It has been a year since the first vaccine against COVID-19 was administered outside of a clinical trial, with the jabs estimated to have saved hundreds of thousands of lives worldwide.
However, a vaccine is not recommended for some people, while many others with a weak or compromised immune systems do not mount a robust enough response to the vaccines to protect them against infection by SARS-CoV-2.
Doctors in the US now have another tool in their kit after the Food and Drug Administration (FDA) approved AstraZeneca’s antibody combination Evushield for emergency use – the first approved therapy for pre-exposure prophylaxis in the US.
Unlike other approved antibody therapies, which are approved to treat people who are already infected with COVID-19, Evusheld – a combination of monoclonal antibodies tixagevimab and cilgavimab, formerly known as AZD7442 – can now be given to high-risk adults and adolescents aged 12 and older who have not yet been infected.
The two antibodies are long-acting and are delivered in a convenient intramuscular dose.
“Vaccines have proven to be the best defence available against COVID-19, however, there are certain immune compromised individuals who may not mount an adequate immune response to COVID-19 vaccination, or those who have a history of severe adverse reactions to a COVID-19 vaccine and therefore cannot receive one and need an alternative prevention option,” said Dr Patrizia Cavazzoni, director of the FDA’s Center for Drug Evaluation and Research. “Today’s action authorises the use of the combination of two monoclonal antibodies to reduce the risk of developing COVID-19 in these individuals.”
It is estimated that around 2% of the population is at increased risk of an inadequate response to a COVID-19 vaccine, while around seven million people in the US are immunocompromised, including those with blood or other cancers being treated with chemotherapy and those taking medications after an organ transplant.
AZ’s head of biopharmaceuticals R&D Mene Pangalos said the company was “proud to play a leading role in fighting the COVID-19 pandemic”, adding that it was “working quickly” to establish how effective Evusheld is at neutralising the new Omicron variant of SARs-CoV-2.
The FDA acted on data from the ongoing PROVENT phase 3 pre-exposure prevention trial which showed that Evushield slashed the risk of developing symptomatic COVID-19 compared to placebo by 77%.
Originally discovered at Vanderbilt University Medical Center – and derived from B-cells donated by convalescent patients after SARS-CoV-2 virus – tixagevimab and cilgavimab are long-acting monoclonal antibodies that act against the spike protein of the virus and block its entry into cells.
AstraZeneca licenced the combination from Vanderbilt in June 2020, agreeing to pay single-digit royalties on future net sales.