Pfizer Inc v. Alembic Pharma Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Pfizer Inc., et al. (Delaware)
  • Defendant: Alembic Pharmaceuticals, Inc. (Delaware) and Alembic Pharmaceuticals, Ltd. (India)
  • Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP
• Case Identification: 1:19-cv-00745, D. Del., 04/25/2019
• Venue Allegations: Venue is alleged to be proper as to the U.S. defendant, Alembic Pharmaceuticals, Inc., because it is a Delaware corporation, and as to the foreign defendant, Alembic Pharmaceuticals, Ltd., because it is subject to personal jurisdiction in the district.
• Core Dispute: Plaintiff alleges that Defendant’s submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of the cancer drug IBRANCE® constitutes an act of patent infringement.
• Technical Context: The technology concerns a specific chemical compound, Palbociclib, which functions as a cyclin-dependent kinase (CDK) inhibitor for treating certain types of cancer.
• Key Procedural History: This action arises under the Hatch-Waxman Act, triggered by a notice letter dated March 19, 2019, in which Alembic informed Pfizer of its ANDA filing. This notice included a Paragraph IV certification alleging that the patent-in-suit is invalid, unenforceable, or will not be infringed by Alembic’s proposed generic product.

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

The Invention Explained

• Problem Addressed: The patent describes that cyclin-dependent kinases (CDKs) are essential for regulating cell division, and their abnormal or increased activity is a hallmark of human tumor development. The background notes the technical challenge of identifying compounds that can selectively inhibit specific CDKs without affecting other enzymes, which could cause undesirable side effects ('612 Patent, col. 1:14-19; col. 2:20-29).
• The Patented Solution: The invention provides a class of chemical compounds, specifically substituted 2-aminopyridines, that are potent and selective inhibitors of cyclin-dependent kinase 4 (cdk4). The patent discloses these compounds as a means to treat cell proliferative disorders like cancer by halting or slowing the cell cycle ('612 Patent, Abstract; col. 3:32-41).
• Technical Importance: The invention provided a class of molecules with the potential for selective cdk4 inhibition, offering a targeted therapeutic approach against cancers driven by aberrant cell cycle regulation ('612 Patent, col. 2:31-41).

Key Claims at a Glance

• The complaint asserts independent claim 1 and dependent claim 2 ('Compl. ¶32).
• Independent 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.
• Dependent Claim 2:
  • A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 1.
  • And a pharmaceutical carrier therefor.

III. The Accused Instrumentality

Product Identification

The accused instrumentality is Alembic's proposed generic versions of IBRANCE® (Palbociclib) capsules in 75 mg, 100 mg, and 125 mg dosages, as described in Alembic's ANDA No. 213128 ('Compl. ¶¶ 1-2).

Functionality and Market Context

The accused product is intended to be a bioequivalent generic version of Pfizer's branded drug, IBRANCE®, which is approved for treating certain types of breast cancer ('Compl. ¶1). The active pharmaceutical ingredient is Palbociclib, which the complaint alleges is the specific compound claimed in the ’612 Patent ('Compl. ¶¶ 27, 32). The act of infringement alleged is the submission of the ANDA to the FDA seeking approval to market this generic drug prior to the expiration of the ’612 Patent ('Compl. ¶34). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

'612 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: The complaint alleges that Alembic did not contest infringement of the asserted claims in its notice letter, instead focusing its challenge on the patent's validity (Compl. ¶33). This suggests that infringement of the compound claim itself may not be a primary point of dispute. The central issue is more likely to be whether the claims are valid and enforceable.
  • Technical Questions: A key question for the court will be whether Alembic can prove by clear and convincing evidence that the asserted claims are invalid for reasons such as anticipation or obviousness, notwithstanding the presumption of validity.

V. Key Claim Terms for Construction

The asserted independent claim recites a single, specific chemical compound by its IUPAC name. As such, claim construction is not anticipated to be a central issue in the dispute. The structure of the compound is unambiguously defined by its name, and terms such as "pharmaceutical composition" and "pharmaceutical carrier" in dependent claim 2 have well-understood meanings in the art.

VI. Other Allegations

• Indirect Infringement: The complaint alleges active inducement, stating that Alembic plans to induce infringement through its proposed product labeling, which will direct medical professionals and patients to use the product in an infringing manner (Compl. ¶¶ 37-38). The complaint also alleges contributory infringement, asserting that Alembic's product is not a staple article of commerce and is especially adapted for an infringing use (Compl. ¶39).
• Willful Infringement: Willfulness is alleged based on Alembic's full knowledge of the ’612 Patent, evidenced by its Paragraph IV certification and notice letter sent to Pfizer prior to the lawsuit (Compl. ¶¶ 30-31, 42).

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

• A core issue will be one of patent validity: given that infringement of the compound claim appears to be uncontested according to the complaint, the case will likely center on whether Alembic can successfully prove its assertion that the asserted claims of the ’612 patent are invalid or otherwise unenforceable.
• A secondary procedural question is one of remedy: should the patent be found valid and infringed, what is the appropriate effective date for the approval of Alembic's ANDA, and is a permanent injunction to prevent marketing of the generic product prior to patent expiration warranted?