FDA Revises Evusheld Emergency Use Authorization, Ups Dosage

Last week, the US Food and Drug Administration (FDA) revised the Emergency Use Authorization (EUA) they had previously granted to the COVID-19 pre-exposure prophylactic drug Evusheld.

Evusheld, a co-package of tixagevimab and cilgavimab, was approved under EUA to prevent COVID-19 infection in certain specified adult and pediatric populations. With their revision on February 24, the FDA opted to change the initial authorized dose.

After examining the most recent data, the FDA concluded that Evusheld may be less effective against Omicron. Therefore, they upped the dosage to increase the likelihood of protection against the BA.1 and BA.1.1 COVID-19 variants.

The initial authorized dose was increased to 300 mg of tixagevimab and 300 mg of cilgavimab. Previously, the starting dose was 150 mg each of tixagevimab and cilgavimab. The FDA noted that anyone given the previously authorized dose should recieve an additional 150 mg of tixagevimab and 150 of cilgavimab as soon as possible to ensure adequate monoclonal antibody levels.

Evusheld was developed by AstraZeneca Pharmaceuticals LP, who originally requested an EUA on September 30, 2021. Evusheld, tixagevimab co-packaged with cilgavimab, was granted an EUA by the FDA to be administered to prevent COVID-19 infection in certain adults and children 12 and older and weighing at least 40 kg (~88 lbs), who are not currently positive for COVID-19 and have not had a recent exposure.

Evusheld is only authorized for persons who are moderately-to-severely immunocompromised or who receive immunosuppressive medications and/or treatments, and who therefore may not have the adequate antibody response to COVID-19 vaccination. Evusheld is also available to individuals for whom COVID-19 vaccination is contraindicated, due to a history of severe adverse reaction to vaccine components.

The EUA was originally issued on December 10, 2021, after the FDA reviewed the positive results of the PROVENT phase 3, randomized, double-blind, placebo-controlled, clinical trial (NCT04625725).

The active ingredients, tixagevimab and cilgavimab, are neutralizing IgG1 monoclonal antibodies that bind to distinct epitopes in the SARS-CoV-2 spike protein receptor binding domain.