DCT

1:18-cv-00055

Eli Lilly Co v. Lupin Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:18-cv-00055, D. Del., 01/04/2018
  • Venue Allegations: Venue is alleged to be proper based on Defendant Lupin Inc. being incorporated in Delaware, both defendants having continuous business contacts in the district, and both having previously consented to jurisdiction in the district. Jurisdiction is also asserted based on the filing of the Abbreviated New Drug Application (ANDA) which purposefully directs future commercial activity toward the district.
  • Core Dispute: Plaintiffs allege that Defendants' submission of an ANDA to the FDA seeking approval to market a generic version of Cialis® (tadalafil) constitutes an act of infringement of a patent covering a method of using tadalafil for treating sexual dysfunction.
  • Technical Context: The technology relates to phosphodiesterase type 5 (PDE5) inhibitors, a class of drugs used to treat male erectile dysfunction by modulating smooth muscle function.
  • Key Procedural History: This action was filed under the Hatch-Waxman Act, specifically 35 U.S.C. § 271(e)(2), which defines the submission of an ANDA for a patented drug as a statutory act of infringement. The lawsuit was triggered by a "Notice Letter" in which Defendants informed Plaintiffs of their ANDA filing and included a "Paragraph IV certification" asserting that the patent-in-suit is invalid, unenforceable, and/or will not be infringed by the proposed generic product.

Case Timeline

Date Event
1999-04-30 U.S. Patent No. 6,943,166 Priority Date
2005-09-13 U.S. Patent No. 6,943,166 Issue Date
2017-11-21 Defendant's Notice Letter sent to Plaintiffs
2018-01-04 Complaint Filing Date

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

U.S. Patent No. 6,943,166 - "Compositions Comprising Phosphodiesterase Inhibitors for the Treatment of Sexual Dysfunction," Issued September 13, 2005

The Invention Explained

  • Problem Addressed: The patent's background describes prior art PDE5 inhibitors, such as sildenafil (Viagra®), as having significant adverse side effects, including facial flushing, vision abnormalities, and a dangerous hypotensive effect when taken with organic nitrates. (’166 Patent, col. 2:1-7, 2:57-65). This limited their use in certain patient populations.
  • The Patented Solution: The invention is a method of treating sexual dysfunction using a specific compound, (6R,12aR)-2,3,6,7,12,12a-hexahydro-2-methyl-6-(3,4-methylenedioxyphenyl)-pyrazino[2',1':6,1]pyrido[3,4-b]indole-1,4-dione (tadalafil), at a low oral dose of "about 1 to about 20 mg." (’166 Patent, Abstract). This specific dosage range is described as providing an effective treatment while minimizing or eliminating the adverse side effects associated with prior treatments, thereby expanding its utility to patients who were previously untreatable. (’166 Patent, col. 2:27-44).
  • Technical Importance: The claimed invention provided a method of treatment that was allegedly effective but with a more favorable side-effect profile, particularly regarding the lack of dangerous interactions with nitrates, which are commonly prescribed for cardiovascular conditions. (’166 Patent, col. 2:36-44).

Key Claims at a Glance

  • The complaint asserts infringement of independent claim 1 and dependent claims 2, 4-5, and 7-12. (Compl. ¶37).
  • Independent Claim 1:
    • A method of treating sexual dysfunction in a patient in need thereof
    • comprising orally administering one or more unit dose
    • containing about 1 to about 20 mg,
    • up to a maximum total dose of 20 mg per day,
    • of a compound having a specific chemical structure (tadalafil).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is Defendants' "proposed tadalafil ANDA product," identified as being filed under ANDA No. 210567. (Compl. ¶1).

