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Therapeutic drug monitoring of new formulation Kaletra in pregnancy

Purpose of the study

The new LPV/r tablet formulation has significant patient benefits over the old LPV/r SGC, including a lack of food/fluid restrictions, no need for refrigeration and a reduced daily pill count. However, like many antiretroviral drugs, the pharmacokinetics of the new LPV/r tablet during pregnancy is poorly understood. Here we report total and unbound LPV plasma concentrations during pregnancy and at post-partum.


In this prospective, open-labelled study, pregnant HIV-positive patients received the LPV/r tablet formulation as part of their routine pre-natal care. Demographic and clinical data were collected and LPV plasma (total) and ultrafiltrate (unbound) concentrations were determined in the first (T1) and/or second (T2) and/or third (T3) trimester using HPLC-MS/MS. Post-partum (PP) sampling was performed where applicable. Ante-partum and post-partum PK parameters were compared using a one-way ANOVA (for independent data sets) and a paired t-test (for paired data).

Summary of results

From January 2007, 33 women were enrolled in the study; 31/33 received LPV/r tablet at the standard dose of 2 tablets BID. The remaining two patients were prescribed 4 tablets OD and 3 tablets BID, respectively. 30/33 women initiated LPV/r treatment during pregnancy. Median gestation at initiation was 25 weeks. 3/33 women were receiving HAART prior to pregnancy. Median baseline CD4 count was 349 (14–836). Median baseline viral load was 9,100 copies/ml (<50–267,408).

LPV/r (total and unbound) concentrations were determined in 1/33 (T1); 10/33 (T2); 29/33 (T3) and 8/33 (PP) (≤12 weeks) patients. 2/10 patients at T2 and 3/29 patients at T3 fell below the recommended LPV MEC (<1000 ng/ml), respectively. Median total LPV concentrations at T2 and T3 were 2770 ng/ml (1759–4202) and 3371 ng/ml (2331–4310), respectively; and were significantly lower relative to LPV concentrations observed at PP [5352 ng/ml (2667–7293)] (p = 0.042). Equally, in a paired analysis of eight patients (T3 vs. PP), total LPV concentrations were significantly reduced at T3 vs. PP (p = 0.021). However, no significant difference was observed in the % unbound LPV at T3 [0.93% (0.71–1.10)] vs. PP [0.96% (0.81–1.19)].


Standard dosage of LPV/r during pregnancy resulted in adequate therapeutic drug levels in the majority women examined. In addition, the similarities in the percentage of unbound LPV in the third trimester versus post-partum suggest that the standard dose of LPV/r is appropriate during pregnancy. Further research into this is required.

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Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Jackson, V., Else, L., Khoo, S. et al. Therapeutic drug monitoring of new formulation Kaletra in pregnancy. JIAS 11 (Suppl 1), P199 (2008).

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