DR Reddy's Laboratories Inc v. AstraZeneca Ab

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Dr. Reddy’s Laboratories, Inc. (New Jersey) and Dr. Reddy's Laboratories, Ltd. (India)
  • Defendant: AstraZeneca AB (Sweden), AstraZeneca LP (Delaware), Aktiebolaget Hässle (Sweden), and Zeneca Inc. (Delaware)
  • Plaintiff’s Counsel: Budd Larner, P.C.
• Case Identification: 1:18-cv-16057, D.N.J., 11/12/2018
• Venue Allegations: Venue is alleged based on Defendants conducting substantial business in the district, including sales of the NEXIUM® 24HR product, and having previously consented to jurisdiction by filing patent infringement suits in the district.
• Core Dispute: Plaintiff seeks a declaratory judgment that its proposed generic esomeprazole magnesium tablets, for which it has filed an Abbreviated New Drug Application (ANDA), do not infringe Defendant's patent related to a specific pharmaceutical formulation.
• Technical Context: The technology concerns formulations of omeprazole (the active ingredient in drugs like Nexium®) designed to be stable and have a predictable release rate by using a specific type of polymer in a protective separating layer.
• Key Procedural History: This is a Hatch-Waxman Act case. Plaintiff (DRL) filed an ANDA with a Paragraph IV certification, asserting its generic product does not infringe the patent-in-suit. Defendant (AstraZeneca) did not file an infringement suit within the 45-day statutory window. DRL is now blocked from market entry by the 180-day market exclusivity held by an unidentified "First Filer." DRL has filed this declaratory judgment action to obtain a court decision of non-infringement, which would trigger a forfeiture of the First Filer's exclusivity and allow DRL's product to be approved by the FDA.

Case Timeline

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

U.S. Patent No. 6,428,810 - "Pharmaceutical Formulation Comprising Omeprazole"

• Patent Identification: U.S. Patent No. 6,428,810, "Pharmaceutical Formulation Comprising Omeprazole," issued August 6, 2002.

The Invention Explained

• Problem Addressed: The patent addresses two main problems with oral formulations of omeprazole, an acid-sensitive compound. First, it must be protected from stomach acid to remain effective (ʼ810 Patent, col. 2:1-4). Second, the patent notes that different batches of hydroxypropyl cellulose (HPC), a polymer used in a protective "separating layer" in prior art formulations, could lead to inconsistent drug release rates over time, compromising the product's shelf life and stability (ʼ810 Patent, col. 2:41-47).
• The Patented Solution: The invention is a multi-layer oral formulation where a core containing omeprazole is covered by a separating layer, which is in turn covered by an acid-resistant enteric coating (ʼ810 Patent, col. 1:15-23). The innovation lies in the separating layer, which must comprise a specific quality of HPC defined by a "cloud point of not less than 38° C." (ʼ810 Patent, col. 3:1-3). This specific HPC quality is disclosed to prevent the degradation of the release rate over time, thereby ensuring a stable and reliable product with a longer shelf life (ʼ810 Patent, col. 2:62-65).
• Technical Importance: By specifying and controlling a physical property of the HPC (its cloud point), the invention provided a method to guarantee consistent product performance and stability across different manufacturing batches, a critical factor for regulatory approval and commercial viability.

Key Claims at a Glance

• The complaint asserts non-infringement of all claims, focusing on the sole independent claim, Claim 1 (Compl. ¶45, ¶47).
• Essential elements of Independent Claim 1 include:
  • An enteric coated oral pharmaceutical formulation comprising:
  • (a) a core material which comprises an active ingredient (omeprazole or a related salt/enantiomer);
  • (b) a separating layer; and
  • (c) an enteric coating layer,
  • wherein the separating layer comprises a hydroxypropyl cellulose (HPC) with a cloud point of at least 38° C., and
  • wherein the light transmission at cloud point is measured under specific conditions (1.0% (w/w) HPC in a specific mixed buffer solution is 96%).
• The complaint notes that all other claims depend on Claim 1 (Compl. ¶47).

