Concentrations of protease inhibitors in cord blood after in utero exposure

Objective. To determine the concentrations of protease inhibitors in cord blood after prenatal protease inhibitor use by pregnant women. Design. Retrospective analysis of samples collected in a clinical trial. Methods. Protease inhibitor concentrations were measured in cord blood samples collected from women enrolling in the PACTG 316 study who were receiving prenatal protease inhibitor antiretroviral therapy. Results. In cord blood samples from 68 women treated with protease inhibitors during pregnancy, the concentration of these drugs was below the assay lower limit of detection in most samples, including all samples from women receiving indinavir (n 21) and saquinavir (n 8), 5 of 6 samples (83%) from women receiving ritonavir and 24 of 38 samples (63%) from women receiving nelfinavir. Conclusions. Low protease inhibitor concentrations in the fetus decrease the likelihood of teratogenic and toxic effects of these drugs but could fail to provide protection from transplacental or intrapartum transmission of HIV-1.