The agency, building on rules established earlier this year to assess shots and treatments, has been meeting with drugmakers and setting guidelines for the studies and data needed to swiftly evaluate products targeting the new Omicron Covid-19 variant, the people said.
The FDA wants to be sure Omicron shots and therapies work safely and can be made correctly before authorizing their use, while moving as quickly as it can to conduct the assessment to aid efforts to stay ahead of the variant, according to people familiar with the matter.
Under the rules that the FDA is putting into place, drugmakers working on new vaccines would be expected to meet standards similar to those required for authorization of boosters, a person familiar with the matter said.
For vaccines, the companies wouldn’t have to conduct large, lengthy trials enrolling thousands of subjects that wait for a certain number to catch symptomatic Covid-19. Instead, they could, for example, study the immune responses in a few hundred subjects.
Drugmakers would need about three months to develop and test the new vaccines, a person familiar with the matter said. Then the companies would seek authorization of the shots through an expedited review process, and it would take the FDA one to two weeks to make a decision, according to the person.
Pfizer Inc. Chief Executive Albert Bourla said this week that the company and its partner BioNTech SE could have the vaccines ready in 100 days, while Moderna Inc. has said the company can advance new candidates to clinical testing in 60 to 90 days.
The preparations are another element of the rapid response to Omicron. Since the new variant was identified by South Africa scientists last week, health authorities and drug researchers have sought to figure out the threat it could pose to vaccines, drugs and people.
Testing to determine whether the new variant can evade current vaccines and medicines is continuing, and expected to take another week or two. To be prepared, drugmakers such as Moderna along with Pfizer and BioNTech are already moving to develop Omicron-targeted shots and treatments.
President Biden said Monday that he is directing the FDA and the Centers for Disease Control and Prevention to use "the fastest process available without cutting any corners for safety" to authorize new vaccines and make them available if needed.
Acting FDA Commissioner Janet Woodcock said Tuesday that the agency would work quickly with companies to develop and test vaccine modifications if they are determined to be necessary.
The FDA had limited the use of some monoclonal antibody treatments depending on their effectiveness against circulating variants, Dr. Woodcock said, and is working with pharmaceutical companies to determine the impact of the Omicron variant on treatments.
By directing what kind of studies and data it will need to evaluate new medicines, the FDA helps drugmakers save time designing studies and gathering the evidence the agency wants to see for its evaluations.
Drugmakers will also know what kind of evidence the agency wants to see to make sure the companies can manufacture the new products correctly, another typically time-consuming part of the FDA review process.
The FDA’s Omicron guidance stems from preliminary work to pave the way for variant-specific vaccines and drugs completed earlier this year. The companies have tested vaccines for other variants, but none has been rolled out.
Under the updates, the agency would clear products that were already authorized but are being tweaked to fight Omicron with less data than required for the initial authorization, a person familiar with the matter said.
"It’s a way of looking at the strength of the body’s response, that gives you answers more quickly," said Jesse Goodman, a professor of medicine at Georgetown University and a former FDA chief scientist, speaking generally about such studies.
The late-stage studies that the agency reviewed before authorizing Covid-19 vaccines were far larger, with Pfizer-BioNTech enrolling more than 43,000 people and Moderna enrolling about 30,000 people. And the studies looked at how many vaccinated people compared with volunteers on placebo developed symptomatic Covid-19, rather than their immune responses.
The FDA is still determining how much the effectiveness of current vaccines would need to drop to merit authorizing new ones, a person familiar with the matter said.
Agency officials have been discussing the matter with Pfizer and BioNTech, as well as with Moderna and Johnson & Johnson companies and U.S. officials have said.
In addition to establishing their own requirements, U.S. officials expect to be in contact with health authorities from other countries and the World Health Organization before deciding whether a new vaccine is needed, a person familiar with the matter said.
They will discuss what new candidates would target because the vaccine makers aren’t likely to make different shots for different places, one of the people familiar with the matter said.
The FDA said it believes that PCR and rapid tests will continue to work well, but is prepared to adjust course if needed.