Two experimental Ebola treatments significantly increase survival rates for those infected with a disease often considered a death sentence, scientists announced Monday, providing fresh hope for containing an outbreak that has ravaged eastern Congo.
The drugs, tested in a nearly nine-month clinical trial, have performed so well that health professionals will now administer them to every patient in Congo.
“It’s the first example that a therapeutic intervention can have a dramatic effect on decreasing the mortality of the Ebola virus disease,” Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said in an interview.
Jean-Jacques Muyembe Tamfum, a Congolese doctor who has spent his career researching Ebola treatments and oversaw the trial on the ground, said in a conference call Monday that he “could not have imagined” that such a day would come.
“From now on, we will no longer say that Ebola is incurable,” he said.
But in a place where suspicion of health workers and violent conflict are widespread, finding effective medical therapies is only half the battle, experts say.
The outbreak — the world’s second-worst — has infected nearly 2,800 people and killed nearly 1,900 since it began a year ago. The World Health Organization designated it a “public health emergency of international concern” last month.
The new therapies were tested in a multi-drug, randomized, controlled trial conducted on the front lines of the Ebola outbreak since November. Researchers administered one of four drugs to the 681 patients who had participated in the study as of Friday.
When a monitoring group determined that two of those drugs were vastly outperforming the others based on data from 499 patients, scientists called off the study and said they would exclusively treat Ebola patients with the more effective drugs going forward.
The two antibody-based treatments, REGN-EB3 and mAb-114, work by blocking a critical protein in the Ebola virus. Patients receive them once, intravenously, and “ideally, as soon as possible” after infection, Fauci said.
They saved about 90 percent of patients with low levels of infection, according to preliminary data released from the trial. Across all levels of infection, patients who received REGN-EB3 had a mortality rate of 29 percent, while those treated with mAb-114 had a mortality rate of 34 percent. The average mortality rate for Ebola has been about 50 percent, according to the WHO.
These rates were far enough below those of the two other treatments — including ZMapp, first tested in the 2014 West Africa outbreak — that scientists decided to end the trial early. Now, all Ebola patients will receive one of the two more effective drugs.
“This underscores the importance of doing randomized, controlled trials. You can get ethically sound and scientifically sound information rapidly,” Fauci said.
He added, “Now you can get the two best antibodies quickly to the people who need them.”
Fauci said that based on current infection levels, medical professionals on the ground in Congo have sufficient stores of both drugs to administer them to all infected people.
While they heralded the fact that this groundbreaking research took place in the turbulent environment of eastern Congo, researchers also acknowledged that social and political factors will complicate health workers’ ability to get these new drugs to patients.
Efforts to treat Ebola have been hampered by widespread distrust of health workers among residents of eastern Congo. Tedros Ghebreyesus, the WHO director general, said last month that more than 200 health professionals had been attacked since January and several had been killed.
The region is also a conflict zone, and attacks by armed groups have at times forced health workers to pause their efforts. So even though these two new drugs have a high likelihood of curing patients, violence and misinformation may prevent many of those infected from accessing them.
“The success is clear, but there is also a tragedy linked to this success, and the tragedy is that not enough people are being treated,” said Michael J. Ryan, executive director of the WHO Health Emergencies Program.
“We are still seeing too many people stay away from Ebola treatment units, too many people not coming to hospitals [who] are not being found in time to benefit from these therapies,” he added.
Muyembe Tamfum called it a “huge responsibility” to make the drugs accessible to infected people.
“This is our moral responsibility and a lifelong burden on our shoulders that we are ready to assume with pride,” he said.