The experimental Ebola treatment ZMapp, which is composed of 3 different monoclonal antibodies, prevents progression of Ebola virus disease by targeting the main surface protein of the virus. According to findings from the clinical trial PREVAIL II, ZMapp is safe and well tolerated. But because the Ebola epidemic is “waning,” NIH says, the study enrolled too few people to determine definitively whether it is a better treatment than the best available standard of care.
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The study involved 72 men and women with confirmed infection. However, the researchers closed the study early because they could not enroll the target number of 200 participants due to the decline in cases. All patients received the optimized standard of care—IV fluids, electrolyte balance, maintaining oxygen and blood pressure levels—and half also received 3 IV infusions of ZMapp 3 days apart.
At 28 days, 13 of the 35 patients (37%) in the standard care group had died, compared with 8 of 36 (22%) in the ZMapp group. That difference, a 40% lower risk of death with ZMapp, still did not reach statistical significance.
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The findings are “promising and provide valuable scientific data,” says Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases. Moreover, he adds, “Importantly, the study establishes that it is feasible to conduct a randomized, controlled trial during a major public health emergency in a scientifically and ethically sound manner.”