AstraZeneca’s antibody therapy Evusheld can help protect most vulnerable from getting Covid-19 - including Omicron variant
Those most at risk from Covid-19 due to weakened immune systems could be protected against the Omicron variant by AstraZeneca’s combination antibody therapy Evusheld, studies have shown.
The UK government is reported to be ordering doses of the drug, although it has yet to be authorised by the MHRA.
Live virus studies from University College, Oxford, and Washington University School of Medicine, in St Louis, US, have now shown Evusheld is able to neutralise the Omicron variant at a level similar to individuals who have previously been infected with and recovered
Evusheld is the first antibody therapy to be cleared for the pre-exposure preventative treatment of Covid-19 in the US, after being granted emergency use authorisation by the Food and Drug Administration on December 8.
This means it can be given as a measure to help protect the most at-risk individuals aged over 12, providing they have not got Covid-19 or recently been exposed to someone with the virus.
It is designed to be given to individuals with weak immune systems, those who do not develop an adequate immune response to Covid-19 vaccination, and those with a history of severe side effects from coronavirus vaccines.
Those given Evusheld – which is administered as two consecutive jabs – could include cancer and organ transplant patients, and those on immunosuppressive drugs for conditions such as multiple sclerosis and rheumatoid arthritis.
For everyone else, Covid-19 vaccines remain the most effective method of protection.
The US – where there are seven million immune-compromised people – has ordered 700,000 doses, with the first ones arriving before Christmas. Abu Dhabi received the first global shipment on December 20.
Primary analysis from the Phase III PROVENT trial showed Evusheld led to a 77 per cent reduced risk of developing Covid-19. Protection is shown to last for six months, but there are hopes that it could last as long as a year.
Sir Mene Pangalos, executive vice president, biopharmaceuticals R&D, AstraZeneca, said: “Consistent data across three independent studies now provide confidence that Evusheld, a combination of two highly potent antibodies, retains neutralising activity against the Omicron variant at a level that will continue to provide benefit to patients.
“Evusheld is the only antibody therapy authorised for pre-exposure prophylaxis of Covid-19 in the US, and we’re excited that Evusheld is now available to help protect vulnerable populations, such as the immunocompromised, who are unable to mount an adequate response to vaccination and who remain at high risk for Covid-19.”
Evusheld (tixagevimab co-packaged with cilgavimab) was derived from B-cells donated by convalescent patients recovering from the SARS-CoV-2 virus.
It was discovered by Vanderbilt University Medical Center in the US and licensed to Cambridge-based AstraZeneca in June 2020.
The long-acting human monoclonal antibodies in Evusheld bind to distinct sites on the SARS-CoV-2 spike protein. They were optimised by AstraZeneca with half-life extension and reduced Fc receptor and complement C1q binding, to help them evade potential resistance as new SARS-CoV-2 variants emerge.
About two per cent of the global population is considered at increased risk of an inadequate response to a Covid-19 vaccine.
Myron J Levin, professor of paediatrics and medicine, University of Colorado School of Medicine, US, and principal investigator on the PROVENT trial, said: “Millions of people in the US and around the world remain at serious risk for Covid-19 because their immune systems do not generate a sufficient immune response, even after receiving all recommended doses of vaccine.
“I am excited to offer my patients Evusheld as an easily-administered new option that provides long-lasting protection that could help them return to their everyday lives.”
Meanwhile, studies have confirmed that a third dose of AstraZeneca’s Covid-19 vaccine – which it calls Vaxzevria – do significantly boost levels of antibodies against Omicron.
In common with other vaccines, two doses offer a reduced level of protection against the highly mutated variant.
In the UK, only the Pfizer and Moderna vaccines are being given as boosters.
Sir Mene said: “Vaxzevria plays an important role in vaccination programmes around the world and these data give us confidence that the vaccine should be given as a third dose booster.
“It is also important to look beyond antibodies to better understand how vaccines offer protection against Omicron.
“As we better understand Omicron, we believe we will find that T-cell response provides durable protection against severe disease and hospitalisations.”
Other studies have suggested Vaxzevria helps to generate a diverse and durable T-cell response to multiple variants.