Functionality and Market Context

  • The complaint alleges that the proposed product is a generic version of Lilly's Cialis® tablets. (Compl. ¶1). It is described as a tablet containing tadalafil as the active ingredient, to be offered in 2.5 mg, 5 mg, 10 mg, and 20 mg dosage strengths. (Compl. ¶39). The complaint alleges that upon approval, Defendants will market the product for the treatment of male erectile dysfunction, consistent with the FDA-approved label for Cialis®. (Compl. ¶41, ¶44).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

'166 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a method of treating sexual dysfunction in a patient in need thereof Defendant will allegedly market its proposed tadalafil product to treat male erectile dysfunction, a form of sexual dysfunction. ¶41, ¶44 col. 1:19-22
comprising orally administering one or more unit dose Defendant's proposed product is a tablet for oral administration. ¶39, ¶47 col. 3:56-59
containing about 1 to about 20 mg...of a compound having the structure [tadalafil] Defendant's proposed product will contain tadalafil as the active ingredient in 2.5 mg, 5 mg, 10 mg, and 20 mg dosage strengths, all of which fall within the claimed range. ¶39 col. 2:58-61
up to a maximum total dose of 20 mg per day Defendant will allegedly market its product consistent with the FDA-approved label for Cialis®, which contains this dosing instruction. ¶41 col. 3:1-3
  • Identified Points of Contention:
    • Scope Questions: The complaint's infringement theory relies on the premise that the instructions for use on the Defendant's proposed product label will direct users to perform the patented method. A central question for the court will be whether the final, FDA-approved label for Defendant's product will indeed teach every element of the asserted claims.
    • Technical Questions: The complaint alleges that Defendant "does not deny" that its proposed product will induce infringement of the asserted claims if they are found valid. (Compl. ¶37). This suggests the primary dispute may center on the validity of the '166 patent's claims, an issue raised by Defendant's Paragraph IV certification but not detailed in the complaint itself.

V. Key Claim Terms for Construction

  • The Term: "about 1 to about 20 mg"
  • Context and Importance: This dosage range is the central feature of the claimed invention, distinguishing it from prior art by allegedly providing efficacy with reduced side effects. The infringement allegation hinges on the fact that Defendant's proposed dosages (2.5, 5, 10, and 20 mg) fall within this range. (Compl. ¶39). Practitioners may focus on the word "about" to determine if there is any flexibility around the 20 mg upper limit, though it appears less critical here since the accused dosages are within the literal range.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The use of "about" itself suggests the patentee did not intend to be limited to the precise numerical endpoints. The specification discloses clinical trial data for a 25 mg dose, indicating the inventors contemplated dosages outside the claimed range, which could be used to argue "about 20 mg" encompasses values slightly higher than 20. (’166 Patent, col. 14:11).
    • Evidence for a Narrower Interpretation: The specification repeatedly emphasizes the "about 1 to about 20 mg" range as the key to the invention's improved safety profile. (’166 Patent, Abstract; col. 2:40-44). The clinical data table shows a marked increase in adverse events like headache and dyspepsia at the 25 mg dose compared to the 10 mg dose, which could be cited to argue that the "about 20 mg" limit is a critical tipping point for safety and should be construed narrowly. (’166 Patent, col. 14, Treatment-Emergent Adverse Events Table).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon FDA approval, Defendant will infringe under 35 U.S.C. §§ 271(b) and/or (c). (Compl. ¶58). The basis for the inducement allegation is that Defendant's product, when marketed, will have a label consistent with the FDA-approved Cialis® label, which instructs physicians and patients to administer the drug in a manner that practices the method of the asserted claims. (Compl. ¶41, ¶44).
  • Willful Infringement: The complaint does not contain a separate count for willful infringement. However, it establishes a basis for knowledge by noting that the '166 patent is listed in the FDA's "Orange Book" and that Defendant sent Plaintiffs a Notice Letter acknowledging the patent. (Compl. ¶31, ¶33). This pre-suit knowledge could potentially support a later claim for enhanced damages if infringement is found.

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

  • A core issue will be one of patent validity: although not detailed in the complaint, the Defendant's Paragraph IV certification asserts that the '166 patent is invalid. The case will likely turn on whether the claimed method of using tadalafil in a specific low-dose range was obvious or anticipated by the prior art at the time of the invention.
  • The primary infringement question is one of induced infringement based on the product label: will the instructions for use on Defendant's proposed generic product inevitably direct medical professionals and patients to perform all steps of the patented method? The complaint alleges this will occur, making the content of the proposed label a key piece of evidence.