Medical charities say they have started trials of untested drug treatments on Ebola patients in Liberia and Guinea for the first time in an effort to control an epidemic that has killed more than 8,000 people in the region.

The World Health Organization gave its approval for the use of experimental drugs on West African Ebola patients in August, but it has taken months to organize trials and get limited supplies of the drugs to the affected countries.

Medecins Sans Frontieres said on Tuesday it began giving brincidofovir, developed by North Carolina-based Chimerix Inc., to consenting confirmed Ebola patients this month at the ELWA 3 center in Monrovia.