ERYTHROPOIETIN ORPHAN EXCLUSIVITY IS BASED ON "DRUG" COMPARISONS

Executive Summary

ERYTHROPOIETIN ORPHAN EXCLUSIVITY IS BASED ON "DRUG" COMPARISONS, not "active ingredient" or "active moiety" distinctions, Chugai-Upjohn maintained in Nov. 24 comments to FDA. The comments respond to Amgen's Oct. 16 petition for a stay of approval of Chugai-Upjohn's Marogen until FDA publishes orphan regs and defines how it will differentiate between biotech products ("The Pink Sheet" Oct. 30, p. 5). One of Amgen's arguments in the petition is that FDA has distinguished products for Waxman/Hatch market exclusivity and patent extension based on whether similar products contain the same "active moiety," and that the same criteria should be used for orphan drug exclusivity. "The exclusivity and patent term provisions of the 1984 Act -- unlike the Orphan Drug Act -- expressly limit eligibility to the first approval of the 'active ingredient (including any ester or salt of the active ingredient),'" Chugai-Upjohn pointed out. "Indeed, by using the term 'drug' in the Orphan Drug Act, rather than the more limited term 'active ingredient,' Congress vested the agency with substantial discretion to approve subsequent orphan drugs," the firm said. To date, FDA's orphan drug exclusivity determinations seem to have been based on the molecular structure of compounds -- for example, the decision that an additional amino acid on Lilly's human growth hormone differentiated it from Genentech's Protropin. The molecular differences between Marogen and Amgen's Epogen, however, appear to present a more complicated situation. The distinction between the two products reportedly relates to differences in glycosylation (carbohydrates attached to the basic molecule). In response to Amgen's request that FDA delay the approval of Marogen until the agency publishes orphan regs, Chugai-Upjohn argued that FDA "does not have a statutory duty . . . to issue rules under the market exclusivity provision." Chugai-Upjohn continued: "even if such a duty existed," FDA would not have to hold up approvals until rules were published. Responding to Amgen's request that it be given a chance to comment on evidence that Marogen and Epogen are different, Chugai-Upjohn maintained that the Orphan Drug Act does not contain any "requirement for notice to prior applicants before subsequent applications are approved." Such a procedure, Chugai-Upjohn said, would conflict with FDA's long standing policy that pending marketing applications are confidential. * The Amgen petition is one of several fronts on which the firms are currently battling as the Marogen PLA moves through FDA. Earlier in November, Chugai-Upjohn petitioned FDA to stay Epogen's market exclusivity, claiming that FDA violated the Orphan Drug Act by granting exclusivity for a broader indication than the product's original orphan designation ("The Pink Sheet" Nov. 27, T&G-7). The companies are also awaiting a final decision on the patent dispute between Amgen and Chugai-Upjohn licensor Genetics Institute in Boston federal court. A ruling on that case is expected by Dec. 11.