An experimental drug is helping patients infected with Ebola survive the virus as it sweeps across the Democratic Republic of Congo, where an outbreak has already killed at least 1,800 people.

Strongly positive results with the treatment made by U.S. drugmaker Regeneron Pharmaceuticals Inc., called REGN-EB3, led investigators to stop the trial just nine months after it began and change its design, dropping the previous standard of care and another experimental therapy. Patients across the country will now get either REGN-EB3 or mAb114, a drug that’s being developed by the U.S. National Institute of Allergy and Infectious Diseases that also appeared promising.

The medications may help reduce deaths and encourage those who are just starting to show signs of the disease to seek care. So far, two-thirds of the people infected in the latest outbreak have died. Violence in Congo has added to the difficulties in containing the epidemic.

“We do have now what looks like treatments for a disease which not too long ago we really had no therapeutic approach at all,” said Anthony Fauci, director of the institute. “We may be able to improve the survival of people with Ebola, and it may even make people more enthusiastic about coming to care.”

The study compared experimental medicines with Mapp Biopharmaceutical Inc.’s ZMapp, which was considered the standard of care after a previous trial suggested it may help reduce death rates. An independent group of advisers halted the trial on Friday after 681 patients were treated because those getting Regeneron’s REGN-EB3 were significantly less likely to die than those on ZMapp.

It is known as the PALM study, an acronym of Pamoja Tulinde Maisha, which means Together Saves Lives in Swahili.

Survival Rates

In the study, 29% of patients given REGN-EB3 died, compared with 49% of those treated with ZMapp and 53% on remdesivir, which was developed by Gilead Sciences Inc. About one-third of those treated with mAb114 died, a figure low enough that the researchers concluded they should continue to included. Ridgeback Biotherapeutics LP licensed mAb114 from the National Institutes of Health in the fourth quarter of 2018.

While Ebola typically kills about 50% of people infected, rates have varied in previous outbreaks. The mortality rate for the current one is higher, with most patients dying in their community and without treatment, according to Mike Ryan, executive director of the World Health Organization’s Health Emergencies Programme. Symptoms include vomiting and diarrhea, and in severe cases damage to the patients’ platelets can cause uncontrolled bleeding.

Survival rates in the trial were far better when patients were treated early, before the virus had replicated through the body at a high rate. In those patients, who have what’s called low viral load, 94% who got Regeneron’s drug survived.

“This advance will make a huge impact in saving thousands of lives that would have had a fatal outcome in the past,” said Jean-Jacques Muyembe-Tamfum, director-general of the Institut National de Recherche Biomedicale, the DRC’s national medical research organization.

The Congo Ebola outbreak began in August 2018. The WHO has said it has confirmed more than 2,600 cases, as of an Aug. 8 report.

Regeneron Research

The trial news is a victory for Regeneron, a Tarrytown, New York-based biotechnology company that prides itself on the quality of its science even as it has fallen out of favor with Wall Street.

Regeneron specializes in making monoclonal antibodies, complex drugs that can be effective in fighting off various types of ailments. During the 2014-2016 Ebola outbreak, which killed 11,000 people, scientists at the company believed that the same technology that produced treatments that cut cholesterol and cleared eczema might also be effective in treating the deadly virus.

Beginning in October 2014, teams of researchers set off on a sort of scientific relay race. Some scientists created a mouse model while another team grew the cell lines that would be needed for early testing. Another group made more than 1,000 potential drug candidates. In the end, the company had narrowed down the experimental compounds to three antibodies that would make up the cocktail whose results were announced Monday, according to Neil Stahl, executive vice president of research and development at Regeneron.

“It’s our intention to provide drug for this outbreak and whoever needs it,” Stahl said. “We have a stockpile of doses that are ready to go.”

The improved treatment alone won’t be enough to control the outbreak, and more still needs to be done, said Ryan from the WHO’s Health Emergencies Programme.

“The news today is fantastic. It gives us a new tool in our toolbox against Ebola,” Ryan said. “But it doesn’t itself stop Ebola.”

What is needed is good surveillance and monitoring, infection prevention and control, community engagement, vaccination and the use of these new medications in the most effective way possible, he said.

“Not enough people are being treated,” he said.

To contact the reporters on this story: Michelle Fay Cortez in Minneapolis at mcortez@bloomberg.net;Rebecca Spalding in Boston at rspalding@bloomberg.net

To contact the editors responsible for this story: Drew Armstrong at darmstrong17@bloomberg.net, Timothy Annett, Mark Schoifet