A Randomized Controlled Trial of ZMapp for Ebola Virus Infection
The PREVAIL II Writing Group for the Multi-National PREVAIL II Study Team. (2016). A Randomized, Controlled Trial of ZMapp for Ebola Virus Infection. The New England Journal of Medicine. 375:1448-1456.
A randomized, controlled trial involving 72 patients found that the experimental treatment ZMapp plus the current standard of care was superior to the current standard of care alone by a 91.2% posterior probability. While this is less than the 97.5% pre-study specified probability for superiority and therefore is an inconclusive result, the authors found the results to suggest a positive outcome from the addition of ZMapp to the current standard of care, identified a similar percentage of patients with serious adverse events in both groups, and argued that the study established the feasibility of conducting a randomized, controlled trial during a major public health emergency. Among the factors impacting the results were the inability to enroll the planned 200 patients, which resulted in wide 95% credible intervals, and the deaths of patients before they received all three infusions of ZMapp.