Coronavirus: Antibody treatment trial to move to next phase © Getty Images

Coronavirus: Antibody treatment trial to move to next phase

The drug is being tested for early treatment of patients who are at high risk of being taken to hospital.

Pharmaceutical giant GlaxoSmithKline (GSK) and Vir Biotechnology have announced the trial of their potential coronavirus treatment will move on to phase three. In this phase, the treatment will be tested for safety and effectiveness through intravenous infusion.

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The Comet-Ice (COVID-19 monoclonal antibody efficacy trial-intent to care early) study is evaluating antibody treatment Vir-7831 for the early treatment of COVID-19 in patients who are at high risk of being taken to hospital.

Antibodies are proteins the body makes when an infection occurs and vaccines trick the body into thinking there is an infection so it makes these antibodies. But it can take weeks for COVID-19 immunity to form after natural infection or a vaccine.

Vir-7831 (also known as GSK4182136) is a fully human antibody that was selected based on its ability to neutralise SARS-CoV-2, the virus that causes COVID-19. It is thought to kill infected cells, provide a high barrier to resistance, and achieve high concentrations in the lungs.

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Following encouraging results from earlier stages of the trial, the study will now expand globally to additional sites in North America, South America and Europe.

“The rapid achievement of this important milestone reflects the urgency with which we’re mobilising our resources in the hope of preventing the worst consequences of this deadly virus,” said George Scangos, chief executive officer of Vir.

“Vir-7831 is an antibody with characteristics that may enable it to prevent hospitalisation or death via multiple mechanisms. We look forward to continuing to collaborate with GSK to accelerate its development.”

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Initial results may be available as early as the end of 2020, with complete results anticipated in January 2021.

How do scientists develop vaccines for new viruses?

Vaccines work by fooling our bodies into thinking that we’ve been infected by a virus. Our body mounts an immune response, and builds a memory of that virus which will enable us to fight it in the future.

Viruses and the immune system interact in complex ways, so there are many different approaches to developing an effective vaccine. The two most common types are inactivated vaccines (which use harmless viruses that have been ‘killed’, but which still activate the immune system), and attenuated vaccines (which use live viruses that have been modified so that they trigger an immune response without causing us harm).

A more recent development is recombinant vaccines, which involve genetically engineering a less harmful virus so that it includes a small part of the target virus. Our body launches an immune response to the carrier virus, but also to the target virus.

Over the past few years, this approach has been used to develop a vaccine (called rVSV-ZEBOV) against the Ebola virus. It consists of a vesicular stomatitis animal virus (which causes flu-like symptoms in humans), engineered to have an outer protein of the Zaire strain of Ebola.

Vaccines go through a huge amount of testing to check that they are safe and effective, whether there are any side effects, and what dosage levels are suitable. It usually takes years before a vaccine is commercially available.

Sometimes this is too long, and the new Ebola vaccine is being administered under ‘compassionate use’ terms: it has yet to complete all its formal testing and paperwork, but has been shown to be safe and effective. Something similar may be possible if one of the many groups around the world working on a vaccine for the new strain of coronavirus (SARS-CoV-2) is successful.

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