Therapeutic drug monitoring (TDM) of atazanavir in pregnancy

Retrospective analysis of the associations and effectiveness of performing therapeutic drug monitoring in pregnant HIV-positive women in two large centres in Manchester

There is no proven benefit for the routine use of therapeutic drug monitoring in HIV-positive pregnant women either for improving viral control or preventing mother-to-child transmission. This analysis reviewed a cohort of 171 HIV-positive pregnant women delivering between 1 January 2008 and 28 May 2013 to first establish which baseline characteristics are associated with having therapeutic drug monitoring performed, and whether therapeutic drug monitoring was associated with improved HIV control during pregnancy or mother-to-child transmission. Therapeutic drug monitoring was performed in 39% ( n = 66) of patients; it was associated with baseline characteristics of poor adherence to therapy (therapeutic drug monitoring 23% versus non-therapeutic drug monitoring 10%, p = 0.025) and the use of protease inhibitors (therapeutic drug monitoring 94% versus non-therapeutic drug monitoring 77%, p = 0.005). By multivariate analysis therapeutic drug monitoring was associated with medication alterations during pregnancy (therapeutic drug monitoring 68% versus non-therapeutic drug monitoring 12%, p = < 0.001), but not associated with any difference in viral load breakthrough during pregnancy (therapeutic drug monitoring 12% versus non-therapeutic drug monitoring 7%, p = 0.456) and viral load detectable at birth (therapeutic drug monitoring 14% versus non-therapeutic drug monitoring 9%, p = 0.503). There were no instances of mother-to-child transmission. Therapeutic drug monitoring's association with medication changes is postulated as partially causal in this cohort. There was no evidence of any association with improved control or reduced transmission of HIV to advocate routine therapeutic drug monitoring use.

A systematic review of the use of atazanavir in women infected with HIV-1

BACKGROUND

Despite increasing numbers of women with HIV worldwide, females are under-represented in clinical trials of antiretrovirals and literature addressing gender differences in clinical outcomes, treatment discontinuation, adverse events and adherence are limited. Most recommendations specific to women in current guidelines relate to pregnant women or women wishing to become pregnant. The purpose of this systematic review is to provide clinicians with an overview of available literature regarding the use of ritonavir-boosted atazanavir (ATV/r) in women.

METHODS

The online databases PubMed and EMBASE, HIV-related conference abstracts and reference lists of relevant articles were searched according to predefined terms and limited to items published from 1 October 2007 to 1 October 2012. Updates to conference presentations were checked for substantive journal publication up to 28 November 2013.

RESULTS

Of the 294 initial citations retrieved, manual selection identified 19 relevant publications describing gender-based analyses of ATV/r. Publications describing gender-based differences in efficacy, safety, tolerability, pharmacokinetics, drug-drug interactions and adherence are critically evaluated.

CONCLUSIONS

As part of a combination antiretroviral therapy regimen, ATV/r appears to be a safe, effective and durable option for treatment-naive and early treatment-experienced patients with HIV-1 infection, including non-pregnant and pregnant women.

Atazanavir pharmacokinetics, efficacy and safety in pregnancy: a systematic review

BACKGROUND

For some antiretroviral therapies, drug concentrations are reduced during pregnancy, potentially compromising effective virological suppression.

METHODS

Data on atazanavir boosted with ritonavir in pregnancy are reviewed.

RESULTS

With standard atazanavir/ritonavir 300/100 mg once-daily dosing: atazanavir area-under-the-concentration-time curves were reduced during pregnancy in most studies, but overall interpretation differed according to the data used for comparison; atazanavir concentration 24 h post-dose was maintained >150 ng/ml in 97.6% of women; no instance of mother-to-child transmission occurred in treatment-adherent mothers; and infant hyperbilirubinaemia was not elevated beyond levels expected in the neonatal period.

CONCLUSIONS

With concurrent medications that reduce atazanavir drug concentrations, optimal therapy during pregnancy may require once-daily atazanavir/ritonavir 400/100 mg; however, using this dose during the third trimester doubled maternal grade 3-4 hyperbilirubinaemia rates.