Antibiotic lifts stock of Exton, Pa., pharmaceutical firm.( ViroPharma Inc.)

Byline: Linda Loyd

Aug. 31--A small Exton drug firm, ViroPharma Inc., is the comeback kid.

Five years ago, the company was developing a medicine that attacked the common cold virus and was touted in some media as a potential cure, sending the stock to an all-time high of $106. Federal regulators rejected the viral treatment in June 2002 because of safety concerns, and shares plummeted as the Chester County company struggled and cut jobs.

Now ViroPharma is profitable thanks to an antibiotic called Vancocin that it bought from Eli Lilly & Co. last fall. It has been able to pay down debt, and investors have taken notice.

Shares of ViroPharma are up 600 percent since May and hit a 52-week high of $17.30 on Aug. 26. Yesterday, shares closed at $16.19, down 47 cents.

"Last year, in 2004, we decided to reinvent the company quite radically," said chairman and chief executive officer Michel de Rosen. "It's the same name but nearly everything is new: new strategy, new focus, new products, new building, new people, new …