MSD confirms investigation HIV vaccine ‘not effective’

Merck, Sharp and Dohme (MSD) has confirmed that one of two Phase II trails as part of its Step study showed that its investigational HIV vaccine (V520) was not effective in two areas.

Study results demonstrated that the vaccine failed to prevent infection in volunteers not previously infected with HIV as well as not reducing the viral load in volunteers who became infected with HIV during the trial.

Keith Gottesdiener, vice-president at Vaccine and Infection Disease Clinical Research at Merck Research Laboratories, indicated that the data from the trial was “remarkably complex” and that it would take some time to understand why the vaccine did not work.

“We recognise that understanding Step is important for the study volunteers, investigators and for the entire field of HIV vaccine research and we remain committed to continuing to thoroughly analyse the data and share it as broadly and as quickly as possible,” he added.

Data showed that for volunteers who had pre-existing immunity to the cold virus used as a carrier for synthetic HIV genes in the vaccine, there were more infections in those volunteers who received the vaccine than for those who received the placebo.

Last month, MSD described the development of its HIV treatment Isentress (raltegravir) as a significant landmark in the treatment of HIV and Aids.