Chlamydia Trachomatis ImmunizationPhase 1NCT06891417
Phase 1 Study of Chlamydia Trachomatis mRNA Vaccine in Adults.
A Phase 1 study testing Chlamydia mRNA Vaccine in people with Chlamydia Trachomatis Immunization, run by Sanofi at 7 sites in Australia.
Trial summary
The purpose of this study is to evaluate the safety of two doses (Dose 1 and Dose 2) of Chlamydia mRNA Vaccine candidate in adult participants aged 18 to 29 years (Chlamydia trachomatis seronegative) or 18 to 44 years (Chlamydia trachomatis seropositive). Read more about this study
- Who is it for?
- Ages 18 to 44 yearsHealthy volunteers can take part
- Conditions the study is for
- Chlamydia Trachomatis Immunization
- What is being tested?
- Chlamydia mRNA Vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 7 sitesAustralia
- Study dates
- 27 Mar 2025to 3 Nov 2027
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 44 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Aged 18 to 29 years (Chlamydia trachomatis seronegative) or 18 to 44 years (Chlamydia trachomatis seropositive) on the day of inclusion
- A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
- Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be surgically sterile.
- OR
- Is of childbearing potential and agrees to use an effective contraceptive method from at least 4 weeks prior to study intervention administration until at least 4 weeks after the last study intervention administration.
- A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) at the screening visit and before each subsequent study intervention administration.
Who cannot join
- Any screening laboratory parameter with laboratory abnormalities as per local reference range and that are greater than Grade 2 or deemed clinically significant in the opinion of the Investigator.
- Participants who are Chlamydia trachomatis (CT) and/or Neisseria gonorrhea (NG) NAAT positive at screening visit
- Self-reported or documented seropositivity for HIV antigen and/or antibodies (Abs), hepatitis B virus surface antigen (HBsAg), hepatitis B core antibodies (HBcAbs), or hepatitis C virus (HCV) Abs infection at screening visit.
- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
- Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention(s) used in the study or to a product containing any of the same substances.
- Previous history of myocarditis, pericarditis, and/or myopericarditis
Show all 17Show fewer
- Known history of previous history of Guillain-Barre syndrome and other immune mediated demyelinating conditions that include but are not limited to Multiple Sclerosis (MS), Neuromyelitis Optica (NMO), acute disseminated encephalomyelitis (ADEM), Transverse myelitis.
- Screening electrocardiogram (ECG) value that is consistent with possible myocarditis, pericarditis, and/or myopericarditis or screening ECG that demonstrates clinically relevant abnormalities, per investigator, that may affect participant safety or study results.
- Self-reported thrombocytopenia, contraindicating intramuscular injection, based on investigator's judgment.
- Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular injection, based on investigator's judgment.
- Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
- Moderate or severe acute febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
- Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion.
- Receipt of any mRNA vaccine/product in the 2 months preceding study enrollment or planned receipt of any mRNA vaccine/product within the 2 months following any study intervention administration.
- Receipt of any vaccine (other than the study vaccine) in the 4 weeks preceding any study intervention administration or planned receipt of any vaccine (other than the study vaccine) in the 4 weeks following any study intervention administration, except influenza which may be received at least 2 weeks before or 2 weeks after any study vaccination.
- Receipt of immune globulins, blood, or blood-derived products in the past 3 months.
- The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.
Trial locations and contacts
7 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Trial Transparency email recommended (Toll free for US & Canada) contact
7 sites in 1 country
Australia7 sites, 7 recruiting
- Recruiting
Investigational Site Number : 0360001
Albion, Queensland, 4010
- Recruiting
Investigational Site Number : 0360002
Bruce, Australian Capital Territory, 2617
- Recruiting
Investigational Site Number : 0360006
Maroubra, New South Wales, 2035
- Recruiting
Investigational Site Number : 0360010
Melbourne, Victoria, 3000
- Recruiting
Investigational Site Number : 0360004
Morayfield, Queensland, 4506
- Recruiting
Investigational Site Number : 0360003
Southport, Queensland, 4222
- Recruiting
Investigational Site Number : 0360005
Sydney, New South Wales, 2010
About this study
Official title: A Phase 1, Randomized, Placebo-controlled, Multi-arm, Study to Evaluate the Safety of a Chlamydia Trachomatis mRNA Vaccine Candidate in Adults
The purpose of this study is to evaluate the safety of two doses (Dose 1 and Dose 2) of Chlamydia mRNA Vaccine candidate in adult participants aged 18 to 29 years (Chlamydia trachomatis seronegative) or 18 to 44 years (Chlamydia trachomatis seropositive). There will also be an assessment to potentially obtain an early immunogenicity signal of the Chlamydia mRNA vaccine candidate.
This study will consist of 2 Cohorts assessing the safety of the two different doses: Cohort A (Dose 1 or placebo) and Cohort B (Dose 2 or placebo).
All participants will be followed up to 12 months after the last study intervention administration. Thus, the expected duration of the participant's involvement will be 18 months.
