Washington, Feb 28 (IANS): The US and Liberian governments Friday launched a clinical trial to evaluate the safety and efficacy of an experimental Ebola drug on humans, the US National Institute of Allergy and Infectious Disease (NIAID) said.

"Although ZMapp has been used to treat several Ebola-infected patients in recent months, we cannot determine if the drug actually benefited those patients because it was not administered within the context of a clinical trial," Xinhua quoted Anthony Fauci, director of the NIAID, as saying.

"This clinical trial will help us determine if ZMapp and other treatments are safe and effective for use in the current devastating outbreak in West Africa as well as in (case of) future outbreaks," Fauci added.

ZMapp, developed by the California-based Mapp Biopharmaceutical Inc, is composed of three different proteins called monoclonal antibodies that work to prevent the spread of the Ebola virus within the body.

Studies in non-human primates demonstrated that ZMapp has a strong anti-viral character and rescued the animals from death as late as five days after an Ebola infection. But there have been no human trials so far to support this.

The human trial now will be co-led by investigators from the NIAID and the Ebola Incident Management System in the Liberian capital Monrovia.

It will enroll Ebola patients in Liberia, healthcare workers returning to the US for treatment after Ebola infection and those who may have acquired Ebola infection in the US through secondary transmission.

The participants of the trial would be monitored for up to 30 days following their discharge from hospital and might have to return for follow-up visits, the NIAID said.

The trial is expected to conclude in December 2016.

So far, there have been more than 9,400 deaths since the Ebola outbreak last year in Liberia, Sierra Leone and Guinea. The virus causes hemorrhagic fever in humans and currently has no approved therapy or vaccine.