DCT

1:23-cv-00936

Pfizer Inc v. Synthon Pharma Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:21-cv-00157, M.D.N.C., 02/25/2021
  • Venue Allegations: Venue is alleged to be proper in the Middle District of North Carolina primarily because Defendant Synthon Pharmaceuticals, Inc. is a North Carolina corporation with its principal place of business in the district. Venue for foreign-domiciled defendants is alleged based on their purposeful availment and business contacts within the state.
  • Core Dispute: Plaintiff alleges that Defendant's submission of an Abbreviated New Drug Application (ANDA) to market a generic version of the breast cancer drug IBRANCE® (palbociclib) constitutes an act of infringement of four U.S. patents covering the palbociclib compound, its specific solid forms, and methods of use.
  • Technical Context: The technology relates to small-molecule kinase inhibitors, specifically selective inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6), used in the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Plaintiff's receipt of a notice letter from Defendant, dated January 13, 2021, which stated that Defendant had filed an ANDA with a Paragraph IV certification. This certification alleges that Plaintiff's patents-in-suit are invalid, unenforceable, and/or will not be infringed by the proposed generic product. The complaint notes that Defendant’s notice letter did not contest infringement of the compound patents on any basis other than alleged invalidity.

Case Timeline

Date Event
2002-01-22 Patent Priority Date (’612, ’739, and ’168 Patents)
2005-08-30 U.S. Patent No. 6,936,612 Issued
2008-11-25 U.S. Patent No. 7,456,168 Issued
2013-02-21 Patent Priority Date (’730 Patent)
2019-11-26 U.S. Patent No. RE47,739 Issued
2020-07-28 U.S. Patent No. 10,723,730 Issued
2021-01-13 Defendant Notified Plaintiff of ANDA Filing
2021-02-25 Complaint Filed

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

U.S. Patent No. 6,936,612 - "2-(PYRIDIN-2-YLAMINO)-PYRIDO[2,3-D] PYRIMIDIN-7-ONES"

  • Issued: August 30, 2005

The Invention Explained

  • Problem Addressed: The patent describes the need for potent and selective inhibitors of cyclin-dependent kinases (Cdks) to treat cell proliferative diseases like cancer, noting the difficulty in developing small molecules that inhibit specific Cdk proteins without affecting other essential enzymes (’612 Patent, col. 2:19-29).
  • The Patented Solution: The invention provides a class of substituted 2-aminopyridine compounds, specifically pyrido[2,3-d]pyrimidin-7-ones, which are described as potent inhibitors of Cdk4, useful for treating disorders such as cancer and restenosis (’612 Patent, col. 2:5-14, Abstract). The patent discloses a genus of compounds and specifically claims the compound that would become known as palbociclib.
  • Technical Importance: This class of compounds represented an advance in providing selective Cdk4/6 inhibitors, which play a crucial role in regulating the cell cycle and whose abnormal activation is associated with tumor development (’612 Patent, col. 1:21-32).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 2 (Compl. ¶33, 34).
  • Claim 1:
    • A compound which is 6-Acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8H-pyrido[2,3-d]pyrimidin-7-one.
  • Claim 2:
    • A pharmaceutical composition comprising a therapeutically effective amount of the compound according to claim 1 and a pharmaceutical carrier therefor.

U.S. Patent No. RE47,739 - "2-(PYRIDIN-2-YLAMINO)-PYRIDO[2,3-D] PYRIMIDIN-7-ONES"

  • Issued: November 26, 2019

The Invention Explained

  • Problem Addressed: The ’739 Patent is a reissue of U.S. Patent No. 7,208,489 and shares a specification with the ’612 Patent. It addresses the same technical problem of identifying selective Cdk inhibitors for treating cell proliferative diseases (’739 Patent, col. 2:19-29).
  • The Patented Solution: This patent claims a genus of compounds encompassing the palbociclib molecule, defined by a Markush structure. Reissue patents are typically sought to correct errors in the original patent, which may include narrowing or broadening the scope of the claims to accurately reflect the invention. The solution remains the same class of pyrido[2,3-d]pyrimidin-7-one compounds (’739 Patent, Abstract).
  • Technical Importance: As with the ’612 Patent, this patent family provided a foundation for selective Cdk4/6 inhibition as a cancer therapy (’739 Patent, col. 1:21-32).

Key Claims at a Glance

  • The complaint asserts independent claim 2 (Compl. ¶73).
  • The complaint states that claim 2 recites "a compound of the formula recited in claim 2" (Compl. ¶¶73, 92). The complaint does not provide the full text of the claim or its structural formula.

Multi-Patent Capsules

  • Patent Identification: U.S. Patent No. 7,456,168, "2-(PYRIDIN-2-YLAMINO)-PYRIDO[2,3, D]PYRIMIDIN-7-ONES," issued November 25, 2008.

  • Technology Synopsis: Belonging to the same family as the ’612 Patent, this patent addresses the use of the claimed compounds for cancer treatment. It specifically claims a method of treating breast cancer by administering a compound of a specified formula, which encompasses palbociclib (’168 Patent, Abstract; Compl. ¶112).

  • Asserted Claims: Claims 1-4 are asserted (Compl. ¶119). Claim 1 is the independent method-of-treatment claim.

  • Accused Features: The accused act is Defendant's filing of an ANDA for a generic palbociclib product, which the complaint alleges will be used according to its proposed labeling to treat breast cancer, thereby inducing infringement of the claimed method (Compl. ¶¶120-121).

