Two of four Ebola treatments prove highly effective in a clinical trial
Two Ebola treatments haveproven to be effective in preventing death during a clinical trial conductedamid the ongoing outbreak in Congo, preliminary data suggest.
The trial began in November, with participantsrandomly given one of four experimental treatments (SN: 3/16/19,p. 9). Data from 499 patients reviewed August 9 suggest that those people takingone of two antibody treatments —mAb114 or REGN-EB3 —had a greater chance of survival than those on the antiviral drug remdesivir orthe antibody treatment ZMapp. Researchers reported the trial results in a news release August 12, but these findings haveyet to be finalized.
“One thing that won’t change is thatthose two therapies are better than the other two — that’s for sure,” saysAnthony Fauci, director of the National Institute of Allergy and InfectiousDiseases at the National Institutes of Health in Bethesda, Md. The trial nowenters a phase with only the two most effective treatments in order to gathermore data on their safety and the immune response to each drug. Researchers won’tstudy enough patients, however, to determine which drug works best.
The percentage of patients who died while taking one of the treatments was 29 percent for REGN-EB3 and 34 percent for mAb114. That’s a big improvement over the current 67 percent mortality rate reported for Congo’s outbreak, which began August 1, 2018. (Regeneron Pharmaceuticals Inc., which makes the REGN-EB3 therapy, is a major financial supporter of the Society for Science the Public, the nonprofit that also publishesScience News.)
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Results were even better for patientswith a low viral load, or less of the virus in their blood — which may be an indication that their infections werecaught early. Among those patients, 6 percent taking REGN-EB3 died and 11percent on mAb114 died.
Among patients given the ZMapp antibodytreatment, which was considered the key comparison group, 49 percent died, with24 percent of low-viral load patients on ZMapp succumbing to the disease, Faucisays. Results for remdesivir were slightly worse than for ZMapp.
Antibody treatments provide the immunesystem with an immediate supply of antibodies that can target the virus. The mAb114therapy is made of a single antibody cloned from an Ebola survivor of a 1995outbreak, while REGN-EB3 is a cocktail of three antibodies.
The World Health Organization declared Congo’sEbola outbreak a public health emergency on July 17, due to fears of the disease spreading to neighboringcountries (SN Online: 7/17/19). ByAugust 10, the outbreak had killed 1,888 of the 2,816 people reported infected,WHO says.