The University of Oxford reported Friday that data from the so-called RECOVERY trial  of drugs for COVID-19 indicate that hydroxychloroquine provided "no clinical benefit" to patients hospitalised with the infection, and enrollment in this arm of the study has stopped. "These data convincingly rule out any meaningful mortality benefit of hydroxychloroquine in [these] patients," chief investigators Peter Horby and Martin Landray said in a joint statement, adding that full results would be made available as soon as possible.
RECOVERY has an estimated enrolment of over 11,000 patients from 175 NHS hospitals in the UK who were randomised to one of multiple arms testing potential treatments for COVID-19. Aside from hydroxychloroquine, these include AbbVie's HIV drug Kaletra/Aluvia (lopinavir/ritonavir), Roche's IL-6 inhibitor Actemra/RoActemra (tocilizumab), the antibiotic azithromycin, convalescent plasma and low-dose corticosteroids, as well as a "no intervention" standard care arm.
Eligible participants could be children, adults and older adults, and had to be hospitalised with SARS-CoV-2 infection that was either laboratory-confirmed or clinically suspected. The primary endpoint is all-cause mortality within 28 days after randomisation, while secondary goals are assessing duration of hospital stay, need for ventilation and for how long, as well as a composite endpoint of death or need for mechanical ventilation or extracorporeal membrane oxygenation.
A total of 1542 patients were randomised to hydroxychloroquine and compared with 3132 patients who received usual care alone. The Oxford researchers said 28-day mortality for the two groups was 25.7% and 23.5%, respectively, a difference that was not statistically significant. They added that there was also "no evidence of beneficial effects" on hospital stay duration or other outcomes.
'Should change medical practice'
Landray said "today's preliminary results from the RECOVERY trial are quite clear – hydroxychloroquine does not reduce the risk of death among hospitalised patients with this new disease. This result should change medical practice worldwide." Horby noted that while it is "disappointing that this treatment has been shown to be ineffective, it does allow us to focus care and research on more promising drugs."
These latest results follow study findings published  this month in the NEJM, which suggested that hydroxychloroquine did not prevent COVID-19 in people after recent exposure to patients infected with the virus. The antimalarial also showed no benefit  in a pair of studies published last month in the BMJ.
Meanwhile, a recent influential study published in The Lancet , linking hydroxychloroquine and chloroquine to an increased risk of irregular heart rhythms and death among COVID-19 patients, has since been retracted after three of its authors said they could "no longer vouch for the veracity of the primary data sources."