The FDA asked ICN Pharmaceuticals Inc. to amend itsapplication seeking approval of the antiviral agentVirazole in the treatment of chronic hepatitis C.

Company officials would offer no specifics on whatchanges were needed, but they hinted that an amendmentmight include use of Virazole capsules in combinationtherapy, likely with alpha interferon.

"The file is still open" on the new drug application,"David Calef, ICN's vice president, communications, toldBioWorld. "We don't have to start from ground zero.Whatever additional information requested by the FDAwill be amended into the existing file."

ICN's stock (NYSE:ICN) fell $2.88 per share, to $19.12,after the company's amendment announcement onMonday. The stock gained 38 cents Tuesday to close at$19.50.

Virazole (ribavirin) formerly was being developed byICN subsidiary Viratek Inc. But Viratek and two otherICN companies, all of Costa Mesa, Calif., merged intothe parent holding company in November. Virazole, abroad-spectrum antiviral drug, already is approved in 47countries in various formulations for several indications,including general hepatitis. Calef said 1993 sales of thedrug were about $30 million.

Calef said ICN's timetable for U.S. approval of the drugwas six to 24 months when it filed its new drugapplication six months ago. So, he said, "we're wellwithin that window." No new trials have been scheduledat this point, either as a monotherapy or in combinationwith another drug, he said. Applications for marketingapproval of Virazole are pending in Europe, Canada andAustralia.

Bharat Pandya, an analyst with Kemper Securities inChicago, told BioWorld that he still is evaluating thenews that the FDA wants an application amendment."What I've learned so far," he said, "is that the FDArequested the company come back to apply for acombination therapy approach."

Pandya said that the agency responded to ICN'sapplication in six months, showing that "the FDA has agreat deal of interest in hepatitis C, the FDA has a fairamount of interest in Virazole, and the FDA really wantsto see a combination therapy for hepatitis."

Abstracts from two Phase III trials of Virazole for chronichepatitis C were presented in October at the 45th AnnualMeeting of the American Association for the Study ofLiver Diseases. One 59-patient study concluded thatVirazole was well tolerated and normalized serum ALTlevels in 43 percent of chronic hepatitis C patients,compared to 3 percent of controls. But there was nosignificant difference between treatment groups in HCVRNA levels.

The other study, involving 114 patients, showed similarresults: significant reductions in ALT levels, but the drugwas no more effective than placebo in reducing oreliminating HCV DNA levels.

"This just means that ICN will have to join forces" withthe maker of an alpha interferon product, Pandya said."Virazole continues to be a viable drug in combinationtherapy in treatment of hepatitis C."

Calef said, "The medical community has expressed a lotof interest in the combination therapy of interferon andVirazole. That's one of the things we're going to belooking at." n

-- Jim Shrine

(c) 1997 American Health Consultants. All rights reserved.