FOOL A COLD

By Christine Gorman

If anyone ever does discover a cure for the common cold, he or she will be a shoo-in for a Nobel Prize. Not only are colds enormously costly--$10 billion annually in lost wages and productivity in the U.S. alone--but they're almost impossible to prevent. Colds are caused by hundreds of different viruses from several major viral families, virtually ruling out the possibility of a single, one-shot-stops-all vaccine. Treatment is further complicated because the disease is a moving target. Rhinoviruses, which account for about 40% of all colds, attack mainly in the fall and spring; other cold-causing microbes, such as the respiratory syncytial viruses, tend to strike in the dead of winter.

Well, Stockholm isn't calling yet, but good news on the cold front was reported at a medical conference in Toronto last week. In preliminary tests sponsored by Boehringer Ingelheim Pharmaceuticals, an experimental compound with an ungainly moniker--BIRR 4--managed to cut the severity of cold symptoms in half without major side effects. The results were immediately hailed in the media as a breakthrough, although Dr. Ronald Turner, a pediatrician at the Medical University of South Carolina in Charleston who helped direct the research, was quick to add a dose of caveat. "We've got a ways to go," he insists, "before we can say the word cure."

What Turner and his colleagues have done is nonetheless something of a scientific coup, opening up a new line of attack against an ancient scourge. Rather shrewdly, they opted not to attack cold viruses head on. Instead, they resorted to a little bit of molecular camouflage that would, in effect, hide the nose from its microscopic foes.

Cold viruses have had millions of years to evolve different ways of infecting the cells that line the nasal passages. (The "rhino" of rhinoviruses comes from the Greek word for nose.) But it turns out that almost all the rhinoviruses use the same molecular doorway on the surface of the cell, a protein called ICAM-1, to gain entry to the upper-respiratory tract. Doctors have suspected since the late 1980s that if they could somehow flood the nose with decoy ICAM-1 molecules, they might be able to keep the rhinoviruses from attaching to the real thing.

It wasn't until the development of genetic engineering, however, that researchers were able to build synthetic ICAM-1 convincing enough to act as a decoy. With that in hand, Dr. Turner and his team recruited 177 volunteers who were willing to catch a cold for science. Half the volunteers (the experimental group) were sprayed with the BIRR 4 solution. The others (the control group) were given a simple saline spray. All the volunteers were deliberately infected by placing droplets of active rhinoviruses in their nasal passages.

About two-thirds of the control group and half the experimental group got sick. The volunteers who received the BIRR 4 spray seven hours before they were exposed fared pretty well, often reporting only a mild case of the sniffles. Even those who waited 12 hours after exposure before taking the decoy compound experienced the same protective benefits.

It could be years before BIRR 4 (or any similar compound with a flashier name) is available at your local pharmacy. The long FDA-approval process has only just begun, and there are a lot of unanswered questions about how the drug would work. For one thing, BIRR 4 has so far proved effective only when it's given at an early stage of infection, yet most people aren't aware that they are coming down with a cold until a few days after they have been exposed. And since colds are relatively minor nuisances from which most patients recover on their own, drugmakers have an extra burden to prove that their cure isn't more hazardous than the disease. "In our small study group we didn't see any side effects," Turner notes. "But if you give it to a million people, you might find a different answer."

Still, there may well be a market for a good cold-decoy drug. Parents, for example, could take a whiff of BIRR 4 whenever their children come home from school with a cold. So could patients with severe asthma or emphysema, for whom colds can sometimes trigger a life-threatening battle for air. "It's a huge challenge to find a way to prevent colds," says Dr. Robert Couch, professor of microbiology at the Baylor College of Medicine in Houston. But think of the glory--and the prizes--for the scientist who finally does.

--Reported by Lawrence Mondi/New York

With reporting by Lawrence Mondi/New York