US regulators approved the first drug for the treatment of Ebola on Wednesday. The Food and Drug Administration OK'd the drug developed by Regeneron

Pharmaceuticals to treat the Zaire Ebola virus strain, the most lethal of six known varieties, for adults and infants. Usually, it kills 60 to 90% of patients. 


During an epidemic in Congo that killed nearly 2,300 people before it ended in June, the drug was one of four tested. In the study participants, survival was substantially better given Regeneron's Inmazeb or a second experimental drug. 


Last year, the trial was terminated ahead of time so that all patients could have access to those medications. 


The treatment of Regeneron is a mixture of three antibodies which work by killing the virus. It is given once by IV


“When you have three drugs that bind to the (virus), there's a low chance that the virus will evade any of them,” said Leah Lipsich, who heads Regeneron 's global programme for infectious diseases. She said that preventing the virus from being immune to the drug could help. 


A common strategy for drugmakers to develop treatments for diseases mainly found in the tropics and in developing countries is to seek US approval first. In African countries, where the approval process is not straightforward, the FDA 's intervention would make it easier for Regeneron to get approval or allow emergency use during outbreaks, Lipsich said. 


In Congo, the study included 681 individuals who were given one of four therapies. Four weeks later, about a third of those who received the medication from Regeneron died. The findings for the second drug were about the same. But among the groups given one of the other two medications, ZMapp or remdesivir, about half died.


Remdesivir is now being used as a coronavirus drug by Gilead Science. 


Ebola is extremely infectious and is transmitted mostly by contact with infected people's body fluids. Symptoms include fever, pain in the muscles, vomiting, damage to the kidneys and liver, and internal and external bleeding occasionally. 


The first vaccine for Ebola was approved last December by the FDA. 


Over the next six years, the US government, which helped finance the production of the approved medication, would purchase thousands of doses to go into the Strategic National Stockpile. Ebola cases are uncommon in the US, but travellers returning from areas with an epidemic are sometimes diagnosed.