A Study of mRNA-1283.222 Injection Compared With mRNA-1273.222 Injection in Participants ≥12 Years of Age to Prevent COVID-19

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the safety, reactogenicity, and relative vaccine efficacy (rVE) of the mRNA-1283.222 vaccine as well as its immunogenicity in comparison to the mRNA-1273.222 vaccine.

Official Title
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A Randomized, Observer-Blind, Active-Controlled Phase 3 Study to Investigate the Safety, Immunogenicity, and Relative Vaccine Efficacy of mRNA-1283.222 Administered as a Booster Dose Compared With mRNA-1273.222 in Participants Aged 12 Years and Older for the Prevention of COVID-19

Conditions
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COVID-19

Intervention / Treatment
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* Biological: mRNA-1283.222
* Biological: mRNA-1273.222


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Investigator's assessment that the participant understands and is willing and physically able to comply with protocol-mandated follow-up, including all procedures. For female participants of childbearing potential: negative pregnancy test, adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, and agreement to continue adequate contraception or abstinence through 90 days following the vaccine administration. Has previously received a primary series of an authorized/approved COVID-19 vaccine. For participants ≥18 years of age, at least 1 booster dose must have also been received. Proof of prior vaccination is required. A heterologous vaccine regimen is acceptable. Key Exclusion Criteria: Has had close contact, as defined by the Centers for Disease Control and Prevention (CDC), with someone who had a SARS-CoV-2 infection in the past 14 days, or COVID-19 in the past 10 days. Participant is acutely ill or febrile (temperature ≥38.0 degree Celsius [°C]/100.4 degree Fahrenheit [°F]) 72 hours prior to or at the Screening Visit or Day 1. Any medical, psychiatric, or occupational condition, including reported history of substance abuse, that, in the opinion of the investigator, might pose additional risk due to participation in the study or could interfere with the interpretation of study results. Has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 181 days prior to Screening (for corticosteroids ≥10 mg/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study. Has received or plans to receive any licensed vaccine ≤60 days prior to the study injection (Day 1) or plans to receive a licensed vaccine within 60 days after the study injection. Has received systemic immunoglobulins or blood products within 90 days prior to the Screening Visit or plans to receive during the study. Has donated ≥450 milliliters (mL) of blood products within 28 days prior to the Screening Visit or plans to donate blood products during the study. Has participated in an interventional clinical study within 28 days prior to the Screening Visit based on the medical history interview or plans to do so while participating in this study. Note: Other inclusion and exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 12 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: mRNA-1283.222<br>Participants will receive single intramuscular (IM) injection of mRNA-1283.222 on Day 1. | Biological: mRNA-1283.222<br>* Sterile liquid for injection<br>|
| Experimental: mRNA-1273.222<br>Participants will receive single IM injection of mRNA-1273.222 on Day 1. | Biological: mRNA-1273.222<br>* Sterile liquid for injection<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Geometric Mean Ratio (GMR) of Omicron BA.4/5 mRNA-1283.222 Over the Omicron BA.4/5 mRNA-1273.222 After the Booster Dose |  | Day 29 | 
| Seroresponse Rate (SRR) Difference of Omicron BA.4/5 Between mRNA-1283.222 and mRNA-1273.222 After the Booster Dose | Seroresponse at the participant level is defined as an antibody value change from baseline below the lower limit of quantification (LLOQ) to ≥4 × LLOQ, or at least a 4-fold rise if baseline is ≥LLOQ and <4 × LLOQ, or at least a 2-fold rise if baseline is ≥4 × LLOQ. | Day 29 | 
| GMR of the Ancestral SARS-CoV-2 D614G mRNA-1283.222 Over the Ancestral SARS-CoV-2 D614G mRNA-1273.222 After the Booster Dose |  | Day 29 | 
| SRR Difference of Ancestral SARS-CoV-2 D641G Between mRNA-1283.222 and mRNA-1273.222 After the Booster Dose | Seroresponse at the participant level is defined as an antibody value change from baseline below the (LLOQ) to ≥4 × LLOQ, or at least a 4-fold rise if baseline is ≥LLOQ and <4 × LLOQ, or at least a 2-fold rise if baseline is ≥4 × LLOQ. | Day 29 | 
| rVE of mRNA-1283.222 and mRNA-1273.222 to Prevent the First Event of COVID-19 | The rVE is defined as the percent of reduction in the hazards of the first occurrence of COVID-19 (mRNA-1283.222 vs. mRNA-1273.222) starting 14 days after the booster dose. | From 14 days after injection to Day 365 | 
| Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs) |  | Up to Day 7 (7-day follow-up after vaccination) | 
| Number of Participants with Unsolicited Adverse Events (AEs) |  | Up to Day 28 (28-day follow-up after vaccination) | 
| Number of Participants with Any Serious AEs (SAEs), Medically Attended AEs (MAAEs), AEs Leading to Withdrawal From Study, and AEs of Special Interest (AESIs) |  | Day 1 to end of study (EOS) (Day 365) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Geometric Mean Titers (GMTs) of Omicron BA.4/5 and Ancestral SARS-CoV-2 D614G |  | Days 91, 181, and 365 | 
| SRR Against Omicron BA.4/5 and Ancestral SARS-CoV-2 D614G | Seroresponse at the participant level is defined as an antibody value change from baseline below the (LLOQ) to ≥4 × LLOQ, or at least a 4-fold rise if baseline is ≥LLOQ and <4 × LLOQ, or at least a 2-fold rise if baseline is ≥4 × LLOQ. | Days 29, 91, 181, and 365 | 
| Number of Participants with a SARS-CoV-2 Infection (Symptomatic or Asymptomatic) |  | From 14 days after injection to Day 365 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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mRNA-1283.222, mRNA-1273.222, SARS-CoV-2, SARS-CoV-2 Vaccine, Coronavirus, Virus Diseases, Messenger RNA, COVID-19, COVID-19 Vaccine, Moderna