FDA updates Covid-19 variant guidance for vaccines and therapies

US healthcare regulator the Food and Drug Administration (FDA) has updated its guidance to help vaccine and therapeutics companies to address the emergence of new variants of SARS-CoV-2, the virus that causes Covid-19.

Over the past few months, multiple SARS-CoV-2 variants have been emerging across the world. This has created concerns that drugs and vaccines in development and authorised for Covid-19 will no longer be effective against the viral disease.

For vaccines, the FDA has updated its October 2020 guidance to support companies in amending their emergency use authorisations. The guidance informs companies of the additional data needed for modified vaccines to tackle the viral variants. It also notes that a modified vaccine must be “clearly distinguished” from the original prototype vaccine.

The FDA is asking companies to demonstrate the modified vaccine’s efficacy in clinical immunogenicity studies, which compare the efficacy of the modified vaccine against the variants and the original prototype vaccine against the original variant of SARS-CoV-2.

The guidance also allows for booster studies to be carried out. This is where the modified vaccine is administered to people who have received the original prototype vaccine. Another version is where a booster of the original prototype is trialled to see if it protects against the new variants.

The FDA stated that the studies only need to be conducted in a single age group, and the results can then be extrapolated to other age groups.

With regard to safety, the FDA said safety assessments must occur daily for at least seven days after the study vaccination. However, it recommends that studies should prepare for longer-term assessment of serious adverse events.

The FDA said its guidance concludes that “further discussions will be necessary to decide whether in the future, modified Covid-19 vaccines may be authorized without the need for clinical studies.”

Only two Covid-19 vaccines are currently approved in the US: Moderna Covid-19 vaccine and Pfizer and BioNTech’s BNT162b2. Pfizer focused on carrying out studies to confirm if its existing vaccine is effective against the new variants. Moderna has confirmed its vaccine is effective against the variation, but is considering developing a booster candidate against the emerging variants.

For therapeutics, the FDA has issued brand-new guidance for monoclonal antibody drugs, which are the main therapeutic approved for Covid-19 in the US, in the context of the new variants. The guidance allows for a streamlining of data necessary to support the development of products targeting the variants.

The regulator noted that monoclonal antibody products need to be developed with the expectation that they will be combined with other drugs. Studies combining different companies’ products have already begun; for instance, Eli Lilly, GlaxoSmithKline and Vir Biotechnology’s recently announced partnership.

FDA acting commissioner Janet Woodcock said: “The FDA is committed to identifying efficient ways to modify medical products that either are in the pipeline or have been authorized for emergency use to address emerging variants.

“By issuing these guidances, we want the American public to know that we are using every tool in our toolbox to fight this pandemic, including pivoting as the virus adapts.

“We need to arm health care providers with the best available diagnostics, therapeutics and vaccines to fight this virus. We remain committed to getting these life-saving products to the frontlines.”

The updated guidance comes within a week of the European Union announcing a new incubator focused on tackling the threat of Covid-19 variants.