Moderna has announced updates to its strategy to address SARS-CoV-2 variants of concern, given the emergence of the B.1.1.529 (Omicron) variant.
What is Omicron?
The recently described Omicron variant includes mutations seen in the Delta variant that are believed to increase transmissibility and mutations seen in the Beta and Delta variants that are believed to promote immune escape. The combination of mutations represents a significant potential risk to accelerate the waning of natural and vaccine-induced immunity.
What is currently available to tackle the variant?
A booster dose of an authorised vaccine represents the only currently available strategy for boosting waning immunity. The Moderna Covid-19 vaccine (mRNA-1273) is authorised as a booster for most adults at the 50 µg dose level. The company is working rapidly to test the ability of the current vaccine dose to neutralise the Omicron variant and data is expected in the coming weeks.
Since early 2021, Moderna has advanced a comprehensive strategy to anticipate new variants of concern. This strategy includes three levels of response should the currently authorised 50 µg booster dose of mRNA-1273 prove insufficient to boost waning immunity against the Omicron variant.
First, Moderna has already tested a higher dose booster of mRNA-1273 (100 µg) in healthy adults. Moderna has completed dosing of 306 participants in a safety and immunogenicity study of this high dose (100 µg) booster. The 100 µg dose of mRNA-1273 has also recently been studied by the National Institutes of Health (NIH) in the U.S. and has generally resulted in the highest neutralising titres against prior SARS-CoV-2 strains. Moderna is working to rapidly test sera from its high dose booster recipients in neutralising assays to determine if the 100 µg dose provides superior neutralising protection against Omicron.
Second, Moderna is already studying two multi-valent booster candidates in the clinic that were designed to anticipate mutations such as those that have emerged in the Omicron variant. The first candidate (mRNA-1273.211) includes several mutations present in the Omicron variant that were also present in the Beta variant of concern1. The company has completed dosing in a potentially pivotal safety and immunogenicity study of mRNA-1273.211 at the 50 µg (N=300) and 100 µg (N=584) dose levels. A second multi-valent candidate (mRNA-1273.213) includes many of the mutations present in the Omicron variant that were also present in the Beta and Delta variants2. The company has completed dosing at the 100 µg (N=584) dose level and also plans to explore the 50 µg dose level in approximately 584 participants. Moderna will rapidly expand testing of sera from completed and ongoing multi-valent booster studies to determine if these multi-valent candidates are able to provide superior neutralising protection against Omicron.
Third, Moderna will rapidly advance an Omicron-specific booster candidate (mRNA-1273.529). This candidate is part of the company’s strategy to advance variant-specific candidates for a subset of variants of significant concern. During 2021 this has already included Beta- and Delta-specific boosters. The Company has repeatedly demonstrated the ability to advance new candidates to clinical testing in 60-90 days.
“From the beginning, we have said that as we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves. The mutations in the Omicron variant are concerning and for several days, we have been moving as fast as possible to execute our strategy to address this variant,” said Stéphane Bancel, Chief Executive Officer of Moderna. “We have three lines of defense that we are advancing in parallel: we have already evaluated a higher dose booster of mRNA-1273 (100 µg), second, we are already studying two multi-valent booster candidates in the clinic that were designed to anticipate mutations such as those that have emerged in the Omicron variant and data is expected in the coming weeks, and third, we are rapidly advancing a Omicron-specific booster candidate (mRNA-1273.529).”
- Identical or similar S mutations (n=4): K417N, E484K/A, N501Y, D614G
- Identical or similar S mutations (n=8): T95I, G142D, K417N, T478K, E484K/A, N501Y, D614G, P681R/H