DCT
1:17-cv-00342
Pfizer Inc v. Par Pharmaceutical Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Pfizer Inc. (Delaware), Pfizer Limited (England), and Pfizer Ireland Pharmaceuticals (Ireland)
- Defendant: Par Pharmaceutical, Inc. (New York)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP
- Case Identification: 1:17-cv-00342, D. Del., 03/30/2017
- Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant is registered to conduct business in the state, maintains a registered agent there, and has previously availed itself of the court by initiating litigation and consenting to jurisdiction in other cases.
- Core Dispute: Plaintiff alleges that Defendant’s filing of an Abbreviated New Drug Application (ANDA) seeking to market a generic version of the antiarrhythmic drug Tikosyn® (dofetilide) constitutes an act of infringement of a patent covering a specific crystalline polymorph of dofetilide.
- Technical Context: The technology concerns pharmaceutical polymorphs, which are different crystalline forms of the same active ingredient that can have distinct physical properties, such as stability and manufacturing suitability.
- Key Procedural History: This action was triggered by Defendant's submission of ANDA No. 208519 to the FDA, which included a "Paragraph IV" certification alleging that Plaintiff’s patent is invalid, unenforceable, and/or will not be infringed by the proposed generic product. Such a filing is defined as a statutory act of infringement under the Hatch-Waxman Act to enable resolution of patent disputes before the generic drug enters the market.
Case Timeline
| Date | Event |
|---|---|
| 1997-10-27 | ’363 Patent Priority Date |
| 2000-09-26 | ’363 Patent Issue Date |
| 2017-02-13 | Defendant sends ANDA Notice Letter to Plaintiff |
| 2017-03-30 | Complaint Filing Date |
| 2018-10-09 | ’363 Patent Expiration Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,124,363 - “Dofetilide Polymorphs”
- Patent Identification: U.S. Patent No. 6,124,363, “Dofetilide Polymorphs,” issued September 26, 2000.
The Invention Explained
- Problem Addressed: The patent explains that dofetilide is a highly potent antiarrhythmic drug, requiring very low dosages in capsule form. To ensure a homogeneous blend and consistent dosing, the active ingredient must have a small and uniform particle size. Previously known methods of producing dofetilide yielded crystalline forms that were agglomerated and required an additional milling or micronization step to achieve the necessary particle size (’363 Patent, col. 1:46-61).
- The Patented Solution: The invention provides a "substantially pure, crystalline, polymorphic form of dofetilide known as P162." This specific polymorph is produced by a crystallization process from aqueous acetonitrile that consistently yields flakes or plates with a small particle size distribution (less than 45 µm), eliminating the need for milling. The patent also describes this P162 form as non-hygroscopic and stable, making it well-suited for use in a capsule formulation (’363 Patent, Abstract; col. 2:1-13).
- Technical Importance: The invention provides a specific polymorph of dofetilide with physical characteristics that streamline the manufacturing process for the final drug product, enhancing efficiency and quality control (’363 Patent, col.1:62-col. 2:4).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claims 1 and 9.
- Independent Claim 1 (Composition):
- Substantially pure, crystalline, dofetilide polymorph P162
- which is characterised by differential scanning calorimetry (DSC) in which it exhibits an endothermic thermal event at about 162° C.
- Independent Claim 9 (Method of Use):
- A method of treating cardiac arrhythmia
- which comprises administering an effective amount of dofetilide polymorph P162 as claimed in claim 1 or a pharmaceutically acceptable composition thereof
- to an animal in need of such treatment.
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are Defendant’s proposed generic dofetilide capsules in 0.125 mg, 0.25 mg, and 0.50 mg dosage strengths, as described in ANDA No. 208519 (“Par’s ANDA Products”) (Compl. ¶¶1, 10). The statutory act of infringement is the filing of the ANDA itself (Compl. ¶26).
Functionality and Market Context
The proposed generic products are intended to be therapeutic equivalents to Pfizer's Tikosyn® capsules (Compl. ¶1; ¶19). The complaint alleges that the proposed labeling for Par's ANDA Products copies indications from the approved label for Tikosyn®, which is used for the treatment of cardiac arrhythmias such as atrial fibrillation and atrial flutter (Compl. ¶19, ¶24). The complaint notes that Defendant is among the "leading generic pharmaceutical companies in the United States" (Compl. ¶13).
IV. Analysis of Infringement Allegations
The complaint alleges that the filing of the ANDA is a direct infringement of claim 1, and that the future intended use of the product as directed by its label will induce infringement of claim 9.
