14 and 19 times (rats and rabbits, respectively, TDF) the human dose based on body surface area comparisons [see Data]. Likewise, no adverse developmental effects were seen when elvitegravir or cobicistat was administered to rats through lactation at exposures up to 18 times or 1.2 times, respectively, the exposure at the recommended daily therapeutic dose, and when emtricitabine was administered to mice through lactation at exposures up to approximately 60 times the exposure at the recommended daily therapeutic dose. No adverse effects were observed in the offspring of rats when TDF was administered through lactation at tenofovir exposures of approximately 2.7 times the exposure at the recommended daily dosage of STRIBILD.

Data

Human Data

A prospective study, reported in the literature, enrolled 30 pregnant women living with HIV who were receiving elvitegravir and cobicistat-based regimens in the second or third trimesters of pregnancy and through 6 to 12 weeks postpartum to evaluate the pharmacokinetics (PK) of antiretrovirals during pregnancy. Twenty-eight women completed the study through the postpartum period. Paired pregnancy/postpartum PK data were available from 14 and 24 women for the second and third trimesters, respectively. Exposures of elvitegravir and cobicistat were substantially lower during the second and third trimesters compared to postpartum. The proportion of pregnant women who were virologically suppressed was 77% in the second trimester, 92% in the third trimester, and 76% postpartum. No correlation was observed between viral suppression and elvitegravir exposure. HIV status was also assessed for infants: 25 were uninfected, 2 had indeterminate status, and no information was available for 3 infants.

Prospective reports from the APR of overall major birth defects in pregnancies exposed to the components of STRIBILD are compared with a U.S. background major birth defect rate. Methodological limitations of the APR include the use of MACDP as the external comparator group. Limitations of using an external comparator include differences in methodology and populations, as well as confounding due to the underlying disease.

Elvitegravir: The APR has received prospective reports of 5 birth defects among 180 first trimester exposures to elvitegravir-containing regimens during pregnancy resulting in live births. No birth defects were reported among 52 exposures during the second/third trimester. The number of exposures is insufficient to make a risk assessment compared to a reference population.

Cobicistat: Based on prospective reports to the APR of 204 first trimester exposures to cobicistat-containing regimens during pregnancy, there was no increase in overall major birth defects with cobicistat compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of birth defects in live births was 2.5% (95% CI: 0.8% to 5.6%) with first trimester exposure to cobicistat-containing regimens; the 58 second/third trimester cobicistat exposures reported to the APR are insufficient to make a risk assessment.

Emtricitabine: Based on prospective reports to the APR of exposures to emtricitabine-containing regimens during pregnancy resulting in live births (including over 2,700 exposed in the first trimester and over 1,200 exposed in the second/third trimester), there was no increase in overall major birth defects with emtricitabine compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of birth defects in live births was 2.4% (95% CI: 1.9% to 3.1%) with first trimester exposure to emtricitabine-containing regimens and 2.3% (95% CI: 1.5% to 3.3%) with second/third trimester exposure to emtricitabine-containing regimens.

Tenofovir DF: Based on prospective reports to the APR of exposures to TDF-containing regimens during pregnancy resulting in live births (including over 3,500 exposed in the first trimester and over 1,500 exposed in the second/third trimester), there was no increase in overall major birth defects with TDF compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of birth defects in live births was 2.3% (95% CI: 1.8% to 2.9%) with first trimester exposure, and 2.2% (95% CI: 1.6% to 3.1%) with the second/third trimester exposure to TDF-containing regimens.

Animal Data

Elvitegravir: Elvitegravir was administered orally to pregnant rats (at 0, 300, 1000, and 2000 mg/kg/day), and rabbits (at 0, 50, 150, and 450 mg/kg/day) through organogenesis (on gestation days 7 through 17 and days 7 through 19, respectively). No significant toxicological effects were observed in embryo-fetal toxicity studies performed with elvitegravir in rats at exposures (AUC) approximately 23 times higher and in rabbits at approximately 0.2 times higher than human exposures at the recommended daily dose. In a pre- and postnatal developmental study in rats, elvitegravir was administered orally at doses of 0, 300, 1000, and 2000 mg/kg from gestation day 7 to day 20 of lactation. At doses of 2000 mg/kg/day of elvitegravir, neither maternal nor developmental toxicity was noted. Systemic exposures (AUC) at this dose were 18 times the human exposures at the recommended daily dose.

Cobicistat: Cobicistat was administered orally to pregnant rats at doses of 0, 25, 50, and 125 mg/kg/day on gestation day 6 to 17. Increases in post-implantation loss and decreased fetal weights were observed at a maternal toxic dose of 125 mg/kg/day. No malformations were noted at doses up to 125 mg/kg/day. Systemic exposures (AUC) at 50 mg/kg/day in pregnant females were 1.8 times higher than human exposures at the recommended daily dose.

In pregnant rabbits, cobicistat was administered orally at doses of 0, 20, 50, and 100 mg/kg/day during the gestation days 7 to 20. No maternal or embryo/fetal effects were noted at the highest dose of 100 mg/kg/day. Systemic exposures (AUC) at 100 mg/kg/day were 4.3 times higher than human exposures at the recommended daily dose. In a pre- and postnatal developmental study in rats, cobicistat was administered orally at doses of 0, 10, 30, and 75 mg/kg from gestation day 6 to postnatal day 20, 21, or 22. At doses of 75 mg/kg/day of cobicistat, neither maternal nor developmental toxicity was noted. Systemic exposures (AUC) at this dose were 1.2 times the human exposures at the recommended daily dose.

Emtricitabine: Emtricitabine was administered orally to pregnant mice (at 0, 250, 500, or 1000 mg/kg/day), and rabbits (at 0, 100, 300, or 1000 mg/kg/day) through organogenesis (on gestation days 6 through 15, and 7 through 19, respectively). No significant toxicological effects were observed in embryo-fetal toxicity studies performed with emtricitabine in mice at exposures (AUC) approximately 60 times higher and in rabbits at approximately 120 times higher than human exposures at the recommended daily dose. In a pre/postnatal development study in mice, emtricitabine was administered orally at doses up to 1000 mg/kg/day; no significant adverse effects directly related to drug were observed in the offspring exposed daily from before birth (in utero) through sexual maturity at daily exposures (AUC) of approximately 60 times higher than human exposures at the recommended daily dose.

Tenofovir DF: Tenofovir DF was administered orally to pregnant rats (at 0, 50, 150, or 450 mg/kg/day) and rabbits (at 0, 30, 100, or 300 mg/kg/day) through organogenesis (on gestation days 7 through 17, and 6 through 18, respectively). No significant toxicological effects were observed in embryo-fetal toxicity studies performed with TDF in rats at doses up to 14 times the human dose based on body surface area comparisons and in rabbits at doses up to 19 times the human dose based on body surface area comparisons. In a pre/postnatal development study in rats, TDF was administered orally through lactation at doses up to 600 mg/kg/day; no adverse effects were observed in the offspring at tenofovir exposures of approximately 2.7 times higher than human exposures at the recommended daily dose of STRIBILD.