Vaccine Info

HSV529 Genital Herpes Vaccine

HSV529 Vaccine Description

HSV529 is a vaccine candidate that is classified as a replication-defective virus, where the virus possesses all the components of the wild-type HSV virus with the exception of two proteins UL5 and UL29 that are involved in viral DNA replication. This replication-defective HSV2 vaccine can infect cells and should result in a broader immune response. HSV529 uses a replication-defective mutant virus, which is genetically altered to prevent the virus from replicating.

This Sanofi Pasteur vaccine candidate is derived from HSV2 strain 186, which was produced in Vero cells expressing HSV2 UL5 and UL29 and is manufactured by Sanofi Pasteur. 

In October 2014, Sanofi Pasteur and Immune Design announced a collaboration: Sanofi Pasteur will contribute HSV-529, a clinical-stage replication-defective HSV vaccine product candidate, and Immune Design will contribute G103, its preclinical trivalent vaccine product candidate

HSV529 Vaccine Indication

The HSV529 vaccine candidate is indicated to treat herpes simplex virus (HSV).

Worldwide, about 400 million people are infected with herpes simplex virus type 2 (HSV2), the predominant cause of genital herpes. HSV2 can also cause encephalitis or disseminated infection in neonates and severe disease in immunocompromised patients.

Genital herpes is an STD caused by two types of viruses. The viruses are called herpes simplex virus type 1 (HSV-1) and HSV-2.

Genital herpes infection is common in the United States. The CDC estimates that, annually, 776,000 people in the United States get new genital herpes infections. Nationwide, 11.9 % of persons aged 14 to 49 years have HSV-2 infection. However, the prevalence of genital herpes infection is higher than that because an increasing number of genital herpes infections are caused by HSV-1.

Of the more than 100 known herpesviruses, 8 routinely infect only humans: herpes simplex virus types 1 and 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human herpesvirus 6, human herpesvirus 7, and Kaposi's sarcoma virus or human herpesvirus 8. A simian virus, called B virus, occasionally infects humans. All herpesviruses can establish latent infection within specific tissues, which are characteristic of each virus.

Vaccine-elicited protection against HSV is challenging to achieve due to the ability of herpesviruses to evade many aspects of the mammalian immune response.  Subunit vaccines, which consist of individual or small groups of viral antigens, remove the risk of complications resulting from the production of vaccine-associated infectious viral particles but are limited in the degree and scope of immunity that can be produced in vaccinated individuals. 

The challenge of developing experimental vaccines that are both safe and effective has led to two opposing approaches in HSV vaccine development: increasing the efficacy of subunit vaccines and increasing the safety of live-attenuated vaccines.

HSV529 Vaccine Dosage

The vaccine candidate was delivered by intramuscular injections. Each dose in the last clinical trial was a 0.5-mL solution containing 1 × 107 plaque-forming units of HSV529.

HSV529 Vaccine Updates

August 2019: This first-in-human study of the replication-defective HSV vaccine HSV529 showed that it was safe and well-tolerated, with evidence of immunogenicity in HSV-naive and previously infected subjects, and elicited neutralizing antibody and modest CD4+T-cell responses in HSV-seronegative vaccinees.

  • 89 percent of vaccinees experienced mild to moderate solicited injection site reactions compared with 47 percent of placebo recipients
  • 64 percent of vaccinees experienced systemic reactions compared with 53 percent of placebo recipients
  • 78 percent of HSV1 /HSV2 vaccine recipients had a greater than 4-fold rises in neutralizing antibody titer after 3 doses of vaccine, whereas none of the participants in the other serogroups had such responses
  • HSV2-specific CD4+ T-cell responses were detected in 36% 46%, and 27%, of HSV1 /HSV2 , HSV1 /HSV2 , and HSV1 /HSV2 participants, respectively, 1 month after the 3rd dose of vaccine
  • CD8+ T-cell responses were detected in 14%, 8%, and 18% of participants in each group, respectively

Prior studies to prevent HSV infection have focused on subunit vaccines with a goal to induce neutralizing antibodies. HSV2 dl5-29 is a replication-defective HSV2 vaccine that can infect cells and should result in a broader immune response. Based on animal studies demonstrating that HSV2 dl5-29 was superior to an HSV2 glycoprotein D (gD2) subunit vaccine.

October 8, 2015 - Phase 1 Clinical Trial for HSV529 Vaccine in HSV-2 Seropositive Adults launches. Last updated on January 14, 2019.

October 16, 2014 - Sanofi Pasteur, the vaccines division of Sanofi and Immune Design Corp., a clinical-stage immunotherapy company, today announced that they have entered into a broad collaboration for the development of a herpes simplex virus (HSV) immune therapy.

HSV529 Vaccine Clinical Trials

Clinical Trial NCT01915212:  Study of the Safety of a Particular Herpes Vaccine in Adults With or Without Herpes Infection (Completed)

  • The goals of the study are to determine:
    • the safety of HSV529 vaccine in persons with or without HSV infection
    • the ability of the vaccine to elicit immune responses to HSV-2 
    • including virus-specific antibodies and T cell responses to the virus
  • Three groups of 20 subjects each will be randomized and will receive 3 doses of HSV529 (15 subjects per group) or saline placebo injection (5 subjects per group).
  • Each subject will be followed for 6 months after the last dose of the vaccine.
  • The 3 groups will be (a) subjects who were infected with HSV-2 in the past but may or may not have been infected with HSV-1 (HSV-1+/-/HSV-2+), (b) subjects who have been infected only with HSV-1 (HSV-1+/HSV-2-), and (c) subjects who have not been infected with HSV-1 or HSV-2 (HSV-1-/HSV-2-).
  • Vaccine or placebo will be administered on Day 0 and approximately 1 month and 6 months after enrollment.

Herpes vaccine news is published by Precision 


January 16th, 2020