REGN-EB3 is made by Regeneron Pharmaceuticals of Tarrytown, N.Y., which also makes other antibody treatments. Dr. Fauci’s institute, which is part of the National Institutes of Health, developed mAb114 and licensed production last year to Ridgeback Biotherapeutics, a Miami company. Antibodies are Y-shaped proteins normally made by the immune system that clump onto the outer shells of viral particles, preventing them from entering cells. The two new treatments are synthetic versions grown under laboratory conditions. The two new therapies were among four that were tested in a trial that has enrolled almost 700 patients since November. The two worked so well that a committee meeting on Friday to look at preliminary results in the first 499 patients immediately recommended that the other two treatments, ZMapp, made by Mapp Biopharmaceutical, and remdesivir, made by Gilead Sciences, be stopped. All patients will now be offered either the Regeneron or the Biotherapeutics drug. Among patients who were brought into treatment centers with low viral loads — which suggested that they had been infected only days before — only 6 percent of those who got Regeneron drug died, and only 11 percent of those who got the Biotherapeutics drug died, Dr. Fauci said. By contrast, 33 percent of those who received the antiviral drug made by Gilead died, as did 24 percent of those who got ZMapp, an older monoclonal antibody cocktail that was tested briefly during the Ebola outbreak in West Africa in 2014. The death rate among untreated and unvaccinated patients in this outbreak is thought to be over 70 percent, said Dr. Michael J. Ryan, director of emergency response for the W.H.O. [Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.] The difference in mortality rates between the Regeneron product and the Ridgeback one was considered too small to be statistically significant, so both are still being used, Dr. Fauci said.
Scientists have announced a potential cure for Ebola. Amid the second biggest Ebola outbreak, scientists in the Democratic Republic of Congo have stated that two new antibody-based experimental treatments for the disease have saved 33 percent of infected patients, and the drug will now be offered to all patients.