Antibody cocktail drugs, which have offered “great hope” in treating Covid-19, are ineffective against concerns about new variants of the virus, the research said.
Laboratory tests showed that the experimental treatments known as monoclonal antibodies failed to neutralize the strains of one or more of the strains found in Kent, South Africa and Brazil.
The drugs come from the cloning of a single antibody, a type of white blood cell found in people who have recovered from Covid. Scientists make many copies of the antibody in a laboratory before injecting them into people who have difficulty developing an immune response on their own.
One of the most promising candidates for monoclonal antibodies, manufactured by Regeneron in the US, was used on Donald Trump during his Covid battle and may have helped him recover.
Another, developed by UK pharmaceutical giant GlaxoSmithKline, is currently being tested in NHS hospitals as part of a government-sponsored study of new Covid treatments.
The data on the effectiveness of the drugs in the new variants are limited. There are only two forms in South Africa and China, but both are a strong indication that they will not be successful.
The three new variants all have key mutations on their spike protein that alter the appearance of the immune system and allow them to get past some antibodies.
It is believed that monoclonal antibody treatments based on a single type of antibody that was effective against the original strain of Covid cannot recognize the new strains.
Whereas during a Covid infection in a healthy person, different types of antibodies and T cells are sent to clear the infection as part of a larger immune response. This means that some of the antibodies cannot recognize the new strains while others can.
All three therapy candidates from GlaxoSmithKline (GSK) from Brentford, the American biotech company Regeneron and Eli Lilly fail because of one or more variants
The specially developed antibodies can act like a vaccine and protect a patient from serious illnesses or stimulate the patient’s immune system to attack antigens. Pictured: Regeneron, New York
The researchers now have the task of finding “conservative” regions of the virus that do not mutate so that they can be attacked with antibodies. Pictured: Eli Lill, California
Dr. Nick Cammack, director of the Covid-19 therapeutics accelerator at Wellcome Trust in London, told The Guardian: ‘The challenge came around Christmas when these new varieties appeared – especially those in South Africa and Brazil.
“The changes the virus makes to its spike proteins are actually shed by these antibodies.”
According to Dr. Cammack still effective against the South African and Brazilian variants, but not against the British strain that occurred in Kent.
WHAT IS MONOCLONAL ANTIBODY THERAPY?
Monoclonal antibody therapy is a form of immunotherapy that uses monoclonal antibodies (mAb).
It is given as an injection under the skin or through a drop into a vein.
Treatment works in many different ways. It can act like a vaccine, protecting a patient from serious illness, or stimulating the patient’s immune system to attack antigens.
Hybridoma technology is a method of producing large numbers of monoclonal antibodies – identical antibodies that are clones of a unique parent cell.
The process begins with the injection of an antigen, which triggers an immune response in an animal such as a mouse.
B cells produce antibodies that bind to the antigen. These antibody-producing B cells are then harvested and used to grow more antibodies.
The monoclonal antibodies are examined for their ability to work in first animal experiments.
Great advances in technology have made the discovery and development of mAb therapies faster and more efficient, and have derived the antibodies from humans, not animals.
Scientists can create a mAb specific for almost any antigen and are working on one for the coronavirus.
The spike protein on the SARS-CoV-2 virus is the primary target being screened for potential Covid-19 monoclonal antibodies.
The aim is for the antibody to neutralize the SARS-CoV-2 virus by targeting the spike protein and thus prevent it from infecting healthy cells.
A particularly interesting way is to give it to people who are not yet infected as a preventive tool. If the antibodies are effective and long-lasting enough, they can provide adequate protection for a period of time before a vaccine is found.
Research and development are ongoing to develop antibodies against diseases such as rheumatoid arthritis, multiple sclerosis, Alzheimer’s and various types of cancer.
However, many are already in use in the US and UK.
48 new mAbs have been approved since 2008, which, according to the US FDA, will contribute to a total global market of 61 mAbs in clinical use at the end of 2017.
This is a major blow to the UK as the Kent variant is already the dominant variety in the UK. Therefore, any new treatment must aim to reduce transmission.
The Kent variant’s N501Y makes it at least 50 percent more contagious than regular Covid, and early data in the UK suggests it’s 30 percent more deadly as well.
Dr. Cammack added, “So this is a virus that is making a change that will help make it more attached to the cell. So these monoclonals are lost. ‘
The South African and Brazilian variants have a mutation called E484K, which is also on the spike protein that many antibodies would normally target.
This mutation has already been shown to hinder the current wave of vaccinations, but not enough to prevent people from receiving protection.
In another worrying development this week, the E484K mutation was found in 11 cases of the Kent variant, suggesting the strain is developing again.
The researchers now have the task of finding new regions of the virus other than the tip that do not mutate so that they can be attacked with antibodies.
Dr. Cammack explained that it would require mass sequencing and genetic sequencing of the virus from around the world to determine what changes are there and where the “conservative” regions are.
The monoclonal antibodies are still effective against the original virus and have been used in Europe and the United States. However, because the new strains have an “evolutionary advantage” over this strain, scientists believe it will have faded in the coming months.
An early study of 20 patients in the US found the new GSK antibody treatment, known as Vir-7831, was safe and had no harmful effects on the old variant.
Monoclonal antibodies came into the spotlight after it was revealed that former US President Donald Trump had received an experimental cocktail of the proteins made by Regeneron following his Covid-19 diagnosis.
Although not approved, the company agreed to give Mr. Trump a single dose at the request of his doctor, in accordance with “compassionate use” regulations.
Monoclonal antibodies are already used to treat tetanus, Ebola and diphtheria and are described as “one of the most powerful tools in modern medicine” according to a recent Wellcome report.
However, the treatment being tried for HIV is expensive and can be difficult, so affluent countries have only seen the benefits of HIV.
It comes as aAnother 33 cases of the problematic South African variant of Covid have been discovered in the UK, health chiefs said yesterday amid growing fears about mutant strains that experts say could affect the effectiveness of vaccines.
Public Health England claimed 143 people have been affected by the variant since it was first discovered on British soil in December – including five in Scotland and nine in Wales. None were found in Northern Ireland.
Officials also announced that they had found 11 cases of the Kent coronavirus variant, which has an additional mutation in Bristol.