Objective: To describe the pharmacokinetics of abacavir 600mg once daily (q.d.) in HIV-1-positive women during pregnancy and postpartum. Design: A nonrandomized, open-label, multicentre, phase-IV study. Methods: HIV-positive pregnant women receiving abacavir 600mg q.d. as part of clinical care were included. Intensive 24-h pharmacokinetic sampling was performed during the third trimester and at least 2 weeks after delivery. Pharmacokinetic parameters were calculated by noncompartmental analysis. Paired cord blood and maternal blood samples were taken at delivery when feasible. Results: A total of 14 women were included in the analysis. Geometric mean ratios (90% confidence intervals) of third trimester versus postpartum were 1.05 (0.92-1.19) for AUC 0-24h and 1.00 (0.83-1.21) for C max. The median (range) ratio of abacavir cord plasma to maternal plasma was 1.0 (0.7-1.0, n=3). Viral load at the third trimester visit was less than 50copies/ml in 13 participants (93%; one unknown). In total, 13 (93%; one unknown) children were tested HIV-negative. Conclusion: The pharmacokinetics of abacavir 600mg q.d. during pregnancy are equivalent to postpartum. No dose adjustments are required during pregnancy and similar antiviral activity is expected.

abacavir, combination antiretroviral therapy, HIV, perinatal transmission, pharmacokinetics, placental transfer, pregnancy, prevention of mother-to-child transmission
dx.doi.org/10.1097/QAD.0000000000001046, hdl.handle.net/1765/90555
Erasmus MC: University Medical Center Rotterdam

Schalkwijk, S, Colbers, A, Konopnicki, D, Weizsäcker, K, Moltó, J, Tenorio, C.H, … Burger, D.M. (2016). The pharmacokinetics of abacavir 600mg once daily in HIV-1-positive pregnant women. AIDS, 30(8), 1239–1244. doi:10.1097/QAD.0000000000001046