Sumitomo Dainippon Pharma Co Ltd v. Amneal Pharma LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Sumitomo Dainippon Pharma Co., Ltd. (Japan) and Sunovion Pharmaceuticals Inc. (Massachusetts)
  • Defendant: Amneal Pharmaceuticals LLC (Delaware)
  • Plaintiff’s Counsel: Saul Ewing LLP
• Case Identification: 2:16-cv-04596, D.N.J., 07/29/2016
• Venue Allegations: Venue is alleged to be proper in the District of New Jersey based on Defendant Amneal having its principal place of business in the state, maintaining at least five business locations there, and developing, manufacturing, or importing generic pharmaceuticals within the district.
• Core Dispute: Plaintiffs allege that Defendant’s filing of an Abbreviated New Drug Application (ANDA) to market generic lurasidone hydrochloride tablets constitutes an act of infringement of the patent covering Plaintiffs' branded drug, LATUDA®.
• Technical Context: The technology involves novel imide derivative compounds developed as antipsychotic agents for treating mental health conditions such as schizophrenia and bipolar disorder.
• Key Procedural History: The complaint notes that this matter is related to other consolidated actions involving the same patent and other defendants seeking to market generic versions of the same drug product. This is a Hatch-Waxman action triggered by Amneal’s submission of a Paragraph IV certification, asserting that its generic product would not infringe the patent-in-suit or that the patent is invalid.

Case Timeline

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

• Patent Identification: U.S. Patent No. 5,532,372, "Imide derivatives, and their production and use," issued July 2, 1996. (Compl. ¶18).

The Invention Explained

• Problem Addressed: The patent describes a significant problem with "conventional antipsychotic agents," namely that they are generally accompanied by severe side effects, such as extrapyramidal motor disturbances (e.g., Parkinsonism) and orthostatic hypotension, which create clinical challenges (’372 Patent, col. 2:2-8).
• The Patented Solution: The invention claims to solve this problem with a novel class of imide compounds. The inventors discovered that compounds structured with an imide portion and a piperazine or piperidine ring, connected by an alkylene chain that incorporates a "non-aromatic hydrocarbon ring," exhibit the desired antipsychotic pharmacological action with suppressed side effects (’372 Patent, col. 2:10-18, col. 2:62-68).
• Technical Importance: The patented chemical structures offered a new class of therapeutic agents for psychoses that possessed a potentially more favorable side-effect profile compared to then-existing treatments (’372 Patent, col. 2:8-12).

Key Claims at a Glance

• The complaint alleges infringement of "one or more claims" and specifically notes that Defendant’s notice letter did not allege invalidity of claim 14 (Compl. ¶¶26, 31). The primary independent claims are Claim 1 (genus) and Claim 14 (species).
• Independent Claim 1 (Genus Claim):
  • An imide compound of the formula: Z-D-N-G-Ar
  • Wherein Z is a specific imide group structure
  • Wherein D is a linker group, -(CH2)p-A-(CH2)q-, where A is a non-aromatic hydrocarbon ring
  • Wherein G-Ar is a terminal group where Ar is, among other things, a benzisothiazolyl group and G is >N-
  • Or an acid addition salt thereof
• Independent Claim 14 (Species Claim):
  • The imide compound of the formula: [a specific chemical structure corresponding to lurasidone]
  • Or an acid addition salt thereof
• The complaint reserves the right to assert additional claims, including dependent claims (Compl. ¶31).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Defendant Amneal's proposed generic lurasidone hydrochloride tablets in 20 mg, 40 mg, 60 mg, 80 mg, and 120 mg strengths, for which Amneal seeks FDA approval under ANDA No. 208002 (collectively, "ANDA Products") (Compl. ¶¶14, 20).

Functionality and Market Context

• Amneal’s ANDA Products are generic versions of Plaintiffs’ branded drug LATUDA® (Compl. ¶¶16-17).
• LATUDA® is an approved treatment for schizophrenia and for depressive episodes associated with Bipolar I Disorder (Compl. ¶17). The complaint alleges that Amneal seeks to market its generic versions for these uses prior to the expiration of the ’372 Patent (Compl. ¶20).

IV. Analysis of Infringement Allegations

The complaint alleges infringement under 35 U.S.C. § 271(e)(2)(A), which defines the submission of an ANDA seeking approval to market a patented drug before the patent's expiration as a statutory act of infringement (Compl. ¶30). The complaint does not contain a detailed claim chart, but the infringement theory for a compound patent in an ANDA case is that the active pharmaceutical ingredient in the proposed generic product is the same as the claimed compound.

