The Golden Age of Antiviral Drugs
Bacteria are distinct invader cells that are easily targeted by a drug. But viruses aren't distinct organisms. They are parasitic, roving bits of genetic material wrapped in membrane-piercing proteins. Hundreds of viruses exist, but only some cause visible symptoms and debilitating diseases. To thrive, they latch onto a healthy host cell and hijack its reproductive machinery, cranking out copies of themselves and spinning off mutant versions that resist any one drug. That makes it tougher to target, separate out and kill viruses without also killing the cells they have infiltrated.
The first antiviral didn't emerge until the 1960s, and only four won approval in the next 25 years or so. Then the AIDS (news - web sites) pandemic triggered a cascade of antiviral research, spawning 23 HIV drugs in 15 years. That, in turn, boosted understanding of hepatitis B and C and still other viruses. And the mapping of the genome let scientists decode the genetic blueprint of new viruses like SARS (news - web sites), the virus that swept China in the spring, in a few days.
Forty-two antivirals have been approved by the Food & Drug Administration, and four newcomers have been cleared in the last 13 months. Another 60 antivirals have begun clinical trials, aimed primarily at HIV, the virus that can lead to AIDS, and hepatitis B and C. Also in the works: an oral pill to prevent smallpox (thereby disabling a terror weapon) and a drug to treat SARS. In a decade or so we may have a cure-all for the cold. (Drugs for the flu already are available.) Sales of antivirals will total $10.6 billion this year, less than half the size of the market for antibiotics ($24 billion), but antivirals could approach $14 billion in three years, says market research firm Business Communications.
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