[Federal Register: June 30, 2005 (Volume 70, Number 125)]
[Page 37862]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Food and Drug Administration

[Docket No. 2004P-0295]

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Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness

AGENCY: Food and Drug Administration, HHS.

ACTION: Notice.


SUMMARY: 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ZYVOX (linezolid) tablets, 400 milligrams (mg), were not withdrawn from 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.

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

SUPPLEMENTARY INFORMATION: 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 Under FDA regulations, drugs are withdrawn from the list if the 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drug was withdrawn from sale for reasons of safety or effectiveness 
(Sec.  314.162 (21 CFR 314.162)).
    Under Sec.  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determine whether a listed drug was withdrawn from sale for reasons of 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 
    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 Sec.  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 Sec. Sec.  
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.

    Dated: June 22, 2005.
Jeffrey Shuren,
Assistant Commissioner for Policy.
[FR Doc. 05-12909 Filed 6-29-05; 8:45 am]