A Covid antibody drug has been approved for UK patients — but it may be weaker against super-strain Omicron.
Britain’s medical regulator gave sotrovimab, sold under the brand name Xevudy, the green light after clinical trials found it could treat patients who were already sick.
It showed that among patients with mild to moderate Covid, it slashed hospitalisations by 79 per cent.
Regulators say it should be used in Covid patients at risk of developing serious illness, including over-60s, and those who are obese or suffer from diabetes.
It is administered over 30 minutes through an intravenous drip.
The UK has secured 100,000 doses.
Its developers say the drug works against some mutations on Omicron, but experts fear it will be less effective against the strain. This is yet to be tested in clinical trials.
Sotrovimab is the second monoclonal antibody treatment approved in the UK, which works by mounting an immune response in patients too weak to make their own.
In August the Ronapreve drug was cleared for use in UK patients by medical regulators, and is now being administered to patients in NHS hospitals.
British medical regulators today gave the green light to Covid antibody treatment Sotrovimab for patients with mild to moderate illness who are more likely to develop severe disease
Monoclonal antibodies are lab-produced molecules that mimic human antibodies — disease-fighting proteins made by the immune system
The Medicines and Healthcare products Regulator Agency (MHRA) said sotrovimab was found to be ‘safe and effective’ at reducing the risk of hospital admission.
Monoclonal antibodies are manufactured in laboratories and work by mounting an immune response against the virus in people whose bodies are too weak to do it on their own.
It binds to the Covid spike protein — which it uses to invade cells — stopping the virus from sparking a serious infection.
How does sotrovimab work?
Britain’s medical regulators have approved a second Covid antibody drug.
Sotrovimab, sold under the brand name Xevudy, contains lab-made antibodies that can fight the virus off.
They are based on those extracted from patients that cleared an infection.
The drug works by mounting an immune response in patients whose bodies are too weak to do it on their own.
Its lab-made antibodies bind to the Covid spike protein — which it uses to invade cells — helping to stop an infection progressing.
Medical regulators recommend it is used in Covid patients with mild to moderate symptoms.
It should be administered within five days of the first warning signs appearing.
Some 100,000 doses have been ordered for the UK.
Seriously ill patients are currently receiving Ronapreve — also a monoclonal antibody drug — in NHS hospitals.
Sotrovimab has been authorised for use in people who have mild to moderate Covid infection and at least one risk factor for developing severe illness, such risk as being over 60, obesity, diabetes mellitus or heart disease.
Dr June Raine, MHRA chief executive, said: ‘I am pleased to say that we now have another safe and effective Covid-19 treatment, Xevudy (sotrovimab), for those at risk of developing severe illness.
‘This is yet another therapeutic that has been shown to be effective at protecting those most vulnerable to Covid-19 and signals another significant step forward in our fight against this devastating disease.
‘With no compromises on quality, safety and effectiveness, the public can trust that the MHRA have conducted a robust and thorough assessment of all the available data.’
Professor Penny Ward, an independent pharmaceutical physician, told BBC Radio 4’s Today programme that the drug could be effective against Omicron.
She said: ‘Well, they have tested a wide range of the different variants that have emerged, many of which contain mutations similar to that that we see in Omicron.
‘This paritoulcar antibody which was deisgned by a company called Vir — a US-based monoclonal antibody company — binds to a portion of the spike protein that is not prone to mutation.
‘So, you would expect it to have very broad antiviral effects and indeed that’s what they’ve shown.
‘They do have to test it in vitro against the virus itself [Omicron] but certainly, based on its mechanism of action and the fact that it wasn’t inhibited by other mutations, [this] indicates that it will probably be effective against Omicron.’
Other monoclonal antibody treatments have already been found to be less effective against the variant.
Preliminary tests found Ronapreve — already in use in the UK — was not as good at stopping infections with Omicron compared to other strains.
Separate testing of another monoclonal antibody manufactured by US-based company Eli Lilly also indicates it is less effective against the variant.
Vaccines are a country’s first line of defence against the virus.
But in cases where jabs do not trigger immunity in some patients, or the virus starts to get around jab-induced antibodies, then these drugs are the second line of defence.
George Scangos, chief executive of Vir, said: ‘Sotrovimab was deliberately designed with a mutating virus in mind.
‘By targeting a highly conserved region of the spike protein that is less likely to mutate, we hoped to address both the current Sars-CoV-2 virus and future variants that we expected would be inevitable.
‘This hypothesis has borne out again and again, with its ongoing ability to maintain activity against all tested variants of concern and interest to date, including key mutations found in Omicron, as demonstrated by preclinical data.
‘We have every expectation that this positive trend will continue and are working rapidly to confirm its activity against the full combination sequence of Omicron.’