  • Patent Identification: U.S. Patent No. 10,723,730, "Solid Forms of a Selective Cdk4/6 Inhibitor," issued July 28, 2020.

  • Technology Synopsis: This patent addresses challenges in pharmaceutical development related to the solid-state properties of the palbociclib free base. It claims a specific crystalline form (Form A) of the compound, distinguished by its powder X-ray diffraction (PXRD) pattern and specific particle size characteristics, which allegedly provide improved physicochemical and manufacturability properties compared to forms produced by traditional methods (’730 Patent, col. 2:1-11, Abstract).

  • Asserted Claims: Independent claims 1, 7, and 15 are asserted (Compl. ¶¶153, 155, 157).

  • Accused Features: The complaint alleges that Defendant's ANDA Products contain the specific crystalline form of palbociclib defined by the patent's claims, including its characteristic PXRD peaks and particle size distributions (Compl. ¶¶152, 154, 156, 158).

III. The Accused Instrumentality

Product Identification

  • Defendant's proposed generic palbociclib tablets in 75 mg, 100 mg, and 125 mg dosage strengths, as described in ANDA No. 215570 ("Synthon's ANDA Products") (Compl. ¶2).

Functionality and Market Context

  • The accused products are generic versions of Plaintiff's IBRANCE® drug product (Compl. ¶26). IBRANCE® is approved for the treatment of HR-positive, HER2-negative advanced or metastatic breast cancer (Compl. ¶25). The complaint alleges that Defendant intends to commercially manufacture, market, and sell its generic product for this same use upon receiving FDA approval (Compl. ¶20).

IV. Analysis of Infringement Allegations

The central act of infringement alleged under the Hatch-Waxman Act is Defendant's submission of its ANDA to the FDA seeking approval to market a generic drug prior to the expiration of the patents-in-suit, which constitutes a technical act of infringement under 35 U.S.C. § 271(e)(2)(A) (Compl. ¶¶40, 79). The complaint alleges that the product described in the ANDA, if approved and marketed, would infringe the asserted patents.

No probative visual evidence provided in complaint.

’612 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A compound which is 6-Acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8H-pyrido[2,3-d]pyrimidin-7-one. Synthon's ANDA Products are alleged to contain as their active ingredient the compound palbociclib, which is the compound recited in claim 1. ¶38, ¶42 col. 10:1-55

Identified Points of Contention:

  • Factual Question: The primary question is one of chemical identity: does the active pharmaceutical ingredient in Synthon's ANDA Products meet the structural definition of the compound claimed in the ’612 Patent? The complaint alleges that Defendant did not contest infringement on any basis other than invalidity, which suggests this point may not be in dispute (Compl. ¶39).

’739 Patent Infringement Allegations

Claim Element (from Independent Claim 2) Alleged Infringing Functionality Complaint Citation Patent Citation
The complaint does not provide the full text of claim 2 but alleges it claims, inter alia, a compound of a specified formula. Synthon's ANDA Products are alleged to contain a compound that is covered by the formula recited in claim 2 of the '739 patent. ¶77, ¶81 col. 2:32-47

Identified Points of Contention:

  • Scope Question: A potential question is whether the compound in the ANDA product falls within the scope of the Markush group defined in claim 2 of the ’739 Patent. As with the ’612 Patent, the complaint alleges that Defendant did not contest infringement on grounds other than invalidity, suggesting the primary dispute will be over the patent's validity (Compl. ¶78).

V. Key Claim Terms for Construction

For the asserted compound patents (’612 and ’739 Patents), the claims define specific chemical structures. Claim construction disputes over the meaning of terms are less common than factual disputes over whether an accused product contains the identical chemical entity. The complaint does not provide sufficient detail for a meaningful claim construction analysis of these patents. The central disputes for these patents will likely revolve around validity rather than claim scope.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon FDA approval, Defendant will actively induce infringement and contribute to infringement of all four patents-in-suit. The allegations are based on the premise that Defendant's proposed product labeling will instruct and encourage physicians and patients to administer the generic product in a manner that directly infringes, particularly with respect to the method-of-use claims in the ’168 Patent (Compl. ¶¶44, 83, 121, 163). It is further alleged that the product is not a staple article of commerce and is not suitable for substantial noninfringing use (Compl. ¶¶45, 84, 122, 164).
  • Willful Infringement: The complaint alleges that Defendant has acted with full knowledge of the patents-in-suit and without a reasonable basis for believing it would not be liable for infringement (Compl. ¶¶48, 87, 125, 167). This allegation is predicated on Defendant's act of filing a Paragraph IV certification, which required it to identify and analyze Plaintiff's patents.

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

  • A central issue for all asserted patents will be validity: Defendant's Paragraph IV certification places the validity of the patents directly at issue. The case will likely involve significant disputes over whether the claimed compound, method of use, and specific crystalline form are novel and non-obvious over the prior art.
  • A key evidentiary question for the ’730 patent will be one of technical identity: does the crystalline form of palbociclib in Synthon's ANDA product exhibit the specific powder X-ray diffraction peaks and particle size distributions required by the claims, and if so, was that specific polymorph obvious to develop?
  • A primary legal question regarding the ’168 method-of-use patent will be induced infringement: does Synthon’s proposed product label provide sufficient instruction and encouragement for physicians to prescribe, and patients to use, the generic drug in a manner that directly infringes the claimed method of treating breast cancer?