ANDA/PATENT LAW's MARKETING EXCLUSIVITY PROVISIONS FOR NEW USES & FORMULATIONS REQUIRE HUMAN EFFICACY STUDIES, REP. WAXMAN ASSERTS IN LETTER TO FDA's YOUNG
The ANDA/patent law's provisions for three years of marketing exclusivity for new uses and formulations of previously marketed products apply only to products approved on the basis of "human efficacy testing," Rep. Waxman (D-Calif.) asserted in an Aug. 5 letter to FDA Com. Young. The congressional intent in drafting three-year exclusive marketing provision in the law passed last November, Waxman maintained, is that "the investigations must be 'clinical' studies and they must relate to efficacy. Congress wanted and required human efficacy testing." Noting that the term "clinical" refers to human studies, Waxman continued: "Congress imposed this requirement because human efficacy studies are the best indication that the new aspect of the marketed drug, which aspect is under testing, is an important new change in the marketed drug, such as a new use." The intent was "to limit eligibility to changes in a drug which are so significant that human efficacy studies are required before approval is possible." * The law's two principal authors, Waxman and Sen. Hatch (R-Utah), sent the agency letters to support its denial of a petition by Zenith, which is seeking three-year exclusivity for having conducted rat teratology studies of tolazamide in obtaining approval of the first generic version of Upjohn's Tolinase ("The Pink Sheet" Aug. 12, T&G-2). Zenith subsequently sued FDA, and on Aug 16 Newark Federal Judge Clarkson Fisher denied the firm's request for a preliminary injunction barring agency approval of subsequent versions of tolazamide. Fisher also denied FDA's motion for dismissal and granted intervenor status to Mylan, Chelsea, and Bolar. In an Aug. 8 letter to Young, Hatch pointed out that "the three-year moratorium on ANDA approvals was intended to provide a non-patent incentive for the development and approval of new drugs or indications which would benefit the public." Because "its thrust is to offer the valuable three-year protection only to pharmaceuticals or indications which represent significant innovation and effort," the "essential" clinical testing requirement was established, the senator continued. "We used the word 'clinical' advisedly, understanding that in drug approval matters it referred only to human and not animal studies." Hatch added that "there was a consensus that human studies are required in the case of, and thus provide an indicator of, innovative new drugs or drug uses, and that they generally consume substantially more time and money than animal tests." Further, Hatch said, "it was felt that the inclusion of animal tests would so dilute the criteria that it would be difficult to keep the three-year provision from protecting practically all new approvals." Waxman told Young the three-year rule "was the subject of constant negotiations, several amendments, and careful congressional scrutiny. Congress knew exactly what it was passing and why." Had FDA granted Zenith's petition, he said, the agency "would have undermined Congress' resolution of one of the most contentious issues in the act -- marketing exclusivity." Waxman maintained Congress "did not intend to provide eligibility under the act for human bioavailability studies or animal tests that provide additional evidence of safety regarding current uses of a drug." Zenith's tolazamide request was properly denied because the firm "did nothing innovative," he said. "It has sought approval for the same use of the same drug already on the market."
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