Objectives: An observational, open-label study was performed to assess changes of lopinavir/ritonavir plasma concentrations during pregnancy.
Methods: Adult HIV-1-infected women during the third trimester of pregnancy and on stable antiretroviral treatment including zidovudine/lamivudine plus lopinavir/ritonavir tablets (400/100 mg twice daily) were asked to participate. This group was compared with a group of non-pregnant HIV-1-infected women receiving the same antiretroviral regimen. The trough plasma concentration (C(trough)) of lopinavir and ritonavir was assessed at steady-state by a validated high-performance liquid chromatography (HPLC)-tandem mass spectrometry method.
Results: A total of 41 HIV-positive female patients were enrolled in the study, with a median age of 28 y (range 20-37 y). These patients were stratified into 2 groups: 21 women in the third trimester of pregnancy (group A) and 20 non-pregnant women (group B). The geometric mean (95% confidence interval (CI)) plasma C(trough) of lopinavir was 4205 (2418-6896) ng/ml in group A and 5098 (3187-8084) ng/ml in group B. The reduction in lopinavir plasma levels observed in group A was not significant (geometric mean ratio 0.87, 95% CI 0.62-1.32; p = 0.411). No correlation was found between lopinavir plasma levels and adverse events (such as diarrhoea and hyperlipidaemia) or immunological parameters of HIV disease, and no changes in plasma HIV viral load were reported.
Conclusion: In this study, a slight but not significant decrease in the plasma lopinavir C(trough) was found during the third trimester of pregnancy, suggesting that standard dosing of the tablet formulation is also appropriate during the later stages of pregnancy.