Pfizer Inc v. Aizant Drug Research Solutions Pvt Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Pfizer Inc., Warner-Lambert Company LLC, PF Prism CV., Pfizer Manufacturing Holdings LLC, and Pfizer PFE Ireland Pharmaceuticals Holding 1 B.V. (collectively "Pfizer") (Various jurisdictions, led by Delaware corporation)
  • Defendant: Aizant Drug Research Solutions Pvt. Ltd. (India) and Makro Technologies Inc. (New Jersey) (collectively "Aizant")
  • Plaintiff’s Counsel: Gibbons P.C.; Williams & Connolly LLP
• Case Identification: 1:19-cv-11737, D.N.J., 04/29/2019
• Venue Allegations: Venue is based on Defendant Makro Technologies Inc. being a New Jersey corporation and acting as the U.S. agent for Defendant Aizant Drug Research Solutions. The complaint alleges Aizant intends to market, sell, and distribute its generic product in New Jersey upon FDA approval.
• Core Dispute: Plaintiff alleges that Defendant's submission of an Abbreviated New Drug Application (ANDA) to the FDA for generic versions of the cancer drug IBRANCE® (Palbociclib) constitutes an act of infringement of three patents covering the compound, a genus of related compounds, and its method of use for treating breast cancer.
• Technical Context: The patents relate to Palbociclib, a small molecule inhibitor of cyclin-dependent kinases (CDK) 4 and 6, a class of enzymes critical for cell division, which is approved for the treatment of certain types of breast cancer.
• Key Procedural History: This action was initiated under the Hatch-Waxman Act following Pfizer's receipt of a notice letter from Aizant dated March 27, 2019, regarding Aizant's ANDA filing. The complaint alleges that Aizant's notice letter did not contest infringement of the asserted patents but instead asserted that the patents are invalid.

Case Timeline

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”

• Patent Identification: U.S. Patent No. 6,936,612, entitled “2-(Pyridin-2-ylamino)-pyrido[2,3-d]pyrimidin-7-ones,” issued August 30, 2005 (the "’612 Patent"). (Compl. ¶18).

The Invention Explained

• Problem Addressed: The patent addresses the role of cyclin-dependent kinases (Cdks) in regulating the cell cycle and notes that increased or abnormal Cdk activity is a common feature of human tumors. (Compl. ¶1; ’612 Patent, col. 1:42-53). The technical problem was the need for small-molecule Cdk inhibitors to treat cell proliferative diseases like cancer. (’612 Patent, col. 2:8-12).
• The Patented Solution: The invention provides a class of substituted 2-aminopyridine compounds that are potent inhibitors of Cdk4, an enzyme essential for cell cycle progression. (’612 Patent, Abstract). The patent describes these compounds as useful for treating disorders arising from abnormal cell proliferation, such as cancer and restenosis. (’612 Patent, col. 1:10-12).
• Technical Importance: The invention provided a specific chemical structure for Palbociclib, which became a commercially successful targeted therapy that selectively inhibits Cdk4 and Cdk6, offering a mechanism to halt the growth of certain cancer cells. (’612 Patent, col. 2:8-16, 35-37).

Key Claims at a Glance

• The complaint asserts independent claim 1 and dependent claim 2. (Compl. ¶¶20-21).
• 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 of claim 1 and a pharmaceutical carrier.

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U.S. Patent No. 7,208,489 - “2-(pyridin-2-ylamino)-pyrido [2,3-d]pyrimidin-7-ones”

• Patent Identification: U.S. Patent No. 7,208,489, entitled “2-(pyridin-2-ylamino)-pyrido [2,3-d]pyrimidin-7-ones,” issued April 24, 2007 (the "’489 Patent"). (Compl. ¶58).

The Invention Explained

• Problem Addressed: As with the related ’612 Patent, the ’489 Patent is directed to inhibitors of cyclin-dependent kinases to address uncontrolled cell proliferation in diseases like cancer. (’489 Patent, col. 1:13-20).
• The Patented Solution: The ’489 Patent claims a genus of compounds defined by a Markush formula that encompasses the specific compound Palbociclib. (’489 Patent, Abstract, col. 2:30-47). This structure provides a chemical scaffold for potent Cdk4 inhibition.
• Technical Importance: By claiming a genus of related chemical structures, the patent provides broader protection for the core chemical scaffold responsible for the therapeutic effect beyond the single Palbociclib compound. (Compl. ¶60).

Key Claims at a Glance

• The complaint asserts independent claim 1 and dependent claims 2-7 and 9. (Compl. ¶64).
• Claim 1:
  • A compound of the formula recited in claim 1. (Compl. ¶60).

