ORPHAN DRUG DIFFERENTIATION AS DEFINED BY "CLINICAL SUPERIORITY"
ORPHAN DRUG DIFFERENTIATION AS DEFINED BY "CLINICAL SUPERIORITY" is the "best tool" for creating incentives for drug sponsors "to develop safer and more effective orphan drugs," FDA said in a final rule implementing section two of the Orphan Drug Act. The final reg, published in the Dec. 29 Federal Register, states: FDA "agrees that a small demonstrated improvement in efficacy or diminution in adverse reactions may be sufficient to allow a finding of clinical superiority." FDA acknowledges in the final rule that the definition of clinical superiority is not altogether solidified. Nevertheless, "despite the agency's inability to define 'clinical superiority' as precisely as some would like, the agency believes that it is a useful concept," the rule states. FDA "believes that [clinical superiority] constitutes the best tool for giving effect to the intent of Congress to provide incentives for potential sponsors to develop safer and more effective orphan drugs." Several comments on the proposed rule focused on FDA's use of the concept of clinical superiority to differentiate a competitor drug from an already approved orphan drug as a basis for approval without violating the first product's seven-year marketing exclusivity under the Orphan Drug Act. The final rule notes that "two comments challenged the use of the concept of clinical superiority, contending that the criteria for demonstrating it are insufficiently clear" and that "to a sick patient removing even a minor adverse reaction can result in clinical superiority." The final rule defines "same drug" as follows: "if it is a drug composed of large molecules (macromolecules), a drug that contains the same principal molecular structural features (but not necessarily all of the same structural features) and is intended for the same use as a previously approved drug, except that, if the subsequent drug can be shown to be clinically superior, it will not be considered to be the same drug." The clinically superior concept also applies to drugs composed of small molecules. The final regulation, which becomes effective Jan. 23, 1993, is substantially unchanged from the Jan. 29, 1991 proposed rule ("The Pink Sheet" Feb. 4, 1991, p. 3). In response to the proposed rule, FDA received 40 comments from drug companies, trade associations and associations representing patients with rare diseases or conditions. Several holders of orphan drug approvals with marketing exclusivity "requested that such holders be accorded notice and an opportunity for a hearing when faced with the imminent approval of a similar drug that FDA considers to be a different drug for purposes of the act." FDA said it will not adopt such procedures. The reasons FDA offers for not setting up such procedures are: "neither the Constitution, nor the Administrative Procedure Act, nor the Orphan Drug Act requires a hearing of this kind; hearings are time consuming and resource intensive; and the citizen petition procedure is available to a holder of exclusive approval." The agency added that it "is still concerned about the potential for holders of exclusive approval to delay the marketing of competitors' approvable subsequent drugs by use of any challenge procedure." The final rule adds the requirement that orphan drug sponsors must submit annual reports describing the R&D progress of designated orphan drugs. "The agency believes that this provision is within the scope of the [proposed rule] and will allow FDA to follow the development of orphan drugs and to identify and help to remove roadblocks to drug development and marketing."
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