DCT

1:18-cv-00932

Astellas Pharma Inc v. Aurobindo Pharma Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:18-cv-00932, D. Del., 06/25/2018
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant Aurobindo Pharma Limited regularly conducts business and derives substantial revenue from the sale of pharmaceutical products in the state.
  • Core Dispute: Plaintiffs allege that Defendant’s filing of an Abbreviated New Drug Application (ANDA) with the FDA to market a generic version of Plaintiffs’ overactive bladder drug, VESIcare®, constitutes an act of infringement of a patent covering the active ingredient, solifenacin succinate.
  • Technical Context: The technology concerns a specific class of chemical compounds, known as quinuclidine derivatives, that act as selective antagonists for M3 muscarinic receptors to treat overactive bladder with potentially fewer side effects than earlier, non-selective drugs.
  • Key Procedural History: The action arises from Defendant’s submission of ANDA No. 206817, which included a certification under 21 U.S.C. § 355(j)(2)(B)(iv) (a "Paragraph IV certification") alleging that the patent-in-suit is invalid. The patent-in-suit was previously granted a patent term extension by the USPTO based on the FDA's regulatory review of VESIcare®.

Case Timeline

Date Event
1994-12-28 U.S. Patent No. 6,017,927 Priority Date
2000-01-25 U.S. Patent No. 6,017,927 Issue Date
2004-11-19 FDA Approval of VESIcare® (solifenacin succinate) NDA No. 21518
2018-06-05 Plaintiffs received Defendant's notice letter regarding ANDA filing
2018-06-25 Complaint Filing Date

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

U.S. Patent No. 6,017,927 - "Quinuclidine Derivatives and Medicinal Composition Thereof"

  • Patent Identification: U.S. Patent No. 6,017,927, issued January 25, 2000.

The Invention Explained

  • Problem Addressed: The patent’s background section describes the problem that existing drugs for conditions like overactive bladder, such as atropine, are non-selective muscarinic receptor antagonists. They block not only the target M3 receptors in the bladder but also M2 receptors in the heart, leading to undesirable cardiac side effects. (’927 Patent, col. 1:25-40).
  • The Patented Solution: The invention provides a novel class of quinuclidine derivatives that are described as having "excellent selective antagonistic activity against muscarinic M3 receptor" (’927 Patent, col. 2:22-24). By selectively targeting the M3 receptor, the claimed compounds are intended to treat urologic diseases while avoiding the cardiac side effects associated with M2 receptor antagonism (’927 Patent, col. 9:61-68).
  • Technical Importance: This claimed selectivity represented a path toward developing a more targeted and potentially safer therapy for overactive bladder and related conditions. (’927 Patent, col. 1:35-40).

Key Claims at a Glance

  • The complaint asserts at least claims 1-7 (Compl. ¶32). The independent claims are 1 and 7.
  • Independent Claim 1 recites:
    • A quinuclidine derivative represented by a specified general chemical formula (I), which defines a genus of related compounds through several variable groups (Ring A, R, X, l, m, n).
    • The claim also covers a salt thereof, an N-oxide thereof, or a quaternary ammonium salt thereof.
  • Independent Claim 7 recites:
    • A pharmaceutical composition which comprises a quinuclidine derivative according to claim 1.
    • And a pharmaceutically acceptable carrier.
  • The complaint reserves the right to assert other claims, which would include dependent claims that further narrow the chemical structure.

III. The Accused Instrumentality

Product Identification

  • Defendant's proposed generic drug product, described in ANDA No. 206817, which are 5 mg and 10 mg tablets containing solifenacin succinate ("ANDA Product") (Compl. ¶26).

Functionality and Market Context

  • The ANDA Product contains the active ingredient solifenacin succinate and is intended for the treatment of overactive bladder (Compl. ¶26). The complaint provides a chemical structure diagram for solifenacin succinate, identifying it as the compound at issue (Compl. ¶19, p. 5). The product is a generic version of Plaintiffs' branded drug VESIcare®, intended for commercial manufacture, use, and sale in the United States upon FDA approval (Compl. ¶¶18, 28).

