New Method Sought to Make Ebola Drug Grown From Tobacco.

http://www.bloomberg.com/news/2014-10-10/new-method-sought-to-make-ebola-drug-grown-from-tobacco.html

Biotechnology researchers and U.S. officials are rushing to try to make more of what may be the most promising experimental drug to treat Ebola after supply ran out in August.

The drug, ZMapp, is made by Mapp Biopharmaceutical Inc. Mapp and its partners have had early discussions with Amgen Inc. (AMGN) about the feasibility of increasing production of the antibody cocktail using a traditional biotechnology manufacturing technique, said Bryan Callahan, a senior program officer with the Bill & Melinda Gates Foundation.

The foundation gave Mapp a $150,000 grant to look at whether a new large-scale production technique is possible. “No final decision has been made on the pharma partner,” Callahan said in an e-mail. Amgen, based in Thousand Oaks, California, is the world’s biggest biotechnology company by sales.

ZMapp is currently made using tobacco plants, which can be induced to grow the antibodies in the drug. Federal officials have also considered an expanded tobacco-based production process.

The cocktail of three antibodies has been used to treat two Ebola-infected American health workers who recovered, a Spanish priest who died and three Liberian health workers.

Mapp, a closely held, San Diego-based company, developed ZMapp with the Public Health Agency ofCanada and the U.S. government. For now, production has been limited to a handful of doses. That’s far too few to have an impact on the current outbreak in West Africa that, according to the World Health Organization, has infected more than 8,000 people, killing about half.

Tobacco Plants

To produce therapeutic proteins inside a tobacco plant, genes for the desired antibodies are fused to genes for a natural tobacco virus. The tobacco plants are then infected with the artificial virus, producing the antibodies. The plants are then ground up and the antibodies extracted.

Drug Manufacturing

“We possess high capabilities for production in plants, which is the process necessary for manufacturing the experimental Ebola therapeutic, ZMapp,” Brett P. Giroir, chief executive office of the Texas A&M Health Science Center, in an e-mailed statement.

The Caliber facility could produce 25 kilograms to 75 kilograms of ZMapp antibody per year, based on preliminary estimates, starting within weeks to months of an order from the U.S., Giroir said. The production facility and its capabilities were created in a joint effort between Texas A&M and Caliber, he said.

ZMapp is difficult to make in large quantities for a number of reasons, researchers said. It involves three antibodies, which triples the amount of tobacco plants needed. In addition, the dose used to treat patients is high compared with many drugs, increasing the needed supply.

Timeline Unpredictable

While it is unclear what the best dose of ZMapp is, by some estimates, the 25 kilograms to 75 kilograms may translate into enough of the drug to treat several thousand patients.

Kay estimates the production capacity of Caliber is about 100 kilograms of ZMapp per year, which he said could yield enough to treat 20,000 patients with the drug cocktail.

Ebola is normally treated by keeping patients hydrated, and using antibiotics to fight off opportunistic infections. The hope is that a patient’s immune system will eventually fight off the virus’s aggressive attack.