A new therapy to prevent people from getting sick with SARS-CoV-2

Scientists in the UK have just recruited the first participants in the world to be part of a new long-acting antibody study.

If the treatment is effective, those who have already been exposed to SARS-CoV-2 can offer protection against the development of COVID-19.

“We know that this antibody combination can neutralize the virus,” explains Catherine Houlihan, a virologist at University College London Hospitals (UCLH).

“We therefore hope to find that giving this treatment via injection can lead to immediate protection against the development of COVID-19 in exposed people – when it would be too late to offer a vaccine.”

This may not be the first antibody treatment for COVID-19 you’ve heard of. Outgoing US President Donald Trump received monoclonal antibodies when he contracted the disease, and in the United States two different antibody treatments – casirivimab and imdevimab – were approved in November.

But the antibody treatments are given to patients with a mild or moderate COVID-19, who are at risk of progressing to a severe version of the disease.

In a clinical trial of patients with COVID-19, casirivimab and imdevimab, co-administered, have been shown to reduce COVID-19 related hospitalization or emergency visits in patients at high risk for disease progression within 28 days after treatment compared with placebo, “the FDA explained in a press release when the drugs were approved.

This new antibody therapy, called AZD7442 and developed by UCLH and AstraZeneca, is a little different.

AZD7442 is a combination of two monoclonal antibodies AZD8895 and AZD1061, both of which focus on the receptor binding domain of the SARS-CoV-2 vein protein.

“By targeting this region of the virus’ ear protein, antibodies can block the virus from attaching to human cells, and therefore it is expected to block infection,” the team wrote on the American ClinicalTrials.gov website.

“Amino acid substitutions have been introduced into the antibodies to prolong both their half-lives, which should extend their potential prophylactic benefit, and reduce the Fc effector function to reduce the potential risk of antibody-dependent improvement of the disease.”

Antibodies are small Y-shaped proteins that attach to a specific part – an antigen – of a virus, bacterium or other pathogen, and ‘mark’ it to be attacked by the immune system, or block the pathogen directly around us. . selle.

Normal antibodies are produced by your body after an infection, while monoclonal antibodies are cloned in a laboratory and can be injected into a person who is already infected, to give the immune system a hand in the fight.

The researchers hope that AZD7442 – which is currently conducting the Storm Chaser study (the name for its Phase 3 study) – provides protection for those who have been exposed to the virus but do not yet have symptoms. Effectively, they are trying to stop COVID-19 from happening in the first place.

“If you are dealing with outbreaks in institutions such as nursing homes, or if you have patients who are particularly at risk of getting severe COVID, such as the elderly, it can save many lives,” the University of East Anglia said. told infectious disease expert Paul Hunter The guardian.

“If you live with your elderly grandmother and you or someone else in the house becomes infected, you can give it to her to protect her.”

But they also hope that it can be effective over a period of 6-12 months, which means that people who for medical reasons cannot receive the vaccine have another option to protect themselves against the disease.

The researchers are investigating how it may work for people with an affected immune system in a second trial called PROVENT.

“We will recruit people who are older or in long-term care, and who have conditions such as cancer and HIV, which may affect the ability of their immune system to respond to a vaccine,” said Nicky Longley, consultant at UCLH Infectious Diseases, said . The guardian.

“We want to reassure someone for whom a vaccine does not work that we can offer an alternative that is just as protective.”

We look forward to seeing where it leads.