A 11-Year-Old, Survivor-Derived Antibody Becomes Second Ebola Therapy to Bag FDA Approval

On December 21st, the US food and drug administration (FDA) approved the second Ebola treatment, Ebanga from Ridgeback Biotherapeutics, for treatment of infection caused by deadly Zaire Ebolavirus in adults and children including neonates. This treatment gets the FDA nod nearly seven years after the Ebola epidemic emerged in West Africa. With this, Ebanga became the second FDA-approved Ebola treatment after Regeneron’s Inmazeb, which received approval in October.

Ebanga

Ebanga was originally developed by the National Institute of Health’s Vaccine Research Center and the Democratic Republic of Congo’s Institut National pour la Recherche Biomédicale (INRB). However, it was later licensed to Ridgeback Biotherapeutics, which then overlooked its development.

Ebanga is a monoclonal antibody that was isolated from a human survivor of the 1995 Ebola outbreak in Kikwit city. Interestingly, this survivor retained the antibodies 11 years after the infection. The team of scientists from NIAID, VRC isolated antibodies from the blood of this patient. All the different variants of the antibodies against Ebola derived were screened, and the most favorable ones were picked for further analysis. Ansuvimab or Ebanga or mAb114 was found most promising in nonhuman primates and was sent for clinical trials.

Antibody therapies such as Ebanga work by binding to a virus and blocking its interaction with the human cells. The very first treatment approved for Ebola, Inmazeb, is a cocktail of three antibodies that targets the glycoprotein present on the surface of the Ebola virus. By doing so, it prevents the glycoprotein from attaching to the human cell membrane-a step which is essential for the entry of the virus into the cell.

Drug Development

Ebanga was tested in the PALM (Pamoja Tulinde Maisha) study during the 2018-2019 outbreak in Congo. The trial compared the efficacy of Ebanga with Mapp Biopharmaceutical’s ZMapp or Gilead’s remdesivir-both of which were considered the standard of care at the time of the outbreak. The study showed that the patients on Ebanga had a better chance of survival than on the standard of care treatments. Of the 174 patients who received Ebanga, 35.1% died after 28 days, compared with 49.4% of the 168 control patients. The most common symptoms that the patients receiving Ebanga experienced were fever, tachycardia, diarrhea, vomiting, low blood pressure, fast breathing. However, all these symptoms also occur during Ebola infection and hence are not conclusively drug-related.

The treatment comes at an opportune time when sporadic Ebola outbreaks recorded in Congo claimed 55 lives. This treatment will be effective at keeping any future outbreaks at bay. Dr. Sabue Mulangu, Senior Vice President of Global Affairs at Ridgeback, commented: “We were hopeful that news of an effective treatment would encourage patients with Ebola symptoms to present early in the disease course, which should lead to even better outcomes for patients and less spread in the community.

Besides the two approved treatments, the fight against the virus was put on high gear with the FDA approval of Merck’s Ebola vaccine, Ervebo. However, the regulators have advised not to combine treatments with the vaccine as it may nullify the effect of the vaccine, which contains live virus antigen.

By Ruchi Jhonsa, Ph.D.

Related Article: Regeneron’s FDA Success with Ebola Treating Antibody Cocktail, Inmazeb, Bodes Well for its COVID-19 Candidate

References

1. https://www.businesswire.com/news/home/20201222005421/en/Ridgeback-Biotherapeutics-LP-Announces-the-Approval-of-EbangaTM-for-Ebola
2. https://www.fda.gov/drugs/drug-safety-and-availability/fda-approves-treatment-ebola-virus
3. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-ebola-virus

Author

Ruchi Jhonsa