Trial Outcomes & Findings for A Study of an Investigational mRNA-1273.815 COVID-19 Vaccine in Previously Vaccinated Adults (NCT NCT06354998)
NCT ID: NCT06354998
Last Updated: 2025-05-25
Results Overview
Antibody values reported as below the lower limit of quantification (LLOQ) were replaced by 0.5 \* LLOQ. Values reported greater than the upper limit of quantification (ULOQ) were replaced by the ULOQ if actual values were not available. LLOQ was 38 arbitrary unit (AU)/milliliter (mL) and ULOQ was 6960 AU/mL. 95% confidence interval (CI) of GM value was calculated based on the t-distribution of the log-transformed values for antibodies, then back transformed to the original scale for presentation.
COMPLETED
PHASE3
217 participants
Day 15
2025-05-25
Participant Flow
Participant milestones
| Measure |
Investigational mRNA-1273.815
Participants received Investigational mRNA-1273.815 by intramuscular (IM) injection on Day 1.
|
Licensed Spikevax Vaccine
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Overall Study
STARTED
|
108
|
109
|
|
Overall Study
Received Study Vaccination
|
106
|
109
|
|
Overall Study
COMPLETED
|
105
|
109
|
|
Overall Study
NOT COMPLETED
|
3
|
0
|
Reasons for withdrawal
| Measure |
Investigational mRNA-1273.815
Participants received Investigational mRNA-1273.815 by intramuscular (IM) injection on Day 1.
|
Licensed Spikevax Vaccine
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Overall Study
Withdrawal by Subject
|
3
|
0
|
Baseline Characteristics
A Study of an Investigational mRNA-1273.815 COVID-19 Vaccine in Previously Vaccinated Adults
Baseline characteristics by cohort
| Measure |
Investigational mRNA-1273.815
n=106 Participants
Participants received Investigational mRNA-1273.815 by IM injection on Day 1.
|
Licensed Spikevax Vaccine
n=109 Participants
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
Total
n=215 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
48.2 years
STANDARD_DEVIATION 16.09 • n=5 Participants
|
46.0 years
STANDARD_DEVIATION 17.47 • n=7 Participants
|
47.1 years
STANDARD_DEVIATION 16.80 • n=5 Participants
|
|
Sex: Female, Male
Female
|
48 Participants
n=5 Participants
|
52 Participants
n=7 Participants
|
100 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
58 Participants
n=5 Participants
|
57 Participants
n=7 Participants
|
115 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
3 Participants
n=5 Participants
|
5 Participants
n=7 Participants
|
8 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
93 Participants
n=5 Participants
|
85 Participants
n=7 Participants
|
178 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
10 Participants
n=5 Participants
|
19 Participants
n=7 Participants
|
29 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · White
|
82 Participants
n=5 Participants
|
92 Participants
n=7 Participants
|
174 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Black or African American
|
1 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Asian
|
12 Participants
n=5 Participants
|
10 Participants
n=7 Participants
|
22 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Native Hawaiian or other Pacific Islander
|
1 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
1 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Multiple
|
2 Participants
n=5 Participants
|
3 Participants
n=7 Participants
|
5 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Other
|
7 Participants
n=5 Participants
|
2 Participants
n=7 Participants
|
9 Participants
n=5 Participants
|
|
Race/Ethnicity, Customized
Race · Not reported
|
1 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
PRIMARY outcome
Timeframe: Day 15Population: The Per-protocol Immunogenicity Subset (PPIS) included participants who received planned dose of study injection per schedule, complied with immunogenicity testing schedule and had no major protocol deviations that impacted key or critical data.
Antibody values reported as below the lower limit of quantification (LLOQ) were replaced by 0.5 \* LLOQ. Values reported greater than the upper limit of quantification (ULOQ) were replaced by the ULOQ if actual values were not available. LLOQ was 38 arbitrary unit (AU)/milliliter (mL) and ULOQ was 6960 AU/mL. 95% confidence interval (CI) of GM value was calculated based on the t-distribution of the log-transformed values for antibodies, then back transformed to the original scale for presentation.
