Agouron Pharmaceuticals reported early results Saturday for a drug it hopes will eventually offer a cure for the common cold.
The experimental drug stopped the growth of the virus that causes the common cold in test tubes. Agouron now expects to start clinical trials on humans before the end of the year.
Even if the drug proves to be a cure for the cold, years of study will be required before it gets government approval and hits the market.
The most frequent cause of the common cold is the human rhinovirus.
Scientists at Agouron have unraveled the structure of the virus and found an enzyme called 3C protease that is responsible for the growth and spread of the virus through the body.
The drug, called AG7088, inactivates the 3C protease enzyme, stopping the spread of the virus.
Researchers tested 46 of the more than 100 known and found the drug effective against them all.
"We tested this compound against 46 different (virus) types, and we found that every single one of them was inhibited by the compound," said Dr. Amy Patick of Agouron.
Dr. Patick reported her findings at the American Society for Microbiology's Interscience Conference on Antimicrobial Agents and Chemotherapy in San Diego.
Agouron's drug is the latest in a long line of attempts to cure the common cold. One of the problems with finding a cure for the cold is the many different human rhinoviruses. Finding a vaccine effective against all of them is difficult.
Most of the viruses, however, have the 3C protease enzyme, which is why Agouron thinks its new drug will help against all colds.
By targeting this enzyme, Agouron is taking a novel approach. Most of the previous failed attempts attacked proteins on the outside of the virus. But 3C protease is on the inside.
Many potential cures developed over the years failed because they were effective only during a certain part of the virus' spread, while Agouron's approach had the potential to treat a cold at any stage in its development, Dr. Patick added.
"We want to be able to use this drug before patients get infected with the virus, and we would like to use it after the patients becomes infected," she said.
Although many drugs in the laboratory have appeared to offer the elusive cure for the common cold only to fail when tested in humans, Dr. Patick remains optimistic.