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 Organization and seen by the Financial Times.

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.