Outcome measures
| Measure |
Investigational mRNA-1273.815
n=103 Participants
Participants received Investigational mRNA-1273.815 by IM injection on Day 1.
|
Licensed Spikevax Vaccine
n=104 Participants
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Geometric Mean (GM) Value of Neutralizing Antibodies (nAbs) Against SARS-CoV-2-specific Strain at Day 15
|
1180.55 AU/mL
Interval 927.67 to 1502.38
|
1300.25 AU/mL
Interval 1056.39 to 1600.4
|
SECONDARY outcome
Timeframe: Day 1 through Day 15Population: Safety Set included all enrolled participants who received study drug.
An SAE was defined as any AE that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in disability/permanent damage, was a congenital anomaly/birth defect, or was an important medical event. AESIs included thrombocytopenia, new onset of or worsening of the protocol specified neurologic diseases, anaphylaxis, and myocarditis/pericarditis. Number of participants with SAEs, AESIs, and AEs leading to discontinuation up to Day 15 are reported in this outcome measure. A Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.
Outcome measures
| Measure |
Investigational mRNA-1273.815
n=106 Participants
Participants received Investigational mRNA-1273.815 by IM injection on Day 1.
|
Licensed Spikevax Vaccine
n=109 Participants
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Number of Participants With Serious Adverse Events (SAEs), Adverse Events (AEs) of Special Interest (AESIs), and AEs Leading to Withdrawal From the Study
SAEs
|
1 Participants
|
0 Participants
|
|
Number of Participants With Serious Adverse Events (SAEs), Adverse Events (AEs) of Special Interest (AESIs), and AEs Leading to Withdrawal From the Study
AESIs
|
0 Participants
|
0 Participants
|
|
Number of Participants With Serious Adverse Events (SAEs), Adverse Events (AEs) of Special Interest (AESIs), and AEs Leading to Withdrawal From the Study
AEs Leading to Withdrawal
|
0 Participants
|
0 Participants
|
SECONDARY outcome
Timeframe: Day 15Population: The PPIS included participants who received planned dose of study injection per schedule, complied with immunogenicity testing schedule and had no major protocol deviations that impacted key or critical data.
Seroresponse at a participant level was defined as a change from baseline below the LLOQ to equal or above 4 \* LLOQ, or at least a 4-fold rise if baseline was equal to or above the LLOQ. LLOQ was 38 AU/mL.
Outcome measures
| Measure |
Investigational mRNA-1273.815
n=103 Participants
Participants received Investigational mRNA-1273.815 by IM injection on Day 1.
|
Licensed Spikevax Vaccine
n=104 Participants
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Seroresponse Rate of nAb Against the SARS-CoV-2-specific Strain: Percentage of Participants With Seroresponse
|
66.0 percentage of participants
Interval 56.0 to 75.1
|
69.2 percentage of participants
Interval 59.4 to 77.9
|
Adverse Events
Investigational mRNA-1273.815
Licensed Spikevax Vaccine
Serious adverse events
| Measure |
Investigational mRNA-1273.815
n=106 participants at risk
Participants received Investigational mRNA-1273.815 by IM injection on Day 1.
|
Licensed Spikevax Vaccine
n=109 participants at risk
Participants received a licensed Spikevax vaccine by IM injection on Day 1.
|
|---|---|---|
|
Gastrointestinal disorders
Small intestinal obstruction
|
0.94%
1/106 • Number of events 1 • Day 1 through Day 15
The all-cause mortality was based on the randomization set. The serious and other (not including serious) adverse events were based on the safety set which consisted of all enrolled participants who received the study drug.
|
0.00%
0/109 • Day 1 through Day 15
The all-cause mortality was based on the randomization set. The serious and other (not including serious) adverse events were based on the safety set which consisted of all enrolled participants who received the study drug.
|
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place