GlaxoSmithKline (GSK) has made the decision not to pursue further worldwide development of Simplirix (Herpes Simplex Vaccine), an experimental vaccine intended to prevent genital herpes disease in women.

The decision was made following receipt of the results of the Herpevac Trial for Women, a phase III trial evaluating efficacy of Simplirix, which was conducted collaboratively with the US National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health (NIH).

The trial began in 2002 and 8,323 women ages 18-30 were vaccinated at 50 sites in the United States and Canada. An assessment of the final trial results showed that the vaccine had an acceptable safety profile, but the primary trial endpoint, prevention of genital herpes disease, was not met. GSK and NIH continue to evaluate data from the trial and plan to present details of the analysis in the near future in an appropriate scientific forum.

Gary Dubin, vice president and director, Late Clinical Development at GlaxoSmithKline Biologicals commented, "We would like to express our gratitude towards our partner NIAID for their proactive collaboration and substantial contribution in the program and the volunteers for their participation in the study."