EXPLORE: A Randomized Clinical Trial of the Efficacy of a Behavioral Intervention to Prevent Acquisition of HIV among Men who have Sex with Men (MSM)
Explore Primary Study Results
The Lancet, a prominent medical journal, has published the results from Explore. What follows on this web page is a summary of the Explore results and several study results documents, including the article from The Lancet, in downloadable PDF format.
The article reports that there were fewer new HIV infections in the intervention group compared with the control group. This difference was not statistically significant, however, and was not at the level of benefit targeted by the research team.
The results suggest that the intervention had a somewhat (at most) modest benefit in preventing HIV infection and decreasing high-risk behavior among participants compared with standard biannual counseling and testing, and that that benefit occurred early in follow-up (within the first 18 months).
The Explore intervention affected some important risk behaviors. For example, it significantly reduced the occurrence of unprotected receptive anal intercourse (i.e., being a "bottom") with HIV positive or unknown status partners by 20.5%.
Declines in HIV incidence and sexual risk were seen in both arms of the study. The full effect of the intervention may have been muted since participants in both arms received considerable attention over the course of the study to maintain involvement and retention. Thus, participation in the standard arm was not equivalent to "usual care" in which persons would voluntarily seek anonymous counseling and testing.
Based on the results, the EXPLORE intervention, as currently designed, should not be distributed for widespread implementation. Further analyses of the Explore data, such as whether or not the intervention was more beneficial for certain sub-populations, are ongoing to generate ideas to help develop more highly effective behavioral interventions.
The Explore study has made several notable achievements and provided some valuable research lessons:
There are still many questions to answer about both Explore and behavioral/MSM/HIV prevention research in general. Some topics that will be important as "next steps" are:
Lancet Article (Primary Study Results Paper)
This article was published on July 3, 2004 by The Lancet. It is the official word on the Explore study results. The document is in PDF format and is downloadable free of charge for your own personal use only. The article is reprinted with permission from Elsevier (The Lancet, 2004, Vol 364, pp. 41-50).
Explore National Press Release
This is the official press release from the HPTN announcing the Explore results and the publication of the article in The Lancet.
Explore Executive Summary
This document summarizes the Explore results. It contains much of the same information that appears in the Lancet article.
Frequently Asked Questions
This document addresses some common questions about Explore and the study results in a question-and-answer format.