Oclassen Pharmaceuticals is preparing a response to a warning letter from the FDA regarding its activities as a sponsor and monitor of clinical trials of fialuridine (FIAU) and its FIAC analog conducted between 1989 and 1992.

The letter continues the fallout from the highly publicized deaths of five hepatitis patients participating in a Phase II trial of the drug conducted by Eli Lilly and Co., which licensed the antiviral drug from Oclassen in 1992.

The San Rafael, Calif., company wasn't involved in those studies. Oclassen's trials were Phase I/II studies testing the drugs in HIV-positive patients as a treatment for cytomegalovirus and hepatitis B.

'Significant violations'

The FDA letter, dated May 11, said the agency has concluded that Oclassen had failed to adhere to federal regulations as sponsor and monitor of the trials. "The agency's findings represent significant violations of the Federal Food, Drug, and Cosmetic Act," the letter said. The letter was one of several sent to the companies and investigators who