Two Novartis AG leukemia drugs, Gleevec and Tasigna, fought the deadly Ebola virus in laboratory experiments, suggesting the products could be used against a disease for which there are no treatments.
The two medicines stopped the release of viral particles from infected cells in lab dishes, a step that in a person may prevent Ebola from spreading in the body and give the immune system time to control it, researchers from the U.S. National Institute of Allergy and Infectious Diseases wrote in the journal Science Translational Medicine today.
There’s no cure and no vaccine for Ebola, a virus that causes high fever, diarrhea, vomiting and internal and external bleeding. Death can ensue within days, and outbreaks in Africa have recorded fatality rates of as much as 90 percent, according to the World Health Organization.
In some forms of leukemia, Gleevec and Tasigna reduce levels of a protein called Bcr-Abl that causes malignant white blood cells to multiply.
The researchers found that Ebola uses a related protein called c-Abl1 tyrosine kinase to regulate its own reproduction. They showed that by blocking c-Abl1, Tasigna may reduce the pathogen’s ability to replicate by as much as 10,000-fold. In addition to showing how the two drugs might be used to treat infected patients, the findings also suggest that new medicines could be developed to target c-Abl1, they wrote.
Gleevec and Tasigna, also known as imatinib and nilotinib, earned Basel, Switzerland-based Novartis a combined $5.45 billion in sales last year. Gleevec is sold as Glivec outside the U.S.
Source: Yahoo! Health
Some cancer drugs used to treat patients with leukemia may also help stop the Ebola virus and give the body time to control the infection before it turns deadly, US researchers said on Wednesday.
The much-feared Ebola virus emerged in Africa in the 1970s and can incite a hemorrhagic fever which causes a person to bleed to death in up to 90 percent of cases.
While rare, the Ebola virus is considered a potential weapon for bioterrorists because it is so highly contagious, so lethal and has no standard treatment.
But a pair of well-known drugs that have been used to treat leukemia — known as nilotinib and imatinib — appear to have some success in stopping the virus from replicating in human cells.
Lead researcher Mayra Garcia of the US National Institute of Allergy and Infectious Diseases and colleagues reported their finding in Wednesday’s edition of the journal Science Translational Medicine.
By experimenting with human embryonic kidney cells in a lab, they found that a protein called c-Abl1 tyrosine kinase was a key regulator in whether the Ebola virus could replicate or not.
The leukemia drugs work by stopping that protein’s activity. In turn, a viral protein called VP40 stopped the release of viral particles from the infected cells, a process known as filovirus budding.
“Drugs that target filovirus budding would be expected to reduce the spread of infection, giving the immune system time to control the infection,” the study authors wrote.
“Our results suggest that short-term administration of nilotinib or imatinib may be useful in treating Ebola virus infections.”
Imatinib, which is marketed as Gleevec and Glivec, is used to treat chronic myelogenous leukemia in humans, a disease which is caused by dysregulation of c-Abl enzyme.
Nilotinib, also known as Tasigna, has been used in chronic myelogenous leukemia patients who are resistant to imatinib.
Both “have reasonable safety profiles, although some cardiac toxicity has been reported with long-term administration in a small number of patients,” the study added.
According to the UN’s World Health Organization (WHO), about 1,850 cases of Ebola, with some 1,200 deaths, have occurred since 1976.
The virus has a natural reservoir in several species of African fruit bat. Gorillas and other non-human primates are also susceptible to the disease.
The Ebola virus causes a hemorrhagic fever that can be deadly. (up)
Ebola is one virus you never want to catch. Ever.
After some aches and a fever, many infected people develop uncontrolled bleeding. The mortality rates from Ebola infection can run as high as 90 percent.
There’s no cure for Ebola. But a group of scientists is exploring whether some drugs already approved to treat cancer might help tame the virus.
Sounds wild. But there’s a reason — and now some evidence — to think it might work.
To reproduce, the Ebola virus needs the help of cells it invades. And a couple of cancer drugs tweak a human protein that new copies of the virus use to leave their host cells so they can infect others.
The tested drugs — Gleevec and Tasigna, both sold by Novartis — are called tyrosine kinase inhibitors. Tyrosine kinases are enzymes that put a phosphate group on a particular amino acid. Amino acids, as you might remember from high school biology, are the building blocks of proteins.
When a phosphate group gets attached to the right tyrosine block on the right protein, it changes the shape and function of the protein. And that might change everything when it comes to Ebola.
“Proteins are like little machines,” says Emory University’s Dan Kalman, one of the researchers. “As with a machine, they can be turned or turned off. The switch for turning things on or off is a modification. And one of those modifications is a phosphate group.”
In some cancers, the tyrosine kinases help trigger the uncontrolled division of cells. Gleevec and Tasigna help stop that.
When it comes to Ebola, the researchers think drugs like these could turn off a transport protein and could keep new viruses bottled up inside cells.
The Ebola lab work using collections of human cells was published in the latest issue of Science Translational Medicine. It showed that the drugs dramatically decrease the ability of Ebola to replicate. “The effect was quite pronounced,” Kalman told Shots.
And, if the theory holds, such a reduction might be enough to allow an infected person’s immune system to mop up the Ebola viruses.
“Ebola is a very nasty infection,” Kalman says. “The whole concept of containing the disease in a local group before it spreads all over the planet is something clearly we want to do.”
The next step will be to see if the drugs can make a difference in animal experiments.