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Two experimental treatments are effective at preventing death in Ebola patients, according to the preliminary results of a clinical trial described yesterday (August 12) by the National Institutes of Health.

The study, which monitored responses to four experimental treatments in Democratic Republic of Congo (DRC), has now been halted to allow all trial participants to receive one of the two successful drugs, REGN-EB3 (made by Regeneron Pharmaceuticals) and mAb114 (developed by the US National Institute of Allergy and Infectious Diseases).

“From now on, we will no longer say that Ebola is incurable,” Jean-Jacques Muyembe, the director general of the Institut National de Recherche Biomédicale in DRC, which is overseeing the trial, said during a press conference, The Guardian reports. “These advances will help save thousands of lives.”

DRC’s most recent outbreak of Ebola began last August. It has so far killed nearly 1,900 people, and infected a further 1,000.

Since last fall, researchers have been testing the monoclonal antibody–based drugs REGN-EB3 and mAb114 along with Mapp Biopharmaceutical’s monoclonal antibody treatment ZMapp and Gilead Sciences’s antiviral drug remdesivir in a four-armed drug trial known as the Pamoja Tulinde Maisha study. The trial enrolled nearly 700 patients between November 2018 and August 2019 at four Ebola Treatment Centers across the country.

Reviewing the results last week (August 9), an independent data and safety monitoring board found that patients receiving REGN-EB3 or mAb114 had a lower chance of death than those receiving one of the other two drugs or no treatment at all.

In contrast to the 67 percent mortality rate associated with the current outbreak of Ebola, just 29 percent and 34 percent of people died while taking REGN-EB3 and mAb114, respectively. Nearly half of the people taking ZMapp died, as did 53 percent of patients receiving remdesivir.

The results were more striking for patients with a low viral load in their blood: more than 90 percent survived while taking either REGN-EB3 or mAb114, provided they got treatment early.

“Getting people into care more quickly is absolutely vital,” Michael Ryan, the executive director of the World Health Organization’s Health Emergencies Programme, tells reporters, according to the Associated Press. “The fact that we have very clear evidence now on the effectiveness of the drugs, we need to get that message out to communities.”

The final analysis of the data, which are still being collected for REGN-EB3 and mAb114, is expected in the fall of this year, after which the findings will be published, according to a press release by the National Institutes of Health.

Catherine Offord is an associate editor at The Scientist. Email her at cofford@the-scientist.com.