AstraZeneca has reported that its antibody combination, AZD7442, has shown robust efficacy in preventing and treating Covid-19 with one intramuscular dose.
What is it: AZD7442 is a combination of two long-acting antibodies (LAABs). AstraZeneca has also developed one of the key Covid-19 vaccines with the University of Oxford. India’s Covishield is a version of the Oxford-AstraZeneca vaccine.
AstraZeneca, based in the UK, had licensed coronavirus-neutralising antibodies from Vanderbilt University, US, in June 2020, and had advanced a pair of these monoclonal antibodies mAbs into clinical development. AZD7442 is a combination LAABs called ‘tixagevimab’ and ‘cilgavimab’, discovered by Vanderbilt University Medical Center, these human monoclonal antibodies bind to distinct sites on the SARS-CoV-2 spike protein. They were optimised by AstraZeneca’s technology, which more than triples the durability of its action compared to conventional antibodies, AstraZeneca said.
The trials: The findings come from the AZD7442 COVID-19 PROVENT prevention and TACKLE outpatient treatment phase 3 trials. The PROVENT trial is assessing a single IM 300mg dose of AZD7442 compared to placebo, among participants who did not have SARS-CoV-2 infection at baseline. The TACKLE trial is assessing a single 600mg IM dose for outpatient treatment of Covid-19. AstraZeneca said the trial demonstrated benefit in both pre-exposure prophylaxis, and treatment of Covid.
PROVENT was conducted on 5,197 participants at 87 sites in the US, UK, Spain, France and Belgium. One 300mg IM dose of AZD7442 was found to reduce the risk of developing symptomatic Covid-19 compared to placebo by 83%. More than 75% of PROVENT participants at baseline had comorbidities that put them at high risk. After six months, there were no cases of severe Covid or Covid-related deaths in those treated with AZD7442. In the placebo arm, there was a total of five cases of severe Covid and two Covid-related deaths.
In TACKLE, done on 903 participants ù outpatients with mild-to-moderate Covid. One 600mg IM dose was found to reduce the risk of developing severe Covid-19 or death (from any cause) by 88% compared to placebo. A total of 90% of participants were from populations at high risk of progression to severe Covid if infected.
In both trials, AZD7442 was generally well tolerated, AstraZeneca said.
Why it matters: At a virtual press meet announcing the findings, experts said about 2% of the global population is considered at increased risk of an inadequate response to a Covid vaccine. These include people with blood cancers or other cancers being treated with chemotherapy, patients on dialysis, those taking medications after an organ transplant, or who are taking immunosuppressive drugs for conditions including multiple sclerosis and rheumatoid arthritis.
PROVENT is the first phase 3 trial prospectively designed to evaluate a monoclonal antibody for pre-exposure prophylaxis of symptomatic Covid, with targeted inclusion of high-risk and immunocompromised participants, they said.
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