The study of the 53 patients in the U.S., Europe and Canada who required respiratory support showed that about two-thirds benefited from the drug.
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Gilead Sciences is running at least five clinical trials for its experimental antiviral drug remdesivir against COVID-19. Readouts for at least one or two of them will occur this month. Meanwhile, more than 1,800 patients have been treated using the drug on an individual compassionate use basis so far. And they published data in the New England Journal of Medicine on 53 of those patients suggesting promising results.
The study of the 53 patients in the U.S., Europe and Canada who required respiratory support showed that about two-thirds benefited from the drug. About half of the patients received mechanical ventilation and four were on a heart-lung by-pass machine. Eight patients were excluded from analysis, one because of a dosing error and seven because there was no information available on how they did.
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All the patients received remdesivir for up to 10 days. Over 18 days, 68% showed improvement, with 17 of the 30 patients on ventilators able to be taken off the devices. Almost half of patients were discharged, while 13% died. Mortality was highest in patients receiving ventilation, with 18% dying.
“We cannot draw definitive conclusions from these data, but the observations from this group of hospitalized patients who received remdesivir are hopeful,” said lead author Jonathan Grein, director of hospital epidemiology at Cedars-Sinai Medical Center in Los Angeles.
The company is quick to point out that the study has limitations. It is running two Phase III trials of remdesivir, the SIMPLE trials, in countries with high prevalence of COVID-19. Data from the SIMPLE trial in patients with severe COVID-19 are expected sometime this month. Data from the SIMPLE trial in patients with moderate disease are expected in May. It is also supporting several trials led by other groups, including two in Hubei Province, China. A trial in China in patients with severe disease was terminated early because of low enrollment. The data is still pending. A China study in mild-to-moderate disease is ongoing. A global trial led by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) continues to enroll patients. Data is expected in May. Other studies based on a master protocol by the World Health Organization have also started patient enrollment worldwide.
Researchers doubt this recent study data is anything more than suggestive, if that.
“The data from this paper are almost uninterpretable,” Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, told Bloomberg. “There is some evidence suggesting efficacy, but we simply do not know what would have happened to these patients had they not been given the drug.”
Which is why more organized clinical trials with controls are necessary. And Gilead is not denying that.
“In studying remdesivir, the question is not just whether it is safe and effective against COVID-19, but in which patients it shows activity, how long should they receive treatment and at what stage of their disease would treatment be most beneficial,” said Daniel O’Day, Gilead’s chairman and chief executive officer. “Many answers are needed, which is why we need multiple types of studies involving many types of patients.”
Remdesivir is a broad-spectrum antiviral originally developed to treat Ebola, but was ineffective. In preclinical work conducted at the University of North Carolina and Vanderbilt University before the pandemic, it had shown promise against a wide range of viruses, including coronaviruses. In Ebola it had been found to be safe but ineffective. But the data acquired in those trials helped move it to more advanced trials in COVID-19.
That being said, about 25% of patients receiving it have severe side effects, including multiple-organ dysfunction syndrome, septic shock, acute kidney injury and low blood pressure. Another 23% demonstrated evidence of liver damage on lab tests.
