Ebola Drug Shows Signs of Efficacy in Small Clinical Trial

The New York Times
By Andrew Pollack
February 23, 2016

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The drug ZMapp, viewed as perhaps the most promising potential treatment for Ebola, seemed to prevent death from the disease in its first rigorous clinical trial, researchers reported on Tuesday.

However, they said, the results were not conclusive, probably because the Ebola outbreak in West Africa ended before enough patients could be enrolled in the study.

ZMapp rose to the top of the list of possible Ebola treatments during the outbreak in 2014 when two American aid workers working in Liberia seemed to make a rapid recovery after being treated by it. The drug was experimental, and there was almost none of it available, setting off a clamor for it among desperate patients and their doctors.

But not all the patients who received the drug survived, so researchers conducted a randomized clinical trial to find out if the drug was effective. It enrolled 72 patients, mostly in Sierra Leone, but also in Liberia, Guinea and the United States. All received the optimized standard of care treatment, such as intravenous fluids and maintenance of oxygen levels and blood pressure. Half were randomly assigned to also receive ZMapp.

Of the 36 patients who got ZMapp, eight died within 28 days, a mortality rate of 22 percent. That was less than the 37 percent rate — 13 out of 35 — in the control group. However, the difference was not statistically significant, meaning it could have occurred by chance.

That could be because there were not enough patients in the study. The goal was 200, but the number of people contracting Ebola dwindled as the epidemic ebbed, and enrollment was stopped at the end of last month.

Patients who had higher levels of the virus at the start of the trial were much more likely to die than those with low levels, researchers said. ZMapp cut the death rate for both those with high viral level and those with low viral levels, but again, the differences with the control group were not statistically significant.

The study was organized by the National Institute of Allergy and Infectious Diseases and the governments of the three African nations, as well as other organizations. The results were presented late Tuesday in Boston at the Conference on Retroviruses and Opportunistic Infections.

Despite the inconclusive results, some experts were encouraged.

“It is the strongest sign yet that we may have a drug that can reduce mortality and save lives for patients infected with the Ebola virus,” Dr. Adam Levine, director of Ebola research for the aid group International Medical Corps, said in a statement. The group said that one-third of the patients in the study were treated at its centers in Sierra Leone.

Mapp Biopharmaceutical, the tiny, privately held company in San Diego that is developing ZMapp, said it would press ahead to have the drug approved by the Food and Drug Administration.

“The outcome of this truncated study is supportive of ZMapp’s antiviral activity in humans,” Larry Zeitlin, president of the company, said in a statement.

ZMapp, administered in three intravenous infusions, is a combination of three monoclonal antibodies, which are proteins that attack the Ebola virus.