Vaccine Info

HSV529 Herpes Vaccine

Last Reviewed
January 23, 2021

HSV529 Herpes Vaccine Description

HSV529 is a herpes vaccine candidate classified as a replication-defective virus. The virus possesses all the wild-type HSV virus components except two proteins UL5 and UL29, involved in viral DNA replication. 

This replication-defective HSV-2 vaccine can infect cells and result in a broader immune response. HSV529 uses a replication-defective mutant virus genetically altered to prevent the virus from replicating, says Sanofi.

Vaccine-elicited protection against HSV is challenging to achieve due to herpesviruses' ability 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 produced in vaccinated individuals.  

The Sanofi Pasteur vaccine candidate HSV529 is derived from HSV-2 strain 186, produced in Vero cells expressing HSV2 UL5 and UL29. 

In October 2014, Sanofi Pasteur and Immune Design announced a collaboration: Sanofi Pasteur contributed HSV529, a clinical-stage replication-defective HSV vaccine product candidate, and Immune Design will contribute G103, its preclinical trivalent vaccine product candidate.

On January 10, 2020, a phase 1/2 study, Safety, and Efficacy of 4 Investigational HSV 2 vaccines, evaluating 6 formulations, launched: Identifier: NCT04222985. Last Update Posted: November 27, 2020. The estimated Primary Completion Date is May 2021.

About Sanofi Pasteur.

HSV529 Herpes Vaccine Indication

The HSV529 herpes vaccine candidate is indicated to treat herpes simplex virus (HSV). Worldwide, about 400 million people are infected with herpes simplex virus type 2 (HSV-2), the predominant cause of genital herpes, says the CDC.

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.

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 the B virus, occasionally infects humans. All herpes viruses can establish latent infection within specific tissues, which are characteristic of each virus.

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 live-attenuated vaccines' safety.

HSV529 Herpes Vaccine Dosage

The HSV529 vaccine candidate was delivered by intramuscular injections (deltoid muscle) as a 0.5 ml solution containing 1 x 10(7) plaque-forming units on day 0, one month after the first dose (day 30), and then six months after the first dose (day 180).

HSV529 Herpes Vaccine Updates

August 7, 2020 - The phase 2 study, 'Safety and Efficacy of 4 Investigational HSV 2 Vaccines in Adults With Recurrent Genital Herpes Caused by HSV 2 (HSV15)' was last updated on September 18, 2020.

January 10, 2020 - Phase 1 and 2 studies were posted. The studies' primary objectives are: To describe the safety profile of different investigational vaccine regimens against herpes simplex virus type 2 (HSV-2).To evaluate the efficacy of the investigational vaccine regimens concerning the frequency of herpes simplex virus (HSV) deoxyribonucleic acid (DNA) detection in the genital area (shedding rate) following a 2 dose vaccine schedule; the proportion of participants free of HSV genital recurrence at 6 months after the 2-dose vaccine schedule. Allocation: Randomized, 381 participants.

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.

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 Herpes Vaccine Clinical Trials

Clinical Trial NCT04222985: Phase 1/2 Study of the Safety and Efficacy of 4 Investigational HSV 2 Vaccines in Adults With Recurrent Genital Herpes Caused by HSV 2 (HSV15). Last Update Posted: November 27, 2020.

Clinical Trial NCT01915212: Phase 1 study of the Safety of a Particular Herpes Vaccine in Adults With or Without Herpes Infection (Completed). HSV529 vaccine was safe and elicited neutralizing antibody and modest CD4+ T-cell responses in HSV-seronegative vaccines—Last Update Posted: February 6, 2020.

ClinicalTrial NCT02571166:  The purpose of the phase 1 study is to determine the safety of the HSV529 vaccine in healthy volunteers with HSV infection and determine if administration of the HSV529 vaccine increases the immune response in genital skin. Last Update Posted: January 14, 2019.

PrecisionVaccinations publishes herpes vaccine news.