The US Food and Drug Administration (FDA) has said the monoclonal antibody combinations bamlanivimab/etesevimab and casirivimab/imdevimab (REGEN-COV) should be used only for COVID-19 patients exposed to variants other than Omicron.
In a statement , Dr Patrizia Cavazzoni, director of the FDA’s Center for Drug Evaluation and Research, said: “Because data show these treatments are highly unlikely to be active against the Omicron variant, which is circulating at a very high frequency throughout the United States, these treatments are not authorised for use in any US states, territories, and jurisdictions at this time. In the future, if patients in certain geographic regions are likely to be infected or exposed to a variant that is susceptible to these treatments, then use of these treatments may be authorised in these regions.”
The agency revised the emergency use authorisation (EUA) for the two antibody cocktails for use “only when the patient is likely to have been infected with or exposed to a variant that is susceptible to these treatments”.
FDA cited “markedly reduced activity against the Omicron variant” as the reason for this revision. It said CDC data indicated that more than 99% of US COVID cases were from Omicron. “It’s highly unlikely that COVID-19 patients … are infected with a variant other than Omicron,” Cavazzoni added.
The agency’s decision formalises the recommendation made at the end of December by the NIH COVID Treatment Guidelines panel, which advised against the use of any monoclonal antibody treatment, with the exception of sotrovimab for high-risk COVID patients, the only one with in-vitro efficacy against Omicron.
FDA recommended sotrovimab and other non-monoclonal antibody therapies for outpatients at high risk of progressing to severe COVID, such as oral antiviral nirmatrelvir-ritonavir (Paxlovid), intravenous antiviral remdesivir (Veklury), and oral antiviral molnupiravir, which are “expected to work” against Omicron and are authorised for this high-risk patient population with mild to moderate COVID-19, according to Cavazzoni.
The agency said this action avoids exposing patients to side effects, some potentially serious, such as injection site reactions or allergic reactions from a treatment that “is not expected to provide benefit” against Omicron.
See more from MedicalBrief archives:
FDA greenlights Veklury for children and adult patients with mild-to-moderate COVID
Monoclonal antibodies effective for breakthrough COVID cases — Mayo Clinic
NHS rolls out two new antivirals to reduce COVID19 hospitalisation
Pfizer’s anti-COVID oral tablets show robust efficacy