New Studies May Knock Antiviral Drug Off the Fast Track

From the WebMD Archives

April 11, 2000 (Atlanta) -- Two months ago, a lot of people were talking excitedly about the drug pleconaril. It showed promise in treating viral meningitis and even taming the common cold. It didn't just single out a particular bug; it seemingly had some sort of viral vendetta and went after the entire germ family.

The only thing needed for FDA approval, it seemed, was to get the same good results in larger studies. Developers were hoping to get it on the market as early as the end of this year for viral meningitis and by 2001 for treating colds.

But results from three new studies may be enough to derail pleconaril from its fast track. In one report, researchers say the drug couldn't significantly shorten the time patients battled a severe cold. And two other studies showed it couldn't help most patients shake the telltale headaches of viral meningitis, an infection of the lining of the brain or spinal cord.

Early studies suggested the drug could reduce the duration of a bout of viral meningitis by about two days and a bad cold by about three. The trick was the way the drug seemed to attach itself to a virus, preventing it from attaching to human cells and multiplying.

The latest studies, however, did not produce clear-cut evidence that the drug was effective. In the common cold study, runny nose and other symptoms completely cleared up by 7.7 days among pleconaril users, compared with 9.4 days in those getting dummy pills. The difference was not statistically meaningful. Developers noted, however, that objective measures of cold severity, such as the number of facial tissues used, were significantly better in pleconaril users.

The drug is being developed by ViroPharma in Exon, Pa. The company's chief executive, Claude Nash, said in a statement Tuesday that the firm will sponsor more large studies in cold victims this year, and its timeline for seeking approval of the drug is unchanged.

In January, pleconaril researcher Mark H. Sawyer, MD, told WebMD that the drug held a lot of potential because it acted against a family of viruses "which cause oodles of disease." Sawyer, associate professor of pediatrics at the University of California, San Diego, added that because the same type of virus could cause some very severe diseases in children, he was looking forward to having the drug as a treatment option for young patients.

At that time, pleconaril co-inventor Mark McKinlay, PhD, also told WebMD that the drug showed "some pretty spectacular results" when it was given to patients with a viral infection on top of an immune system weakened from another disease or recent transplant.

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