BETHESDA, Md. -- A Food and Drug Administration advisoryboard on Monday unanimously recommended approval ofSchering-Plough Corp.'s Intron A for treatment of patients withboth chronic active and chronic persistent hepatitis B.
Intron A is an interferon alpha-2b recombinant made from E.coli bacteria.
Schering and the FDA will have to resolve several labelingissues before approval is granted, said Douglass Given,Schering's vice president for regulatory affairs. FDA approvalshould be granted in less than the seven months it took toapprove Intron A for treatment of chronic hepatitis C (non-A,non-B hepatitis) earlier this year, he said.
The Biological Response Modifiers advisory committeerecommended that more data be collected on the effect oftreating patients with chronic persistent hepatitis. It alsorecommended that the FDA monitor ongoing studies of theoptimal duration of Intron A treatment, and of how andwhether special populations should be treated with Intron A.This category includes chronic hepatitis B patients who do notshow a response to initial Intron A treatments, drug abusers,HIV-infected people, hemodialysis and renal transplantpatients, and children.
The data should be used to establish treatment guidelines forthe various populations that would be included in the packageinsert for Intron A, said Dr. Jerome Groopman, chairman of thecommittee and chief of New England Deaconess Hospitals'division of hematology and oncology.
Committee members and advisers agreed that the loss ofvirologic markers, hepatitis B e antigen and HBV-DNA, whichwere used as surrogate markers in Schering's Phase III trials,were "valid and important" end points, Groopman said.
The Phase III results demonstrated a statistically significantassociation between a durable clearance of these markers inpatients treated with Intron A and reduced levels of hepatitisenzymes that are associated with liver damage, said Dr. DavidFinbloom, medical officer at the FDA's Laboratory of CellularImmunology.
"Unfortunately, there is a fair amount of toxicity" at therecommended dose of 30 million to 35 million units per week,Finbloom said. Dose reductions were required for 44 percent ofthe patients in U.S. trials due to effects that included flu-likesymptoms, nausea, anorexia and depression. Six percent weretaken off the treatment.
Schering of Madison, N.J., licensed Intron A from Biogen Inc.(NASDAQ:BGEN) of Cambridge, Mass., in the late 1970s.Schering's worldwide sales of Intron A for 16 indications,including viruses and cancers, should total $177 million thisyear, rising to $250 million next year, said Schering spokesmanLinn Weiss.
Once Intron is approved for all forms of hepatitis, includinghepatitis C and delta hepatitis, worldwide sales for treatment ofhepatitis should be in the $100 million to $200 million range,Weiss told BioWorld.
Hoffmann-LaRoche is also developing an interferon alphatreatment for hepatitis B called Roferon-A.
-- Kris Herbst BioWorld Washington Bureau
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