New shot aims to tame genital herpes outbreaks
NCT ID NCT05298254
First seen Jun 26, 2026 · Last updated Jun 26, 2026
Summary
This study tested an experimental immunotherapy for herpes simplex virus (HSV) in 505 people. In the first part, healthy adults aged 18-40 received different vaccine-like formulations to check safety. In the second part, adults aged 18-60 with recurrent genital herpes got the treatment to see if it reduces outbreaks. The goal is to find a safe and effective way to control the virus.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- HSV-targeted immunotherapy (vaccine-like shots)
- What this could lead to
- If successful, this could lead to a treatment that reduces or prevents genital herpes outbreaks, helping people manage the condition better.
- What could go wrong
- This is an early-phase trial (phase 1/2), so it is primarily testing safety and immune response. The treatment may not reduce outbreaks, and side effects like pain, redness, or fever are possible.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1/2
Runs two stages together: safety and dose first, then whether the treatment works.
- Participants
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505 people
The number who actually took part.
- Started
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Mar 2022
- Finished
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Jun 2025
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 60 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * • Participants, who, in the opinion of the investigator, can and will comply with the requirements of the Protocol. * Written informed consent obtained from the participant prior to performance of any study-specific procedure. * Women of non-childbearing potential can be enrolled in the study. * Women of childbearing potential can be enrolled in the study, if the participant: * Has practiced highly effective contraception for one month prior to study intervention administration, and, * Has a negative pregnancy test result at the Screening visit and on the day of each study intervention administration, and, * For PART I: Has agreed to continue highly effective contraception until the end of the study. * For PART II: Has agreed to continue highly effective contraception until 3 months after last study intervention administration. * Seronegative for human immunodeficiency virus (HIV), as determined by laboratory screening tests. Participants documented to be seropositive to HIV will not be eligible for study participation. * Only for PART I: Healthy participants as established by medical history and physical examination, at the discretion of the investigator, before entering into the study. * Only for PART I: Man or woman aged 18 to 40 years, included, at the time of the first study intervention administration. * Only for PART I: Seronegative for HSV-2 as determined by Western blot performed at the Screening visit. * Only for PART II: Participants with recurrent genital herpes and with no significant health problems as established by medical history and physical examination, at the discretion of the investigator, before entering the study. * Diagnosis of genital herpes for at least one year before the Screening visit. * History of self-reported or documented recurrent lesional genital herpes frequency of at least 3 and no more than 9 reported clinical recurrences in the 12 months preceding the screening visit, or, if still on suppressive therapy within 3 months before the Screening visit, prior to initiation of suppressive therapy. * Only for PART II: Man or woman aged 18 to 60 years, included, at the time of the first study intervention administration. * Only for PART II: Seropositive for HSV-2 as determined by serological testingperformed at the Screening visit, or having documented laboratory-confirmed HSV 2 genital herpes (i.e., HSV-2 DNA positive by a molecular technique such as polymerase chain reaction \[PCR\], or HSV-2 seropositive by a type-specific serology assay such as Western Blot or other immunoassay).Only for PART II (shedding sub-cohort): Participants agreeing to collect 2 swabs per day from anogenital area for the full duration of the 5 swabbing periods planned in the study. * Only for PART II (shedding sub-cohort) after baseline completion: Participants having collected at least 45 out of 56 anogenital swabs during the baseline period. Exclusion Criteria: Medical Conditions * Acute or chronic clinically significant pulmonary, cardiovascular, hepatic, endocrine, or renal functional abnormality, as determined by physical examination or laboratory screening tests. * Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study or that would interfere with the efficacy and immunogenicity assessments planned in this study. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination. * Hypersensitivity to latex. * Recurrent history or uncontrolled neurological disorders or seizures. * Haematological and/or biochemical parameters outside the normal laboratory ranges at the Screening visit, unless the laboratory abnormalities are considered not clinically significant by the investigator. * Body mass index =\<18 kg/m\^2 or \>=35 kg/m\^2. * Past or current Guillain-Barré syndrome. * History of any form of ocular HSV infection, HSV-related erythema multiforme, or HSV-related neurological complications. Prior/Concomitant Therapy * Use of any investigational or non-registered product other than the study intervention during the period beginning as of the Screening visit, or planned use during the study period. * Planned administration/administration of a vaccine not foreseen by the Protocol in the period starting 15 days before each dose and ending 15 days after each dose of study intervention administration. * Administration or planned administration of long-acting immune-modifying drugs at any time during the study period. * Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 3 months before the first dose of study intervention or planned administration during the study period. * Chronic administration of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first study intervention dose. For corticosteroids, this will mean prednisone equivalent \>= 20 mg/day, or equivalent. Inhaled, intra articular and topical steroids are allowed. * Prior receipt of another vaccine containing HSV antigens. * Only for PART II: Planned use of suppressive anti-HSV therapy from the Screening visit until the end of the study. * Only for PART II: Planned use of tenofovir therapy, or other medication known to affect HSV shedding or genital lesions from the Screening visit until the end of the study. Only for PART II: Planned use of topical antiviral medication in the anogenital region from the Screening visit until the end of the study. * Only for PART II: Planned use of any episodic antiviral medications during the swabbing periods (including the baseline period) (only for the shedding sub-cohort). Prior/Concurrent Clinical Study Experience • Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention. Other Exclusions * Pregnant or lactating women. * Woman planning to become pregnant or planning to discontinue contraceptive precautions in the period starting from the Screening visit up to 3 months post-last dose of study intervention.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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GSK Investigational Site
Phoenix, Arizona, 85015, United States
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GSK Investigational Site
Wichita, Kansas, 67207, United States
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GSK Investigational Site
Kansas City, Missouri, 64114, United States
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GSK Investigational Site
Rochester, New York, 14609, United States
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GSK Investigational Site
Richmond, Virginia, 23219, United States
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GSK Investigational Site
Seattle, Washington, 98105, United States
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GSK Investigational Site
Darlinghurst, New South Wales, 2010, Australia
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GSK Investigational Site
Sydney, New South Wales, 2010, Australia
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GSK Investigational Site
Antwerp, 2000, Belgium
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GSK Investigational Site
Brussels, 1000, Belgium
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GSK Investigational Site
Edegem, 2650, Belgium
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GSK Investigational Site
Ghent, 9000, Belgium
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GSK Investigational Site
Montreal, Quebec, H2L 4E9, Canada
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GSK Investigational Site
Tartu, 50106, Estonia
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GSK Investigational Site
Berlin, 10117, Germany
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GSK Investigational Site
Berlin, 10439, Germany
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GSK Investigational Site
Bochum, 44787, Germany
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GSK Investigational Site
Cologne, 50674, Germany
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GSK Investigational Site
Frankfurt, 60596, Germany
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GSK Investigational Site
Hamburg, 20146, Germany
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GSK Investigational Site
Barcelona, 08001, Spain
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GSK Investigational Site
Barcelona, 08015, Spain
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GSK Investigational Site
Madrid, 28010, Spain
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GSK Investigational Site
Madrid, 28040, Spain
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GSK Investigational Site
Madrid, 28222, Spain
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GSK Investigational Site
Marbella, 29600, Spain
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GSK Investigational Site
Brighton, BN2 1ES, United Kingdom
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GSK Investigational Site
Liverpool, L7 8XP, United Kingdom
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GSK Investigational Site
London, WC1E 6JB, United Kingdom
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GSK Investigational Site
Southampton, SO14 0YG, United Kingdom
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