A Phase 1/2 interventional study of Acne mRNA vaccine and Placebo in Acne, sponsored by Sanofi Pasteur, a Sanofi Company. Recruiting at 94 sites in 4 countries. Open to participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-08-21.
Sponsored by Sanofi Pasteur, a Sanofi Company (part of Sanofi) · Phase 1/2, Interventional, and Treatment
The purpose of the trial is to evaluate the safety, efficacy and immunogenicity of up to 3 intramuscular injections of the Acne mRNA vaccine candidate at up to four dose levels in adult participants aged 18 to 45 years with moderate to severe acne.
This trial will consist of a Core Study followed by an optional Long-Term Extension (LTE).
The Core Study will consist of:
Participants from Sentinel Cohorts A and B and from Main Cohort A will be invited to an additional 30-month follow up after completing their last planned Core Study visit to assess the long-term effects of the vaccine. Participants from Main Cohort B will be invited to another LTE study managed through a separate protocol.
Acne vulgaris (acne) is a highly prevalent inflammatory skin disease, especially in adolescents and young adults. Acne is estimated to affect 231 million people worldwide, therefore being one of the most prevalent diseases globally. Acne is also one of the top causes of years lived with disability and nonfatal disease burden. Despite being one of the most prevalent diseases worldwide, the mainstays of acne treatment have remained largely unchanged over the past 30 years. To date there is still no safe and effective treatment that can prevent and cure this disease.
The aim of this first-in-human (FIH), Phase I/II trial is to evaluate the safety, efficacy and immunogenicity of the Acne mRNA vaccine candidate at four different dose levels in adults aged 18 to 45 years with moderate to severe acne. The results of this FIH and proof of concept study will allow selection of the vaccine dose level to be used in Phase III pivotal efficacy trial(s) and to generate preliminary data to further select the vaccine regimen.
790 studies on the registry are indexed under Acne Vulgaris; 93 are open to participants now.
This study's planned enrollment of 800 is above the median of 70 across 672 interventional studies indexed under Acne Vulgaris.
Browse Acne Vulgaris studies →Sanofi Pasteur, a Sanofi Company is the lead sponsor of 374 studies on the registry; 4 are open to participants now.
Of its 94 completed or terminated interventional studies of FDA-regulated products, 73 (78%) have results posted.
First submitted after Sanofi Pasteur became part of Sanofi.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participants are excluded from the study if any of the following criteria apply:
The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Two administrations of the Acne mRNA vaccine will be injected in three increasing doses
Biological: Acne mRNA vaccine
Two administrations of placebo will be injected
Other: Placebo
Three administrations of the Acne mRNA vaccine will be injected in two increasing doses
Biological: Acne mRNA vaccine
Three administrations of placebo will be injected
Other: Placebo
Two administrations of the Acne mRNA vaccine will be injected in three increasing doses
Biological: Acne mRNA vaccine
Two administrations of placebo will be injected
Other: Placebo
Three administrations of the Acne mRNA vaccine will be injected in two increasing doses
Biological: Acne mRNA vaccine
Three administrations of placebo will be injected
Other: Placebo
Pharmaceutical form: Liquid suspension for injection Route of administration: intramuscular
Pharmaceutical form: Liquid solution for injection Route of administration: intramuscular
Core Study - Sentinel Cohorts A and B: Number of participants with unsolicited systemic AEs
Presence of unsolicited systemic adverse events (AEs) reported
Time frame: 30 minutes after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with solicited injection site and systemic reactions
Presence of solicited injection site and systemic reactions (ie, pre-listed in the participant diary \[PDi\] and in the case report form \[CRF\])
Time frame: Up to 7 days after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with unsolicited AEs
Time frame: Up to 28 days after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with MAAEs
Presence of medically attended adverse events (MAAEs)
Time frame: Up to 6 months after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with SAEs
Presence of all serious adverse events (SAEs)
Time frame: Up to 6 months after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with AESIs
Presence of AEs of special interest (AESIs)
Time frame: Up to 6 months after each administration
Core Study - Sentinel Cohorts A and B: Number of participants with out-of-range biological test results (including shift from baseline values)
Time frame: Through 7 days after administration (Day 8)
Core Study - Main Cohort A: Percentage change from baseline (Day 1) in the number of inflammatory acne lesions on face
Time frame: At 2 months post last administration
Core Study - Main Cohort A: Percentage change from baseline (Day 1) in the number of non-inflammatory acne lesions on face
Time frame: At 2 months post last administration
Core Study - Main Cohort B: Percentage change from baseline (Day 1) in the total number of acne lesions on face at
Time frame: At 2 months post last administration
Long-Term Extension - Sentinel Cohorts A, B and Main Cohort: Number of participants with SAEs and AESIs
Presence of all serious adverse events (SAEs) and adverse events of special interest (AESIs)
Time frame: Up to 38 or 40 months after first administration
Core Study - Sentinel Cohorts A, B and Main Cohorts A and B: Assessment of accine-antigen-specific serum antibody titers
Time frame: From baseline (Day 1) to 6 months post last administration
Core Study - Main Cohort B: Absolute change from baseline (Day 1) in the total number of inflammatory acne lesions on face
Time frame: At 1 month post first administration until 9 months post last administration
Core Study - Main Cohorts A and B: Percentage change from baseline (Day 1) in the number of inflammatory acne lesions on face
Time frame: At 1 month post first administration until 6 or 9 months post last administration
Core Study - Main Cohorts A and B: Absolute change from baseline (Day 1) in the number of non-inflammatory acne lesions on face
Time frame: At 1 month post first administration until 6 or 9 months post last administration
Core Study - Main Cohorts A and B: Absolute change from baseline in IGA score
Time frame: At 1 month post first administration until 6 or 9 months post last administration
Core Study - Main Cohorts A and B: Number of participants with unsolicited systemic AEs
Presence of unsolicited systemic adverse events (AEs) reported
Time frame: 30 minutes after each administration
Core Study - Main Cohorts A and B: Number of participants with solicited injection site and systemic reactions
Presence of solicited injection site and systemic reactions (ie, pre-listed in the participant diary \[PDi\] and in the case report form \[CRF\])
Time frame: Up to 7 days after each administration
Core Study - Main Cohorts A and B: Number of participants with unsolicited AEs
Time frame: Up to 28 days after each administration
Core Study - Main Cohorts A and B: Number of participants with MAAEs
Presence of medically attended adverse events (MAAEs)
Time frame: Up to 6 or 9 months after each administration
Core Study - Main Cohorts A and B: Number of participants with SAEs
Presence of all serious adverse events (SAEs)
Time frame: Up to 6 or 9 months after each administration
Core Study - Main Cohorts A and B: Number of participants with AESIs
Presence of AEs of special interest (AESIs)
Time frame: Up to 6 or 9 months after each administration
Core Study - Main Cohorts A and B: Number of participants with out-of-range biological test results (including shift from baseline values)
Time frame: Up to 7 days after each administration
Plan to share: Yes — Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
Started Apr 2024 (actual). Primary completion is estimated for Nov 2028, 55 months after the start.
Of 13 phase 1/2 interventional studies under Acne Vulgaris, half reached primary completion within 16 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 22. This study's planned 55 months is above that.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Sanofi Pasteur, a Sanofi Company →