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U.S. Patent No. 7,456,168 - “2-(pyridin-2-ylamino)-pyrido [2,3-d]pyrimidin-7-ones”

• Patent Identification: U.S. Patent No. 7,456,168, entitled “2-(pyridin-2-ylamino)-pyrido [2,3-d]pyrimidin-7-ones,” issued November 25, 2008 (the "’168 Patent"). (Compl. ¶97).
• Technology Synopsis: This patent claims a method of treating a specific disease rather than a compound. It addresses the need for therapies for breast cancer and claims a method of treating breast cancer in a mammal by administering a compound of the formula that includes Palbociclib. (Compl. ¶99).
• Asserted Claims: Independent claim 1 and dependent claims 2-4. (Compl. ¶103).
• Accused Features: The complaint alleges that Aizant's proposed product labeling will instruct physicians and patients to use Aizant's generic palbociclib product to treat breast cancer, thereby inducing and contributing to infringement of the claimed method. (Compl. ¶¶108-110).

III. The Accused Instrumentality

Product Identification

The accused instrumentality is "Aizant’s ANDA Product," identified as generic Palbociclib capsules in 75 mg, 100 mg, and 125 mg dosage forms. (Compl. ¶2). The act of infringement alleged under 35 U.S.C. § 271(e)(2)(A) is the submission of Abbreviated New Drug Application ("ANDA") No. 213152 to the FDA. (Compl. ¶¶2, 27).

Functionality and Market Context

The Aizant ANDA Product is a generic version of Pfizer’s IBRANCE® drug. (Compl. ¶1). It contains Palbociclib, which functions as an inhibitor of cyclin-dependent kinases 4 and 6 for use in cancer therapy. (Compl. ¶¶1, 99). Aizant seeks FDA approval to commercially manufacture and sell this product in the United States prior to the expiration of the patents-in-suit. (Compl. ¶2). The complaint alleges that upon approval, Aizant will market, sell, and distribute the product throughout the United States, including in New Jersey. (Compl. ¶9).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

’612 Patent Infringement Allegations

’489 Patent Infringement Allegations

Identified Points of Contention

• Scope Questions: The primary dispute foreshadowed by the complaint is not over infringement, but validity. The complaint states that Aizant's notice letter "did not contest the infringement" of the asserted claims "on any basis other than the alleged invalidity of those claims" (Compl. ¶¶26, 65, 104). This suggests that for the purposes of litigation, Aizant may have conceded that its product meets the claim limitations, focusing its defense elsewhere. A question for the court will be whether this position is maintained or if a non-infringement argument (e.g., related to purity, salt form, or other characteristics) emerges during the case.
• Technical Questions: A threshold technical question, though likely not in dispute, is whether the active pharmaceutical ingredient in Aizant's ANDA product is chemically identical to the compound recited in claim 1 of the ’612 Patent and is a species of the genus claimed in the ’489 Patent.

V. Key Claim Terms for Construction

The complaint does not provide sufficient detail to identify specific claim terms that are likely to be in dispute for construction. In litigation concerning a specific chemical compound, where infringement is based on the alleged identity of the accused product to the claimed molecule, claim construction disputes are often less central than in other technology areas. The complaint suggests the central dispute will concern patent validity rather than the meaning of claim terms. (Compl. ¶¶26, 65, 104).

VI. Other Allegations

• Indirect Infringement: The complaint alleges active inducement and contributory infringement for all three patents. The inducement allegations are based on the assertion that Aizant's proposed product labeling will direct medical professionals and patients to use the ANDA product in an infringing manner. (Compl. ¶¶31, 70, 109). The contributory infringement allegations are based on the assertion that Aizant's product is not a staple article of commerce suitable for substantial non-infringing use and is especially made for an infringing use. (Compl. ¶¶32, 71, 110). The allegations are particularly relevant to the ’168 Patent, which claims a method of treating breast cancer. (Compl. ¶109, 110).
• Willful Infringement: The complaint alleges that Aizant has acted with full knowledge of the patents-in-suit, citing the notice letter sent to Pfizer. (Compl. ¶¶33, 35, 72, 74, 111, 113). This pre-suit knowledge forms the basis for the allegation that Aizant's infringement is, and will be, willful.

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

• A central issue will be one of patent validity: as infringement was reportedly not contested in Aizant's notice letter, the case will likely focus on Aizant's defenses that the asserted claims of the patents-in-suit are invalid under 35 U.S.C. §§ 102, 103, and/or 112.
• A key evidentiary question will be one of induced infringement: for the ’168 method-of-use patent, the court will need to determine whether the contents of Aizant's proposed product labeling provide sufficient evidence of intent to encourage or instruct physicians and patients to perform the patented method of treating breast cancer.