Almost 40 years after Ebola emerged from the jungles of Africa as one of the world’s most lethal diseases, scientists are beginning to close in on treatments that may be able to stop the virus.
People who are at risk of infection have little protection for now against a virus that kills as many as 90 percent of those it strikes. The latest outbreak, in Guinea, has infected 88 people, killing 63 of them, the nation’s health ministry said today. A further five people died in neighboring Liberia and there’s one suspected case in Sierra Leone,the World Health Organization said. Still, the agency said the risk to visitors is low and it isn’t recommending any travel restrictions.
The relative rarity of Ebola outbreaks, and the fact that they are largely limited to rural areas of poor African nations, makes the disease an unattractive target for big drugmakers. Instead, much of the research has been funded by the U.S. government. Tekmira Pharmaceuticals Corp. (TKM), for example, began its first human trial of a drug in January with backing from the U.S. Defense Department.
“There are already candidate cocktails that can be used in an emergency,” said Erica Ollmann Saphire, a professor at the Scripps Research Institute in La Jolla, California, who’s leading a consortium of 15 public and private institutions to develop treatments to fight the virus. “It’s a really exciting time to be working on Ebola.”
The WHO has not requested emergency use of any experimental treatments that have not been through the necessary clinical tests, said Tarik Jasarevic, a spokesman for the Geneva-based agency.
Trials showing the drugs are safe, plus ethical and regulatory clearance from the health ministries of affected countries, and regulatory clearance from the country where the drug is made, would be needed before any experimental treatments could be used in an emergency situation, said David Heymann, a professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine who has worked on Ebola since the first outbreak in 1976.
Ebola is one in a handful of diseases that are so deadly and so contagious that they pose a risk to national security, according to the U.S. Centers for Disease Control and Prevention. The agency lists the virus as a Category A bioterrorism agent, alongside anthrax and smallpox.
The virus responsible for the Guinea outbreak is the so-called Zaire strain, Jasarevic said, the most common and most deadly of the five known species.
Tekmira’s product, known as TKM-Ebola, is being developed under a $140 million contract with the Defense Department’s Medical Countermeasure Systems BioDefense Therapeutics Joint Product Management Office. Tekmira, based in Burnaby, Canada, this month won fast-track designation from the U.S. Food and Drug Administration to develop the experimental treatment.
The U.S. National Institutes of Health last week gave a five-year grant of as much as $28 million to Saphire’s group, which is collaborating on antibody cocktails to fight Ebola. Saphire said she didn’t know if any of the experimental treatments were being used in the Guinea outbreak.
While HIV, the AIDS-causing virus that also jumped from animals to humans in Africa, has spawned dozens of approved drugs and a $14 billion market, the small number of Ebola cases is a deterrent for big drug companies, said Stephan Guenther, head of the Bernhard Nocht Institute for Tropical Medicine in Hamburg, Germany.
“If you count all the cases of Ebola since the discovery, it’s below 10,000, so it’s definitely not of commercial interest,” he said by phone.
Guenther led a team of researchers that showed an experimental treatment called favipiravir, developed by Fujifilm Holdings Corp. (4901)’s Toyama Chemical unit as a treatment against the flu, cleared Ebola virus and prevented mice from dying in a study published in February.
Still, there is no clear path to commercialization given the challenge of testing the drug in humans, Yoshinobu Izumi, a spokesman for the unit, said by phone from Tokyo today.
Among the most promising drugs in development are antibody cocktails. One is being developed at Canada’s National Microbiology Laboratory, though it needs more work before it can be tested in humans, Public Health Canada said in an e-mail.
That cocktail prevented 43 percent of monkeys with symptoms of Ebola from dying in a study published last year in Science Translational Medicine. Previous studies showed the treatment, called MB-003, saved all of the monkeys when given an hour after exposure to the virus, and two-thirds of the animals when administered 48 hours after exposure.
Two cancer drugs from Novartis AG (NOVN), Gleevec and Tasigna, also fought the Ebola virus in laboratory experiments, according to a study published in 2012. GlaxoSmithKline Plc (GSK) last year paid 250 million euros ($345 million) for Okairos AG, a Swiss vaccine developer with early-stage products against diseases including Ebola.
Inovio Pharmaceuticals Inc. (INO) of Blue Bell, Pennsylvania, said last year its experimental vaccine protected guinea pigs against the virus. Inovio is looking to partner with a government agency to move the program forward, Chief Operating Officer Niranjan Sardesai said by phone yesterday.
“Ebola is challenging because of a lack of good animal models,” he said.
The virus can cause sudden fever and intense weakness which is followed by vomiting, diarrhea and internal and external hemorrhaging. The disease has a fatality rate of as much as 90 percent, making it one of the most feared infectious diseases.
The virus, first identified in 1976 near the Ebola River in what is now the Democratic Republic of the Congo, is transmitted to people through the blood and other secretions of wild animals such as chimpanzees, gorillas, bats and porcupines, according to the WHO. Humans transmit the virus to each other through contact with blood and other body fluids.
People can also get infected during burial ceremonies involving close contact with the bodies of people who succumbed to the disease, the WHO’s Jasarevic said.
The deadliest recorded outbreak was in Congo in 1995, when 254 of the 315 people infected died, according to the WHO. All the outbreaks in the past decade have been in Congo, the neighboring country of the Republic of Congo, and Uganda, with the exception of one outbreak in Sudan in 2004.
The aid group Medecins Sans Frontieres has begun opening units to isolate patients in areas of Guinea where Ebola cases are concentrated to try to stop the disease from spreading, Julie Damond, a spokeswoman for the group, said in an interview yesterday from Conakry, Guinea’s capital. Guinea banned the sale and consumption of bats and warned against eating rats and monkeys, Remy Lamah, the country’s health minister, said.
The WHO isn’t recommending any restrictions on travel to Guinea, Jasarevic said. Outbreaks usually start in remote villages where people have contact with infected animals, and rarely spread because the disease does its damage so quickly, he said.
“Experience shows that there is a low risk for travelers,” he said by phone. “People who get Ebola tend to get very sick very fast, and they are not really able to travel. That’s why these outbreaks usually are self-contained.”
Only 13 cases in the current outbreak have been confirmed as Ebola in laboratory tests and some of the others will “undoubtedly be ruled out,” Gregory Hartl, a WHO spokesman, said on Twitter.
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