By Matthew Willett

ViroPharma Inc. and Sanofi-Synthelabo revised their 1995 licensing agreement for pleconaril, a drug candidate for the common cold that failed to show statistical significance in a Phase III trial last year.

Kori Beer, ViroPharma's director of corporate communications, said the move aims at making partnering more palatable.

"Our renegotiation of the agreement with Sanofi really represents a milestone for us in our preparation for the potential commercialization of pleconaril for the adult viral respiratory infection marketplace," Beer told BioWorld Today. "This agreement better positions us to attract a co-development and co-promotion partner who will help us maximize the commercial potential for pleconaril in the U.S. and Canada."

The renegotiation reduces royalty rates due Paris-based Sanofi-Synthelabo for U.S. and Canadian sales of pleconaril after selection of a co-promotion partner, and eliminates milestone payment requirements for Exton, Pa.-based ViroPharma.

The reduction drops ViroPharma's royalty payment due Sanofi on U.S. and Canadian pleconaril sales from a rate in the mid-teens to the low single digits after the selection of a marketing partner, and to a rate in the low single digits for sales in the rest of the world.

ViroPharma also will take increased intellectual property rights to pleconaril from Sanofi-Synthelabo in exchange for a 4.6 percent equity stake in ViroPharma, about 750,000 shares. ViroPharma will receive U.S. and Canadian rights to a series of patents and patent applications covering compounds related to pleconaril and other antiviral compounds.

Pleconaril itself remains in the clinic and on schedule for a new drug application submission to the FDA by the middle of the year, Beer said, should trial results prove positive. She added that negotiations for a co-marketing and co-promotion partnership with large pharmaceutical companies are under way, and that the company hopes to have an agreement in place by the middle of the year.

"There are two Phase III trials going on right now across the country for treatment of VRI [viral respiratory infection] in several hundred centers, and we hope to announce data from those by the beginning of April," Beer said. "We are initially pursing adult VRI because we believe this product has tremendous potential there, and we're also conducting Phase II safety trials in pediatric VRI and plan to explore pleconaril for prevention of transmission as well as for prophylactic use."

Beer confirmed that development of pleconaril for treatment of viral meningitis is on hold.

Optimism at the company about the trial's outcome has increased since the failure last spring, thanks in part to a change in the clinical strategy.

"After we did a thorough and careful review of the data from last April we took several steps to try to increase the likelihood of success," Beer said. "After a review of that data from outside sources we came to the conclusion that there was a high degree of variability in the patient population that had a confounding effect on the results. As a result of that review, we made several changes and adjustments to the current trials in an attempt to reduce that variability." (See BioWorld Today, April 12, 2000.)

The failure in April took 68 percent of the company's share value, dropping the stock (NASDAQ:VPHM) $48.50 to close at $23.25. The company's shares gained $1.563 Tuesday to close at $23.563.

Beer said the current trials reduce patient variability by standardizing the use of over-the-counter cold remedies by trial participants, excluding participants with active allergies or a history of allergies that could mimic VRI, and stratifying smokers. The most important adjustment, however, ensured that the patients in the trial actually had the disease pleconaril is designed to treat.

"We found that the hallmark symptom of VRI is runny nose," she said. "Patients who had the hallmark of runny nose in the earlier trial we found are positive for picornavirus, the cause of VRI and what pleconaril treats."

ViroPharma focuses its drug development and discovery efforts on a number of ribonucleic acid, or RNA, virus diseases, including viral respiratory infection, viral meningitis, hepatitis C and respiratory syncytial virus diseases.

ViroPhrama has its small-molecule compound VP 50406 in Phase II testing in hepatitis C, while VP 14637, also a small-molecule therapeutic, is in Phase I testing. n