Roughly two-thirds of patients with severe cases of COVID-19 saw improvement after receiving the antiviral drug Remdesivir at UC Davis Medical Center and other hospitals worldwide, according to an April 10 study published in the New England Journal of Medicine.

UC Davis Health’s Stuart Cohen, who led the clinical investigation, described the results as “promising,” but cautioned that the study was conducted on a compassionate-use basis, which has inherent limitations.

“It had a small number of enrolled patients and relatively short follow-up timeline,” said Cohen, who is chief of the Division of Infectious Diseases in the Department of Internal Medicine. “It didn’t include a randomized control group and did not collect and compare amount of virus present before and after treatment with Remdesivir and other clinical approaches.”

The trial, conducted between Jan. 25 and March 30, was the first such investigation into whether Remdesivir has benefits in the treatment of COVID-19, the respiratory illness caused by the coronavirus. Remdesivir was approved to fight the Ebola virus.

The study findings are based on health outcomes for 53 COVID-19 patients, ages 23 to 82, who were admitted to the hospitals. In order to qualify for the study, patients had to have blood oxygen saturation of 94% or less while breathing on their own or receiving oxygen support. Normal blood oxygen readings are between 95 and 100%.

Nearly two-thirds of these patients were on mechanical ventilators, including four on a device called ECMO, or extracorporeal membrane oxygenation, that takes over the work of the lungs and heart, removing carbon dioxide and returning oxygenated blood to the body.


Doctors gave each patient 200 milligrams of Remdesivir on their first day of treatment and 100 mg on each of nine successive days. The medication was administered intravenously.

When physicians later followed up with these patients, 17 of 30 patients who had been on ventilators had been removed. Thirty-four out of 53 patients showed improvements in oxygen levels. Nearly half of all the patients had been discharged from hospitals.

Seven of the 53 patients died. The risk of dying was higher among patients age 70 and up and for those who had signs of impaired kidney function. Sixty percent of patients had some sort of adverse event: diarrhea, kidney impairment, rashes, increased liver enzymes and low blood pressure.

Given the limitations of the trial, Cohen said he and other study authors await the results of a larger randomized clinical trial that is underway to demonstrate the extent of efficacy and safety of Remdesivir for the treatment of COVID-19.

In February, UC Davis doctors discovered the first case of community transmission of COVID-19 in the United States, triggering vast changes in testing guidelines, just ahead of outbreaks nationwide.