People who get seriously ill from covid-19 could be offered a new lifeline with the first antiviral drug shown to save lives in patients admitted to hospital, researchers have said.
The drug, a combination of two antibodies developed by Regeneron, reduced the risk of death when given to people with severe covid-19 who hadn’t mounted a natural antibody response of their own.
The chances of these patients needing to be put on a ventilator were also reduced, as was the duration of their hospital stay.
In the Recovery trial between 18 September 2020 and 22 May 2021, 9785 patients admitted to hospital with covid-19 in the UK were randomly allocated to receive the usual care plus the antibody combination treatment, or usual care alone.
Of these, about one-third were seronegative, meaning they had no natural antibody response of their own, and half were seropositive, meaning they had already developed natural antibodies against the virus. For one-sixth of those involved in the study, their antibody status was unknown.
Among patients who received usual care alone, mortality within 28 days of being admitted to the trial was 30 per cent in those without an antibody response, compared with 15 per cent in those who were seropositive at the start of the study.
For patients who had no antibody response, the treatment reduced the chance of them dying within 28 days by a fifth, compared with usual care alone.
For every 100 such patients treated with the antibody combination, there would be six fewer deaths, researchers say.
“This is in some ways a first,” said Martin Landray at the University of Oxford, joint chief investigator of the study. “This is an antiviral treatment that is used later on – because these patients are severe, they’ve gone into hospital – and has a demonstrated clear impact on survival, and on those other outcomes.
“So in its own right, it’s an important result because these patients are among the sickest patients, and here we now have a treatment we did not have before.”
For the seronegative patients given the treatment, the duration of hospital stay was four days shorter than the usual care group, and the proportion of patients discharged by day 28 was greater.
The treatment made no difference in patients who had mounted their own antibody response by the time the study started.
“These results are very exciting,” said Peter Horby, the other joint chief investigator, also from the University of Oxford. “The hope was that, by giving a combination of antibodies targeting the Sars-CoV-2 virus, we would be able to reduce the worst manifestations of covid-19. There was, however, great uncertainty about the value of antiviral therapies in late-stage covid-19 disease.
“It is wonderful to learn that even in advanced covid-19 disease, targeting the virus can reduce mortality in patients who have failed to mount an antibody response of their own.”
The researchers say they aren’t sure when the treatment will be approved for use in the UK. It is unlikely to be rolled out quickly as the drug isn’t particularly easy to get hold of and patients would need antibody testing on their admission to hospital – which isn’t currently in place.
The study will be published as a pre-print on medRxiv and hasn’t yet been peer-reviewed.
The treatment uses a combination of two monoclonal antibodies (casirivimab and imdevimab, known as REGEN-COV in the US) that bind specifically to two different sites on the coronavirus spike protein, neutralising the ability of the virus to infect cells.
Previous studies in people in the community showed that the treatment reduced viral load, shortened the time to resolution of symptoms and significantly reduced the risk of being admitted to hospital or death.
Stephen Powis, national medical director for NHS England, said: “These encouraging results from this trial carried out in and by the NHS suggest a new treatment option to help save the lives of some patients hospitalised with covid and are the latest example of research and innovation for patients, which the NHS has played a role in during the pandemic.
“Studies have also suggested the same treatments might help similar patients in the community avoid going to hospital in the first place, which is why yesterday the health service chief executive, Sir Simon Stevens, asked the NHS to rapidly establish a new monoclonal antibody service so we are ready to offer these drugs if backed by regulators.”
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