When the next flu pandemic comes, we may be better prepared. A pharmaceutical company has developed a conventional drug that mimics the effect of antibodies that are effective against a wide range of flu viruses. Conventional drugs are cheaper and easier to make and store than antibodies, and can be taken in pill form.
Mice that were give 25 times the normal lethal dose of one flu virus survived after taking the drug, which is known only as JNJ4796. It was also effective in tests on human cells grown in a dish.
The hope is that this antibody-mimicking strategy could lead to new treatments for many viral diseases, not just flu.
When we are infected by a virus, our immune system defends us by producing antibodies, which are proteins that bind to the virus and prevent them from infecting cells. But it takes days for our bodies to ramp up production, by which time people can become seriously ill.
Injecting antibodies can help treat viral infections, but there are several problems. Firstly, antibodies are large proteins that are expensive to make and have to be injected directly into the blood.
Secondly, flu antibodies usually are specific to a single strain. So an antibody treatment for the flu making people ill one year, will be useless the next year.
But biologists recently discovered antibodies that work against a wide variety of flu viruses because they bind to regions of the virus that seldom change. Several companies are now developing treatments that consist of these “broadly neutralising” antibodies, some of which are already being tested in people seriously ill with flu.
But these antibodies are still hard to produce and have to be injected. So Maria van Dongen of pharma company Janssen in the Netherlands and colleagues set out to mimic their effect with a small molecule.
They engineered JNJ4796 to bind to the same target site as one broadly neutralising antibody. But because it is a small molecule rather than a protein, it can be taken in pill form, assuming it proves safe and effective in humans.
There are already a handful of antiviral drugs for treating flu, the best known being Tamiflu. But their efficacy has been questioned, and some flu viruses are resistant to Tamiflu.
Journal reference: Science, DOI: 10.1126/science.aar6221
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