1:16-cv-00855
Amgen Inc v. Watson Laboratories Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Amgen Inc. (Delaware)
- Defendant: Watson Laboratories, Inc. (Nevada); Actavis, Inc. (Nevada); Actavis Pharma, Inc. (Delaware)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP; Fitzpatrick, Cella, Harper & Scinto
- Case Identification: 1:16-cv-00855, D. Del., 09/22/2016
- Venue Allegations: Venue is alleged based on Defendants’ business activities in Delaware, including the marketing and sale of generic drugs, and prior submission to the jurisdiction of the court in other cases.
- Core Dispute: Plaintiff alleges that Defendants’ submission of an Abbreviated New Drug Application (ANDA) for generic cinacalcet hydrochloride tablets constitutes an act of infringement of a patent covering a specific formulation of the drug.
- Technical Context: The technology concerns pharmaceutical formulations designed to improve the dissolution rate and bioavailability of cinacalcet, a poorly water-soluble compound used to treat hyperparathyroidism associated with chronic kidney disease.
- Key Procedural History: The litigation was triggered by Defendants’ filing of ANDA No. 204377 and a corresponding Paragraph IV certification, asserting that U.S. Patent No. 9,375,405 is invalid or will not be infringed by their proposed generic product. The patent-in-suit is subject to a terminal disclaimer.
Case Timeline
| Date | Event |
|---|---|
| 2003-09-12 | ’405 Patent Priority Date |
| 2004-03-08 | FDA approves Amgen's New Drug Application for SENSIPAR® |
| 2016-06-28 | ’405 Patent Issue Date |
| 2016-08-10 | Defendants notify Plaintiff of ANDA filing and Paragraph IV certification |
| 2016-09-22 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,375,405 - "Rapid Dissolution Formulation of a Calcium Receptor-Active Compound," issued June 28, 2016
The Invention Explained
- Problem Addressed: The patent addresses the challenge that certain calcium receptor-active compounds, such as cinacalcet HCl, are "insoluble or sparingly soluble in water" (’405 Patent, col. 6:10-12). This limited solubility can hinder the development of effective oral dosage forms and may result in "low bioavailability" of the active compound (’405 Patent, col. 6:19-21).
- The Patented Solution: The invention is a specific pharmaceutical composition that achieves a controlled, rapid dissolution profile. It combines the active ingredient (cinacalcet HCl) with a particular combination of excipients, including specific types and amounts of a diluent, a binder, and a disintegrant, to ensure that a target amount of the drug is released from the tablet within approximately 30 minutes under standardized test conditions (’405 Patent, col. 8:12-24, Abstract). The manufacturing process, including granulation and milling steps detailed in Figure 1, is also described as a way to achieve the desired formulation characteristics (’405 Patent, FIG. 1).
- Technical Importance: The technology provides a method to create a reliable oral solid dosage form for a poorly soluble drug, which is critical for consistent therapeutic effect in patients being treated for conditions like secondary hyperparathyroidism (’405 Patent, col. 7:15-25).
Key Claims at a Glance
- The complaint asserts infringement of "at least claim 1" (Compl. ¶¶ 37, 42).
- Independent Claim 1 requires a pharmaceutical composition comprising:
- (a) from about 10% to about 40% by weight of cinacalcet HCl in an amount of from about 20 mg to about 100 mg;
- (b) from about 45% to about 85% by weight of a diluent selected from a specific group (microcrystalline cellulose, starch, etc.);
- (c) from about 1% to about 5% by weight of a binder selected from a specific group (povidone, etc.); and
- (d) from about 1% to 10% by weight of a disintegrant selected from a specific group (crospovidone, etc.).
- The claim further specifies that "the composition is for the treatment of at least one of hyperparathyroidism, hyperphosphonia, hypercalcemia, and elevated calcium phosphorus product." (’405 Patent, col. 12:35-41).
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are Defendants' generic cinacalcet hydrochloride tablets in 30 mg, 60 mg, and 90 mg dosage strengths, for which Defendants filed Abbreviated New Drug Application ("ANDA") No. 204377 with the FDA (Compl. ¶6).
Functionality and Market Context
The complaint alleges that Defendants' ANDA products are generic versions of Amgen’s SENSIPAR® tablets (Compl. ¶26). As such, they are intended to function as a calcium receptor-active compound to treat conditions such as secondary hyperparathyroidism in patients with chronic kidney disease by lowering parathyroid hormone, calcium, and phosphorus levels in the blood (Compl. ¶¶ 19-20). The filing of the ANDA itself represents a commercial effort to enter the market for cinacalcet hydrochloride prior to the expiration of the ’405 patent (Compl. ¶26).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
The complaint alleges that the filing of ANDA No. 204377 constitutes a technical act of infringement under 35 U.S.C. § 271(e)(2) and that the future commercial product will infringe (Compl. ¶¶ 36-37, 42). The infringement theory is that the composition of the proposed generic product meets all the limitations of at least claim 1 of the ’405 patent. The complaint does not provide a detailed claim chart or specific factual allegations mapping each component of Defendants' formulation to the claim elements.
