evidence: ZMapp, Mab114, and REGN-EB3 are all monoclonal antibody products. Monoclonal antibodies are derived from immune system molecules that bind to a specific substance, such as an invading virus. Remdesivir is a type of antiviral drug. [...] After results from the first 499 participants had been reviewed, the trial’s safety monitors recommended that two drugs—ZMapp and remdesivir—be dropped from the remainder of the trial. These two drugs were much less effective at preventing death. Overall, about 50% of people who received either Zmapp or remdesivir died during the trial. In contrast, only about 35% of people who received either Mab114 or REGN-EB3 died. Three participants died of side effects thought to be related to treatment—two in the ZMapp group and one in the remdesivir group.