FDA Working on Guidance to Adapt Vaccines to COVID-19 Variants

The FDA intends to publish draft guidance in the next several weeks outlining the data it will require for modifying authorized vaccines to address new COVID-19 viral variants, according to FDA Acting Commissioner Janet Woodcock.

For authorized coronavirus vaccines, the FDA is currently considering what types of data will be necessary to support changes to a vaccine’s composition, either by modifying the vaccine or adding new components. That includes ways sponsors could demonstrate their vaccines generate immune responses to new variants through “streamlined clinical programs” that can be done quickly but still gather critical data needed to show efficacy, Woodcock said. The draft guidance will be open for comment.

On the therapeutics side, the agency is considering approaches to help speed drug development, particularly for monoclonal antibodies, and will also put out draft guidance on the topic. The agency chief said the FDA is aware that some authorized and investigational monoclonal antibodies have taken efficacy hits from the COVID-19 variants due to their very specific targeting and is working with drug developers to accelerate the development of new antibodies that can effectively combat the strains.

“Relying on our growing experience with this class of drugs, our teams are discussing approaches to the generation and evaluation of pre-clinical, clinical and chemistry, manufacturing and controls data,” she said.

The acting director said that while “we must prepare for all eventualities,” the FDA “[does] not believe there will be the need to start at square one with any of these products.”

The FDA is drawing on the knowledge it gained from initiatives in response to mutations in influenza and HIV viruses and the agency will use its experience with influenza “to help inform a path forward if SARS-CoV-2 variants emerge against which currently authorized vaccines are not sufficiently effective,” she said. “Similarly, the FDA also has vast experience with HIV developing resistance to antiviral drugs and will follow regulatory pathways to quickly enable new antiviral drug development for resistant virus.”

So far, coronavirus vaccines authorized by the FDA still appear to be effective at combating the highly contagious viral variants first identified in the UK and South Africa, but there is growing concern that the virus may eventually mutate in a way that renders inoculations and/or therapies ineffective. Worryingly, the South African strain has shown to significantly diminish the effectiveness of some antibody treatments.

Woodock said that the FDA is fairly confident that current vaccines will be effective against the coronavirus mutations seen to date, but she noted that it’s unclear if the strains will become common in the U.S. or if the U.S. will develop its own worrisome variants. — James Miessler