’363 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| Substantially pure, crystalline, dofetilide polymorph P162... | Par's ANDA Products are alleged to be formulated with or contain the specific dofetilide polymorph P162. | ¶28 | col. 2:1-4 |
| which is characterised by differential scanning calorimetry (DSC) in which it exhibits an endothermic thermal event at about 162° C. | The polymorph used in Par's ANDA Products is alleged to exhibit the specific thermal characteristics required by the claim. | ¶28 | col. 2:24-26 |
| Claim Element (from Independent Claim 9) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of treating cardiac arrhythmia... | Defendant’s proposed product label allegedly directs physicians and patients to use the generic product to treat cardiac arrhythmia. | ¶24, ¶30 | col. 4:46-49 |
| which comprises administering an effective amount of dofetilide polymorph P162 as claimed in claim 1... | The proposed label allegedly instructs administration of Defendant’s product, which is accused of containing the claimed P162 polymorph. | ¶28, ¶30 | col. 4:51-54 |
| to an animal in need of such treatment. | The proposed label is allegedly directed to patients with conditions such as atrial fibrillation or atrial flutter who require such treatment. | ¶19, ¶24 | col. 4:46-49 |
- Identified Points of Contention:
- Technical Questions: The central dispute will likely be factual: does the dofetilide in Defendant's ANDA product actually consist of the specific polymorph P162 as defined by the patent claims? Defendant's Paragraph IV certification alleges non-infringement and/or invalidity (Compl. ¶23), suggesting it may argue its product contains a different, non-infringing polymorph (such as P162a, P143, or others discussed in the ’363 patent) or a mixture of forms. Resolution will likely depend on competing expert testimony and analytical data (e.g., DSC, PXRD, IR).
- Scope Questions: What is the permissible range of the term "about 162° C."? The interpretation of this term will be critical in determining whether a product with a measured thermal event slightly different from 162° C. infringes. Further, the scope of "substantially pure," defined in the patent as at least 95% pure, may be litigated if Defendant’s product has a different purity profile (’363 Patent, col. 3:35-39).
No probative visual evidence provided in complaint.
V. Key Claim Terms for Construction
The Term: "polymorph P162"
Context and Importance: This term is the heart of the composition claim. The entire infringement analysis for claim 1 hinges on whether the accused product contains this specific polymorph. Practitioners may focus on this term because the patent identifies and distinguishes multiple dofetilide polymorphs (e.g., P162, P162a, P143), each with distinct characterization data.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A plaintiff could argue that the plain language of claim 1 defines "polymorph P162" by its DSC characteristic ("an endothermic thermal event at about 162° C."), and any polymorph meeting this definition is infringing.
- Evidence for a Narrower Interpretation: A defendant could argue that "polymorph P162" must be defined by the full suite of characteristics described in the specification, including the specific PXRD pattern (recited in dependent claim 2) and IR spectrum (recited in dependent claim 3). The patent's careful distinction between P162 and P162a, which have "similar PXRD patterns" but different DSC peaks, suggests that the full analytical profile is necessary to uniquely identify the claimed polymorph (’363 Patent, col. 2:57-61).
The Term: "substantially pure"
Context and Importance: This limitation defines the required purity of the claimed polymorph. A defendant whose product contains a mixture of polymorphs or a lower-purity version of P162 might argue it falls outside the claim scope.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification provides an explicit definition: "The expression 'substantially pure' ... means at least 95% by weight pure" (’363 Patent, col. 3:35-37). A plaintiff would likely argue this definition is controlling.
- Evidence for a Narrower Interpretation: The same passage continues: "More preferably, 'substantially pure' means at least 98% by weight pure and most preferably means at least 99% by weight pure" (’363 Patent, col. 3:37-39). A defendant might argue that these preferred embodiments should inform the construction of the term to require a higher level of purity to capture the inventive concept.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that Defendant will induce infringement and contribute to the infringement of method claim 9 (Compl. ¶31-32). The factual basis for these allegations is that Defendant's proposed product labeling will instruct physicians and patients to administer the drug for the treatment of cardiac arrhythmia, and that the product is specially made for this infringing use and has no substantial non-infringing use (Compl. ¶30, ¶33).
- Willful Infringement: The complaint does not explicitly allege willfulness. However, it does allege that Defendant had "knowledge of the '363 patent when it submitted ANDA No. 208519" (Compl. ¶27) and requests a finding that the case is "exceptional" under 35 U.S.C. § 285, which can entitle a prevailing party to attorneys' fees (Prayer for Relief, ¶D).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of polymorphic identity: Will discovery and expert analysis demonstrate that the active pharmaceutical ingredient in Defendant's proposed generic product is, in fact, the specific "dofetilide polymorph P162" as defined in the patent, or a different, non-infringing form?
- A second central question will be one of claim scope: How will the court construe the term "about 162° C."? The breadth of this term will be critical in determining whether minor variations in the thermal properties of Defendant's product are sufficient to avoid infringement.
- Finally, a key question for the method claim will be one of inducement: Assuming the product is found to contain the claimed polymorph, does the proposed product label, by copying the indications of the branded drug, sufficiently instruct an infringing use to establish liability for induced infringement of claim 9?