- Conditions
- Chlamydia Trachomatis Immunization
- Being tested
- Chlamydia mRNA Vaccine, Placebo
- Keywords
- Chlamydia
- Medical subject headings
- Chlamydia Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Chlamydia mRNA VaccineBiological
Pharmaceutical Form: Suspension for injection
Route of Administration:
Intramuscular injection
PlaceboOther
Pharmaceutical Form:
Solution for injection
Route of Administration:
Intramuscular injection
| Study group | Role | What they receive |
|---|---|---|
| Cohort A Group 1: Chlamydia trachomatis Seronegative | Experimental | Participants will receive three dose 1 injections of Chlamydia mRNA Vaccine Receives: Biological: Chlamydia mRNA Vaccine |
| Cohort B Group 2: Chlamydia trachomatis Seronegative | Experimental | Participants will receive three dose 2 injections of Chlamydia mRNA Vaccine Receives: Biological: Chlamydia mRNA Vaccine |
| Cohort A and B Group 3: Chlamydia trachomatis Seronegative | Placebo comparator | Participants will receive three injections of Placebo Receives: Other: Placebo |
| Cohort A Group 4: Chlamydia trachomatis Seropositive | Experimental | Participants will receive three dose 1 injections of Chlamydia mRNA Vaccine Receives: Biological: Chlamydia mRNA Vaccine |
| Cohort B Group 5: Chlamydia trachomatis Seropositive | Experimental | Participants will receive three dose 2 injections of Chlamydia mRNA Vaccine Receives: Biological: Chlamydia mRNA Vaccine |
| Cohort A and B Group 6: Chlamydia trachomatis Seropositive | Placebo comparator | Participants will receive three injections of Placebo Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Presence of immediate unsolicited systemic adverse events (AEs)
Number of participants with immediate unsolicited systemic adverse events (AEs) reported in the 30 minutes after each vaccine injection.
Measured: Within 30 minutes after each vaccine injection
Presence of solicited injection site and systemic reactions
Number of participants with solicited injection site and systemic reactions occurring up to 8 days after each vaccine injection.
Measured: Up to 8 days, including the day of each vaccine injection
Presence of unsolicited AEs
Participants with unsolicited AEs reported up to 28 days after each vaccine injection.
Measured: Up to 28 days after each vaccine injection.
Presence of medically attended adverse events (MAAEs)
Number of participants with MAAEs reported after each vaccine injection and up to 6 months after last vaccine injection.
Measured: Up to 6 months after last vaccine injection
Presence of all serious AEs (SAEs) and all adverse events of special interest (AESIs)
Number of participants with SAEs and all AESIs reported after each vaccine injection and up to 12 months after last vaccine injection
Measured: Up to 12 months after last vaccine injections
Presence of related SAEs, and fatal SAEs
Number of participants with related SAEs, and fatal SAEs throughout the study
Measured: Throughout the study, appriximatley 18 months
Presence of out-of-range biological test results (Sentinel Cohort and Safety Subset of Main Cohort)
Number of participants with out-of-range biological test results up to 8 days after each vaccine injection
Measured: Up to 8 days, including the day of each vaccine injection
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Mar 2025
- Study start27 Mar 2025
- Primary completion3 Nov 2027 (estimated)
- Study completion3 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chlamydia Trachomatis ImmunizationStudies of the same condition, open and under way.
- More trials run by SanofiThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Model description
- Sequential, multi-center
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sanofi
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06891417
- Sponsor's protocol ID
- VAV00023
- Other IDs
- U1111-1308-7349
- Status last verified
- Oct 2026
- First submitted
- 17 Mar 2025
- Last updated
- 2 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- 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
Study at a glance
From the registry record, last updated by the sponsor on 2 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Randomized, Placebo-controlled, Multi-arm, Study to Evaluate the Safety of a Chlamydia Trachomatis mRNA Vaccine Candidate in Adults
- ClinicalTrials.gov ID
- NCT06891417
- Acronym / sponsor ID
- VAV00023
- Conditions
- Chlamydia Trachomatis Immunization
- Keywords
- Chlamydia
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- SanofiIndustry (pharma, biotech, devices)
- Study start
- 27 Mar 2025 (actual)
- Primary completion
- 3 Nov 2027 (estimated)
- Study completion
- 3 Nov 2027 (estimated)
- First posted
- 24 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to evaluate the safety of two doses (Dose 1 and Dose 2) of Chlamydia mRNA Vaccine candidate in adult participants aged 18 to 29 years (Chlamydia trachomatis seronegative) or 18 to 44 years (Chlamydia trachomatis seropositive). There will also be an assessment to potentially obtain an early immunogenicity signal of the Chlamydia mRNA vaccine candidate.
This study will consist of 2 Cohorts assessing the safety of the two different doses: Cohort A (Dose 1 or placebo) and Cohort B (Dose 2 or placebo).
