(Adds details on treatment's use, share activity)
Nov 6 (Reuters) - The U.S. Department of Defense has exercised an option with Canada's Tekmira Pharmaceuticals Corp for the company to make 500 courses of its experimental treatment for Ebola, Tekmira said on Thursday.
The treatment targets the Ebola-Guinea virus variant, which is responsible for the worst outbreak on record that has hit hardest in Liberia, Sierra Leone and Guinea. It works by preventing the virus from replicating.
Supplies of TKM-Ebola-Guinea will be available in early December, with plans to use it for clinical studies in West Africa, Tekmira said. It was not clear if this supply was separate from the U.S. Department of Defense order.
The company's shares closed up 5.4 percent in Toronto and 4.2 percent on the Nasdaq.
Tekmira also produces a treatment called TKM-Ebola, which has been used on several patients, including an infected U.S. medical missionary who contracted the virus in Liberia. The man recovered after treatment with the drug and a "convalescent serum" made up of antibodies taken from the blood of a U.S. Ebola survivor.
Tekmira's investigational new drug application to U.S. regulators for TKM-Ebola remains on partial clinical hold, and that status may not change in 2014 as was previously expected, the company said.
Tekmira conducts its Ebola program under a $140 million contract with U.S. Defense. The value of the option under that contract to produce Ebola-Guinea is $7 million. (Reporting by Rod Nickel in Winnipeg and Bangalore newsroom; Editing by Bernard Orr)