April 20, 2020Immunology
According to the NIH, early treatment with the experimental antiviral drug remdesivir, a drug developed by Gilead Sciences Inc., significantly reduced clinical disease and damage to the lungs of rhesus macaques infected with SARS-CoV-2, the coronavirus that causes COVID-19. The study was designed to follow dosing and treatment procedures used for hospitalized COVID-19 patients being administered remdesivir in a large, multi-center, clinical trial. The authors posted the work on the preprint server bioRxiv. The findings are not yet peer-reviewed and should not be considered clinical advice, but are being shared to assist the public health response to COVID-19. A study detailing the development of the rhesus macaque model of mild- to-moderate human disease, conducted by the same team, was posted to bioRxiv on March 21.
The current study of remdesivir, involved two groups of six rhesus macaques. Twelve hours after infection with SARS-CoV-2, one group of monkeys received remdesivir and the other animals served as an untreated comparison group. Subsequently, all monkeys received a daily intravenous booster dose of active or placebo, for the next six days. The authors timed the initial treatment to occur shortly before the virus reached its highest level in the animals' lungs.
Results showed that 12 hours after the initial treatment, the six treated animals were in significantly better health than the untreated group, a trend that continued during the seven-day study. One of the six treated animals showed mild breathing difficulty, whereas all six of the untreated animals showed rapid and difficult breathing. The amount of virus found in the lungs was significantly lower in the treatment group compared to the untreated group, and SARS-CoV-2 caused less damage to the lungs in treated animals than in untreated animals.
The investigators noted that the data supports initiating remdesivir treatment in COVID-19 patients as early as possible to achieve maximum treatment effect. The authors, from NIAID's Rocky Mountain Laboratories in Hamilton, Montana, also noted that while remdesivir helped prevent pneumonia, it did not reduce virus shedding by the animals. Thus, the finding is of great significance for patient management, where a clinical improvement should not be interpreted as a lack of infectiousness.