The pharmacokinetics of abacavir 600 mg once daily in HIV-1-positive pregnant women

15 May, 2016

Authors: Schalkwijk S, Colbers A, Konopnicki D, et al. For PANNA network

Published inAIDS. 2016;30(8):1239-44.

Objective To describe the pharmacokinetics of abacavir 600 mg 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 600 mg 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 AUC0–24h and 1.00 (0.83–1.21) for Cmax. 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 50 copies/ml in 13 participants (93%; one unknown). In total, 13 (93%; one unknown) children were tested HIV-negative.

Conclusion The pharmacokinetics of abacavir 600 mg q.d. during pregnancy are equivalent to postpartum. No dose adjustments are required during pregnancy and similar antiviral activity is expected.