A potential antiviral drug for the coronavirus has flopped in its first randomised clinical trial, disappointing scientists and investors who had high hopes for remdesivir, according to draft documents published accidentally by the World Health Organisation.

The Chinese trial showed remdesivir – developed by California-based Gilead Sciences – did not improve patients’ condition or reduce the pathogen’s presence in the bloodstream. Researchers studied 237 patients, giving the drug to 158 and comparing their progress with the remaining 79. The drug also showed significant side-effects in some, which meant 18 patients were taken off it.

The WHO said the draft document, which is undergoing peer review, was published early in error. “In response to WHO asking for information and studies to be shared early, a draft document was provided by the authors to WHO and inadvertently posted on the website and taken down as soon as the mistake was noticed,” it said.

Gilead warned that the post included “inappropriate characterisations of the study”.

“Importantly, because this study was terminated early due to low enrolment, it was underpowered to enable statistically meaningful conclusions,” it said. “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.”

Until now, evidence from the use of Gilead’s remdesivir in Covid-19, the disease caused by the new coronavirus, had relied on studies that did not meet the robust scientific standards of being randomised and having a control arm.

There are multiple ongoing Phase 3 studies that are designed to provide the additional data needed to determine the potential for remdesivir as a treatment for Covid-19. These studies will help inform whom to treat, when to treat and how long to treat with remdesivir. The studies are either fully enrolled for the primary analysis or on track to fully enrol in the near future.

Positive feedback

Positive feedback from a clinical trial being conducted at the University of Chicago, leaked last week, buoyed the entire stock market as investors looked for any sign that the availability of a successful drug could help open up locked-down economies.

“In this study of hospitalised adult patients with severe Covid-19 that was terminated prematurely, remdesivir was not associated with clinical or virological benefits,” the filing said.

The WHO collates current trials for possible Covid-19 interventions on a website titled “landscape analysis of candidate therapeutics for Covid-19”. A previous version of the website, which contained five pages and a column called “outcomes”, is no longer available. The new one only contains four pages and no “outcome” column.

The study was terminated early because of a lack of patients. It was conducted in China, which after a surge in cases earlier this year has seen a taper in the number of those affected.

Study

Earlier this month, a study in the New England Journal of Medicine showed early positive results for remdesivir, with 68 per cent of patients improving on the drug. However, the study was not an official trial but rather the collation of data from patients who had been given the drug on a “compassionate use” basis – and was not compared to any control arm. The scientists behind the study and Gilead warned at the time that it was not conclusive.

There had been other positive signs too. Early impressions from a study showed rapid recoveries in almost all of the more than 100 severely ill patients, when they were leaked to healthcare industry publication Stat news.

A recent US National Institutes of Health animal study also found the drug was effective at treating the disease in monkeys, when taken early in its progression.

Much larger randomised controlled trials are under way, comparing remdesivir with controls, which in Covid-19 usually means standard care for a respiratory illness, and to other drugs including the antimalarial hydroxychloroquine.

Gilead originally developed remdesivir as a treatment for Ebola, where it showed promise at stopping the virus from replicating in clinical trials, but it has never been approved. – Copyright The Financial Times Limited 2020