Swiss pharmaceutical company Roche delays a study of its Covid-19 pill because dwindling cases in the UK meant it was becoming too difficult to find patients.
The company hopes to offer its AT-527 pill as an effective antiviral therapy to treat people infected with the coronavirus.
Roche says its drug is easier to administer and cheaper than alternatives such as remdesivir.
But with rising vaccination rates in Britain and Covid-19 cases in retreat, it was becoming too hard to find participants for the trials.
Bill Anderson, head of Roche’s pharmaceutical division, said the positive outlook in the UK had led to a setback for the company.
Scientists are now looking outside Britain to conduct the study.
“There’s just simply not enough patients to enrol ... with the speed we were hoping for,” he said.
“That’s been one of the challenges since the beginning of the pandemic: you set up sites where there’s a lot of Covid, and then by the time you’re ready to enrol, the pandemic has moved somewhere else and you’re chasing it.”
The drug was developed by Roche in collaboration with US company Atea Pharmaceuticals.
On Tuesday, UK Prime Minister Boris Johnson suggested that people with Covid-19 could be treated with tablets at home within months, after the launch of a new task force to find antivirals.
The goal is to have at least two effective at-home treatments by the end of the year.
“Our new Antivirals Task Force will seek to develop innovative treatments you can take at home to stop Covid-19 in its tracks,” he said.
“These could provide another vital defence against any future increase in infections and save more lives.”