Phase 1/2 Study of Chlamydia Trachomatis mRNA Vaccine in Adults Aged 18 to 29 Years

NCT ID: NCT06891417

Last Updated: 2025-07-20

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: PHASE1/PHASE2
• Total Enrollment: 1560 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-03-27
• Study Completion Date: 2028-01-03

Brief Summary

The purpose of this study is to evaluate the safety, efficacy, and immunogenicity of different dose levels (low, medium, and high) of Chlamydia messenger ribonucleic acid (mRNA) Vaccine candidate in adult participants aged 18 to 29 years.

This study will consist of 3 Sentinel Cohorts and a Main Cohort, with the Sentinel Cohorts assessing the safety of the different dose levels in a stepwise manner.

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

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: SEQUENTIAL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: TRIPLE

Study Groups

Sentinel Cohort A Group 1: Chlamydia trachomatis Seronegative

Participants will receive three low dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort B Group 2: Chlamydia trachomatis Seronegative

Participants will receive three medium dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort C Group 3: Chlamydia trachomatis Seronegative

Participants will receive three high dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort A, B and C Group 4: Chlamydia trachomatis Seronegative

Participants will receive three injections of Placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

Pharmaceutical Form:

Solution for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort A Group 5: Chlamydia trachomatis Seropositive

Participants will receive three low dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort B Group 6: Chlamydia trachomatis Seropositive

Participants will receive three medium dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort C Group 7: Chlamydia trachomatis Seropositive

Participants will receive three medium dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Sentinel Cohort A, B and C Group 8: Chlamydia trachomatis Seropositive

Participants will receive three injections of Placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

Pharmaceutical Form:

Solution for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 9: Chlamydia trachomatis Seronegative

Participants will receive three low dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 10: Chlamydia trachomatis Seronegative

Participants will receive three medium dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 11: Chlamydia trachomatis Seronegative

Participants will receive three high dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 12: Chlamydia trachomatis Seronegative

Participants will receive three injections of Placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

Pharmaceutical Form:

Solution for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 13: Chlamydia trachomatis Seropositive

Participants will receive three low dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 14: Chlamydia trachomatis Seropositive

Participants will receive three medium dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 15: Chlamydia trachomatis Seropositive

Participants will receive three high dose injections of Chlamydia mRNA Vaccine

Group Type: EXPERIMENTAL

Chlamydia mRNA Vaccine

Intervention Type: BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Main Cohort Group 16: Chlamydia trachomatis Seropositive

Participants will receive three injections of Placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

Pharmaceutical Form:

Solution for injection

Route of Administration:

Intramuscular injection

Interventions

Chlamydia mRNA Vaccine

Pharmaceutical Form: Suspension for injection

Route of Administration:

Intramuscular injection

Intervention Type: BIOLOGICAL

Placebo

Pharmaceutical Form:

Solution for injection

Route of Administration:

Intramuscular injection

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Aged 18 to 29 years on the day of inclusion
• New sex partner within the past 6 months, or more than one current sex partner, or partner with known previous or coexisting sexually transmitted infection (STI), or inconsistent condom use
• 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

Exclusion Criteria

• 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
• 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

Note: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 29 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Sanofi

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

Investigational Site Number : 0360002

Bruce, Australian Capital Territory, Australia

Investigational Site Number : 0360006

Maroubra, New South Wales, Australia

Investigational Site Number : 0360005

Sydney, New South Wales, Australia

Investigational Site Number : 0360001

Albion, Queensland, Australia

Investigational Site Number : 0360004

Morayfield, Queensland, Australia

Investigational Site Number : 0360003

Southport, Queensland, Australia

Countries

Australia

Other Identifiers

U1111-1308-7349

Identifier Type: OTHER

Identifier Source: secondary_id

VAV00023

Identifier Type: -

Identifier Source: org_study_id