No probative visual evidence provided in complaint.

’372 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: Since claim 14 recites a specific chemical compound (a "picture claim"), the primary infringement dispute, if any, would likely focus on whether Amneal’s proposed product is precisely that compound. This raises the question: Does the lurasidone hydrochloride in Amneal's ANDA product contain any structural or stereochemical variations (e.g., different isomers, polymorphs) that might place it outside the literal scope of "the imide compound" or its "acid addition salt thereof" as defined in the patent? The complaint does not provide information to assess this possibility.
  • Technical Questions: The complaint’s allegation that Amneal does not contest the validity of claim 14 raises the question of Amneal's non-infringement theory (Compl. ¶26). Is there a technical basis, such as a different crystalline form of lurasidone hydrochloride not covered by the patent, that Amneal may argue distinguishes its product from the claim?

V. Key Claim Terms for Construction

• The Term: "non-aromatic hydrocarbon ring" (from claim 1)

• Context and Importance: The presence of this ring in the linker group 'D' is presented as a key feature distinguishing the invention from prior art straight-chain compounds (’372 Patent, col. 2:62-68). The construction of this term is critical for determining the scope of the genus of compounds covered by claim 1 and related claims.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification lists numerous examples of what this ring can be, including "cyclopropane, cyclobutane, cyclopentane, cyclohexane and cycloheptane," as well as various bridged bicyclic structures, suggesting the term is meant to be read broadly to encompass a variety of cyclic structures (’372 Patent, col. 3:57-63, col. 4:1-17).
  • Evidence for a Narrower Interpretation: The specification limits the ring to having "not more than 7 carbon atoms" (’372 Patent, col. 3:58-61). A party could argue that the term should be construed as limited to the simple, unsubstituted cycloalkane rings that are most prominently featured in the patent’s working examples, such as the cyclohexane ring of lurasidone itself.

• The Term: "acid addition salt" (from claims 1 and 14)

• Context and Importance: This term is essential for infringement, as the accused ANDA product is for lurasidone hydrochloride, an acid addition salt (Compl. ¶14).

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification explicitly states the invention covers salts formed with "an organic or inorganic acid" and provides a non-exhaustive list of examples, including "hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid," and several organic acids (’372 Patent, col. 4:45-50). This language may support a construction covering any pharmaceutically acceptable salt.
  • Evidence for a Narrower Interpretation: While a narrow interpretation seems unlikely given the explicit language, a party could potentially argue that the term should be limited to only those salts that are stable and retain the therapeutic efficacy described in the patent, or to the specific salts used in the examples.

VI. Other Allegations

• Indirect Infringement: The complaint makes a prospective allegation of indirect infringement, stating that if Amneal commercially manufactures and sells its ANDA products, it will induce or contribute to infringement under 35 U.S.C. § 271(b) and (c) (Compl. ¶33). The factual basis for inducement would be Amneal’s proposed drug label, which would instruct physicians and patients to use the generic drug for the patented indications.
• Willful Infringement: The complaint does not use the word "willful" but pleads facts to support such a claim. It alleges Amneal had pre-suit knowledge of the ’372 patent as of December 2014 and received a formal notice letter in June 2016 (Compl. ¶¶22, 25). The request for a finding that the case is "exceptional" and for an award of attorneys' fees further suggests an intent to pursue a claim for enhanced damages (Compl. p. 8, ¶E).

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

• A central issue will be one of infringement scope versus product form: Given that the key asserted claim is for a specific chemical compound, a critical question for the court will be whether the precise stereoisomer and crystalline polymorph of lurasidone hydrochloride in Amneal's proposed generic product is identical to the "imide compound" and its "acid addition salt thereof" as claimed in the patent, or if technical differences exist that could support a non-infringement finding.
• A second key question will be one of validity and litigation strategy: Although the complaint alleges infringement, the ultimate dispute in a Hatch-Waxman case typically centers on the patent's validity. The complaint's specific observation that Amneal has not alleged the invalidity of claim 14 is unusual and raises a strategic question: Is Amneal conceding the validity of the core compound claim to focus its invalidity challenge on broader genus claims, or is it relying entirely on a technical non-infringement argument?