IV. Analysis of Infringement Allegations

'927 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A quinuclidine derivative represented by the formula (I),... or a salt thereof... The ANDA Product contains solifenacin succinate. The complaint alleges that solifenacin succinate is a salt of solifenacin, a compound that falls within the scope of the claims. The provided chemical formula for solifenacin succinate depicts the allegedly infringing compound. ¶16, ¶19, ¶26, ¶32 col. 7:50-61; Claim 6
  • Identified Points of Contention:
    • Scope Questions: The infringement allegation hinges on whether "solifenacin succinate" falls within the scope of the asserted claims. The complaint asserts that the patent claims "solifenacin succinate and salts thereof" (Compl. ¶16). A primary question for the court will be whether the definition of "a salt thereof" in the patent unambiguously covers the specific succinate salt form used in the Defendant's ANDA product.
    • Technical Questions: In Hatch-Waxman litigation, the technical composition of the generic drug is typically identical to the branded drug. The complaint alleges that Aurobindo's ANDA product contains the compound claimed in the '927 patent (Compl. ¶¶16, 26, 32). The central technical question is therefore one of direct identity: is the active ingredient in the ANDA Product a compound or salt described and claimed by the '927 patent? The complaint provides no information to suggest any structural difference that might be a point of contention.

V. Key Claim Terms for Construction

  • The Term: "a salt thereof" (Claim 1)
  • Context and Importance: This term is critical because the accused product is specifically "solifenacin succinate," a salt form of the base compound solifenacin (Compl. ¶19). The entire infringement case rests on this salt form being covered by the claims. Practitioners may focus on this term to determine if the patent's disclosure provides adequate written description and enablement for the specific succinate salt, which is often a key validity battleground in pharmaceutical litigation.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent specification explicitly lists "succinic acid" as a potential organic acid for forming an acid addition salt with the claimed compounds (’927 Patent, col. 7:55-57). This language may support a construction where the succinate salt is expressly contemplated and included within the claim's scope.
    • Evidence for a Narrower Interpretation: The patent's working examples describe the preparation of other salt forms, such as an oxalate salt (Example 1) and a hydrochloride salt (Example 2), but do not appear to show the synthesis or use of a succinate salt (’927 Patent, col. 19-20). A party challenging the patent might argue that the lack of a specific working example for a succinate salt limits the scope of "salt" or fails to provide adequate descriptive support for it.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges infringement under 35 U.S.C. § 271(e)(2), which defines the submission of an ANDA for a patented drug as a statutory act of infringement (Compl. ¶32). This is the primary infringement allegation. The complaint also makes a general allegation that the future "use" of the ANDA Product would infringe, but no method-of-use claims are identified as asserted (Compl. ¶33).
  • Willful Infringement: The complaint does not use the word "willful" but alleges that Defendant was "aware of the '927 patent and its infringement" at the time it filed its ANDA (Compl. ¶36). It further requests that the court find the case "exceptional" under 35 U.S.C. § 285, which is the statutory basis for an award of attorney fees (Compl. ¶37). The factual basis for these allegations appears to be the knowledge demonstrated by Defendant's submission of the Paragraph IV certification letter.

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

  • A core issue will be one of direct correspondence: does solifenacin succinate, the active ingredient in the accused ANDA product, fall within the literal scope of the asserted claims of the '927 patent? The patent’s explicit disclosure of "succinic acid" as a possible salt-former suggests a strong basis for infringement, making this less a question of claim construction and more a question of applying the claim language to the accused product.
  • The central question, signaled by Defendant's Paragraph IV certification that the patent is invalid (Compl. ¶29), will likely be one of patent validity: can Defendant prove by clear and convincing evidence that the asserted claims covering solifenacin and its pharmaceutically acceptable salts are invalid, for example, on grounds of obviousness in light of prior art compounds or for lacking adequate written description to support the full scope of the claimed genus or the specific succinate salt?