This collaborative effort also involved researchers from Institute of Biomedical Research and the United States Army Medical Research Institute of Infectious Diseases. A survivor from the 1995 outbreak of Ebola virus disease in Kikwit, Democratic Republic of Congo donated blood to the project that began roughly ten years after they had recovered. Memory B cells isolated from the survivors blood were immortalized, cultured and screened for their ability to produce monoclonal antibodies that reacted with the glycoprotein of Ebola virus. Ansuvimab was identified from one of these cultures and the antibody heavy and light chain gene sequences were sequenced from the cells. These sequences were then cloned into recombinant DNA plasmids  and purified antibody protein for initial studies was produced in cells derived from HEK 293 cells. Ansuvimab and mAb100 combination
In an experiment described in the 2016 paper, rhesus macaques were infected with Ebola virus and treated with a combination of ansuvimab and another antibody isolated from the same subject, mAb100. Three doses of the combination were given once a day starting 1 day after the animals were infected. The control animal died and the treated animals all survived. Ansuvimab monotherapy
In a second experiment described in the 2016 paper, rhesus macaques were infected with Ebola virus and only treated with ansuvimab. Three doses of ansuvimab were given once a day starting 1 day or 5 days after the animals were infected. The control animals died and the treated animals all survived.
Ansuvimab is also being evaluated during the 2018 North Kivu Ebola outbreak.Ansuvimab has also shown success with lowering the mortality rate from ~70% to about 34%. In August 2019, Congolese health authorities, the World Health Organization, and the U.S. National Institutes of Health promoted the use of ansuvimab, alongside toltivimab/maftivimab/odesivimab, a similar Regeneron-produced monoclonal antibody treatment, over other treatments yielding higher mortality rates, after ending clinical trials during the outbreak.The U.S. Food and Drug Administration (FDA) approved ansuvimab based primarily on evidence from a clinical trial (Trial 1/ NCT NCT03719586) of 342 participants with Zaire ebolavirus infection. The trial enrolled newborn, pediatric and adult participants (including pregnant women) with Zaire ebolavirus infection. All participants received standard, supportive care for the disease. In addition to the standard care, participants were randomly assigned to receive either a one-time dose of ansuvimab or one of the three other types of experimental treatments (including one as the control group). The participants and the health care providers knew which treatment was being given. The trial was conducted at four sites in the Democratic Republic of Congo during an outbreak that began in August 2018. Discovery
A 2016 paper describes the efforts of how ansuvimab was originally developed as part of research efforts led by Dr. Nancy Sullivan at the United States National Institutes of Health Vaccine Research Center and Dr. J. J. Muyembe-Tamfum from the Institut National de Recherche Biomedicale (INRB) in the Democratic Republic of Congo.