Scientists in the UK have recruited the world’s first participants who are part of a new long-acting antibody study.
If treatment is effective, it may give those who are already exposed to SARS-CoV-2 protection from the development of COVID-19.
“We know this antibody combination can neutralize the virus,” explains virologist Catherine Houlihan of University College London Hospitals (UCLH).
“We therefore hope that giving this treatment via injection can provide immediate protection against the development of COVID-19 in those exposed – when it will be too late to deliver a vaccine.”
This may not be the first antibody treatment for COVID-19 you’ve heard. Outgoing US President Donald Trump was given monoclonal antibodies when he came down with the disease, and two different antibody treatments in the US – casirivimab and imdevimab – received emergency approval in November.
But those antibody treatments are given to patients with mild or moderate COVID-19, who risk progression to an acute version of the disease.
“COVID-19, in a clinical trial of patients with cesirivamab and imdevimab, reducing emergency room visits in high-risk patients after hospitalization or treatment for patients with COVID-19 for 28 days. Shown when compared to placebo, ”the FDA stated in a press statement when the drugs were approved.
This new antibody therapy, called AZD7442 and developed by UCLH and AstraZeneca, differs slightly.
AZD7442 is a combination of two monoclonal antibodies AZD8895 and AZD1061, which both target the receptor binding domain of the SARS-CoV-2 spike protein.
“By targeting this region of the spike protein, antibodies can block the attachment of the virus to human cells, and therefore, are expected to block infection,” the team wrote on the US clinicaltrial.go website .
“Amino acid replacement has been introduced into antibodies to extend its half-life, which should prolong its potential antimicrobial benefit to reduce the potential risk of increasing immunity, and reduce FC effector function. . “
Antibodies are small Y-shaped proteins that lock onto a particular segment – called an antigen – of a virus, bacterium, or other pathogen, and either ‘tag’ it to attack the immune system, or Block the pathogen from directly attacking our cells.
Normal antibodies are produced by your body after an infection, while monoclonal antibodies are cloned in a laboratory and can be injected into an already infected person, helping the immune system fight.
Researchers are hoping that AZD7442 – which is just starting the Storm Chaser study (the name for its Phase 3 trial) – provides protection for those who have been exposed to the virus but have not yet had symptoms. Effectively, they are trying to stop COVID-19 happening in the first place.
“If you are dealing with an outbreak in settings such as care homes, or if you have found patients who are particularly at risk for severe COVID such as the elderly, it can save a lot of lives,” East Anglia University infectious disease specialist Paul Hunter told Guardian.
“If you live with your elderly grandmother and you or someone else in the house gets infected, you can give it to her to protect her.”
But they are also hoping that it can be effective over a period of 6–12 months, meaning that those who cannot receive the vaccine for medical reasons have another option to protect themselves from the disease .
Researchers are looking at how this might work for people with compromised immune systems in a second test called Provent.
UCLH infectious disease consultant Nikki Long explained, “We will recruit people who are aged or in long-term care, and who have conditions such as cancer and HIV, which can affect their immune system’s ability to vaccinate. ” Guardian.
“We want to assure anyone for whom a vaccine may not work that we can offer an alternative that is simply protective.”
We are looking forward to where it goes.