It is the experimental drug being used to treat Donald Trump’s coronavirus but the US president will not be the first person to receive the new antibody cocktail called REGN-COV2: several hundred patients in the north of England have already been treated with it.

The drug is in such early stages of development that it has not yet been peer-reviewed.

But so promising are initial results that, here in the UK, it has already been rolled out to a handful of hospitals as part of Oxford University‘s national Recovery trial – a clinical scheme to identify treatments for Covid-19.

“This particular drug has probably been given to, I would think now, four or five hundred patients, mild or severe patients in different trials, and so far there’s been no worrying safety signals,” said Professor Peter Horby, co-chief investigator of Recovery.

The treatment itself works by binding to a protein on the surface of the virus, which, in turn, stops the virus from attaching to cells in the body and thereby replicating. This allows the immune system to attack the invader before it is overwhelmed.

It has been developed by Regeneron Pharmaceuticals, which previously developed a similar antibody drug against Ebola.

Speaking on BBC Radio 4, Prof Horby called it “very potent” and “very promising”, and said it was to be rolled out to “another 30 to 40 hospitals” in the UK next week.

He added: “The class of drugs, these artificial antibodies, have been around for quite a while now, and they’ve been extensively used in inflammatory conditions and cancers, and they’re pretty safe and well understood, and so the technology is something that I think we have confidence in.

“This particular drug has probably been given to, I would think now, four or five hundred patients, mild or severe patients in different trials, and so far there’s been no worrying safety signals.

“In the laboratory, in cell cultures it has a very strong effect against the virus, and there have been studies in artificial animals where it also shows benefits. So probably of the drugs that are available, it’s one of the most promising.”

Referring to Mr Trump, he said a single dose of the treatment provides “prolonged protection” for “a month to six weeks”, making it “quite attractive for the older population”.

The US president, who is 74, has also been given Remdesivir, an antiviral treatment which has been shown to help some coronavirus patients recover faster.