By Kim Coghill

Washington Editor

ViroPharma Inc. and Wyeth-Ayerst Laboratories stopped development of a hepatitis C compound that failed to show the desired level of antiviral activity in Phase IIa trials.

The relationship between ViroPharma, of Exton, Pa., and Wyeth-Ayerst, of Radnor, Pa., to develop a small-molecule antiviral drug candidate for hepatitis C dates back to 1999, when the companies signed a deal that gave ViroPharma a $5 million up-front payment plus potential milestones and royalties. (See BioWorld Today, Dec. 14, 1999.)

And although the compound, VP 50406, failed, officials at ViroPharma didn¿t necessarily see the results as a bad outcome.

¿This is part of the process,¿ Marc Collett, ViroPharma¿s vice president of discovery research, told BioWorld Today. ¿We initiated this work two years ago, and at that point in time, the knowledge about hepatitis C in general, and in specific about how to advance compounds in the clinic, was very rudimentary. ViroPharma, realizing this is a very significant disease, and based on the information we had at the time, we thought it was pretty important to take the risk and actually be courageous in trying to move the compound forward.¿

Collett said the companies have gained considerable experience and insight as to how to move an antiviral forward in the clinic. And as for the business relationship between the two, Collett said the trial has strengthened and galvanized it.

In the Phase IIa study, VP 50406 appeared to be safe in humans, but failed to show a significant antiviral effect in hepatitis C-infected patients, Collett said.

So what¿s the next step in hepatitis C? Collett said the alliance has developed technology in the area of hepatitis C. ¿We are using that new technology to evaluate a number of additional compounds that are actually distinct from the compounds we have been working with in the past. We are in a position now to prioritize different compounds that we¿re moving forward based on more information than we had two years ago when we selected 50406 for clinical advancement, and we are ranking those to move into the clinic late next year.¿

Also next year ViroPharma expects the FDA to make a decision on Picovir (pleconaril), its common cold antiviral. The company filed for regulatory approval in July, and about a month later, ViroPharma signed an agreement with Aventis Pharmaceuticals, the U.S. division of Aventis Pharma AG, of Frankfurt, Germany, to co-promote and co-develop the product. (See BioWorld Today, Aug. 1, 2001, and Sept. 11, 2001.)

Analysts expect Picovir to generate $900 million in annual U.S. sales by 2005 and upwards of $1 billion worldwide.

But the road to getting Picovir to the FDA has not been without some bumps. More than a year ago, ViroPharma¿s stock dropped 68 percent to close at $23.25 when a Phase III study of Picovir failed to show statistical significance. (See BioWorld Today, April 12, 2000.)

In other business, ViroPharma has completed Phase I trials of VP 14637, a small-molecule therapeutic for respiratory syncytial virus. Phase II trials are expected to begin soon. The product has not been partnered.

ViroPharma Inc.¿s stock (NASDAQ:VPHM) closed Monday at $23.54, down 28 cents. Wyeth-Ayerst is the pharmaceutical division of American Home Products Corporation, of Madison, N.J.

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