Updated

A clinical trial of Tekmira's experimental drug TKM-Ebola-Guinea will start on Wednesday in Sierra Leone, Britain's Wellcome Trust global health charity said.

The drug, a so-called "synthetic small interfering RNA (siRNA) therapeutic", is designed specifically to target the strain of Ebola virus causing a vast epidemic centered mainly in Guinea, Liberia and Sierra Leone.

An earlier version of the TKM-Ebola drug -- targeted at a different strain -- has already been tested in healthy human volunteers.

The efficacy of the Guinea version will now be tested in Ebola patients in a fast-tracked trial funded by Wellcome, with results expected in the second half of this year, the charity said in a statement.