DCT

1:10-cv-00037

Pfizer Inc v. Teva Parenteral Medicines Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:10-cv-00037, D. Del., 01/15/2010
  • Venue Allegations: Venue is asserted based on Defendants Teva Parenteral Medicines, Inc. and Teva Pharmaceuticals USA, Inc. being residents of Delaware by virtue of their incorporation in the state.
  • Core Dispute: Plaintiff alleges that Defendant’s filing of an Abbreviated New Drug Application (ANDA) to market a generic version of Plaintiff's Zyvox® (Linezolid) antibacterial drug constitutes an act of infringement of a patent covering the drug’s active compound.
  • Technical Context: The technology involves a class of synthetic oxazolidinone antibiotics used to treat serious bacterial infections, particularly those caused by drug-resistant gram-positive pathogens.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Teva's notification to Pfizer of its ANDA filing. The complaint states Teva's ANDA included a "Paragraph IV certification," asserting that U.S. Patent No. 5,688,792 is invalid, unenforceable, or will not be infringed by Teva's proposed generic product. The patent is listed in the FDA’s "Orange Book" for Zyvox® and has been granted a period of pediatric exclusivity, extending its market protection.

Case Timeline

Date Event
1994-08-16 ’792 Patent Priority Date (PCT Filing)
1997-11-18 ’792 Patent Issue Date
2009-12-03 Teva sends Notice Letter to Pfizer regarding ANDA filing
2010-01-15 Complaint Filing Date
2014-11-18 ’792 Patent Original Expiration Date (per Orange Book)
2015-05-18 Pediatric Exclusivity Period for ’792 Patent Expires

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 5,688,792 - "Substituted Oxazine and Thiazine Oxazolidinone Antimicrobials"

  • Patent Identification: U.S. Patent No. 5,688,792, "Substituted Oxazine and Thiazine Oxazolidinone Antimicrobials", issued November 18, 1997.

The Invention Explained

  • Problem Addressed: The patent describes the need for new antimicrobial agents to combat a range of human and veterinary pathogens, with a particular focus on "gram-positive aerobic bacteria such as multiply-resistant staphylococci, streptococci and enterococci" (’792 Patent, col. 1:8-11).
  • The Patented Solution: The invention provides a new class of chemical compounds, namely oxazine and thiazine oxazolidinone derivatives, defined by a core chemical structure referred to as Formula I (’792 Patent, col. 2:53-61). The patent asserts that these novel compounds are unique and exhibit high antibacterial activity, whereas structurally similar prior art compounds, such as unsubstituted piperazinyl oxazolidinones, demonstrated "little useful antibacterial activity" (’792 Patent, col. 1:22-26).
  • Technical Importance: The development of this new class of compounds offered a potential therapeutic option against serious bacterial strains that had developed resistance to existing antibiotics (’792 Patent, col. 1:8-14).

Key Claims at a Glance

  • The complaint asserts infringement of "one or more claims" without specifying them (Compl. ¶26). Independent claim 1 is the broadest composition of matter claim.
  • Independent Claim 1: The claim recites:
    • A compound of structural Formula I, or pharmaceutically acceptable salts thereof, wherein
    • X is O;
    • R is selected from a list of chemical groups including hydrogen and C1-C8 alkyl;
    • R¹ is selected from a list of chemical groups including H and CH3;
    • R² is independently H, F, or Cl;
    • R³ is H, with an exception if R¹ is CH3; and
    • n is 0, 1, or 2.
  • The complaint implicitly reserves the right to assert other claims, including dependent claims that further narrow the chemical structure.

III. The Accused Instrumentality

Product Identification

  • "Teva's ANDA Product," identified as a "Linezolid Injection, 200 mg/100mL" (Compl. ¶21).

Functionality and Market Context

  • The product is a generic version of Pfizer's "highly successful Zyvox® product," intended for approval and sale prior to the expiration of the ’792 patent (Compl. ¶1). Zyvox® is an injectable drug approved for treating "various microbial infections" (Compl. ¶17). The act of infringement alleged is Teva's submission of ANDA No. 200222 to the FDA, which under 35 U.S.C. § 271(e)(2)(A) is a statutory act of infringement enabling the patent holder to litigate before the generic product enters the market (Compl. ¶28).

IV. Analysis of Infringement Allegations

The complaint does not contain a detailed claim chart. The infringement theory is based on the allegation that Teva's proposed generic product, a Linezolid injection, contains an active ingredient that is a compound covered by the claims of the ’792 patent. Example 5 of the patent describes the synthesis of a compound, (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, which is the chemical name for Linezolid.

