Date Published:
2013 May

Publication Type:
Journal Article

Authors:

A. Nguyen
S. Rossi
D. Croteau
B.M. Best
D.B. Clifford
A.C. Collier
B. Gelman
C. Marra
J.C. McArthur
J.A. McCutchan
S. Morgello
D.M. Simpson
R.J. Ellis
I. Grant
E. Capparelli
S. Letendre

Secondary:
J Antimicrob Chemother

Volume:
68

Pagination:
1161-8

Issue:
5

PMID:
23335197

URL:
https://pubmed.ncbi.nlm.nih.gov/23335197

DOI:
10.1093/jac/dks517

Keywords:
Adult;Anti-HIV Agents;Cerebrospinal Fluid;CHARTER;Chromatography, High Pressure Liquid;Cohort Studies;Female;HIV Infections;Humans;Inhibitory Concentration 50;Internal;Isotope Labeling;Male;Middle Aged;Plasma;Protein Binding;Proteins;Pyridazines;Tandem Mass Spectrometry;Ultracentrifugation

Abstract:
<p>OBJECTIVES: Etravirine has high affinity for plasma drug-binding proteins, such as albumin and α1-acid glycoprotein, which limits the amount of unbound etravirine available to enter the CNS. The objective of this study was to compare total and unbound etravirine concentrations in CSF with plasma concentrations and the in vitro median inhibitory concentration (IC50) for wild-type HIV (0.9 ng/mL).METHODS: Total and bound etravirine concentrations were measured in 17 CSF and plasma pairs by isotope-dilution liquid chromatography tandem mass spectroscopy, radioligand displacement and ultracentrifugation. Unbound etravirine concentrations were calculated from the bound fraction. The dynamic range of the assay was 7.8-2000 (plasma) and 0.78-200 (CSF) ng/mL.RESULTS: Subjects were mostly middle-aged (median 43 years) white (78%) men (89%). All CSF etravirine concentrations were above the limit of quantification. Total and unbound median etravirine concentrations in CSF were 9.5 (IQR 6.4, 26.4) and 0.13 (IQR 0.08, 0.27) ng/mL, respectively. Etravirine was 96% (IQR 94.5, 97.2) protein bound in plasma and 98.4% (IQR 97.8, 98.8) in CSF. Total etravirine in CSF was 4.3% (IQR 3, 5.9) of total and 101% (IQR 76, 160) of unbound etravirine in plasma. There were no significant correlations between unbound etravirine concentrations and concentrations of albumin in plasma or CSF. Unbound etravirine concentrations in CSF did not reach the wild-type IC50 in any of the specimens.CONCLUSIONS: Unbound etravirine may not achieve optimal concentrations to inhibit HIV replication in the CNS.</p>