Breastmilk transfer and infant exposure to atazanavir/ritonavir in breastfeeding women with HIV: results from IMPAACT 2026
Year: 2026
Type: article
Abstract: Background: Breastfeeding offers significant health benefits, and guidance for women with HIV increasingly emphasizes individualized, informed infant-feeding decisions. Breastmilk antiretroviral transfer and safety data are needed to inform shared decision-making discussions across all settings. Methods: Breastmilk transfer of ritonavir (RTV)-boosted atazanavir (ATV) was evaluated in the International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) 2026 study. Fourteen breastfeeding women with HIV receiving RTV boosted ATV 100/300 mg daily, as part of a multi-drug regimen, and their infants were enrolled in Kenya, Uganda, and South Africa between 5 and 9 days postpartum and followed through age 16-24 weeks. Paired maternal plasma, breastmilk, and infant plasma samples were collected at each visit. Concentrations were measured using validated LC-MS/MS methods. Relative infant dose (RID) was estimated assuming an infant milk intake of 150 mL/kg/day. Safety outcomes were prospectively assessed. Results: All 14 women reported exclusive breastfeeding. Median maternal plasma and breastmilk concentrations were 1,410 ng/mL and 432 ng/mL for ATV, and 217 ng/mL and 13.6 ng/mL for RTV, respectively. Median breastmilk-to-plasma ratios were 0.253 (ATV) and 0.081 (RTV). RID values were 1.27% (maximum 6.43%) for ATV and 0.12% (maximum 1.10%) for RTV. Infant plasma concentrations were below the lower limit of quantitation (ATV 23.4 ng/mL; RTV 9.8 ng/mL) in all 42 samples. No maternal adverse events occurred; three infants experienced unrelated grade 2 events. Conclusions: In this cohort, ATV and RTV were detectable in maternal plasma and breastmilk but not in infant plasma, with low RID estimates and a favorable safety profile.
Source: Frontiers in Reproductive Health
Authors: Emily Anne Barr, Mauricio Pinilla, Jeremiah D. Momper, Ahizechukwu C. Eke, Lucy Koech, Kristina M. Brooks, Victoria Ndyanabangi, Sandra K. Burchett, Sujith Valiyaparambil, Mark Mirochnick, Alice Marie Stek, Brookie M. Best, Rachael Jeffrey, Chelsea Stotz, Marije Van Schalkwyk, Renee Browning, David E. Shapiro, Kathleen M. Powis
Institutions: University at Buffalo, State University of New York, The University of Texas Health Science Center at Houston, Harvard University, University of California San Diego, Johns Hopkins University, Johns Hopkins Medicine, Kenya Medical Research Institute, University of Colorado Anschutz, Baylor College of Medicine Children’s Foundation, Boston Children's Hospital, Frontier Science & Technology Research Foundation, Inc., Boston University, Boston Medical Center, University of Southern California, Family Health International 360, Stellenbosch University, Tygerberg Hospital, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Massachusetts General Hospital
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,077
Funders: International Maternal Pediatric Adolescent AIDS Clinical Trials Network, National Institutes of Health, National Institute of Mental Health, National Institute of Allergy and Infectious Diseases, National Institute of Child Health and Human Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development
Awards: G1857750563, G3262353703, G32641939, G3342746445, G4853082081, G4927240118, G6585143688, G7502524018, G8709470907, SDMC - IMPAACT Leadership Group, International Maternal, Adolescent and Pediatric Therapeutics Clinical Trials Network, The Johns Hopkins University - Uganda Clinical Trials Unit, IMPAACT Leadership Group
OpenAlex ID: W7203926731