Canadian drug manufacturer Tekmira Pharmaceuticals Corporation announced on Friday that it will no longer continue testing an experimental treatment for Ebola.

According to reports, Tekmira said the second phase of the TKM-Ebola-Guinea clinical trial has reached a statistical futility boundary — which means it is unclear whether the drug had benefitted patients or not. The company added that the trial was scheduled to end in any case. Tekmira is presently analyzing data from the trial and will make the complete results available as soon as possible.

"It is a great tribute to the team in Sierra Leone that the trial has been run so efficiently and that we now have substantial experience on the use of TKM-Ebola-Guinea in patients with Ebola," said lead investigator Dr. Peter Horby at the University of Oxford.

"While the trial has reached a statistical endpoint, final conclusions on the efficacy and tolerability of the drug must await full analysis of the data."

Infectious diseases expert Thomas Geisbert at the University of Texas, however, argued that the discontinuation of the clinical trial means the treatment cannot work.

Geisbert – who had tested the medication on monkeys – explained that this illustrates the challenge of testing drugs on real patients during disease outbreaks.

The version of the drug Tekmira tested in Sierra Leone was not the same one that had protected the monkeys given a deadly dose of the Ebola virus.

"It's not the best product that they have. It's not the best formulation," Geisbert pointed out. "This is not what we tested in monkeys."

The Ebola virus has infected over 27,000 people in West Africa and killed over 11,000 others in an ongoing outbreak. Death rates due to Ebola infections are estimated at 50 percent or more.

By the time the Ebola epidemic had worsened, several governments and countries sent experimental drugs and vaccines into the region. These include blood transfusions from survivors of the infection for patients, complicated plasma transfusions and various medications from drug manufacturers such as Tekmira.

However, since none of the therapies tested were administered in a controlled clinical trial, it is difficult determine which one of them worked. The outbreak has dropped off in recent months, making it harder to enroll people to a proper testing of a drug.

Photo: European Commission DG ECHO | Flickr 

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