The experimental coronavirus treatment remdesivir has failed in its first randomised clinical trial, inadvertently released results have shown, dampening expectations for the closely watched drug.
A draft summary went online briefly on the website of the World Health Organization and was first reported by the Financial Times and Stat, which posted a screenshot.
But Gilead Sciences, the company behind the medicine, disputed how the now-deleted post had characterised the findings, saying the data showed a "potential benefit".
The summary said the Chinese trial involved 237 patients, with 158 on the drug and 79 in a control group. Remdesivir was stopped early in 18 patients because of side effects.
The authors said remdesivir was "not associated with a difference in time to clinical improvement" compared to the control.
After a month, 13.9% of the patients on remdesivir had died compared to 12.8% of those in the control group. The difference is not statistically significant.
The WHO told the Financial Times that the draft is undergoing peer review and was published early in error.
A spokesman for Gilead told AFP: "We believe the post included inappropriate characterizations of the study," saying it was terminated early due to low enrolment and was therefore not statistically meaningful.
"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," the spokesman added.
The study does not represent the final word on the matter, and there are several large-scale trials in advanced stages that should soon provide a clearer picture.
Remdesivir, which is administered intravenously, was among the first drugs suggested as a treatment for the coronavirus and as such has great hopes riding on it.
Remdesivir, which previously failed in trials against Ebola, belongs to a class of drugs that act on the virus directly, as opposed to controlling the abnormal and often lethal autoimmune response it causes.
It mimics one of the four building blocks of RNA and DNA and gets absorbed into the virus's genome, which in turn stops the pathogen from replicating.
The antimalarial drugs hydroxychloroquine and chloroquine are also being widely used on Covid-19 on a so-called "compassionate basis" pending results from large trials, with early studies decidedly mixed.
Other therapies that are being studied include collecting antibodies from COVID-19 survivors and injecting them in patients, or harvesting antibodies from genetically-engineered mice that were deliberately infected.
Elsewhere, according to new research coronavirus is quickly destroyed by sunlight, a senior US official said, though the study has not yet been made public and awaits external evaluation.
William Bryan, science and technology advisor to the Department of Homeland Security secretary, told reporters at the White House that government scientists had found ultraviolet rays had a potent impact on the pathogen, offering hope that its spread may ease over the summer.
"Our most striking observation to date is the powerful effect that solar light appears to have on killing the virus, both surfaces and in the air," he said.
"We've seen a similar effect with both temperature and humidity as well, where increasing the temperature and humidity or both is generally less favourable to the virus."
But the paper itself has not yet been released for review, making it difficult for independent experts to comment on how robust its methodology was.
It has long been known that ultraviolet light has a sterilising effect, because the radiation damages the virus's genetic material and their ability to replicate.
A key question, however, will be what the intensity and wavelength of the UV light used in the experiment was and whether this accurately mimics natural light conditions in summer.
Meanwhile, Jon Barbour, Director of Medical Affairs at GlaxoSmithKline Ireland, has said giving specific dates for when we might have a vaccine for Covid-19 is "not prudent" and should be avoided.
Speaking on RTÉ's Morning Ireland, he said while everyone wants to hear of a possible date for a Covid-19 vaccine, developing one is a challenging process and requires multiple steps.
"It can, in some cases, take up to ten years. The great challenge for Covid-19 is to come up with a vaccine quicker," Mr Barbour said.
He said for the first time in history there has been a global collaboration to find a suitable vaccine and as quickly as possible.
Mr Barbour said he is aware that there are at least five vaccines currently on trial for Covid-19 in different parts of the world.
"It is a complex process, with a lot of people working together to try accelerate that process," he said.
He said those who are trying to develop the vaccines have "ambitious targets".
They are hopeful one could be seen as early as 12 to 18 months from now but it depends on the results from the vaccine trials.
He said it is an "open question" whether a vaccine, when it is found, will mean immunity to Covid-19 indefinitely.
Mr Barbour imagines that this will all be discovered over time as to whether follow up vaccinations will be required or if Covid-19 is more akin to the flu with different strains.
"It is all very hypothetical at the minute."