’792 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A compound of structural Formula I... or pharmaceutically acceptable salts thereof The complaint alleges Teva seeks to market a Linezolid Injection. Linezolid is the common name for a specific chemical compound, (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, which is an embodiment of Formula I. ¶21, ¶26 col. 2:53-61
...wherein: X is O Teva's product is a copy of Zyvox®, whose active ingredient Linezolid contains a morpholinyl group, which satisfies the X=O limitation. ¶21, ¶26 col. 2:58-61
R is...C1-C8 alkyl... The acetamide group in Linezolid includes a methyl group, which is a C1-C8 alkyl, satisfying the definition of R. ¶21, ¶26 col. 2:2-4
R² is independently H, F or Cl The Linezolid structure contains a 3-fluoro substituent on the phenyl ring, satisfying the R² limitation. ¶21, ¶26 col. 2:11
n is 0, 1 or 2 The morpholinyl group in Linezolid is a six-membered ring, corresponding to n=1 for Formula I. ¶21, ¶26 col. 2:13-14
  • Identified Points of Contention:
    • Scope Questions: As the accused product is a generic version of a compound specifically disclosed and claimed in the patent (Example 5; Claim 12), a dispute over literal infringement of the compound claim may be limited. A potential question could arise regarding the "pharmaceutically acceptable salts thereof" language, should Teva's formulation use a salt form not explicitly described in the patent.
    • Technical Questions: The primary technical dispute is unlikely to be about infringement but about validity. Teva’s Paragraph IV certification asserts that the ’792 patent is invalid or unenforceable (Compl. ¶22). The complaint does not detail Teva's invalidity theories, but these will form the core of the technical and legal dispute, likely focusing on issues such as obviousness over prior art or deficiencies in the patent's disclosure (e.g., written description, enablement).

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

  • The Term: "pharmaceutically acceptable salts thereof"

  • Context and Importance: This term is critical because generic drug manufacturers may formulate their product using a different salt of the active ingredient than the branded drug. The infringement analysis may turn on whether Teva’s chosen salt falls within the scope of this term.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification defines the term broadly as "acid addition salts useful for administering the compounds of this invention" and provides a non-exhaustive list of examples, including "hydrochloride, hydrobromide...fumarate and the like" (’792 Patent, col. 3:42-49). The use of "and the like" suggests the list is illustrative, not limiting.
    • Evidence for a Narrower Interpretation: A defendant might argue that the scope should be limited by the types of salts listed or functional properties required for administration, potentially excluding novel or unconventional salt forms not contemplated by the patent.

  • The Term: "C1-C8 alkyl optionally substituted with one or more of the following: F, Cl, hydroxy, C1-C8 alkoxy, C1-C8 acyloxy or -O-CH2-Ph" (as part of the definition of R)

  • Context and Importance: The definition of the "R" group is fundamental to the scope of the core compound claim. Practitioners may focus on this term because the precise nature of this side chain determines whether a given compound infringes.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claim language "optionally substituted" and "one or more" suggests flexibility, allowing for a wide range of modifications to the alkyl group within the specified list of substituents (’792 Patent, col. 23:15-17).
    • Evidence for a Narrower Interpretation: The specification provides specific examples of substituted alkyls, such as "1-chloropropyl" and "1-hydroxy butyl" (’792 Patent, col. 3:38-41). A party could argue that the term's scope should be guided by these disclosed examples, potentially limiting how "optional" substitutions can be combined or positioned.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges Teva will actively induce infringement upon approval of its ANDA. This is based on the allegation that Teva's proposed product labeling will instruct medical providers and patients to use the drug in a manner that infringes the patent claims (Compl. ¶32). It further alleges contributory infringement, stating that Teva's product is "especially made or adapted for use in infringing the '792 patent" and is not suitable for substantial non-infringing use (Compl. ¶33).
  • Willful Infringement: The complaint does not use the term "willful infringement" but alleges Teva had pre-suit "knowledge of the '792 patent when it submitted its ANDA to the FDA" (Compl. ¶27). It also pleads that this is an "exceptional case" under 35 U.S.C. § 285, which requests an award of attorney's fees, a remedy often tied to findings of inequitable conduct or litigation misconduct (Compl. ¶36).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of patent validity: As this is an ANDA case triggered by a Paragraph IV certification, the litigation will not primarily focus on whether Teva’s product infringes, but on whether Pfizer's patent is valid and enforceable against Teva's challenges of invalidity (e.g., obviousness) and unenforceability.
  • A key question for damages and remedies will be the basis for an exceptional case finding: The court will need to determine whether Teva’s Paragraph IV certification and its subsequent litigation positions were objectively baseless or brought in bad faith, which would be necessary to support Pfizer's request for attorney's fees under 35 U.S.C. § 285.
  • A secondary issue may be one of claim scope: Should Teva's product contain a different salt or formulation than Pfizer's Zyvox®, the court may need to construe the term "pharmaceutically acceptable salts thereof" to determine if Teva's specific formulation falls within the literal scope or is equivalent to the claimed invention.