FDA Ups Dose of Preventive COVID Therapy Due to Omicron Subvariants

 A higher initial dose of the monoclonal antibody combination tixagevimab-cilgavimab (Evusheld) may be needed to prevent cases of Omicron subvariants, BA.1 and BA.1.1, the FDA announced on Thursday.

The agency revised the emergency use authorization (EUA) to increase the initial dosing regimen from a 150 mg injection of each drug separately to a 300 mg injection of each drug. This treatment is indicated as COVID pre-exposure prophylaxis for individuals ages 12 and up who are either moderately or severely immunocompromised and may not mount an adequate response to COVID vaccination, or individuals who are allergic to components of the vaccines.

"Available data indicate that a higher dose of Evusheld may be more likely to prevent infection by the COVID-19 Omicron subvariants BA.1 and BA.1.1 than the originally authorized Evusheld dose," the FDA said.

Patients who received the 150 mg doses should receive additional 150 mg doses of each drug as soon as possible, the agency added. The initial treatment regimen, authorized last December, was slated to be one dose of each drug every 6 months, but FDA noted even that may change in the future, perhaps even down to 3 months.

"The duration of protection provided by Evusheld ... may not be as long as was shown in the clinical trial supporting the initial authorization because the clinical trial data came from a time period before the emergence of the BA.1 and BA.1.1 subvariants," the agency wrote.

They noted that the treatment is expected to have "greater neutralizing activity" against BA.2, but since it is unclear which subvariant will become dominant in the U.S., "the recommended timing for repeat dosing cannot be provided at this time."

According to CDC's variant tracker, BA.1.1 currently makes up 75.6% of cases in the U.S., while BA.2 comprises 3.8%.

https://www.medpagetoday.com/infectiousdisease/covid19/97368