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Completed

NCT Number: NCT05137236

A Study to Evaluate the Immunogenicity and Safety of mRNA-1283 COVID-19 Vaccine Boosters

The main goal of Part A of this study is to assess the safety, reactogenicity, and immunogenicity of the study vaccine candidates. The main goal of Part B of this study is to assess the safety, reactogenicity, and immunogenicity of the mRNA-1283.529 booster vaccine candidate.

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Key information

Conditions

SARS-CoV-2 COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

MedPharmics, LLC, Phoenix, Arizona, United States

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About this study

Part A of this study will assess whether a single dose of mRNA-1283 at three different dose levels or mRNA-1283.211 at two different dose levels will boost antibody responses to the Wuhan-Hu-1 (ancestral strain of SARS-CoV-2) virus, and to the B.1.351 variant, and potentially other SARS-CoV-2 variants, and it will also be used to select a dose for subsequent clinical evaluation. The study will include an active comparator group of participants who will receive mRNA-1273.

Participants in Part A who received the primary series of mRNA-1273 with appropriate documentation at least 6 months prior will be randomized 1:1:1:1:1:1 to receive a single boost of mRNA-1283 at one of three dose levels, a single boost of mRNA-1283.211 at one of two dose levels, or a single dose of the active comparator, mRNA-1273.

Part B of this study will assess whether a single dose of mRNA-1283.529 at two different dose levels as the second booster after a first booster of mRNA- 1273, at least 3 months prior, will boost antibody response to the ancestral strain of the SARS-CoV-2 virus, the B.1.1.529 variant, and potentially other SARS-CoV-2 variants, and inform dose selection for mRNA-1283.529 booster vaccine candidate for subsequent clinical evaluation.

Participants in Part B who received the primary series of mRNA 1273 and who received a first booster dose of mRNA-1273 at least 3 months prior will be enrolled in a 1:1 ratio to receive a single boost of mRNA 1283.529 at one of two dose levels.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Female participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause.
  • Female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (Day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to Day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding.
  • Participant must have received their second dose of the mRNA-1273 primary series at least 6 months prior to screening and enrollment (Part A) or have received the mRNA-1273 series and an mRNA-1273 booster dose at least 3 months prior to screening and enrollment (Part B).

Exclusion criteria

  • Had significant exposure to someone with SARS-CoV-2 infection or COVID-19 in the past 14 days, defined by the US Centers for Disease Control and Prevention (CDC) as a close contact of someone who has COVID-19.
  • Is acutely ill or febrile (temperature ≥38.0 degree Celsius [°C]/100.4 degree Fahrenheit [°F]) less than 72 hours prior to or at the screening visit or Day 1.
  • Has a medical, psychiatric, or occupational condition that may pose additional risk as a result of participation, or that could interfere with safety assessments or interpretation of results according to the investigator's judgment.
  • Has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids ≥10 milligrams [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 ≤28 days prior to the injection (Day 1) or plans to receive a licensed vaccine within 28 days before or after the study injection, with the exception of influenza vaccines, which may be given 14 days before or after receipt of a study vaccine.
  • Has received systemic immunoglobulins or blood products within 3 months prior to the screening visit, or plans to receive these 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.
  • Plans to participate in an interventional clinical trial of an investigational vaccine or drug while participating in this study.

Note: Other inclusion and exclusion criteria may apply.

Treatment and study plan

mRNA-1283

Biological

Sterile liquid for injection

mRNA-1283.211

Biological

Sterile liquid for injection

mRNA-1273

Biological

Sterile liquid for injection

mRNA-1283.529

Biological

Sterile liquid for injection

Primary outcomes

  1. Parts A and B: Number of Participants With Solicited Local and Solicited Systemic Reactogenicity Adverse Reactions (ARs)

    Time frame: Up to Day 7

    An AR is any adverse event (AE) related to the IP injection. Solicited local ARs included pain at injection site, erythema (redness) at injection site, swelling (hardness) at injection site, localized axillary swelling or tenderness ipsilateral to the injection arm, and groin or underarm swelling or tenderness ipsilateral to the side of injection. Solicited systemic ARs included headache, fatigue, myalgia (muscle aches all over the body), arthralgia (aching in several joints), nausea/vomiting, fever, chills, irritability/crying, sleepiness, and loss of appetite. Note, not all solicited ARs were considered AEs. The Investigator determined if solicited AR was also to be recorded as an AE. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.

