Lenacapavir and Breastfeeding

Summary of use during lactation

Preliminary data on infant exposure to lenacapavir during breastfeeding is minimal.[1] Achieving and maintaining viral suppression with antiretroviral therapy decreases breastfeeding transmission risk to less than 1%, but not zero. Individuals with HIV who are on antiretroviral therapy with a sustained undetectable viral load and who choose to breastfeed should be supported in this decision. If a viral load is not suppressed, banked pasteurized donor milk or formula is recommended.[2,3] Extended postnatal prophylaxis of breastfed infants with lenacapavir should continue until breastfeeding is stopped.[4]

Drug levels in milk and infant serum

Maternal Levels. Relevant published information was not found as of the revision date. Infant Levels. In an abstract of a study in Africa, breastfed infants whose mothers were receiving twice yearly lenacapavir HIV prophylaxis had serum lenacapavir concentrations that were 5% of the maternal serum concentrations.[1]

Effects in breastfed infants

Relevant published information was not found as of the revision date.

Effects on lactation and breastmilk

Relevant published information was not found as of the revision date.

References

1. Bekker LG, Moodley D, Harkoo I, et al. Inclusion of pregnant and lactating people in the PURPOSE 1 study: Efficacy, safety, and pharmacokinetics. J Int AIDS Soc 2025;28:e26518. doi:10.1002/jia2.2651840657994 PubMed
2. World Health Organization. Consolidated guidelines on HIV prevention, testing, treatment, service delivery and monitoring: Recommendations for a public health approach. 2021 https://www.who.int/publications/i/item/9789240031593 PubMed
3. Department of Health and Human Services. Recommendations for the use of antiretroviral drugs during pregnancy and interventions to reduce perinatal HIV transmission in the United States. 2024 https://clinicalinfo.hiv.gov/sites/default/files/guidelines/documents/perinatal-hiv/guidelines-perinatal.pdf
4. Van de Perre P, Moles JP, Nagot N. HIV postnatal prophylaxis: How long is long enough? Expert Rev Anti Infect Ther 2025;23:1075–81.41216942 PubMed