In September 2007, Merck announced that its vaccination in a phase II clinical trial of the Company's investigational HIV vaccine (V520) was being discontinued because the vaccine was not effective.
The study, known as the STEP trial, was cosponsored with the National Institutes of Health (NIH) and the HIV Vaccine Trials Network (HVTN) and designed to evaluate whether the vaccine prevented HIV infection; and whether the vaccine reduced virus levels in those who developed infection; in an interim analysis, the vaccine did not reduce the incidence of infection nor did it reduce virus levels.
In October 2007, the National Institute of Allergy and Infectious Diseases (NIAID) announced that a second clinical trial being conducted in South Africa, known as Phambili, would be discontinued.
Merck is deeply committed to work with the research community to understand the study results of the STEP trial and its implications to the field of AIDS vaccine R&D.
As part of Merck's continuing commitment to the field of AIDS vaccine R&D, Merck scientists have been studying novel immunogen designs based on essential and conserved regions of the HIV envelope glycoprotein. Merck will continue to follow the field for advances such as the recently announced positive results from the ALVAC/gp120 prime-boost vaccine trial in Thailand (referred to as RV144) and evaluate opportunities to contribute to advancing the quest for an AIDS vaccine.
