Biotechnology company Agenus has finished enrolling patients in a double-blind, multicentre, randomised Phase II study of its recombinant therapeutic vaccine for the treatment of genital herpes in herpes simplex virus-2 (HSV-2) positive patients.
The HerpV vaccine, which is based on the company's HSP platform technology, contains the proprietary QS-21 Stimulon adjuvant, recombinant human heat shock protein-70 complexed with 32 distinct 35-mer synthetic peptides from the HSV-2 proteome.
The study (designated as protocol C-400-02), which has screened 100 HSV-2 positive patients, will test the biological efficacy of HerpV as measured by effect on genital viral shedding after three injections of the therapeutic vaccine.
A booster injection of HerpV will be given at six months after treatment to evaluate the potential durability of treatment effect, according to the company.
During the company's four-arm Phase I study, 35 HSV-2 seropositive patients received three treatments of HerpV (designated in the study as AG-707 plus QS-21), AG-707, QS-21 alone, or placebo at two-week intervals.
The results demonstrated that the vaccine was well-tolerated.
Patients who received HerpV showed a statistically significant CD4+ T cell response (100%; 7/7) to HSV-2 antigens as detected by IFN? Elispot, and the majority of those patients demonstrated a CD8+ T cell response (75%; 6/8).
In addition, Stimulon adjuvant is being used in 17 vaccines, which are currently in clinical development, including four GlaxoSmithKline (GSK) Phase III programmes.
Results from GSK's Phase III trials using MAGE-A3 cancer immunotherapeutic vaccines in lung cancer and melanoma, which incorporate QS-21 Stimulon, are anticipated in 2013.