The 2001 International Maternal Pediatric Adolescent AIDS Clinical Trial Network (IMPAACT) Study on Rifapentine and Isoniazid for Tuberculosis Prevention in Pregnant Women

NIAID Now | July 29, 2021

Tuberculosis (TB) has a significant impact on maternal and infant health and is one of the leading causes of maternal death worldwide. Pregnant and postpartum women with latent TB are at a higher risk of developing active TB and pregnancy complications due to TB infection can result in babies with low birth weight, premature birth, and stillbirth. Additionally, maternal TB more than doubles the risk of mother-to-child transmission of HIV and significantly increases the death rate for all children in the household. Hence, prevention of active TB during pregnancy is a critical public health concern.

One treatment regimen for TB prevention is a 3 month course of weekly isoniazid and rifapentine, referred to as 3HP. When compared to other treatment options for TB prevention, 3HP’s shorter treatment duration allows for better adherence and has fewer associated adverse events, including in people living with HIV. Given the success of 3HP in nonpregnant women, the International Maternal Pediatric Adolescent AIDS Clinical Trial (IMPAACT) network initiated a study to determine the safety of this regimen for use in pregnant women with latent TB and understand how pregnancy impacts the pharmacokinetics (rates of distribution, absorption, metabolism, and excretion) of this combination of drugs in women with and without HIV.

The IMPAACT 2001 study enrolled women in their 2nd and 3rd trimesters in Haiti, Kenya, Malawi, Thailand, and Zimbabwe. These women were provided treatment during their study visits and were monitored throughout the study. Additionally, their babies were monitored for 24 weeks after birth. The results of this small study suggest that 3HP is well-tolerated and safe in pregnant women. While there were some differences in the pharmacokinetics of the drugs between women with or without HIV, all study participants achieved levels that were indicative of prevention and no women or infants developed active TB. These results pave the way for larger studies that are powered to address maternal safety, increase diversity in study participants, and understand the influence of antiretroviral therapy on the TB drug levels in pregnant women living with HIV.

Reference: Mathad et al. Pharmacokinetics and Safety of 3 Months of Weekly Rifapentine and Isoniazid for Tuberculosis Prevention in Pregnant Women, Clinical Infectious Diseases, 2021;, ciab665.

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