Moderna mRNA-1083 Phase 3 data show stronger flu and COVID immune response
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Moderna says its combined flu-COVID vaccine mRNA-1083 met Phase 3 primary endpoints with higher immune responses in adults 50 and older. The readout matters for BD teams and investors tracking combo-vaccine competition, FDA posture, and next filing milestones.
Moderna's mRNA-1083, a flu-plus-COVID multicomponent mRNA shot, met Phase 3 immunogenicity goals in adults 50 and older. A JAMA report in 8,015 participants showed noninferior—and often higher—immune responses versus licensed comparators, with more solicited reactions but no new safety signals.
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Key Takeaways
- Phase 3 enrolled 8,015 adults ≥50 years across two age cohorts (NCT05827926).
- mRNA-1083 met noninferiority on geometric mean ratios and seroconversion/seroresponse differences.
- Responses were higher vs SD-IIV4 (ages 50–64) for all four flu strains and vs HD-IIV4 (≥65) for three clinically relevant flu strains, plus SARS-CoV-2.
- Solicited adverse reactions were more frequent than comparators; most were grade 1–2 and short-lived.
What is Moderna's mRNA-1083?
mRNA-1083 combines components of Moderna’s seasonal influenza candidate mRNA-1010 and next-generation COVID candidate mRNA-1283 targeting Omicron XBB.1.5. The Phase 3 question was whether one shot could match or beat standard separate flu and COVID vaccines on antibody responses.
Adults were randomized to mRNA-1083 plus placebo or to co-administered licensed influenza vaccine plus COVID vaccine (mRNA-1273). Comparator flu shots were high-dose IIV4 for ages ≥65 and standard-dose IIV4 for ages 50–64. See the JAMA Phase 3 publication.
How strong were the immune responses?
Noninferior immunogenicity was shown against all vaccine-matched influenza and SARS-CoV-2 strains. Criteria used the lower bound of the 97.5% CI of the geometric mean ratio greater than 0.667 and the seroconversion/seroresponse rate-difference lower bound greater than −10%.
mRNA-1083 elicited higher responses than SD-IIV4 for all four influenza strains in the 50–64 cohort and higher responses than HD-IIV4 for A/H1N1, A/H3N2, and B/Victoria in the ≥65 cohort, plus higher SARS-CoV-2 responses in both age groups.
- N = 8,015 vaccinated
- Cohorts: 4,017 ≥65; 3,998 ages 50–64
- Sites: 146 in the United States
- Enrollment window: Oct. 19–Nov. 21, 2023
What about safety and reactogenicity?
Solicited adverse reactions were numerically higher after mRNA-1083 than after comparators (≥65 years: 83.5% vs 78.1%; 50–64 years: 85.2% vs 81.8%). Most events were grade 1 or 2 and short in duration.
Authors reported no safety concerns identified in the published analysis. Higher reactogenicity is still a practical issue for pharmacies and clinics planning combination respiratory campaigns.
Where is the trial record?
ClinicalTrials.gov lists the multicomponent influenza and SARS-CoV-2 vaccine study as NCT05827926. Related immunogenicity studies include NCT06694389 and NCT06864143.
Primary public evidence for the ≥50-year immunogenicity claim remains the JAMA report tied to that Phase 3 design. Confirm identifiers on ClinicalTrials.gov NCT05827926.
What remains unproven for approval and uptake
Immunogenicity noninferiority is not clinical efficacy against flu or COVID illness in this publication’s primary framing. Absolute protection estimates and season-to-season strain updates still matter for regulators and payers.
For Moderna's mRNA-1083, the near-term watch is regulatory review completeness—not just whether antibody titers beat Spikevax and licensed flu shots in one season.
Related NovaPharma coverage
Frequently Asked Questions
What did Moderna's mRNA-1083 show in Phase 3?
In 8,015 adults aged 50 and older, mRNA-1083 met noninferior immunogenicity criteria versus co-administered licensed influenza and COVID-19 vaccines and induced higher responses to several matched strains.
Who was enrolled in the pivotal study?
About 4,017 adults ≥65 years and 3,998 adults 50–64 years were vaccinated at 146 U.S. sites between Oct. 19 and Nov. 21, 2023 (NCT05827926).
Does stronger immune response mean the combo is approved?
No. Published Phase 3 immunogenicity is not the same as FDA approval. Regulatory timing still depends on agency review of the full package.
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