Regeneron's bid for COVID-19 drug's full approval hits snag as FDA extends review

Just as Regeneron’s COVID-19 antibody combination, REGEN-COV, is sidelined in the U.S. thanks to omicron, the drug has hit a hiccup on its quest for a full FDA nod.

The FDA has extended the review of REGEN-COV by three months to July 13, Regeneron said Thursday. The agency wants to take the time to review additional data on how well the therapy could prevent COVID before exposure to the SARS-CoV-2 virus, the company said.

An FDA nod in what’s known as the pre-exposure prophylaxis setting would be an expansion from REGEN-COV’s existing emergency use authorization, which currently only covers treatment of mild-to-moderate non-hospitalized patients and COVID prevention after exposure to the coronavirus. Regeneron is currently seeking full approval for all three uses.

The FDA appears to have some questions about the pre-exposure prophylaxis use. The extension comes after Regeneron submitted additional data on that use from a prophylaxis trial during “ongoing discussions” with the FDA. The agency hasn’t requested any new studies at this point, the company added.

Regeneron combined its COVID prevention analysis for REGEN-COV in both pre- and post-exposure settings. In the high-risk household setting with confirmed COVID cases, REGEN-COV reduced the risk of symptomatic COVID by 81.4% among other individuals in the same household during the first month after administration. The risk reduction was 81.6% in the following two to eight months. Regeneron said the first month includes both pre- and post-exposure prophylaxis, while the longer follow-up represents only pre-exposure use.

Meanwhile, as Regeneron navigates regulatory hurdles toward a potential full FDA approval, REGEN-COV is currently not authorized for use in any parts of U.S. The FDA in January limited its use because the antibody combo is no longer effective against the dominant omicron variant. Since January, the federal government hasn’t distributed a single dose of REGEN-COV.

With REGEN-COV having lost its place in the pandemic fight at least for now, Regeneron is working on next-generation antibodies that are active against omicron and other variants of concern. The company said it has launched a first-in-human clinical trial of one of these new antibodies.

AstraZeneca’s long-acting antibody cocktail Evusheld is the only treatment available for COVID prevention before an exposure thanks to an FDA emergency use authorization in December. The drug is reserved as an alternative to vaccines for immunocompromised people.