First Antiviral Common-Cold Drug Faces Key Ruling

Modern science has finally reached this point: It is, just maybe, ready to bring to market a drug to treat the common cold.

If approved by the Food and Drug Administration, Picovir would be the first drug ever developed to treat the underlying cause of an affliction that hits Americans 1 billion times a year. Unlike the multitude of cold medicines on pharmacy shelves today, the new drug does not treat symptoms but directly attacks the viruses that cause most colds.

Picovir, being developed by ViroPharma Inc. of Exton, Pa., may sound like a potential blockbuster, but its approval is far from certain. Shares in the company dropped 20 percent this week after an analyst predicted the FDA will reject the drug.

Even if it wins approval, Picovir is likely to pose some difficult social issues. According to tests conducted by ViroPharma, the drug shaves only about 1.5 days off the duration of the type of cold it is meant to treat.

The company and its big partner, Aventis Pharmaceuticals Inc., have yet to announce a likely price, but antiviral drugs brought to market in recent years have been expensive, usually several dollars for a single pill.

'This drug is, without question, of benefit to patients who have the common cold,' said Harley Rotbart, a professor at the University of Colorado School of Medicine who is an expert on cold viruses. 'The question is: Is the benefit substantial enough for the FDA to consider it meaningful, and is it substantial enough for the marketplace to welcome the drug?'

ViroPharma and Aventis, the U.S. arm of a European pharmaceuticals giant, declined to discuss the drug in detail, saying they would wait for formal action by the FDA. But in past statements, ViroPharma executives have argued that not treating colds has serious social costs, too.

Colds are the biggest reason people miss work, costing employers more than $7 billion in sick pay every year. Shaving a day off that for large numbers of workers could be worth a lot of money to companies.

Moreover, doctors beset by miserable patients with colds write some 20 million prescriptions every year for antibiotics. These drugs are designed to attack only bacteria, not viruses, so they do nothing to treat the common cold.

The flood of unwarranted antibiotic prescriptions is a large social problem in itself, contributing to the rise of antibiotic-resistant germs, a growing threat to public health. Picovir could give those doctors an alternative, ViroPharma has argued -- something likely to do more good than harm.

ViroPharma representatives will appear Tuesday before an FDA advisory committee that is expected to vote on whether the drug should be used to treat colds in adults. Tests on children continue. The agency is not bound by the recommendations of its committees, but it usually follows them.

U.S. Bancorp Piper Jaffray, which has done investment banking for ViroPharma and whose analysts have closely followed the development of Picovir, predicted in a report Thursday that the committee meeting will be 'contentious,' with debate focusing on whether a new drug warrants approval if it chops just a day or so off a minor illness.

The Piper Jaffray analysts forecast a close vote but said they believed the FDA would ultimately approve the drug. They noted that the agency has already approved two antiviral drugs, for influenza, that showed a degree of effectiveness similar to that of Picovir.

The agency is not allowed to consider a drug's cost in its decision but must approve the drug if it is found to be safe and effective.

Other analysts are more skeptical, predicting the data supporting the drug will not impress the FDA committee. 'I don't doubt that the compound has some activity against the cold, but I don't think it's enough to be found to be an overall treatment benefit,' said Darren Mac, an analyst at Fulcrum Global Partners whose 'sell' recommendation sent ViroPharma shares tumbling late in the week. The stock closed yesterday down 3 percent -- about 38 cents -- at $13.92.

Company-sponsored studies focused on people with colds caused by the viruses Picovir is designed to target. Some people got dummy pills, and 11 percent of them said they felt much better the next day. Some people got Picovir, and 21 percent of them said they felt much better a day after starting treatment.

By the standards of research studies, that is a significant difference, and other measures in the studies pointed in the same direction. It is unclear how well the drug would work if people kept it on hand and took it at the first sign of a cold, though some doctors predict that's how it will ultimately be used.

No other company is close to approval of a cold drug, so ViroPharma and Aventis are likely to have the market to themselves for years if they win the FDA nod. The Piper analysts have estimated that the drug could be on the market by this fall and U.S. sales could hit $450 million by 2005, assuming the drug is priced similarly to other antiviral treatments.

Picovir is the latest pill to emerge from a line of research that has produced several significant drugs in recent years.

Scientists once thought it would be impossible to treat viruses, since they are just tiny bits of genetic material that insinuate themselves into the cells of the plants or animals they infect, taking over the cells' machinery to make more viruses. Bacteria, by contrast, are living cells that make easy targets for drugs. For decades, the only available strategy against viruses was to develop vaccines to prevent infection.

But two vast social traumas, herpes in the 1970s and the AIDS epidemic of the 1980s, propelled antiviral research. Scientists learned to design compounds that, without being too toxic to the human body, could directly attack viruses and gum up their genetic machinery.

Picovir targets a large family of viruses called the picornaviruses, which cause anywhere from 30 percent to 80 percent of all colds, depending on the time of year. The hallmark of a picornavirus cold is a runny nose. There are at least 168 strains of picornaviruses, with two sub-families, called rhinoviruses and enteroviruses, being the ones that commonly infect human beings.

With so many strains, scientists consider it impractical to develop vaccines for the cold. But ViroPharma researchers exploited a chink in the armor of these viruses, namely an indentation on their coat that is similar among all strains. Picovir, a pill taken three times a day, is designed to bind to that site and plug it, preventing the virus from functioning normally.

One problem, if the drug is approved, will be that there is no practical way for doctors to tell whether a patient's cold is caused by picornavirus or some other type. If data from patients with other virus types are included when analyzing ViroPharma's studies, the drug looks less impressive, reducing by less than a day the duration of an average cold.

The data suggest the drug would be likely to work for the greatest number of people in the autumn, when 80 percent of all colds are caused by picornaviruses.

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