MEDICINE

Breakthrough: A new drug that could cure everything from colds to HIV

Our most powerful antibiotics can kill many different kinds of bacterial infections at once, but we're still searching for a single all-purpose drug that kills viruses. We may have just discovered it.

Technically speaking, any drug that is used to treat a virus is known as an antiviral, and we use them to treat HIV, hepatitis, and certain flu strains. But those antivirals all have to be very specifically designed to take down one particular virus. The situation is even worse for vaccines, which don't exist for some diseases (and aren't practical for others, like the common cold) and need to be constantly redesigned to remain effective against evolving viral strains.

Creating a single antiviral drug that could kill lots of different viruses is a longstanding dream of medical researchers. Beyond all the obvious benefits of such an honest-to-goodness wonder drug, an all-purpose antiviral would give us a much better chance of fighting back against outbreaks of exotic viruses like SARS and swine flu. As a minor but still rather nice bonus, it could also be that long awaited cure for the common cold.

According to MIT research scientist Todd Rider, we're closer to such an antiviral than ever before. He's developed a drug named Draco, which he says has successfully vanquished 15 different viruses in lab trials on mice and human tissue. Those viruses include a quite literal murderer's row: dengue fever, polio, the swine flu, and the particularly nasty Ebola virus. And, yes, the common cold has also been tested, and Draco was able to get rid of it as well.

So how does Draco work? According to Rider, it combines his backgrounds in engineering and biology, wiring together a pair of proteins. The first protein detects that a virus has entered a cell, which triggers the second protein. In turn, that protein acts as a kill switch, destroying the infected cell to cut off the spread of the virus. That sacrifice represents a grimly practical solution, and so far, it seems to be working.

This is a seriously intriguing result, but there's some room for skepticism here. One cautious voice is that of Cambridge researcher Leo James, whose own antiviral research involves supercharging the immune system. He points out that Rider's results are highly unusual, and as such needs to be replicated by scientists elsewhere before we have a really good understanding of what's really going on here.

Either way, even though Rider has already put Draco to work on human tissue, that doesn't mean we're ready for human testing. There's a long road ahead for this drug, which will require tests on multiple rounds of larger animals before it's ready for human trials. Because viruses and human cells become so closely intertwined during an infection, it can be hard to control for all the side effects of an antiviral.

A good example of this is interferon, which was hailed a potential antiviral wonder drug back in the 1950s. Interferon works by detecting infections and sending signals to other cells to build up their defenses in preparation for an attack. The problem is that the drug also sends white blood cells racing to the infection. That's great news for more serious infections like hepatitis, for which interferon is still used today. But for more mild infections, like a cold, the inflammation, fever, and pain caused by the interferon cure is worse than the virus itself.

Draco has some similarities to interferon - they're both protein-based, which means Draco could also provoke an immune response. According to Rider, there's been no immune response so far in the mice who have received the drug. That's good news, but it may not directly correlate to the experience humans would have with the drug.

If Draco or one of the other antivirals works out, it would change the face of global health overnight. The ability to cure minor infections like the common cold could save people from a few days each year of ill health - which across an entire population would add up to a vastly more efficient workforce. And, looking even more broadly, the existence of an all-purpose antiviral would do a lot to reduce the health scares caused by new viral outbreaks, equipping us with a ready-made tool for the next big pandemic.