The U.S. Food and Drug Administration (FDA) announced Jan. 24 it is restricting the use of two monoclonal antibody treatments for COVID-19, saying data show such treatments are “highly unlikely” to be active against the Omicron variant, currently the dominant strain in the country.
The agency revised its emergency authorization for the two COVID-19 treatments that come from Regeneron and Eli Lilly. Their use is now limited to when the COVID-19 patient is “likely to have been infected with or exposed to a variant that is susceptible to these treatments.”
RationaleThe move to revise the emergency authorization “avoids exposing patients to side effects, such as injection site reactions or allergic reactions, which can be potentially serious, from specific treatment agents that are not expected to provide benefit to patients who have been infected with or exposed to the Omicron variant,” the FDA stated.
The move was recently recommended by the COVID-19 Treatment Guidelines Panel, part of the National Institutes of Health (NIH) on Dec. 23, 2021. At the time, the panel said the Omicron variant “is predicted to have markedly reduced susceptibility” to several COVID-19 monoclonal antibodies, “especially bamlanivimab plus etesevimab and casirivimab plus imdevimab.” Eli Lilly’s monoclonal antibody treatments offers bamlanivimab and etesevimab, and Regeneron offers casirivimab and imdevimab.
The panel added that GlakoSmithKline’s (GSK’s) and Vir Biotech’s antibody treatment, sotrovimab, “appears to retain activity against the Omicron variant.”
Following the FDA revision of the emergency authorization, Regeneron said it “continues to progress next generation antibodies that retain potency against Omicron, Delta and other variants of concern.”
“The company is working urgently and collaboratively with the FDA to determine how to bring additional safe and effective monoclonal antibody treatments to patients as quickly as possible. Pending regulatory discussions, new therapeutic candidates could enter the clinic in coming months,” the company said in a statement on Jan. 24.
Lilly had no immediate comment but pointed to its statement from December 2021 saying its newer antibody candidate, bebtelovimab, maintains neutralization activity against all known variants of concern, including Omicron. The company said earlier this month it is “urgently working with the FDA to make bebtelovimab available under an emergency use authorization,” with a decision expected before April.
Other TreatmentsThe revision in emergency authorization comes days after the FDA on Jan. 21 expanded approval of the antiviral drug remdesivir to treat more COVID-19 patients. Remdesivir was the first government-approved drug for COVID-19 and was previously limited to treat hospitalized patients. It is now authorized for use in adults and children aged 12 and above early in a COVID-19 infection if the patient faces a high risk of ending up in hospital.
GSK and Vir Biotech are boosting production of their sotrovimab to help meet demand in the United States.
Pfizer’s Paxlovid is not recommended in those with severe kidney disease, according to the FDA. The agency also warns that “caution should be exercised” in giving Paxlovid to people with pre-existing liver diseases.
Separately, the FDA warned that sotrovimab may trigger a range of allergic reactions following infusion. The agency also noted, “It is possible that sotrovimab could interfere with your body’s own ability to fight off a future infection of SARS-CoV-2.
“Similarly, sotrovimab may reduce your body’s immune response to a vaccine for SARSCoV-2. Specific studies have not been conducted to address these possible risks. Talk to your healthcare provider if you have any questions.”