All participants will be followed up to 12 months after the last study intervention administration. Thus, the expected duration of the participant's involvement will be 18 months.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 6
- Model description
- Sequential, multi-center
| Arm | Type | Receives |
|---|---|---|
| Cohort A Group 1: Chlamydia trachomatis Seronegative | Experimental | Biological: Chlamydia mRNA VaccineParticipants will receive three dose 1 injections of Chlamydia mRNA Vaccine |
| Cohort B Group 2: Chlamydia trachomatis Seronegative | Experimental | Biological: Chlamydia mRNA VaccineParticipants will receive three dose 2 injections of Chlamydia mRNA Vaccine |
| Cohort A and B Group 3: Chlamydia trachomatis Seronegative | Placebo comparator | Other: PlaceboParticipants will receive three injections of Placebo |
| Cohort A Group 4: Chlamydia trachomatis Seropositive | Experimental | Biological: Chlamydia mRNA VaccineParticipants will receive three dose 1 injections of Chlamydia mRNA Vaccine |
| Cohort B Group 5: Chlamydia trachomatis Seropositive | Experimental | Biological: Chlamydia mRNA VaccineParticipants will receive three dose 2 injections of Chlamydia mRNA Vaccine |
| Cohort A and B Group 6: Chlamydia trachomatis Seropositive | Placebo comparator | Other: PlaceboParticipants will receive three injections of Placebo |
Who may qualify
- Ages
- 18 to 44 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Aged 18 to 29 years (Chlamydia trachomatis seronegative) or 18 to 44 years (Chlamydia trachomatis seropositive) on the day of inclusion
- A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
- OR
- Is of childbearing potential and agrees to use an effective contraceptive method from at least 4 weeks prior to study intervention administration until at least 4 weeks after the last study intervention administration.
- A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) at the screening visit and before each subsequent study intervention administration.
Key exclusion criteria (17 listed)
- Any screening laboratory parameter with laboratory abnormalities as per local reference range and that are greater than Grade 2 or deemed clinically significant in the opinion of the Investigator.
- Participants who are Chlamydia trachomatis (CT) and/or Neisseria gonorrhea (NG) NAAT positive at screening visit
- Self-reported or documented seropositivity for HIV antigen and/or antibodies (Abs), hepatitis B virus surface antigen (HBsAg), hepatitis B core antibodies (HBcAbs), or hepatitis C virus (HCV) Abs infection at screening visit.
- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
- Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention(s) used in the study or to a product containing any of the same substances.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Chlamydia mRNA VaccinePharmaceutical Form: Suspension for injection Route of Administration: Intramuscular injection | Biological | Cohort A Group 1: Chlamydia trachomatis Seronegative, Cohort A Group 4: Chlamydia trachomatis Seropositive, Cohort B Group 2: Chlamydia trachomatis Seronegative, Cohort B Group 5: Chlamydia trachomatis Seropositive |
| PlaceboPharmaceutical Form: Solution for injection Route of Administration: Intramuscular injection | Other | Cohort A and B Group 3: Chlamydia trachomatis Seronegative, Cohort A and B Group 6: Chlamydia trachomatis Seropositive |
Primary outcome
Presence of immediate unsolicited systemic adverse events (AEs)
Time frame: Within 30 minutes after each vaccine injection
Number of participants with immediate unsolicited systemic adverse events (AEs) reported in the 30 minutes after each vaccine injection.
Presence of solicited injection site and systemic reactions
Time frame: Up to 8 days, including the day of each vaccine injection
Number of participants with solicited injection site and systemic reactions occurring up to 8 days after each vaccine injection.
Presence of unsolicited AEs
Time frame: Up to 28 days after each vaccine injection.
Participants with unsolicited AEs reported up to 28 days after each vaccine injection.
Presence of medically attended adverse events (MAAEs)
Time frame: Up to 6 months after last vaccine injection
Number of participants with MAAEs reported after each vaccine injection and up to 6 months after last vaccine injection.
Presence of all serious AEs (SAEs) and all adverse events of special interest (AESIs)
Time frame: Up to 12 months after last vaccine injections
Number of participants with SAEs and all AESIs reported after each vaccine injection and up to 12 months after last vaccine injection
Presence of related SAEs, and fatal SAEs
Time frame: Throughout the study, appriximatley 18 months
Number of participants with related SAEs, and fatal SAEs throughout the study
Presence of out-of-range biological test results (Sentinel Cohort and Safety Subset of Main Cohort)
Time frame: Up to 8 days, including the day of each vaccine injection
Number of participants with out-of-range biological test results up to 8 days after each vaccine injection
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Nov 2026.
- VAV00023 Plain Language Results SummaryLink provided by the sponsor.
- Individual participant dataSharing planned: 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
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Trial Transparency email recommended (Toll free for US & Canada) contact
7 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Chlamydia mRNA Vaccine in people with Chlamydia Trachomatis Immunization, run by Sanofi at 7 sites in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 2 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 7 sites in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Trial Transparency email recommended (Toll free for US & Canada) (800-633-1610 ext. option 6, Contact-US@sanofi.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Presence of immediate unsolicited systemic adverse events (AEs) (time frame: Within 30 minutes after each vaccine injection). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Nov 2026.