Curing the common cold, one of medicine’s most elusive goals, may now be in the realm of the possible. Researchers said on Thursday that they had decoded the genomes of the 99 strains of common cold virus and developed a catalog of its vulnerabilities.
“We are now quite certain that we see the Achilles’ heel, and that a very effective treatment for the common cold is at hand,” said Stephen Liggett, an asthma expert at the University of Maryland and co-author of the finding.
Besides alleviating the achy, sniffly misery familiar to everyone, a true cold-fighting drug could be a godsend for the 20 million people who suffer from asthma and the millions of others with chronic obstructive pulmonary disease. The common cold virus, a rhinovirus, is thought to set off half of all asthma attacks.
Even so, it might be difficult to kindle the interest of pharmaceutical companies. While the new findings are “an interesting piece of science”, said Glenn Tillotson, an expert on antiviral drugs at Viropharma in Exton, Pennsylvania, he noted that the typical cost of developing a new drug was now $700 million, “with interminable fights with financiers and regulators”. Because colds are mostly a minor nuisance, drug developers say, people would not be likely to pay for expensive drugs. And it would be hard to get the Food and Drug Administration to approve a drug with any serious downside for so mild a disease.
Perhaps the biggest reason the common cold has long defied treatment is that the rhinovirus has so many strains and presents a moving target for any drug or vaccine. This scientific link in this chain of problems may now have been broken by a research team headed by Liggett and Ann Palmenberg, a cold virologist at the University of Wisconsin.
Fernando Martinez, an asthma expert at the University of Arizona, said the new rhinovirus family tree should make it possible for the first time to identify which particular branch of the tree held the viruses most provocative to asthma patients. The rhinovirus has a genome of about 7,000 chemical units, which encode the information to make the 10 proteins that do everything the virus needs to infect cells and make more viruses. By comparing the 99 genomes with one another, the researchers were able to arrange them in a family tree based on similarities in their genomes.
That family tree shows that some regions of the rhinovirus genome are changing all the time but that others never change. The fact that the unchanging regions are so conserved over the course of evolutionary time means that they perform vital roles and that the virus cannot let them change without perishing. They are therefore ideal targets for drugs because, in principle, any of the 99 strains would succumb to the same drug.
Sources: The Times Of India