FDA Revises Dosing for Tixagevimab Co-Packaged with Cilgavimab (Evusheld)

The FDA has revised the Emergency Use Authorization (EUA) for AstraZeneca’s tixagevimab co-packaged with cilgavimab (Evusheld) to change the initial dose for authorized use as a pre-exposure prophylaxis of COVID-19 in certain adults and pediatric patients.

The FDA based the change in dosing regimen on data showing tixagevimab/cilgavimab might be less active against certain Omicron subvariants, and a higher dose of Evusheld might be more likely to prevent infection by the COVID-19 Omicron subvariants BA.1 and BA.1.1 than the originally authorized dose.

Previously, the authorized dosage was 150 mg of tixagevimab and 150 mg of cilgavimab administered as two separate consecutive intramuscular injections, with repeat doses every 6 months while SARS-CoV-2 remains in circulation. With this EUA revision, FDA has increased the initial authorized dose to 300 mg of tixagevimab and 300 mg of cilgavimab. Patients who already received the previously authorized dose (150 mg tixagevimab/150 mg cilgavimab) should receive an additional dose of 150 mg of tixagevimab and 150 mg of cilgavimab as soon as possible to raise their monoclonal antibody levels to those expected for patients receiving the higher dose.

The FDA recommends that healthcare professionals contact patients who received previously authorized doses of tixagevimab/cilgavimab to return for an additional 150 mg tixagevimab and 150 mg cilgavimab dose as soon as possible. The volume of each injection for the new higher dose will be larger, 3 mL instead of 1.5 mL. Thus, injections should be limited to large muscles on the body that can accommodate the volume (eg, the gluteal muscles).