- Monoclonal antibodies attach to the antigens present in the protein coat outside the virus
- The antibodies neutralize the ability of coronavirus virus to infect cells
- Recovery trial shows that antibodies can reduce mortality in patients who failed to produce antibody responses of their own.
COVID-19 pandemic is becoming a significant global public health burden that needs effective therapeutic strategies. Monoclonal antibody therapy is the first in COVID-19 therapeutic trial that directly attacks the virus to save hospitalized patients from death.
What are Monoclonal Antibodies?Monoclonal antibodies are artificially manufactured proteins that attack the virus directly by binding to antigens present outside of a disease-causing virus.
They have been effective against some types of cancer, and the Ebola virus helps decrease an overactive immune response as an indirect strategy.
How are they Effective against COVID-19?The proteins present outside the SARS-CoV-2 virus in the shape of spikes enable it to attach itself to human cells and enter the cells to cause infection.
"Here you have really the first direct SARS-CoV-2 drug", says Eric Topol, director of the Scripps Research Translational Institute.
Previous studies conducted among non-hospitalized COVID patients show that monoclonal antibody treatment reduces viral load facilitating faster resolution of symptoms to reduce the risk of hospitalization.
Does it Work for Everyone?Researchers discovered mixed results in several monoclonal antibodies developed against SARS-CoV-2 virus. Though some positive effects on disease progression were seen in outpatients, none demonstrated reducing death risk in severely ill patients in the hospital.
The Recovery trial started to evaluate Regeneron's cocktail effectiveness in mid-September 2020 reported that one third of patients took part in this random study did not have natural antibodies.
In this trial group, 30% of patients given standard care died whereas 24% of those who received the antibody cocktail; that translates to six lives saved for every 100 such patients treated with the drug.
Although it received an emergency use authorization from the U.S. Food and Drug Administration in November 2020, Regeneron's therapy is notwidely used in the United States.
Joint chief investigator for the RECOVERY trial, Sir Peter Horby said, "These results are very exciting. The hope was that by giving a combination of antibodies targeting the SARS-CoV-2 virus we would be able to reduce the worst manifestations of Covid-19. There was, however, great uncertainty about the value of antiviral therapies in late-stage Covid-19 disease."
Another ChallengeThe cost of this antibody drug will put the therapy out of reach for most people living in developing countries. Generally, access to antibody drugs is unequal across the globe.
Initiative to increase the manufacturing and reducing the price to affordable cost can make these drugs accessible to everyone.
New Therapies to Fight COVID-19Dexamethasone and Tocilizumabare being used in COVID-19 treatment to tackle the body's response to the virus by suppressing the immune system's inflammatory reaction to the virus.
The new antibody cocktail therapy can be used in combination with other treatments.
The Recovery trial is also looking at several other potential treatments, including:
- Baricitinib (an immunomodulatory drug used in rheumatoid arthritis)
- Dimethyl fumarate (an immunomodulatory drug used in psoriasis and multiple sclerosis)
- High-dose vs standard corticosteroids
- Jaworski, Juan. (2020). Neutralizing monoclonal antibodies for COVID-19 treatment and prevention. Biomedical Journal. 44. 10.1016/j.bj.2020.11.011.
- Taylor, P.C., Adams, A.C., Hufford, M.M. et al. Neutralizing monoclonal antibodies for treatment of COVID-19. Nat Rev Immunol 21, 382-393 (2021). - (https://doi.org/10.1038/s41577-021-00542-x)
- Anti-SARS-CoV-2 Monoclonal Antibodies - (https://www.covid19treatmentguidelines.nih.gov/therapies/anti-sars-cov-2-antibody-products/anti-sars-cov-2-monoclonal-antibodies/)