For pregnant women living with HIV, antiretroviral treatment (ART) is recommended to treat the infection in the mother and prevent mother-to-child HIV transmission. However, pregnancy may affect the way antiretroviral drugs are metabolized and may result in rendering the drug less effective. Studies that address the pharmacokinetics (rates of distribution, absorption, metabolism, and excretion) of drugs in pregnant women are critical to ensure the most appropriate dose is prescribed for maximum protection of mother and child.
This study evaluated the pharmacokinetics and safety of the combination of two antiretroviral drugs—darunavir and cobicistat—among pregnant women with HIV in the United States. Pregnant women in their second and third trimester taking daily darunavir and cobicistat were enrolled and followed up to twelve weeks after delivery, along with their infants. To assess drug pharmacokinetics over time, study participants underwent intensive sampling for a 24-hour period, starting just prior to taking their daily dose of ART. This 24-hour assessment occurred once during the second trimester, the third trimester, and post-delivery, to compare how the drugs were processed at different stages of pregnancy. Infants enrolled in the study were screened four times after birth on a harmonized schedule. Researchers found that both darunavir and cobicistat levels were much lower during the second and third trimesters when compared to postpartum levels. Additionally, the data revealed that transfer of these drugs across the placenta is limited.
The findings of this study suggest that standard darunavir and cobicistat dosing during pregnancy results in significantly lower exposure to the drug, which may increase the risk of treatment failure and mother-to-child transmission and should be avoided during pregnancy.
Reference: Momper et al. Pharmacokinetics of darunavir and cobicistat in pregnant and postpartum women with HIV, AIDS: July 1, 2021 - Volume 35 - Issue 8 - p 1191-1199.