Gilead drug shows uneven results in treating virus
Remdesivir, an antiviral medicine made by Gilead Sciences of Foster City, is being closely watched as a possible treatment for COVID19 patients.
But leaked results from one clinical trial in China suggest it may not be effective. A summary temporarily posted on the website of the World Health Organization said the drug did not hasten the recovery of coronavirus patients in the study or keep them from dying, according to news reports.
The study was terminated early because it did not enroll enough patients and the drug maker says data still indicate “a potential benefit.”
Gilead has previously said that a limited analysis of remdesivir’s use on 58 people with COVID19 was encouraging, and a Chicago hospital participating in a clinical trial reportedly saw improvements in patients who received the drug, which is administered intravenously.
So for now, it remains unknown whether remdesivir will be a widely used tool in the global fight against the coronavirus pandemic. But investors seemed to be disappointed in the news out of China, with shares of Gilead falling 4.3% to close at $77.78 on Thursday.
Gilead’s chief medical officer, Dr. Merdad Parsey, said information from the study in China — which involved patients with severe cases of COVID19 — had been “prematurely posted on the World Health Organization website.” The summary contained “inappropriate characterizations of the study,” she said.
“The study was terminated early due to low enrollment and, as a result, it was underpowered to enable statistically meaningful conclusions,” Parsey said in the statement. “As such, the study results are inconclusive, though trends in the data suggest a potential benefit for remdesivir, particularly among patients treated early in disease.”
Originally developing the drug as a treatment for Ebola, Gilead hopes remdesivir can get in the way of how the coronavirus copies itself in many patients. The drug has not been licensed or approved to treat COVID19, but various studies are under way and official results are eagerly awaited by doctors, investors and the general public alike.
The Chinese clinical trial involved 237 patients who had tested positive for the coronavirus, according to the summary of the results obtained by the health news outlet Stat. The trial treated 158 people with remdesivir and maintained a control group of 79 people. One control group patient withdrew before being treated.
Among the patients treated with remdesivir, 13.9% died, compared with 12.8% in the control group — a statistically insignificant difference, Stat reported. The summary also said that use of the drug “was not associated with a difference in time to clinical improvement.”
Parsey, the Gilead chief medical officer, said in the statement that the data were submitted for peer review, meaning that “more detailed information” will be available soon. He cited a “growing but still inconclusive body of evidence for remdesivir” and said that multiple advanced studies under way would “provide the additional data needed to determine the potential for remdesivir as a treatment for COVID19.”
“These studies will help inform whom to treat, when to treat and how long to treat with remdesivir,” Parsey said.
Dr. Yvonne Maldonado, an infectious disease expert at Stanford University, said the design of the remdesivir study in China was “a little odd.” Patients were allowed to enroll up to 12 days after their symptoms started, she noted.
“They could have already been pretty far advanced in their disease,” Maldonado said. “It’s really hard to know. ... I would wait for some of the other trials that are coming out through” the National Institutes of Health.
Remdesivir is far from the only drug under investigation as a potential treatment for COVID19. In the Bay Area, local doctors are studying at least two other drugs, colchicine and leronlimab, that may help prevent the body’s immune system from overreacting to the virus — a condition that can prove deadly.
“The virus makes you sick, but (it’s) the immune system that is killing patients,” said Dr. Jay Lalezari, a San Francisco physician who is working for the company that makes leronlimab, in an email. Asked for comment on the leaked study, Lalezari said he believes that by the time patients received remdesivir, “it was too late for just an antiviral medication.”
Gilead expects to share results from other remdesivir studies on COVID19 patients this month and in May. J.D. Morris is a San Francisco Chronicle staff writer. Email: jd.morris@sfchronicle.com Twitter: @thejdmorris