DCT

1:22-cv-00227

KAI Pharma Inc v. AuroMedics Pharma LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:22-cv-00227, D. Del., 02/22/2022
  • Venue Allegations: Venue is alleged to be proper as certain defendants are Delaware corporations that reside in the district for venue purposes, while others are foreign corporations that may be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendants' submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of the drug Parsabiv® constitutes an act of infringement of a patent covering a stable liquid formulation of etelcalcetide.
  • Technical Context: The technology relates to pharmaceutical formulations that keep a therapeutic peptide (etelcalcetide) stable in a liquid, ready-to-use form, primarily for treating secondary hyperparathyroidism in chronic kidney disease patients.
  • Key Procedural History: This is a Hatch-Waxman Act lawsuit triggered by Defendants' submission of ANDA No. 215840 with a Paragraph IV certification, asserting that the patent-in-suit is invalid, unenforceable, or will not be infringed. The complaint was filed within the 45-day statutory window following receipt of Defendants' notice letter, which imposes an automatic 30-month stay on FDA approval of the generic product. The patent-in-suit is listed in the FDA's "Orange Book" for the branded drug Parsabiv®.

Case Timeline

Date Event
2013-06-28 Earliest Priority Date for U.S. Patent No. 11,162,500
2017-02-07 FDA grants approval for Plaintiff's drug Parsabiv®
2021-03-26 Plaintiff receives Defendant's First Notice Letter for ANDA
2021-11-02 U.S. Patent No. 11,162,500 issues
2022-01-20 Plaintiff receives Defendant's Second Notice Letter
2022-02-22 Complaint filed

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

U.S. Patent No. 11,162,500 - “Stable Liquid Formulation of AMG 416 (Etelcalcetide)”

The Invention Explained

  • Problem Addressed: The patent describes that therapeutic peptides, particularly those with disulfide bonds like etelcalcetide, often exhibit poor stability in aqueous solutions, making them prone to degradation (Compl., Ex. A, ’500 Patent, col. 1:56-63). This often requires them to be supplied in a lyophilized (freeze-dried) powder form, which is inconvenient, must be reconstituted before use, and introduces risks of contamination and dosing errors (’500 Patent, col. 2:1-5).
  • The Patented Solution: The invention provides a stable, ready-to-use liquid formulation of etelcalcetide. Stability is achieved by maintaining the aqueous solution within a specific pH range and concentration, which avoids the need for lyophilization (’500 Patent, Abstract; col. 2:6-14). The specification details experiments demonstrating that controlling the formulation's pH is critical to minimizing degradation from competing pathways like deamidation and homodimer formation (’500 Patent, col. 9:45-59; Figs. 10-11).
  • Technical Importance: The invention enables the supply of etelcalcetide in a convenient and safer ready-to-use liquid injectable form, improving upon the standard but cumbersome practice of providing unstable peptides as powders requiring reconstitution (’500 Patent, col. 2:1-14).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 (Compl. ¶48).
  • The essential elements of independent claim 1 are:
    • A pharmaceutical formulation comprising etelcalcetide in aqueous solution,
    • wherein the formulation has a pH of 2.0 to 5.0 and
    • wherein etelcalcetide is present at a concentration of between 0.5 mg/mL to 15 mg/mL.
  • The complaint notes that the accused product is covered by "one or more claims of the '500 patent," reserving the right to assert additional claims (Compl. ¶49).

III. The Accused Instrumentality

Product Identification

  • Aurobindo's Proposed ANDA Product, identified as a generic version of Parsabiv® (etelcalcetide) injection (Compl. ¶1).