’405 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| (a) from about 10% to about 40% by weight of cinacalcet HCl in an amount of from about 20 mg to about 100 mg; | Defendants’ ANDA products are alleged to be tablets containing cinacalcet hydrochloride as the active ingredient in 30 mg, 60 mg, and 90 mg dosages. | ¶¶ 6, 34 | col. 12:20-22 |
| (b) from about 45% to about 85% by weight of a diluent selected from the group consisting of microcrystalline cellulose, starch...and mixtures thereof, | The complaint does not specify the diluents in the ANDA products but alleges the products would infringe claim 1, implying they contain a claimed diluent in the specified proportion. | ¶37 | col. 12:23-28 |
| (c) from about 1% to about 5% by weight of at least one binder selected from the group consisting of povidone...and mixtures thereof; | The complaint does not specify the binder in the ANDA products but alleges the products would infringe claim 1, implying they contain a claimed binder in the specified proportion. | ¶37 | col. 12:29-33 |
| (d) from about 1% to 10% by weight of at least one disintegrant selected from the group consisting of crospovidone...and mixtures thereof, | The complaint does not specify the disintegrant in the ANDA products but alleges the products would infringe claim 1, implying they contain a claimed disintegrant in the specified proportion. | ¶37 | col. 12:34-38 |
| wherein the composition is for the treatment of at least one of hyperparathyroidism... | Defendants’ ANDA seeks approval for a generic version of SENSIPAR®, a drug approved for treating hyperparathyroidism. | ¶¶ 19, 26 | col. 12:39-41 |
- Identified Points of Contention:
- Technical Questions: Since the complaint lacks technical specifics about the accused formulation, a primary point of contention will be factual. Discovery will be required to determine if the specific excipients, their chemical forms, and their weight percentages in Defendants' ANDA products fall within the ranges and Markush groups recited in claim 1.
- Scope Questions: The analysis will raise the question of whether the "for the treatment of" clause is a legally limiting claim element. If it is deemed limiting, a further question is whether Defendants’ act of seeking FDA approval for the same indications as the branded drug satisfies this limitation.
V. Key Claim Terms for Construction
The complaint does not provide sufficient detail for a deep analysis of claim construction disputes. However, based on the nature of the patent and the context of ANDA litigation, certain terms are likely to be central.
The Term: "about" (e.g., "from about 10% to about 40% by weight")
Context and Importance: This term appears repeatedly in claim 1 to define the required weight percentages of the components. The infringement analysis will depend entirely on whether the precise weight percentages of the components in the Defendants' ANDA product fall within the claimed numerical ranges. Practitioners may focus on this term because even a minor deviation in the accused formulation could be dispositive of infringement, making the scope of "about" critical.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent uses the term "about" consistently, suggesting the inventors did not intend for the numerical ranges to be exact and absolute. The specification describes a range of formulations and notes that the dissolution profile can be "from about 50% to about 125% of a target amount," which may support the notion that some variability is contemplated throughout the invention (’405 Patent, col. 8:15-16).
- Evidence for a Narrower Interpretation: The patent provides specific examples with precise component weights (e.g., 18.367% cinacalcet HCl) and resulting dissolution data (’405 Patent, col. 11, Table). A party could argue that these examples define the practical boundaries of the invention and that "about" should not be interpreted so broadly as to cover formulations that produce materially different results.
The Term: "for the treatment of..."
Context and Importance: This clause defines the intended use of the claimed composition. Its construction is critical because it raises the question of whether the claim is a pure composition claim or a method-of-use claim disguised in composition format. Defendants may argue this language is a non-limiting statement of purpose, while Plaintiff will likely argue it is a material limitation that is met by the Defendants' stated purpose in the ANDA filing.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation (Non-limiting): A party could argue that the core of the invention lies in the physical and chemical properties of the formulation itself (the what), not its ultimate use (the why). The patent's focus on dissolution profiles and excipient ratios could be presented as evidence that the "for the treatment of" clause merely provides context.
- Evidence for a Narrower Interpretation (Limiting): The placement of the clause within the body of claim 1, introduced by "wherein," suggests it is intended to be a limitation. The patent consistently links the formulation's properties to its therapeutic purpose, stating the compositions are for treating specific diseases, which supports the view that the intended use is an essential part of the claimed invention (’405 Patent, col. 12:18-25).
VI. Other Allegations
- Indirect Infringement: The complaint alleges that upon FDA approval, Defendants will induce and/or contribute to the infringement of at least claim 1 (Compl. ¶42). The alleged basis for inducement is that Defendants will sell the ANDA products with a label and instructions that will inevitably lead medical professionals to prescribe and patients to use the product in an infringing manner—specifically, for the treatment of hyperparathyroidism.
- Willful Infringement: The complaint does not use the term "willful infringement," but it does request that the case be declared "exceptional" and seeks attorney fees (Compl., Prayer for Relief ¶D). The factual basis for pre-suit knowledge of the patent is Defendants' August 10, 2016 letter to Amgen, which provided notice of the ANDA filing and a Paragraph IV certification against the ’405 patent (Compl. ¶¶ 26-28).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of compositional identity: does the precise formulation disclosed in Defendants’ ANDA—specifically, the identity and weight percentages of its diluent, binder, and disintegrant—fall within the literal scope of the ranges and Markush groups recited in claim 1 of the ’405 patent? The answer will depend on facts that emerge during discovery.
- A key legal question will be the enforceability of the purpose limitation: will the court construe the "for the treatment of..." clause as a binding limitation on the claim scope? If so, is the act of filing an ANDA that seeks approval for indications identical to the branded drug sufficient to meet that limitation?
- An underlying evidentiary question will be one of bioequivalence versus patentable distinction: Defendants will have to show their product is bioequivalent to SENSIPAR® for FDA approval, while simultaneously arguing in court that its formulation is different enough to fall outside the patent claims. The case may turn on whether the specific formulation choices required by the patent are necessary for bioequivalence or represent a distinct, patentable invention separate from other possible bioequivalent formulations.