Failed HIV Vaccine Trial Unblinded

November 21, 2007

Volunteers in a clinical trial of Merck’s failed investigational HIV vaccine V520 will be told whether they received the vaccine or a placebo and will be encouraged to keep visiting their study sites regularly for risk-reduction counseling and additional tests.

The investigators are being advised to provide this information to the STEP study participants, who will receive additional information about the unblinding process from the sites, Merck said.

The STEP Study Oversight Committee, which includes representatives from the three co-sponsors, decided to unblind the participants after discussing the study results at an early November meeting of the HIV Vaccine Trials Network (HVTN).

The study was co-sponsored by Merck, the National Institute of Allergy and Infectious Diseases and the HVTN.