AstraZeneca says its COVID-19 antibody drug has in a six-month follow-up study proven to be 83 per cent effective in cutting the risk of people contracting symptomatic illness.
The injected therapy, called AZD7442 or Evusheld, had previously been shown to offer 77 per cent protection against symptomatic illness after three months, in an earlier readout of the late-stage trial in August.
The Anglo-Swedish company said a separate study in patients with mild-to-moderate COVID-19 showed a higher dose of the therapy cut the risk of symptoms worsening by 88 per cent when given within three days of first symptoms.
The latest results from longer-term follow-ups potentially position AstraZeneca, like rival Pfizer, as a future supplier of both COVID-19 vaccines and treatments, with AstraZeneca having said the therapy's "real advantage" was as a preventative shot.
"These new data add to the growing body of evidence supporting AZD7442's potential to make a significant difference in the prevention and treatment of COVID-19," Executive Vice President Mene Pangalos said in a statement.