CAMBRIDGE – Moderna, Inc. has announced new clinical data on its bivalent (Omicron) COVID booster candidate, mRNA-1273.214. One month after administration in previously vaccinated and boosted participants, a 50 µg booster dose of mRNA-1273.214 elicited potent neutralizing antibody responses against the Omicron subvariants BA.4 and BA.5 in all participants regardless of prior infection. Based on this and prior data, the Company is working to complete regulatory submissions in the coming weeks requesting to update the composition of the booster vaccine to mRNA-1273.214.
In today’s data, mRNA-1273.214 boosted neutralizing titers against BA.4/BA.5 by 5.4-fold (95% CI: 5.0, 5.9) above baseline in all participants regardless of prior infection, and by 6.3-fold (95% CI: 5.7, 6.9) in the subset of seronegative participants. Neutralizing titers against BA.4/BA.5 were approximately 3-fold lower than previously reported neutralizing titers against BA.1. One month after an mRNA-1273.214 booster, neutralizing geometric mean titers (GMT) against BA.4/BA.5 were 941 (95% CI: 826, 1071) in all participants, and 727 (95% CI: 633, 836) in seronegative participants. For context, prior studies of a third dose of the prototype booster induced neutralizing GMT against BA.1 of 629 (95% CI: 526, 751) and against Delta of 828 (95% CI: 738, 928). A third dose of the prototype booster was shown to be effective against Delta and BA.1 infection and hospitalization in observational studies ,.
“In the face of SARS-CoV-2’s continued evolution, we are very encouraged that mRNA-1273.214, our lead booster candidate for the fall, has shown high neutralizing titers against the BA.4 and BA.5 subvariants, which represent an emergent threat to global public health,” said Stéphane Bancel, Chief Executive Officer of Moderna. “We will submit these data to regulators urgently and are preparing to supply our next generation bivalent booster starting in August, ahead of a potential rise in SARS-CoV-2 infections due to Omicron subvariants in the early fall.”
Today’s data add to results shared earlier this month from the Company’s ongoing Phase 2/3 study in approximately 800 participants. Previous results showed a 50 µg booster dose of mRNA-1273.214 met all pre-specified primary endpoints, including superiority in neutralizing antibody GMT against Omicron (BA.1) when compared to a 50 µg booster dose of the prototype booster (mRNA-1273). The bivalent booster was generally well tolerated, with a reactogenicity and safety profile that was consistent with the prototype booster. Moderna believes these data collectively support updating the composition of the Company’s booster to bivalent (Omicron) mRNA-1273.214 for the fall.
The Company has already shared these data with regulators and is submitting a manuscript for peer reviewed publication.