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Determination That ZYVOX (Linezolid) Tablets, 400 Milligrams, Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness

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Food and Drug Administration, HHS.




The Food and Drug Administration (FDA) has determined that ZYVOX (linezolid) tablets, 400 milligrams (mg), were not withdrawn from sale for reasons of safety or effectiveness. This determination will allow FDA to approve abbreviated new drug applications (ANDAs) for linezolid tablets, 400 mg.

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Nicole Mueller, Center for Drug Evaluation and Research (HFD-7), Food and Drug Administration, 5600 Fishers Lane, Rockville, MD 20857, 301-594-2041.

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In 1984, Congress enacted the Drug Price Competition and Patent Term Restoration Act of 1984 (Public Law 98-417) (the 1984 amendments), which authorized the approval of duplicate versions of drug products approved under an ANDA procedure. ANDA sponsors must, with certain exceptions, show that the drug for which they are seeking approval contains the same active ingredient in the same strength and dosage form as the “listed drug,” which is typically a version of the drug that was previously approved. Sponsors of ANDAs do not have to repeat the extensive clinical testing otherwise necessary to gain approval of a new drug application (NDA). The only clinical data required in an ANDA are data to show that the drug that is the subject of the ANDA is bioequivalent to the listed drug.

The 1984 amendments include what is now section 505(j)(7) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 355(j)(7)), which requires FDA to publish a list of all approved drugs. FDA publishes this list as part of the “Approved Drug Products with Therapeutic Equivalence Evaluations,” which is generally known as the “Orange Book.” Under FDA regulations, drugs are withdrawn from the list if the agency withdraws or suspends approval of the drug's NDA or ANDA for reasons of safety or effectiveness or if FDA determines that the listed drug was withdrawn from sale for reasons of safety or effectiveness (§ 314.162 (21 CFR 314.162)).

Under § 314.161(a)(1) (21 CFR 314.161(a)(1)), the agency must determine whether a listed drug was withdrawn from sale for reasons of safety or effectiveness before an ANDA that refers to that listed drug may be approved. FDA may not approve an ANDA that does not refer to a listed drug.

ZYVOX (linezolid) tablets, 400 mg, are the subject of approved NDA 21-130 held by Pharmacia and Upjohn Co., a subsidiary of Pfizer, Inc. ZYVOX (linezolid) tablets, 400 mg, are indicated for the treatment of certain infections caused by susceptible strains of certain microorganisms.

In a citizen petition dated July 9, 2004 (Docket No. 2004P-0295), submitted under 21 CFR 10.30, Lachman Consultant Services, Inc., requested that the agency determine, as described in § 314.161, whether ZYVOX (linezolid) tablets, 400 mg, were withdrawn from sale for reasons of safety or effectiveness. The holder of the NDA for ZYVOX (linezolid) tablets never marketed the 400 mg strength. In previous instances, the agency has determined that, for purposes of §§ 314.161 and 314.162, never marketing an approved drug product is equivalent to withdrawing the drug from sale (see 67 FR 79640, December 30, 2002 (addressing a relisting request for Diazepam Autoinjector)).

The agency has determined that Pfizer's ZYVOX (linezolid) tablets, 400 mg, were not withdrawn from sale for reasons of safety or effectiveness. FDA has reviewed its files for records concerning the withdrawal of ZYVOX (linezolid) tablets, 400 mg, from sale. There is no indication that the decision not to market ZYVOX (linezolid) tablets, 400 mg, commercially is a function of safety or effectiveness concerns, and the petitioner has identified no data or information suggesting that ZYVOX (linezolid) tablets, 400 mg, pose a safety risk. FDA has independently evaluated relevant literature and data for possible concerns regarding the safety or effectiveness of this drug product. FDA has found no information that would indicate that this product was withdrawn for reasons of safety or effectiveness.

For the reasons outlined, FDA determines that Pfizer's ZYVOX (linezolid) tablets, 400 mg, were not withdrawn from sale for reasons of safety or effectiveness. Accordingly, the agency will continue to list ZYVOX (linezolid) tablets, 400 mg, in the “Discontinued Drug Product List” section of the Orange Book. The “Discontinued Drug Product List” delineates, among other items, drug products that have been discontinued from marketing for reasons other than safety or effectiveness. ANDAs that refer to ZYVOX (linezolid) tablets, 400 mg, may be approved by the agency.

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Dated: June 22, 2005.

Jeffrey Shuren,

Assistant Commissioner for Policy.

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[FR Doc. 05-12909 Filed 6-29-05; 8:45 am]