The U.S. Food and Drug Administration (FDA) has issued an emergency use authorization (EUA) for AstraZeneca's Evusheld (tixagevimab and cilgavimab) for the pre-exposure prevention of COVID-19 in certain individuals. This authorization addresses a critical need for those who cannot be adequately protected by COVID-19 vaccines due to medical conditions or contraindications. The decision, announced Wednesday, provides a new option for a vulnerable subset of the population at high risk of severe COVID-19 outcomes.
Target Population and Clinical Efficacy
Evusheld is authorized for adults and pediatric individuals (12 years of age and older weighing at least 40 kg) who are not currently infected with SARS-CoV-2 and who have either a weakened immune system or a medical condition that prevents them from receiving COVID-19 vaccines. The FDA emphasizes that Evusheld is not a substitute for vaccination in individuals for whom COVID-19 vaccination is recommended.
The FDA's authorization was based on data from a clinical trial involving unvaccinated individuals aged 59 and older, or those with chronic diseases placing them at high risk of infection. In this trial, approximately 3,500 participants received Evusheld, while 1,700 received a placebo. Results indicated that Evusheld reduced the risk of developing symptomatic COVID-19 by 77%. This significant risk reduction underscores the potential benefit of Evusheld for preventing COVID-19 in vulnerable populations.
Mechanism of Action and Administration
Evusheld is a combination of two monoclonal antibodies, tixagevimab and cilgavimab, designed to neutralize the SARS-CoV-2 virus. These antibodies target the spike protein of the virus, preventing it from attaching to and entering human cells. The treatment is administered as two separate intramuscular injections, given sequentially.
The expected duration of protection from Evusheld is up to six months. Common side effects associated with Evusheld include allergic reactions, bleeding at the injection site, headache, and fatigue. Healthcare providers are advised to monitor patients for potential adverse reactions following administration.
Addressing Unmet Needs
This authorization fills a crucial gap in the COVID-19 prevention landscape, offering protection to individuals who do not mount an adequate immune response to vaccination or who cannot receive vaccines due to medical reasons. While vaccines remain the primary tool for preventing COVID-19, Evusheld provides an additional layer of protection for those most vulnerable to the virus.
Current Antibody Therapies
Currently, other antibody cocktails from Regeneron and Eli Lilly are authorized for use nationwide, but only in people who have been exposed to the virus shortly before, or who have a strong chance of being exposed and are at high risk of developing a severe case of the disease. Evusheld differs in that it is authorized for pre-exposure prevention, offering a longer-term protective option.
