U.S. regulators Wednesday approved the first drug for the treatment of Ebola.

The Food and Drug Administration OK'd the drug developed by Regeneron Pharmaceuticals for treating adults and children with the Zaire Ebola virus strain, the most deadly of six known types. It typically kills 60% to 90% of patients.

The drug was one of four tested during an outbreak in Congo that killed nearly 2,300 people before it ended in June. Survival was significantly better in study participants given Regeneron's Inmazeb or a second experimental drug.

The study was ended ahead of schedule last year so all patients could get access to those drugs.

Regeneron's treatment is a combination of three antibodies that work by killing the virus. It’s given once by IV.

“When you have three drugs that bind to the (virus), there’s a low probability that the virus can evade all of them,” said Leah Lipsich, who heads Regeneron’s global program for infectious diseases.

She said that should help prevent the virus from becoming resistant to the drug.

Seeking U.S. approval first is a common strategy for drugmakers developing treatments for diseases mainly found in the tropics and in developing countries. The FDA’s action will make it easier for Regeneron to get approval or allow emergency use during outbreaks in African countries, where the approval process is not straightforward, Lipsich said.

The study in Congo involved 681 people, who were give one of four treatments. After four weeks, about a third of those who got Regeneron's drug had died. Results were about the same for a second drug. But about half had died among the groups given one of the other two drugs, ZMapp or remdesivir.

Gilead Science's remdesivir is now being used as a treatment for coronavirus.

Ebola is very contagious and is spread mainly through contact with body fluids from infected people. Symptoms include fever, muscle pain, vomiting, kidney and liver damage, and sometimes internal and external bleeding.

The FDA approved the first vaccine for Ebola last December.

The U.S. government, which helped fund the approved drug’s development, will buy thousands of doses over the next six years to go into the Strategic National Stockpile. Ebola cases are rare in the U.S., but occasionally are diagnosed in travelers returning from areas with an outbreak.

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Follow Linda A. Johnson at https://twitter.com/LindaJ_onPharma

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