III. The Accused Instrumentality

Product Identification

• DRL’s proposed over-the-counter (OTC) esomeprazole magnesium delayed release oral tablets, equivalent to 20 mg base, as described in DRL's Abbreviated New Drug Application (ANDA) No. 211571 (Compl. ¶1, ¶37).

Functionality and Market Context

• The product is a generic version of AstraZeneca's NEXIUM® 24HR, a widely used OTC medication for treating frequent heartburn (Compl. ¶1, ¶6). The complaint alleges that DRL's product is intended to compete in this market and that DRL is blocked from receiving final FDA approval due to the 180-day exclusivity period held by an unidentified "First Filer" ANDA applicant (Compl. ¶31, ¶40). The complaint’s central technical assertion is that its product does not contain the specific formulation claimed in the ’810 patent (Compl. ¶47).
• No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

• ’810 Patent Infringement Allegations

• Identified Points of Contention:
  • Factual Question: The central dispute is factual: does the separating layer in DRL's ANDA product, as formulated, contain an HPC with a "cloud point of at least 38° C." when measured according to the highly specific method recited in Claim 1? The complaint asserts that it does not.
  • Scope Questions: A potential issue for the court is whether the detailed measurement protocol recited in the claim language (e.g., buffer composition, pH, HPC concentration, and light transmission percentage) constitutes a strict definition of the "cloud point" limitation, or if other measurement techniques could be deemed equivalent.

V. Key Claim Terms for Construction

• The Term: "a hydroxypropyl cellulose (HPC) with a cloud point of at least 38° C."
• Context and Importance: This term is the lynchpin of the non-infringement case. DRL's entire declaratory judgment action rests on the assertion that its product does not meet this specific limitation (Compl. ¶45, ¶47). Practitioners may focus on this term because its construction, particularly the method of measurement also recited in the claim, will determine whether there is a literal infringement dispute.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The body of the claim uses the general phrase "cloud point of at least 38° C." before specifying the measurement method. A party might argue that the "cloud point" is a physical property and the subsequent "wherein" clause describes one way to measure it, but not the only way.
  • Evidence for a Narrower Interpretation: The claim itself explicitly defines the conditions under which the cloud point is to be determined: "wherein the light transmission at cloud point ... is 96%" in a specified buffer system (ʼ810 Patent, col. 8:28-34). The specification further reinforces this by detailing the precise instrument ("a Mettler FP90/FP 81C instrument") and test conditions used to establish the claimed property (ʼ810 Patent, col. 3:1-6). This suggests the patentee defined the invention by reference to a specific, replicable measurement protocol, which could be argued to be a definitive and limiting part of the claim.

VI. Other Allegations

• Indirect Infringement: The prayer for relief requests a declaration that DRL's product would not "induce or contribute to the infringement by others" (Compl. p. 13, ¶b). However, the complaint provides no specific factual allegations to support a theory of indirect infringement, such as descriptions of product labeling or user instructions.
• Willful Infringement: Willful infringement is not alleged, as this is a declaratory judgment action for non-infringement filed by the ANDA applicant, not an infringement action filed by the patentee.

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

This case presents a combination of factual and procedural issues common in Hatch-Waxman litigation. The key questions for the court will likely be:

1. A central evidentiary question: Can DRL prove, by a preponderance of the evidence, that its proposed generic product does not contain a separating layer with a hydroxypropyl cellulose (HPC) having a cloud point of at least 38°C, as that property is defined and measured by the specific protocol recited in Claim 1 of the ’810 patent?
2. A question of claim scope: How strictly will the court construe the detailed measurement conditions for "cloud point" that are explicitly recited within Claim 1? The resolution of this question will define the boundaries of the factual inquiry.
3. A procedural outcome question: If DRL succeeds in obtaining a judgment of non-infringement, will it successfully trigger the forfeiture of the unidentified "First Filer's" 180-day market exclusivity, thereby achieving its strategic goal of clearing a path for its own product's market entry?