Patients in China who received Gilead's experimental antiviral drug remdesivir did not appear to recover from COVID-19 any faster than those given a placebo, according to a summary of data posted in error Thursday on the World Health Organization's website.
The results come from a trial conducted in 237 people with severe coronavirus disease. Investigators had originally set out to recruit 450 patients but, due to the ebbing outbreak in China, were unable to fully enroll the study and terminated it early. Data are therefore incomplete, making it difficult to analyze remdesivir's true effects.
The peek provided by the WHO's mistaken posting, though, isn't encouraging. A screenshot of the study abstract taken by STAT, which along with the Financial Times first reported the news, shows researchers concluded "remdesivir was not associated clinical or virological benefits."
Gilead disagreed with that interpretation, claiming in a statement that "trends in the data suggest a potential benefit for remdesivir, particularly among patients treated early in disease."
"Furthermore, we believe the post included inappropriate characterizations of the study," Gilead added. The company said it believes the data from the study have been submitted for publication in a peer-reviewed journal.
According to STAT's screenshot, 14% of the 158 patients treated with remdesivir died 28 days after treatment, compared to 13% of the 79 who were on placebo. Notably, investigators in China stopped giving remdesivir due to side effects in 18 patients versus in just four who received placebo.
Updates about remdesivir are intently followed, as the drug is viewed by many physicians and analysts as one of the more promising existing medicines pressed into trials for COVID-19. Shares in Gilead fell by as much as 8% Thursday afternoon.
A report last week also in STAT, which drew from an online presentation by University of Chicago doctors of patients treated with remdesivir, painted a more encouraging picture, indicating those given the drug experienced rapid easing of fever and respiratory symptoms. But the presentation summarized anecdotal reports from a single trial site, which isn't a true representation of study results.
"I think the truth is somewhere in the middle," wrote Umer Raffat, an analyst at Evercore ISI, in a note sent to clients shortly after the data leaked from the WHO.
In particular, Raffat noted that exactly when COVID-19 patients get remdesivir, which works by stopping viruses from reproducing in the body, could be crucial.
"This is a principle in antivirals for acute infection: the earlier you start, the better the efficacy," Raffat wrote, citing Tamiflu in influenza. The China study enrolled patients who were up to 12 days removed from onset of their symptoms, at which point remdesivir might not help.
Raffat, as well as other analysts, had expected data from the China study to disappoint. Listings of the trial, along with a counterpart study in patients with mild-to-moderate disease, were updated in April to reflect both being stopped early. That no information was readily forthcoming on remdesivir's effect had suggested, analysts thought, that the data were negative or inconclusive.
All the results that have dribbled out to date are only a partial picture. Results from a large study being run by Gilead in severe COVID-19 patients are expected imminently, and a readout from another Gilead trial in patients with moderate disease will likely come within weeks.
Gilead's severe study, while large and randomized, might not tell the world much, however. The company designed the trial without a control arm, instead comparing 5- and 10-day regimens of remdesiver against one another. That could make any potential treatment benefit, unless exceptionally dramatic, hard to suss out, as any improvements or changes in patient condition could reflect what would have happened anyway.
A study led by the National Institutes of Health is also anticipated around the same time and, being both placebo-controlled and blinded, could deliver the most definitive verdict on remdesivir's potential as a treatment for patients infected with the new coronavirus, or SARS-CoV-2.
The urgency of the coronavirus pandemic, and the lack of treatments to combat it, has pushed researchers to launch hundreds of clinical studies in a sprawling and chaotic search for an effective drug. So far those efforts, which have focused first on repurposing existing medicines, have mostly turned up false leads and inconclusive results.
Early studies and anecdotal reports have proven powerful influencers of opinion, however, particularly with the malaria pills chloroquine and hydroxychloroquine. Small tests of the drugs in France and China seemed to indicate antiviral effects, spurring U.S. government officials, including President Dondald Trump, to promote their use.
Subsequent data, while not conclusive, has been much more mixed or even suggestive of potential harms.
Hopes are high remdesivir could prove an exception, and offer physicians around the world an option beyond supportive care like intravenous fluids and oxygen support. Analysts and experts, however, have cautioned that it's highly unlikely the drug, originally but unsuccessfully developed for Ebola virus, could turn out to be a silver bullet.