Gilead's remdesivir looks promising in leaked early results, but don't jump to conclusions: analysts

The world is watching and waiting for data to see whether Gilead Sciences' investigational antiviral remdesivir can help fight COVID-19. And while some leaked early results suggest that it can, industry watchers will need to wait for data from Gilead's own controlled phase 3 study to know for sure.

Researchers at the University of Chicago Medical Center, which is treating patients with severe COVID-19, have seen remdesivir swiftly tamp down both fever and respiratory symptoms, according to a report from Stat. Gilead’s shares leapt more than 15% in after-hours trading following the report.

“The best news is that most of our patients have already been discharged, which is great. We’ve only had two patients perish,” Kathleen Mullane, the University of Chicago infectious disease specialist overseeing the remdesivir studies for the hospital, said. She made the comments this week during a video discussion about the trial results with other University of Chicago faculty members. The discussion was recorded, and Stat obtained a copy of the video.

The hospital recruited 125 patients into two phase 3 studies, including 113 with severe disease. The study has no control arm, with all of the patients receiving daily infusions of remdesivir.

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Remdesivir, which was originally tested in Ebola patients, has emerged as one of the top near-term hopes for COVID-19 patients. In addition to carrying out its own clinical trials, Gilead has made the drug available to studies run by other sponsors, as well as to more than 1,700 people on a compassionate use basis. Last week, The New England Journal of Medicine published data from 53 patients with severe disease, but that data set also lacked a control group.

And that's a key point. In a note to clients, Jefferies analyst Michael Yee called the leaked results an “incremental positive” but wrote that the short-term stock move "will probably pull back in a bit given eventual broader awareness that this is not the actual phase 3 data.”

“[We] reiterate that similar to the NEJM publication last week, today's reports are based on one site and there is no placebo," he added.

RELATED: Gilead shares slip as a 2nd remdesivir COVID-19 trial halted in China

Gilead itself echoed the sentiment.

“We understand the urgent need for a COVID-19 treatment and the resulting interest in data on our investigational antiviral drug remdesivir,” the company said in an emailed statement.

"The totality of the data need to be analyzed in order to draw any conclusions from the trial. Anecdotal reports, while encouraging, do not provide the statistical power necessary to determine the safety and efficacy profile of remdesivir as a treatment for COVID-19," Gilead said.

Gilead expects to report data from a study testing two regimens of remdesivir in patients with severe disease by the end of April, with data from a study of patients with moderate disease coming in late May. The latter study is comparing a 5- or 10-day course of remdesivir against standard of care.

“[If] the data looks similar to the NEJM results (10-20% mortality rate), then this is likely to be construed positive and could expand use,” Yee wrote.

Evercore ISI analyst Umer Raffat urged cautious optimism in a note, pointing out that the study did not include the sickest patients: "GILD-run severe trial specifically excluded pts on mechanical ventilation."

"Thus, it would be one thing if STAT article was on a trial where patients are on invasive ventilation and yet “majority” are getting discharged.  That’s NOT the case here," Raffat wrote.

Editor's note: This story was updated with analyst comments and a statement from Gilead.