A Cambridge-based biotech company that has developed an experimental treatment for the Ebola virus is urging federal officials to consider allowing the unproven medication to be used on patients who have been infected in Africa’s deadly outbreak and brought to the United States for treatment.
Sarepta Therapeutics says it has enough doses of its injectible drug — AVI-7537 — to treat about two dozen patients within a week and could ramp up a supply for another 100 patients within a few months.
Such a move would be highly risky, but in the case of such a dangerous disease, the risks could be worth it in the eyes of some patients and their doctors. A different experimental drug, made by a San Diego company, has been given to two infected American relief workers who were flown to Atlanta for treatment.
The Sarepta treatment has been tested in Ebola-infected rhesus monkeys, with a cure rate of 60 to 80 percent, the company said. It has also been tested in healthy human volunteers for safety, but thus far, it has never been tried in a human infected with Ebola.
“We’ve seen favorable safety with respect to our drug, and so when you’re facing a disease that’s so lethal and there’s no available approved treatment, you have to weigh the risk and benefit of taking the drug versus the potential of dying,” said Diane Berry, Sarepta’s vice president of global health policy and government affairs.
Sarepta Therapeutics executives have been in touch with the White House, the Centers for Disease Control and Prevention, the US Food and Drug Administration, and other federal agencies to alert them to the drug supply the company currently has available, the company said.
So far, Berry said, no one has asked for the drug. But federal officials have assured the company that the agencies would probably approve use of the drug if patients request it, she said.
Sarepta, better known for its development of a drug to treat Duchenne muscular dystrophy that company officials expect the FDA to approve next year, began working on an Ebola treatment in 2010 through a program funded by the Department of Defense. The company was awarded up to $291 million to develop treatments for Ebola and Marburg viruses.
But the program was cancelled in 2012 because of federal budget constraints. The sudden starts and stops — and limited market demand — illustrate the difficulties of bringing drugs dependent upon government funding to market. Only a handful of companies are working on an Ebola treatment because there is no commercial potential, which limits profits.
AVI-7537 works by preventing the production of an Ebola protein, which keeps the virus from replicating in its host. By doing so, Berry said, it allows the person’s immune system to kick in and overcome the virus.
Other researchers, in Boston and elsewhere, are exploring promising avenues for stopping the virus in its tracks or vaccinating against it.
“There’s a tremendous amount of research trying to make effective therapies,” said John Connor, associate professor of microbiology at the Boston University School of Medicine.
Researchers are hopeful that the current attention to the outbreak will prompt more funding and are heartened by the news last week that the federal government intended to start vaccine trials next month.
“I’m sorry that it has taken a very large outbreak that seems so poorly controlled to arrive at that,” Connor said.
Connor and Dr. Elke Mühlberger, a BU microbiology professor, are investigating ways to block a protein that the virus needs to replicate. Connor is also developing a portable device that uses a light-emitting diode to quickly “read” a blood sample and identify viruses, allowing earlier intervention.
Neither a treatment nor a vaccine is on the immediate horizon, however. “There are both scientific and practical limitations,” said Dr. William Schaffner, professor of preventive medicine and an infectious disease specialist at Vanderbilt University School of Medicine. “Ebola, although severe, is rare and, relatively speaking, infrequent. . . . The commercial imperative to develop a treatment and vaccine is just not there. All the research is in government and academic labs.”
Even though Ebola has killed nearly 900 people so far this year, the disease typically happens in small, scattered outbreaks, which also makes it hard to test potential treatments on patients. Before the current outbreak in Sierra Leone, Liberia, and Guinea, fewer than 1,700 Ebola deaths had been recorded since the virus was first identified in 1976.
“There are challenges because of the very nature of the disease and the difficulties of doing clinical trials, and the reality of what the major health care problems are in countries where Ebola virus is a problem,” said Sean P. J. Whelan, professor of microbiology and immunobiology at Harvard Medical School. “The progress that has been made is encouraging. It’s difficult to predict when a candidate vaccine or therapeutic can be available for people at risk for the disease.”
Whelan has studied how the Ebola virus enters cells. His group identified the protein within cells that the virus binds to and is now testing substances that might block Ebola from latching onto the cell. Other researchers, he said, have found ways to prevent the virus from replicating, curing Ebola-infected monkeys.
Another approach is man-made antibodies, the body’s defense against infections. This is the kind of drug given to the American relief workers, but it is unknown whether it works. In any case, Whelan notes, antibodies need to be kept cold, always a challenge in Africa, and tend to be expensive to produce.
Thomas W. Geisbert, professor of microbiology and immunology at the University of Texas Medical Branch at Galveston, says that one of Ebola’s challenges is its swiftness: Infections move so quickly that the window for intervening is very brief.
The virus immediately attacks critical immune cells, shutting down the body’s first line of defense. Then it replicates freely, and by the time symptoms appear, the person’s body is overwhelmed.
The Department of Defense, which owns the inventory of Sarepta’s Ebola treatment, has steered billions of dollars to pharmaceutical companies, research labs, and universities since 9/11 and the subsequent anthrax attacks launched through the US mail.
Many US troops were inoculated against anthrax, but more ambitious research brought mixed results at best. As a result, the scope of the military’s research was narrowed in 2011.
The Department of Defense, even amid heightened concerns about the Ebola outbreak in West Africa, has not indicated an intention to restart the program, Berry said. The department said Tuesday night that officials were not available to comment on plans involving the experimental drug.
“This really illustrates why technologies like ours are a critical asset to our nation’s infrastructure,” Berry said. “You just don’t know what the next threat is around the corner. We’ve demonstrated over the years that we can adapt our technology to go from bug to drug within days.”