gD-AS04 vaccine

The gD-AS04 vaccine, also known by the proposed brand name Simplirix, is an investigational prophylactic subunit vaccine developed by GSK for the prevention of genital herpes. It consists of a recombinant, truncated version of the Herpes Simplex Virus type 2 (HSV-2) glycoprotein D (gD) formulated with the AS04 adjuvant system. The AS04 system combines aluminum hydroxide (alum) with 3-O-desacyl-4'-monophosphoryl lipid A (MPL), a Toll-like receptor 4 (TLR4) agonist. This combination is designed to enhance both the humoral and cellular immune responses. In a large Phase 3 trial known as the Herpevac study, the vaccine demonstrated significant efficacy in preventing genital herpes disease and infection caused by HSV-1 in seronegative women; however, it failed to provide significant protection against HSV-2, which was the primary objective. Consequently, development for the prevention of genital herpes was discontinued.

Brand names

Simplirix

Other names

HSV-2 gD vaccineHSV2 gD vaccineHSV 2 gD vaccineHerpevac vaccinegD-Alum/MPL vaccine