A recent study of the potential COVID-19 drug, Regeneron, reports promising results.

Since the start of the COVID-19 pandemic, attempts to create effective drugs have been complicated and ongoing. Previously created therapies have used monoclonal antibodies, unique virus-fighting white blood cells, against COVID-19. However, their development has been predominantly for prevention, and they have yet to be extensively assessed in an in vivo setting. Two studies recently reported in Science evaluate the efficacy of the Regeneron drug – an antibody cocktail for COVID-19 – REGN-COV2.

The Regeneron drug for COVID-19 is a cocktail including two human antibodies named REGN10933 and REGN10987. The goal is to reduce the risk of a drug-resistant viral strain from developing, as well as to limit the viral load and course of illness in infected individuals. Two different animal models, rhesus macaque monkeys and golden hamsters, were used in the study to cover the diverse pathology of COVID-19. Rhesus macaques display a milder course of illness while golden hamsters develop a much more serious form of the disease along with rapid weight loss. The researchers conducted both prophylactic (preventative), and therapeutic studies for REGN-COV2. In order to test how effectively REGN-COV2 protects against the development of COVID-19, the authors gave either REGN-COV2 or a placebo several days prior to infecting the animals with the virus. To further assess the protection capabilities of REGN-COV2, the authors then increased the amount of virus administered along with the treatment or a placebo. Nasopharyngeal and oral swabs were collected to measure virus genomic RNA.

REGN-COV2 is effective in protecting against and treating COVID-19

In rhesus macaques, preventative dosing of the drug resulted in only mild COVID-19 symptoms. When REGN-COV2 was administered three days before the virus, the treatment nearly blocked the viral infection. The authors also reported a faster ability of the animals to clear the infection as opposed to the untreated placebo group. In golden hamsters, those treated with REGN-COV2 two days before infection exhibited significant protection from weight loss and a decrease in their lung viral load compared to the untreated animals. When the researchers analysed the lungs they found no drug related toxicity at either of the high or low doses tested.

In assessing the efficacy of REGN-COV2, the study determined that the drug cocktail was in fact effective in preventing a high viral load and acting as a treatment after infection. By demonstrating reduced virus in animal lungs, decreased course of infection, and limited weight loss, the researchers were able to show the benefits of REGN-COV2 in protecting and treating COVID-19. Further evaluation of the drug is required to determine any additional therapeutic benefits it may have and to validate its results in human trials. The results of the study offer clinical insight into its use to treat patients in a hospital setting.

Written by Melody Sayrany

References:

1. Aaas. More evidence of benefits of REGN-COV2 antibody cocktail to both protect from and treat disease. EurekAlert! https://www.eurekalert.org/pub_releases/2020-10/aaft-meo100920.php.

• Baum, A., Ajithdoss, D., Copin, R., Zhou, A., Lanza, K., Negron, N., … Kyratsous, C. A. (2020). REGN-COV2 antibodies prevent and treat SARS-CoV-2 infection in rhesus macaques and hamsters. Science. https://doi.org/10.1126/science.abe2402

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