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HVTN 504 - Observational follow-up of adult participants enrolled in the Step Study (Merck V520 Protocol 023/HVTN 502)

HVTN 504 is an observational follow-up study to monitor volunteers previously enrolled in the Merck 023 HIV vaccine study, also called “The Step Study.” The Merck 023 study was stopped in September 2007 due to an interim data analysis that showed the vaccine to be ineffective and the presence of a trend towards more HIV infections in the vaccine group than in the placebo group. Subsequent analyses have shown this trend was more pronounced in volunteers with high Ad5 neutralizing antibody (nAb) titers on blood tests done at study enrollment visits and in uncircumcised volunteers.

Because it has been shown conclusively that the vaccine used in the Merck 023 study was not efficacious, the primary objective of that study (to evaluate the efficacy of the vaccine) has been met. Understanding why the experimental vaccine failed is extremely important for the future of HIV vaccine research. Continued follow-up is needed to determine the longevity of any vaccine-induced effects on susceptibility to HIV infection and to assess possible vaccine effects on the course of HIV disease. This follow-up study will allow us to continue to study whether the vaccine makes it more likely for someone to become infected with HIV and to see how the study vaccine affects the health and well-being of people if they get infected with HIV. The follow-up study will also allow us to provide additional counseling that we hope will help volunteers avoid HIV infection.

The HVTN 504 research study was created to provide this needed follow-up. Through this study, we will follow Step Study volunteers through the end of 2009 or through 4 years of follow-up post-enrollment, whichever comes first. Subjects will be seen every 3 months instead of every 6 months as they were in the Merck 023 study. Subjects will receive HIV testing and counseling at each study visit.

Eligible candidates:

  • Must have been enrolled in the Merck 023 HIV vaccine study, also called the "Step Study”

Study Sponsors:

  • HIV Vaccine Trials Network/National Institutes of Health (NIH - DAIDS)
  • Industry-sponsored (Merck and Co., Inc.)

Study Staff

  • Michael Marmor, PhD
  • Demetre Daskalakis, MD
  • Robert Hagerty
  • Gary Carlisle, RN
  • Richard Hutt, RN
  • Richard Silvera
  • Dylan Stein

Study Volunteers Receive:

  • Cost-free lab work
  • Free HIV testing
  • Reimbursement for time and travel costs