New article: BJCP - Pharmacokinetic parameters of bictegravir in breastmilk of healthy, lactating volunteers without HIV after a single dose of 50 mg (co-formulated with emtricitabine 200 mg and tenofovir alafenamide 25 mg)
Introduction:
The risk of HIV transmission through breastfeeding is very low when the mother maintains viral suppression with antiretroviral therapy. However, it's not fully known how much of these drugs pass into breastmilk, especially newer ones like bictegravir, which was only recently approved for use during pregnancy. This study aimed to assess how much bictegravir infants are exposed to through breastmilk.
Materials and Methods:
Researchers measured bictegravir levels in the plasma and breastmilk of healthy, HIV-negative lactating women after a single 50 mg dose (combined with tenofovir alafenamide and emtricitabine). Samples were collected at specific timepoints post-dose and analyzed using validated LC–MS/MS methods. Pharmacokinetic parameters were calculated, and infant exposure was estimated using breastmilk-to-plasma ratios, daily infant dosage, and relative infant dose.
Results:
Twelve women participated. The average bictegravir exposure in plasma was 1.58 mgh/L, while in breastmilk it was only 0.01 mgh/L, giving a breastmilk-to-plasma ratio of 0.008. The median daily infant dose was 0.008 mg/kg/day, and the relative infant dose was 0.11%. For exclusively breastfed infants consuming 200 mL/kg/day, the estimated dose was 0.046 mg/kg/day, with a relative infant dose of 0.90%.
Conclusion:
Infant exposure to bictegravir through breastmilk is very low, with a relative dose under 1%. Despite the immature drug metabolism in newborns, this low exposure is not expected to cause toxicity
Additional information to the following link: Pharmacokinetic parameters of bictegravir in breastmilk of healthy, lactating volunteers without HIV after a single dose of 50 mg (co‐formulated with emtricitabine 200 mg and tenofovir alafenamide 25 mg) - Van Der Wekken‐Pas - 2025 - British Journal of Clinical Pharmacology - Wiley Online Library