gD2t + MPL vaccine

The gD2t + MPL vaccine (also known as Simplirix or Herpevac) is a recombinant subunit vaccine developed by GSK for the prevention of genital herpes caused by herpes simplex virus (HSV). It consists of a truncated form of the HSV-2 glycoprotein D (gD2t) formulated with the AS04 adjuvant system, which combines monophosphoryl lipid A (MPL), a TLR4 agonist, and aluminum hydroxide. The vaccine was designed to induce high titers of neutralizing antibodies and cellular immune responses against HSV. In a large-scale Phase 3 trial (the Herpevac study), the vaccine demonstrated significant protection against HSV-1 infection and disease in women who were seronegative for both HSV-1 and HSV-2 at baseline, but it failed to provide protection against HSV-2, its primary target. Consequently, GSK discontinued the development of this specific formulation for genital herpes.

Brand names

Simplirix

Other names

HerpevacGSK herpes simplex vaccinegD2t + MPL