ORPHAN EXCLUSIVITY FOR SIMILAR BIOTECH PROTEIN DRUGS:
ORPHAN EXCLUSIVITY FOR SIMILAR BIOTECH PROTEIN DRUGS: establishment of an FDA expert panel on the issue is recommended in a Feb. 15 joint letter from 22 molecular biologists to FDA Acting Commissioner Benson. Noting that "FDA is now considering the issue of the standards for determining whether two protein drugs are the 'same drug' for the purpose of deciding whether the exclusivity provision of the Orphan Drug Act is applicable," the letter urges Benson "to convene an ad hoc advisory panel of experts to provide FDA with sound scientific advice on this critical issue." The joint advisory letter was organized by a member of Genentech's scientific resources board, Stuart Kornfeld, MD, a Washington University School of Medicine professor. In a personal cover letter to the joint letter, Kornfeld stated that "the views expressed are my own, and I undertook this mission because I believe strongly in everything I have written." Kornfeld said he sent the letter to the other 21 scientists who agreed to sign it. The letter points out that "a disproportionate number of orphan drugs are biotechnology products" and that many biotech products, because of an uncertain patent environment, depend on the marketing exclusivity offered by the Orphan Drug Act. Resolution of what makes two protein drugs the same or different under the Orphan law "will have an enormous impact on the entire biotechnology industry and on the scientists who do research in the field," the letter states. The apparent impetus behind the letter is the pending licensing application at FDA for a second erythropoietin product, Chugai-Upjohn's Marogen, to follow Amgen's Epogen into the market. While he does not focus specifically on EPO, Kornfeld remarked in his cover letter that "FDA's most recent pronouncements about this issue [of similar biotech proteins] suggest that the agency is ready to announce a policy which would consider drugs to be different products if they differed in any aspect of their structure." Noting that "it is a relatively simple matter to induce small changes in glycosylation [attachment of carbohydrate structures to the basic molecule], which will often have no measurable effect on the activity of a protein," Kornfeld, a researcher in glycosylation, stated that such a policy "would have the effect of writing most protein products out of the Orphan Drug Act." Chugai-Upjohn has maintained in petitions to FDA that its product is different from Epogen due to different patterns of glycosylation and that the product should therefore be approved despite Amgen's orphan exclusivity. Amgen has petitioned FDA to issue new orphan regs stating that a biological product is similar to another if it has the same amino acid sequence or a sequence sufficiently duplicative to yield the same biological activity. A neutral panel of experts, Kornfeld said, "could provide information about the degree of innovative work that is required to induce any given kind or amount of structural dissimilarity in a recombinant protein, once its production process is known." He added that the panel "could also provide FDA with information on the expected biologic effects of such alterations in structure." Kornfeld asserted in his cover letter that he has "no relationship with or interest in Amgen or any other party in the dispute over erythropoietin." Genentech has served as an amicus curiae in Amgen's appeal to the International Trade Commission to bar Chugai-Upjohn from importing its EPO product Marogen into the U.S. from Japan.
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