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Vax Update: Large-scale trials with Ad5-vectored vaccines

This page includes information on the Step and Phambili trials of Merck's MRK-Ad5 vaccine candidate (immunizations were stopped in September 2007). It also includes information on the NIH Vaccine Research Center's DNA prime/Ad5 boost vaccine strategy—initially planned to be tested in the proposed but never conducted PAVE 100 vaccine trial—tested in the trial HVTN 505.

Visit our vaccines page for more on the latest research.

National Institute of Allergy and Infectious Diseases Mini-Summit on Adenovirus Platforms for HIV Vaccines
The Mini-Summit focused discussion on questions pertaining to the impact of Ad5 vaccines on HIV acquisition, potential mechanisms involved and how this informs future human clinical trials.

HVTN 505 Trial Stops Immunizations

Step and Phambili Trials

Key publications and materials on the Step results:
An Advocates' Guide to Recent Publications on the STEP AIDS Vaccine Trial Data - AVAC, December 2008
This publication discusses key articles looking at and analyzing data from the STEP AIDS vaccine trial. Two of the pieces reviewed were published in The Lancet and go over findings to date that have also been reported in conferences over the past years. These Lancet articles were accompanied by a commentary by Merlin Robb of the US Military HIV Research Program. Links to the abstract for all three articles can be found below.

HIV-1 vaccine-induced immunity in the test-of-concept Step Study: a case-cohort analysisLancet. 2008 Nov 29; 372(9653):1894-1905. 

Failure of the Merck HIV vaccine: an uncertain step forward. Lancet, 2008 Nov 29; 372(9653):1857-1858.

Efficacy assessment of a cell-mediated immunity HIV-1 vaccine (the Step Study): a double-blind, randomised, placebo-controlled, test-of-concept trial. Lancet. 2008 Nov 29; 372(9653)1881-1893.

HIV Vaccine Trials Network fact sheet on the HVTN 505 trial. November 2008.

STEP Study Volunteers to be Informed Whether They Received Vaccine or Placebo. November 13, 2007.
Merck and the HVTN announce that they will disclose to Step study volunteers information on whether they received vaccine or placebo.

A timeline of the release of Step results:
November 7, 2007
Additional data from the Step study was presented at a public forum at the HIV Vaccine Trials Network full group meeting:
November 2007 HVTN Conference Presentations. (downloadable slide sets)
AVAC statement.
Draft Q&A on new data.
Merck/HVTN press release.
Statement from Dr. Anthony Fauci, Director of NIAID.
IAVI statement.

October 23, 2007
After further review of Step data, Phambili oversight committee decides to permanantly suspend enrollment and vaccination:
AVAC statement.
NIAID press release.
SAAVI press release.
Trials Q&A from NIAID.

September 21, 2007
Vaccinations discontinued in Step study of Merck Ad5 candidate and companion trial, Phambili, is paused:
AVAC statement.
IAVI statement.
Merck and HVTN press release.
NIAID press release.
Treatment Action Group (TAG) statement (September 24, 2007).
WHO statement (September 24, 2007).

AVAC summary coverage of the December 12, 2007 meeting of the AIDS Vaccine Research Subcommittee of the NIH AIDS Research Advisory Committee - PDF (December 20, 2007)

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