(CNN) Researchers in the United Kingdom have put an abrupt stop to an arm of their Covid-19 trial that involves the antimalarial drug hydroxychloroquine.
The Recovery trial, a large UK-based trial investigating potential coronavirus treatments, has stopped including hydroxychloroquine in its study due to there being "no evidence of benefit," researchers announced on Friday. Other arms in the trial, which has enrolled more than 11,000 patients from 175 hospitals across the UK, will continue.
"We reviewed the data and concluded that there is no evidence of a beneficial effect of hydroxychloroquine in patients hospitalized with Covid and decided to stop enrolling patients to the hydroxychloroquine arm, with immediate effect, and that has been actioned this morning," Martin Landray, deputy chief investigator of the trial and a professor at the University of Oxford, said during a media briefing on Friday.
As part of the trial, 1,542 Covid patients were randomly selected to receive hydroxychloroquine as a treatment compared with 3,132 patients who received the usual standard care.
The data showed that after about 28 days, 25.7% of the patients who received hydroxychloroquine had died compared with 23.5% of patients who received usual care alone.
"That is not statistically significant, but as you can see from the numbers, that result shows that there's really no evidence of a benefit," Landray said.
"I think we can say that this data convincingly rule out any meaningful mortality benefit," Landray said. "Our conclusion is that this treatment does not reduce the risk of dying from Covid among hospital patients. That clearly has a significant importance for the way that patients are treated not only in the UK, but all around the world."
Last week, the World Health Organization temporarily paused the hydroxychloroquine arms of its Solidarity Trial due to concerns surrounding the drug's safety and in order to review its own data. Then on Wednesday, after that review, WHO announced that it decided to resume studying hydroxychloroquine as a potential Covid-19 treatment in the trial.
Peter Horby, chief investigator for the Recovery Trial and a professor at the University of Oxford, said on Friday that his colleagues and he have notified WHO about the data found in their trial and the decision to end this arm of the study.
"We've been on the telephone this morning with the World Health Organization," Horby said during Friday's presser. "They will be convening their committee to reconsider their decision based on the events of today."
WHO confirmed during a media briefing in Geneva on Friday that it had received notice from the organizers of the Recovery trial that the trial ended its hydroxychloroquine arm.
"As Solidarity and Recovery are two of the larger trials, and moreover they have very, very similar study designs, we have been in touch," Dr. Soumya Swaminathan, WHO chief scientist, said during the briefing.
"They informed us about the preliminary results, which they have gone to the press with. We await to see the final data analysis and the publication that's going to come out of it and certainly our committee will be considering these results as we go on," Swaminathan said. "However, they are two distinct trials, with their own protocols, their own oversight committees and therefore we will continue for now and our committee will consider the data as it becomes available."