Under regulations proposed Tuesday by the Food and DrugAdministration, developers seeking approval of drugs similarto those that have been granted a seven-year exclusive marketunder the Orphan Drug Act would need to show that theirs are"clinically superior."

The proposed rules could affect efforts to gain FDA approval fora second brand of erythropoietin (EPO), an orphan-designateddrug used to treat anemia in kidney dialysis patients. GeneticsInstitute Inc. of Cambridge, Mass., and its marketing partner,Chugai-Upjohn Inc., want marketing approval for their EPOdrug, trade named Marogen. It would compete with AmgenInc.'s Epogen, an approved drug that holds orphan status andenjoys market exclusivity.

Amgen and its marketing partner, the Ortho Biotech Division ofOrtho Pharmaceuticals Corp., were also granted approval earlierthis month for EPO as a treatment for anemia in AIDS patientstaking the drug AZT.

GI contends that its EPO is slightly different and should also beconsidered an orphan drug for chronic renal failure.

The FDA this month denied citizens' petitions, filed by GI andChugai-Upjohn, that asked approval of Marogen. The FDArejected GI's arguments that Epogen addressed a patientpopulation that exceeded the 200,000-patient ceiling set by theOrphan Drug Act and the contention that Amgen receivedbroader approval for Epogen than it requested.

"The FDA can't approve Marogen because Amgen has orphandrug status," said Wayne Turner, a reviewer in the FDA's Officeof Orphan Drug Development. The only way for GI to obtainapproval for Marogen now, Turner said, would be for thecompany to develop it for another disease.

Genetics Institute had no immediate comment on the proposedregulation. "We are evaluating the proposed rules at this time,"said spokeswoman Clare Midgley.

The proposed regulations would be the first formal instructionson how the FDA is to apply the Orphan Drug Act, which wassigned into law in 1983. Besides placing higher hurdles in thepath of "me-too" products, the regulations would allow drugmakers to request orphan drug status for additionalapplications of an already approved drug.

The FDA will accept written comments on the proposedregulations until April 1. After reviewing the comments, theagency will publish final regulations, which will take effect 30days later.

Drugs that have already been granted orphan drug statuswould not be affected by a rule change. These would includeGenentech Inc.'s Protropin human growth hormone (HGH) fortreating HGH deficiency in children. In 1987, the FDA decidedEli Lilly & Co. should also be granted orphan drug status for itsHumatrope brand of HGH because Lilly's drug differed fromGenentech's by one amino acid.

-- Carol Ezzell Washington Bureau Chief

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