Skip Navigation


Biostatistics Advance Access originally published online on April 14, 2005
Biostatistics 2005 6(3):374-394; doi:10.1093/biostatistics/kxi014
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
6/3/374    most recent
kxi014v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Gilbert, P. B.
Right arrow Articles by Sun, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gilbert, P. B.
Right arrow Articles by Sun, Y.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2005. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oupjournals.org.

Failure time analysis of HIV vaccine effects on viral load and antiretroviral therapy initiation

Peter B. Gilbert*

Department of Biostatistics, University of Washington and Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA pgilbert{at}scharp.org

Yanqing Sun

Department of Mathematics and Statistics, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA

* To whom correspondence should be addressed.

The world's first efficacy trial of a preventive HIV vaccine was completed in 2003. Study participants who became HIV infected were followed for 2 years and monitored for HIV viral load and initiation of antiretroviral therapy (ART). In order to determine if vaccination may have altered HIV progression in persons who acquired HIV, a pre-specified objective was to compare the time until a composite endpoint between the vaccine and placebo arms, where the composite endpoint is the first event of ART initiation or viral failure (HIV viral load exceeds a threshold xvl copies/ml). Specifically, with vaccine efficacy, VE({tau}, xvl), defined as one minus the ratio (vaccine/placebo) of the cumulative probability of the composite endpoint (with failure threshold xvl) occurring by {tau} months, the aim was to estimate the four parameters {VE({tau}, xvl): xvl {1500, 10 000, 20 000, 55 000} copies/ml with simultaneous 95% confidence bands. A Gaussian multipliers simulation method is devised for constructing confidence bands for VE({tau}, xvl) with xvl spanning multiple discrete values or a continuous range. The new method is evaluated in simulations and is applied to the vaccine trial data set.

Keywords: Gaussian multipliers technique; HIV vaccine efficacy trial; Kaplan–Meier estimator; Simultaneous confidence bands


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.