"We have administered it [treatment] to two patients so far," Brett Adamson, MSF medical coordinator in Monrovia, told The Anadolu Agency.
"The second patient has received the drugs and this week we have seen an increase in admission," he said.
Clinical trials are being conducted at ELWA 3, the MSF's Ebola management center in Paynesville, Monrovia.
The center currently has a total of ten confirmed Ebola cases, while the MSF's second Ebola-treatment unit in Lofa County – which had been the epicenter of the virus – has registered no cases for almost 40 days.
The trials aim to determine whether the antiviral drug Brincidofovir is an effective treatment for Ebola.
"It is to assess and see how it brings benefits," Adamson said.
The experimental drug trials are being conducted by Oxford University. They are funded by the Wellcome Trust, a global biomedical research charity based in London.
Brincidofovir is produced by an American company, Chimerix, and administered to patients free of charge.
According to Adamson, it is the first time for the drug to be given to Ebola patients.
"We believe there is hope in this experimental treatment to improve the disease cause for Ebola patients," he said.
In recent months, Ebola – a contagious disease for which there is no known treatment or cure – has killed 8,235 people, mostly in West Africa, according to the World Health Organization (WHO).
In Liberia alone, the virus has claimed a total of 3,496 lives out of 8,157 registered infections.
It is the second time for experimental drugs – believed to help cure the Ebola virus – to be dispensed on a clinical trial basis in Liberia. The first involved the drug ZMapp, which was administered a few months ago.
Adamson, the MSF coordinator, said participation in the trials was voluntary.
"It is strictly by consent," he told AA. "A patient must agree and sign the consent form before the drug is administered to him or her."
Adamson said the trials were designed without a control group in order to include as many Ebola-positive patients as possible.
The MSF, an international humanitarian organization and Nobel Peace Prize laureate, said that – while it hoped to provide the experimental treatment to Liberians with Ebola – it would remain vigilant in order to ensure patients' safety.
"We are monitoring [the trials] very closely to ensure there is no harm done to patients," Adamson said.
Adamson added that the drug would not be available at drugstores, but only under specific conditions at the ELWA 3 facility.
On the effectiveness of Brincidofovir as compared to ZMapp, Adamson said the new drug was quite different.
"We know ZMapp had a very short supply and is not proven to have cured Ebola," he told AA. "Brincidofovir is a different kind of substance."
He noted that adequate stocks of Brincidofovir had been made available by Oxford University, stopping short of saying how much was currently available.
According to Adamson, Brincidofovir has been used in other countries facing serious health crises and had proven effective.
"We certainly have enough for the trial, which is the first step," he told AA. "When there is hope, we'll bring enough."
The MSF coordinator said that, if the trials proved successful, the drug would be administered at other Ebola-treatment units across the country following recommendations by Oxford University and discussions with the Liberian government.