Tenofovir Alafenamide (TAF) Breast Milk Pharmacokinetics (PK) study
Breast Milk Pharmacokinetics of Vemlidy® (Tenofovir Alafenamide: TAF) After its use in the Prevention of Mother-to-Child Transmission in the Setting of Hepatitis B Virus (HBV) infection
South Western Sydney Local Health District
10 participants
Mar 11, 2019
Interventional
Conditions
Summary
Pharmacokinetics (metabolism) of tenofovir alafenamide (TAF) used in HBV-infected women that are breast feeding. Both analogues of tenofovir, differing only by their side chains, TAF has been demonstrated to be safer than tenofovir disoproxil fumurate (TDF), especially in patients with osteopaenia or osteoporosis, thus TAF is likely to be also superior to TDF for pregnant and breast feeding women. Women in this study may choose to take TAF in pregnancy or only postpartum whilst breast feeding. The study will be a one day pharmacokinetic study. There is no registration data on TAF or TDF in pregnancy, but both are allowable and TAF has superior pharmacology to TDF. TDF has been available for ten years and post-registration safety data for TDF are excellent. This project will determine if TAF is detectable in breast milk, maternal blood and infant urine.
Eligibility
Inclusion Criteria8
- Pregnant women with HBV and high viral load (greater than or equal to 6 log10 IU/ml)
- Aged 18 years or older at the time of Screening
- Taking antiviral therapy for the prevention of mother to child transmission (MTCT) of HBV
- Willing to take 25mg of TAF routinely, ideally commenced at 28-32 weeks of gestation and continued to 12 weeks post-partum OR Willing to take TAF postpartum switching from routine tenofovir disoproxil fumurate (TDF) during pregnancy.
- Pregnant women presenting later than 32 weeks gestation (including post-partum) can be included, but TAF must have been commenced no less than 4 weeks prior to the PK study visit
- Pregnant women already taking TDF for the prevention of MTCT can be included if willing to switch to TAF either during the pregnancy or after delivery, (PK study will be performed after a minimum of 4 weeks on TAF which is a sufficient time period for full washout of any TFV present attributable to TDF).
- Willing to participate in PK study (over 24 hours) between 2-12 weeks post-partum, in a totally breast fed infant a minimum of 4 weeks after commencing TAF.
- Willingness to give informed consent and willingness to participate and comply with the study.
Exclusion Criteria3
- Nucleos(t)ide analogue therapy within prior 6 months except for TDF
- Significant co-morbidities including advanced liver disease and systemic disease
- Any concomitant regular medications except iron or folate for pregnancy
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Interventions
Breastfeeding mothers will receive tenofovir alafenamide (TAF; 25mg oral tablet taken once per day) for a minimum of 4 weeks prior to the pharmacokinetics visit day. Participants will be instructed to take their tablet in the morning (8am-9am) and to document the time it is taken in a pill diary. TAF will be provided for a maximum of 20 weeks. The PK visit day will take place 2-12 weeks post-partum. Maternal blood (MB), breast milk (BM) and infant urine sample will be collected after a clinical review including h physical examination, TAF adherence check, and AE check. MB and BM sampling will take place at the following time points: pre-dose, 0.5hrs post-dose, 1-1.5hrs post-dose, 2.5-3.5hrs post-dose, 5-6hrs post-dose, 8hrs post-dose, and 24hrs post-dose.
Locations(2)
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ACTRN12619000419167