Moderna's COVID-19 vaccine may work better in the elderly than competitors’
Immunogenicity from Moderna’s COVID-19 vaccine sustained in older adults
Moderna’s Phase I COVID-19 vaccine readout shows induction of antibody, T cell responses in elderly volunteers as robust as in younger adults, suggesting similar protection in the more vulnerable group.
New Phase I data suggest Moderna’s COVID-19 vaccine maintains its immunogenicity in elderly individuals better than two other leading vaccines. Assuming neutralizing antibodies are key determinants of protection, and that the early results hold up, that could mean mRNA-1273 will do a better job of protecting the high-risk population.
The weakening immune systems in older individuals have been a concern for vaccine developers, given that immune function is needed for vaccines induce protection against pathogens.
During a Wednesday meeting of the Advisory Committee on Immunization Practices (ACIP), Moderna Inc. (NASDAQ:MRNA) presented encouraging immunogenicity data from two older cohorts in the company’s Phase I trial and said the subjects’ adverse events were mostly mild to moderate, with the most severe being grade 3 fatigue.
On a separate conference call Wednesday to discuss the data, CMO Tal Zaks said neutralizing antibody titers induced by 100 µg mRNA-1273 — the dose Moderna is testing in Phase III — were “generally the same” across the study’s three age groups: 18-55, 56-70 and 71 and older.
The 71 and older group in Moderna’s study had titers that were just a hair less than those in the 18-55 group, and about 25% less than those in the 56-70 group. Zaks did not speculate about why the 56-70 age group had the highest titers. One possibility is that the small number of subjects in each group contributed to variability; the two oldest groups each contained 10 individuals and the youngest group contained 15.
Zaks noted that the elderly are a high-risk population more susceptible to severe disease, and predicted that higher neutralization titers “will translate into better performance and more protection to these vulnerable people.”
In contrast to what appears to be a minimal decline in the antibody response to mRNA-1273, two other vaccines have shown steeper declines in early clinical studies.
Neutralizing titers induced by BNT162b2 from Pfizer Inc. (NYSE:PFE) and BioNTech SE (NASDAQ:BNTX) fell by about 60% in subjects aged 65-85 years compared with 18-55 year-olds. Each cohort included 12 individuals.
Ad5-nCoV from CanSino Biologics Inc. (HKEX:6185; Shanghai:688185), which produced somewhat weaker titers to begin with, showed a drop of 36% from 18-44 years to age 55 and up. The youngest cohort in CanSino’s trial enrolled 152 subjects; the 45-55 year-old cohort included 67 subjects and the oldest cohort included 34.
Across age groups, the average titers induced by mRNA-1273 were were two to three times higher than those in convalescent sera obtained from 38 donors, about two thirds of whom had recovered from mild disease.
BNT162b2 produced titers in 18-55 year-olds that were 3.8 times higher than those in convalescent plasma; in 65-85 year-olds, the difference fell to 1.6 times higher. The convalescent sera used in the study also primarily came from mild patients (unhospitalized and symptomatic).
CanSino did not compare its vaccine titers to convalescent sera.