Tekmira stops adding new patients to study of drug targeting Ebola strain behind outbreak

Shares of drugmaker Tekmira slumped Friday after the company said it stopped enrolling new patients in a trial of a treatment for a strain of Ebola.

The Canadian company said the mid-stage study "reached a predefined statistical endpoint" and that it was no longer enrolling patients. It did not describe that statistical goal, but said adding new patients probably wouldn't have demonstrated a benefit for the drug. Tekmira said it is analyzing results from the trial and will make the results available as soon as possible.

The company's shares dropped $1.74, or 11.6 percent, to $13.28 on Friday.

Tekmira Pharmaceuticals Corp. calls the drug TKM-Ebola-Guinea and it is designed to target the strain of the virus that is responsible for the active outbreak in West Africa. More than 11,000 people have died since that outbreak began in December 2013.

The company has been studying the drug in Ebola patients in Sierra Leone.

It is also running an early-stage trial of a drug called TKM-Ebola, which targets a different strain of the virus. That study is happening in the U.S. and it involves only healthy patients. Tekmira expects results from that study in the second half of this year.

Tekmira does not have any approved drugs and is also studying a potential treatment for hepatitis B.