AstraZeneca’s antibody cocktail fails to prevent Covid

AstraZeneca Plc's antibody cocktail was found to be only 33 per cent effective at preventing Covid-19 symptoms in people who had been exposed to the virus, failing the study's main goal and dealing a setback to the drugmaker.

The study, named Storm Chaser, looked at whether the long-acting antibody combination could protect people who had recently been in contact with the Sars-CoV-2 virus in places like care homes.

The outcome is a blow to Astra for a drug that was hoped to be a bright spot in the company's pandemic efforts following the mixed success of its vaccine with the University of Oxford. One of the first shots to be authorised, the vaccine has since faced issues with take-up after a link emerged with rare blood clots.

The study looked at about 1,121 unvaccinated adults in the US and UK. As many as 23 volunteers who got the drug cocktail developed symptomatic Covid-19 after exposure, compared with 17 cases in the group that got a placebo, Astra said in a statement on Tuesday.

The antibody trial is one of six advanced-stage studies Astra is running to test its drug against different endpoints. Another study called Provent, looking at whether the cocktail can prevent infection in people at high risk of catching Covid or with compromised immune systems, is also expected to readout soon. The US has ordered up to 700,000 doses of the medicine for delivery in 2021, while the UK was already reconsidering an earlier order for one million.