How the Ebola drug ZMapp is made

How Ebola drug ZMapp is made
How Ebola drug ZMapp is made

With the Ebola scare growing, at least three drugs are being used experimentally in animal and human trials.

One drug, ZMapp, has already been used on at least two victims, who’ve survived.

There is no federally approved treatment, and no vaccine for Ebola. One of the drugs the world is pinning its hopes on is a drug cocktail called ZMapp.

ZMapp had only been tested successfully on monkeys before being used to save the lives of two American missionaries this summer.

But, experts say, there is no proof that ZMapp or any drug is effective in treating Ebola.

The experimental treatment is the result of a collaboration between San Diego based Mapp Biopharmaceutical and two other companies.

Here’s how ZMapp is made: First a genetically engineered virus is injected into a tobacco plant. The plant then produces antibodies. Unlike earlier attempts in mice, the tobacco plant can produce enough antibodies for dozens of doses.

The ZMapp given to the missionaries in August was apparently made from tobacco leaves at a facility in Kentucky.

“As the plant starts turning yellow, ’cause it’s going to die from the viral infection, once you see that the plant has gotten to that point, the guys in Kentucky harvest the leaf material,” explains Dr. Charles Arntzen, Regents’ Professor at Arizona State University.

Cloned “humanized” antibodies are separated from the plant, purified, and turned into doses. In a patient, those antibodies attach themselves to Ebola’s harmful cells and destroy the virus.

Trouble is, the whole process takes time, as long as six months per dose.

There’s another reason the supply of ZMapp has already run dry, the lack of funding for government agencies focused on bio-defense. Last year, the CDC lost $13-million in bio-defense budget cuts and the budget for the National Institute of Health was reduced by 5 percent.

“They’re right now manufacturing additional lots. It probably won’t be ready now until maybe a month-and-a-half to two months,” said Dr. Anthony Fauci, Dir., National Institutes of Health.

Help is on the way now. Just this year, the U.S. Department of Health and Human Services provided nearly $25 million in funding to ZMapp’s manufacturer..

But for those who need it now, there’s fear it will be too little too late.

Below are the experimental drugs that have been used on Ebola patients in the current outbreak:

  • Chimerix Inc.’s brincidofovir, being used on the Dallas Ebola patient, is an oral medicine developed to treat other types of viruses. It is in late-stage testing for cytomegalovirus. Durham, North Carolina-based Chimerix is also developing it as a smallpox treatment. Laboratory tests suggest it may be active against Ebola.
  • ZMapp from San Diego-based Mapp Pharmaceuticals was developed specifically as an Ebola treatment, a cocktail of antibodies engineered to recognize the virus and bind to infected cells. Supplies are exhausted; work is underway to produce more.
  • The TKM-Ebola injection, by Tekmira Pharmaceuticals of Canada, works by blocking genes that help the Ebola virus reproduce and spread. It has been used in at least one patient and is said to be in limited supply.
  • A fourth drugmaker, North Carolina’s BioCryst, has government funding to research another experimental antiviral drug for Ebola, called BCX4430.

Another option endorsed by the World Health Organization is to attempt a blood transfusion from an Ebola survivor.

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