Functionality and Market Context

  • The accused product is an injectable drug intended for intravenous use for the treatment of secondary hyperparathyroidism in adult patients with chronic kidney disease on hemodialysis (Compl. ¶1, ¶46). The complaint alleges, upon information and belief, that the product is "a pharmaceutical formulation comprising etelcalcetide in an aqueous solution having a pH of 2.0 to 5.0 and an etelcalcetide concentration of between 0.5 mg/mL to 15 mg/mL" (Compl. ¶42). The product is intended to be a generic competitor to Plaintiff's branded Parsabiv® product (Compl. ¶1). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

'500 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A pharmaceutical formulation comprising etelcalcetide in aqueous solution, On information and belief, the accused product is a pharmaceutical formulation comprising etelcalcetide in an aqueous solution. ¶42, ¶49 col. 2:15-17
wherein the formulation has a pH of 2.0 to 5.0 and On information and belief, the accused product's formulation has a pH of 2.0 to 5.0. ¶42, ¶49 col. 2:18-19
wherein etelcalcetide is present at a concentration of between 0.5 mg/mL to 15 mg/mL. On information and belief, the accused product's formulation has an etelcalcetide concentration between 0.5 mg/mL and 15 mg/mL. ¶42, ¶49 col. 2:31-34
  • Identified Points of Contention:
    • Technical Questions: The complaint's infringement allegations are made "on information and belief" regarding the specific characteristics of the formulation described in the confidential ANDA filing (Compl. ¶42). A central question for discovery will be to obtain the ANDA specification and determine if the accused product's pH and concentration values, as defined therein, fall literally within the ranges recited in the asserted claims.
    • Scope Questions: The asserted claim limitations are defined by numerical ranges ("pH of 2.0 to 5.0," "concentration of between 0.5 mg/mL to 15 mg/mL"). If discovery reveals that Aurobindo's formulation is specified at or near the boundaries of these ranges, the case may raise questions regarding the proper interpretation of these limits and the precision of measurement, potentially implicating the doctrine of equivalents.

V. Key Claim Terms for Construction

  • The Term: "pH of 2.0 to 5.0"
  • Context and Importance: This limitation is central to the invention, as the patent's specification teaches that maintaining the pH within a specific range is critical for achieving long-term stability in a liquid formulation (’500 Patent, col. 9:45-59). Infringement of claim 1 directly depends on whether the accused product's pH falls within this claimed range. Practitioners may focus on this term because the patent's own data shows varying stability levels across this range, which could invite arguments about the scope of the invention.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification frequently uses the term "about" when discussing the inventive pH range (e.g., "a pH of about 2.0 to about 5.0"), which a plaintiff could argue supports interpreting the claimed range as encompassing values slightly outside the strict numerical boundaries (’500 Patent, col. 2:18-19).
    • Evidence for a Narrower Interpretation: The claim language itself is precise and does not use the word "about." A defendant could argue that the claim is limited to the exact numerical range recited. Furthermore, the specification identifies an optimal pH range of "about 3.0 to 3.5" for maximum stability, which could be used to argue that the patent's true inventive contribution is narrower than the full 2.0-to-5.0 range claimed (’500 Patent, col. 9:55-59).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges active inducement of infringement under 35 U.S.C. § 271(b). The factual basis alleged is that Aurobindo knows of the '500 patent and intends for its product to be used in an infringing manner, as its proposed product label will instruct healthcare providers to use the formulation in a way that infringes (Compl. ¶44, ¶56, ¶57). Specific intent is alleged based on Aurobindo's knowledge of the patent's listing in the FDA's Orange Book (Compl. ¶56).
  • Willful Infringement: The complaint alleges facts that may support a claim for willful infringement. It states that Aurobindo was aware of the '500 patent when it filed its ANDA with a Paragraph IV certification and had "no reasonable basis to believe" its product would not infringe (Compl. ¶41, ¶52). Plaintiffs also request a declaration that the case is "exceptional" and seek an award of attorneys' fees pursuant to 35 U.S.C. § 285 (Compl., p. 14).

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

  • A central issue will be evidentiary and factual: does the formulation specified in Aurobindo's confidential ANDA submission literally meet the pH and concentration ranges of Claim 1? The resolution of this question, which depends on discovery, will likely be dispositive for the literal infringement analysis.
  • A secondary question will be one of claim scope: how should the court construe the precise numerical boundaries of the "pH" and "concentration" limitations? The dispute may focus on whether the invention is limited to the exact ranges recited in the claims or if intrinsic evidence supports a slightly broader or narrower interpretation, which would become critical if the accused product is formulated near the edges of the claimed ranges.