On Jun. 5, 2020, the Chief Investigators of the randomised evaluation of COVid-19 thERapY (RECOVERY) trial on hydroxychloroquine reported no clinical benefit from use of hydroxychloroquine in hospitalised patients with COVID-19. The trial proceeded at unprecedented speed, and enrolled over 11,000 patients from 175 NHS hospitals in the UK.

The independent Data Monitoring Committee concluded that there was no beneficial effect of hydroxychloroquine in patients hospitalised with COVID-19 and decided to stop enrolling participants to the hydroxychloroquine arm of the RECOVERY trial.