A Study of mRNA-1608, a Herpes Simplex Virus -2 (HSV-2) Therapeutic Candidate Vaccine, in Healthy Adults 18 to 55 Years of Age With Recurrent HSV-2 Genital Herpes

A Phase 1/2, Randomized, Observer-Blind, Controlled, Dose-Ranging Study of mRNA-1608, an HSV-2 Therapeutic Candidate Vaccine, in Healthy Adults 18 to 55 Years of Age With Recurrent HSV-2 Genital Herpes

The purpose of this study is to generate safety and immunogenicity data and establish a proof-of-concept of clinical benefit of the mRNA-1608 vaccine candidate.

Participants with a history of recurrent genital herpes will be randomly assigned in a 1:1:1:1 ratio to receive mRNA-1608 at 1 of the 3 dose levels or control (BEXSERO) administered as 2 doses at 0 and 2 months (Day 1 and Day 57).

Inclusion Criteria:

• Participant has a diagnosis of genital HSV-2 infection for at least 1 year before the Screening Visit.
• Seropositive for HSV-2 as determined by Western Blot.
• Participant has a history of recurrent genital herpes defined as at least 3 and no more than 9 reported genital herpes recurrences in the 12 months preceding the Screening Visit, or if currently on suppressive therapy, prior to initiation of suppressive therapy.
• Willing to refrain from taking suppressive antiviral therapy from the Screening Visit until the end of the study.
• Willing to refrain from the use of episodic antiviral therapy during the three 28-day anogenital swabbing periods. Episodic therapy may be used outside the three 28-day swabbing periods.
• For female participants of childbearing potential: negative pregnancy test, adequate contraception, and not currently breastfeeding.

Exclusion Criteria:

• Prior immunization with a vaccine containing HSV antigens.
• History of any form of ocular HSV infection, HSV-related erythema multiforme, or HSV-related neurological complications.
• History of genital HSV-1 infection.
• History of hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) types 1 or 2 (HIV-1, HIV-2).
• Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any mRNA vaccine(s) or any components of the mRNA vaccines.
• Previously received BEXSERO or other vaccine to prevent serogroup B meningococcal disease (also known as meningitis B).
• History of allergic disease or reactions likely to be exacerbated by any component of BEXSERO vaccine.
• Has received or plans to receive any licensed or authorized vaccine, including COVID-19 vaccines, ≤ 28 days prior to the first study injection (Day 1), or plans to receive a licensed or authorized vaccine within 28 days before or after study injection with the exception of licensed influenza vaccines, which may be received more than 14 days before or after any study injection.

Note: Other inclusion and exclusion criteria may apply.