Emerging coronavirus variants could pose threats to existing monoclonal antibodies and vaccines, and the FDA’s taken note, revising its emergency use authorizations to Eli Lilly’s and Regeneron’s drugs.
In edited letters of authorization re-issued in late February and early March, the FDA’s asking the two companies to monitor new variants of SARS-CoV-2, the coronavirus behind COVID-19 and potentially conduct additional tests of their authorized antibody drugs against variants.
The update came as evidence points to increased resistance of emerging coronavirus variants, especially the B.1.351 version first identified in South Africa, to antibody therapies.
The letters, first reported by Endpoints, were for existing EUAs for Lilly’s bamlanivimab (PDF) and its combo (PDF) with etesevimab, and Regeneron’s cocktail (PDF) of casirivimab and imdevimab, in mild-to-moderate COVID-19 patients with high risk of disease progression in the outpatient setting.
Specifically, the FDA attached two new conditions to the EUAs focused on monitoring and assessment of variants. The agency’s asking both Lilly and Regeneron to establish a process for monitoring genomic databases for variants and provide monthly summaries of their findings.
What’s more, the FDA specified that it may require further testing of the authorized antibody regimens against a particular variant.
A recent Nature study by Columbia University researchers raised red flags of reduced antibody potency against variants. In lab dishes, neither bamlanivimab monotherapy nor its etesevimab combo was able to neutralize B.1.351, and the Regeneron dual-drug regimen also showed a “noticeable” decrease in its activity against the variant, the team found.
Regeneron has been tracking the emergence of variants, as well as how its antibodies perform against them, since very early in the pandemic, a company spokeswoman said in a statement Tuesday. The company chose the dual-drug approach with potential viral mutations in mind because the two antibodies bind to different locations on the virus, she explained.
The company is going one step beyond FDA’s request by “working on a publicly available dashboard that shares how we are seeing variants emerge and travel across the world into specific geographies,” she added.
While she declined to comment on specific FDA submissions or requests, she said both Regeneron’s internal research and outside studies have confirmed that its cocktail remains potent against the variants first identified in the U.K., South Africa, Brazil and California.
“Lilly continually monitors the COVID-19 environment, assessing the neutralization of our antibody therapies against a wide array of emerging mutations and variants,” the Indianapolis pharma said in a statement. Antibody drugs “will need to be developed to address the evolution of the virus, including emerging variants that can differ by country or even by state,” it added.
Simultaneously for the letter revisions, the FDA also relaxed a previous stipulation around instructional or educational materials for the drugs. With the updates, the agency no longer requires prior review and approval of such documents before they’re distributed to the public.
Editor's Note: The story has been updated with Eli Lilly's statement.