  2. Parts A and B: Number of Participants With Unsolicited AEs

    Time frame: Up to Day 28

    An unsolicited AE was defined as any AE reported by the participant that was not specified as a solicited AR in the protocol or was specified as a solicited AR but started outside the protocol-defined period for reporting solicited ARs. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.

  3. Parts A and B: Number of Participants With Serious Adverse Events (SAEs), Medically Attended AEs (MAAEs), AEs Leading to Withdrawal From Study Participation and AEs of Special Interest (AESIs)

    Time frame: Day 1 to Day 366

    SAEs were AEs that resulted in death, were life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, a congenital anomaly or birth defect, or was a medically important event. MAAEs were AEs that lead to an unscheduled visit to a healthcare provider. AESIs were AEs (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program for which ongoing monitoring and immediate notification by the investigator to the Sponsor was required. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.

  4. Part A: Geometric Mean Titer (GMT) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Specific Neutralizing Antibody (nAb) Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Day 29

    The GMT (50% inhibitory dose [ID50]) of nAb against ancestral SARS-CoV-2 and against SARS-CoV-2 variant B.1.351 are reported.

  5. Part A: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Day 29

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  6. Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Day 29

    Seroresponse was defined as an increase of SARS-CoV-2 specific binding antibody (bAb) level or nAb titer to at least 4x lower limit of quantification (LLOQ) if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.

  7. Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Day 29

    The GMT (ID50) of nAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.

  8. Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Day 29

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  9. Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Day 29

    Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.

Secondary outcomes

  1. Part A: GMT of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Days 1, 29, 91, 181, and 366

    The GMT (ID50) of nAb against ancestral SARS-CoV-2 and against SARS-CoV-2 Variant B.1.351 are reported.

  2. Part A: GMT of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Days 1, 29, 91, 181, and 366

    The GMT of bAb against ancestral SARS-CoV-2 and against SARS-CoV-2 Variant B.1.351 are reported.

  3. Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Days 1, 29, 91, 181, and 366

    The GMT (ID50) of nAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.

  4. Part B: GMT of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Days 1, 29, 91, 181, and 366

    The GMT of bAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.

  5. Part A: GMFR of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Days 29, 91, 181, and 366

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  6. Part A: GMFR of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Days 29, 91, 181, and 366

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  7. Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Days 29, 91, 181, and 366

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  8. Part B: GMFR of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Days 29, 91, 181, and 366

    The GMFR measures the changes in immunogenicity titers or levels within participants.

  9. Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351

    Time frame: Days 29, 91, 181, and 366

    Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.

  10. Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)

    Time frame: Days 29, 91, 181, and 366

    Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.

Other outcomes

  1. Number of Deaths Related to Study Drug

    Time frame: Day 1 to Day 366

    A death that occurred during the study or that came to the attention of the investigator during the study was reported to the Sponsor, whether or not it was considered related to study drug. The investigator assessed causality (that is, whether there is a reasonable possibility that the study drug caused the death). The relationship was characterized using the following classifications: Not related: There was not a reasonable possibility of a relationship to the study drug. The temporal sequence of the death relative to administration of the study drug was not reasonable AND/OR the death was more likely explained by a cause other than the study drug. Related: There was a reasonable possibility of a relationship to the study drug. There was evidence of exposure to the study drug. The temporal sequence of the death relative to the administration of the study drug was reasonable. The death was more likely explained by the study drug than by another cause.

Sponsors and collaborators

Lead sponsor

ModernaTX, Inc.

Industry

Registry information

Official study title

A Phase 2A, Randomized, Stratified, Observer-Blind Study to Evaluate the Immunogenicity and Safety of mRNA-1283 Vaccine Boosters for SARS-CoV-2

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Nov 30, 2021
Registry last updated
Jul 17, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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