A clinical trial of the widely-used antibiotic azithromycin in Covid-19 patients in hospital has found no convincing evidence of benefit, prompting doctors to announce on Monday that they have closed that section of the trial.
"Our results show very clearly that for patients hospitalised with Covid-19, azithromycin is not an effective treatment," said Peter Horby, a co-lead investigator on the UK Recovery trial, which is exploring a range of existing drugs for their potential to treat the pandemic disease.
He said that while results for azithromycin were "disappointing", they would provide guidance for doctors around the world caring for patients infected with the SARS-CoV-2 coronavirus.
The Recovery trial was the first to show that dexamethasone, a steroid that, like azithromycin, is cheap and widely available, could save the lives of people severely ill with Covid-19.
It also showed that the anti-malarial drug hydroxychloroquine, once touted by US President Donald Trump, was of no benefit in treating Covid-19 patients.
In the azithromycin arm of the trial, 2,582 patients were randomised to azithromycin and compared with 5,182 patients who were randomly assigned to usual care alone.
A preliminary analysis showed no significant difference in death rates after 28 days, which were 19% in both groups.
There was also no evidence of beneficial effects on the risk of patients needing mechanical ventilation or on how long they needed to be in hospital. The data have yet to be peer reviewed, but were published on Monday (bit.ly/3gMFcsM) on the medRxiv website.
Given the lack of benefit, experts on the steering committee overseeing the trial agreed it should be closed on Nov. 27, Horby said in a statement.
Since the trial only included hospitalised Covid-19 patients, he said it could not offer any conclusions about the effectiveness of azithromycin in treating people with Covid-19 whose illness is less severe.
The Recovery trial will continue to assess several other potential Covid-19 treatments, he said, including convalescent plasma and an antibody cocktail made by Regeneron.
"Further results are likely over the next couple of months," Horby said.