With Ebola flaring up once again, the Democratic Republic of the Congo (DRC) has authorized the experimental use of five treatments for infected patients. These are Mapp Biopharmaceutical's ZMapp, Regeneron's REGN-EB3, the National Institute of Allergy and Infectious Diseases' mAb114, Gilead Sciences' remdesivir and MediVector's favipiravir.

ZMapp consists of a cocktail of three monoclonal antibodies (mAbs) that target separate glycoprotein epitopes on the Ebola viral envelope to inactivate the virus. It yielded promising signs of benefit when trialled in the 2014–2015 Ebola outbreak in West Africa, but this trial did not reach its enrolment goals and failed to hit its prespecified statistical threshold for efficacy. REGN-EB3 is also a cocktail of three mAbs that bind the glycoprotein. It has promising efficacy in animal models of disease, and has completed a phase I safety study. mAb114 binds the glycoprotein as well. It entered into phase I safety trials earlier this year.

Remdesivir is a nucleoside analogue that blocks Ebola's RNA polymerase to prevent viral replication. It was used successfully in at least one patient, in combination with ZMapp and a white blood cell transfusion from an Ebola survivor, during the last Ebola outbreak. But efficacy experience remains anecdotal. Favipiravir is a broad-spectrum RNA polymerase inhibitor. It is also in phase III trials for treatment of influenza.

In May, a scientific advisory panel to the WHO noted that ZMapp had “the highest-quality data” for use in this emergency setting. They also prioritized the use of remdesivir over REGN-EB3 and favipiravir where possible. The said more data was needed before they could recommend mAb114 (see Nature Reviews Drug Discovery for more details on these drugs).

The WHO and Merck & Co. are also testing the prophylactic efficacy of Ebola vaccine rVSV-ZEBOV in the DRC. rVSV-ZEBOV consists of a recombinant vesicular stomatitis virus that expresses the Zaire Ebolavirus glycoprotein. Researchers reported in The Lancet in 2017 that the vaccine offered substantial protection in a trial in around 4,000 at-risk individuals in the last outbreak. No cases of infection were found among vaccinated individuals from day 10 after vaccination.