DCT
1:16-cv-00853
Amgen Inc v. Aurobindo Pharma Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Amgen Inc. (Delaware)
- Defendant: Aurobindo Pharma Ltd. (India) and Aurobindo Pharma USA, Inc. (Delaware)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP
- Case Identification: 1:16-cv-00853, D. Del., 09/22/2016
- Venue Allegations: Venue is alleged to be proper based on Aurobindo USA's incorporation in Delaware, both defendants' transaction of business in the district, and defendants' prior litigation conduct in the district, where they allegedly availed themselves of Delaware courts.
- Core Dispute: Plaintiff alleges that Defendants' filing of an Abbreviated New Drug Application (ANDA) for a generic version of Plaintiff's SENSIPAR® drug constitutes an act of infringement of a patent covering a rapid-dissolution pharmaceutical formulation.
- Technical Context: The technology relates to pharmaceutical formulations for calcium receptor-active compounds, designed to improve the dissolution rate and bioavailability of drugs that are otherwise sparingly soluble in water.
- Key Procedural History: The lawsuit is a Hatch-Waxman Act action initiated in response to Defendants’ filing of ANDA No. 206125 with a Paragraph IV certification, which asserts that the patent-in-suit is invalid or will not be infringed by the proposed generic product. The complaint was filed within the 45-day statutory period following receipt of Defendants' notice letter, triggering a potential 30-month stay of FDA approval for the ANDA.
Case Timeline
| Date | Event |
|---|---|
| 2003-09-12 | U.S. Patent No. 9,375,405 Priority Date |
| 2004-03-08 | FDA approves Amgen's SENSIPAR® for secondary hyperparathyroidism (HPT) |
| 2011-02-25 | FDA approves SENSIPAR® for severe hypercalcemia in primary HPT |
| 2016-06-28 | U.S. Patent No. 9,375,405 Issues |
| 2016-08-08 | Amgen receives Defendants' Paragraph IV notice letter |
| 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’s background section states that certain calcium receptor-active compounds, such as cinacalcet HCl, are "insoluble or sparingly soluble in water," particularly at neutral pH ('405 Patent, col. 1:10-13). This limited solubility can reduce formulation and delivery options and may result in low bioavailability of the compound when administered to a patient ('405 Patent, col. 1:19-24).
- The Patented Solution: The invention claims to solve this problem through a pharmaceutical composition with specific excipients and a defined dissolution profile ('405 Patent, Abstract). The formulation is designed to release a significant portion of the active ingredient—from 50% to 125% of the target amount—no later than 30 minutes after the start of a standardized dissolution test, thereby improving its potential uptake ('405 Patent, col. 2:40-51). The detailed description outlines specific compositional ranges and manufacturing processes, such as granulation, to achieve this rapid dissolution characteristic ('405 Patent, col. 9:18-50, Fig. 1).
- Technical Importance: Developing an oral dosage form with a reliable and rapid dissolution profile for a poorly soluble compound is critical for ensuring consistent therapeutic effects in patients ('405 Patent, col. 1:25-30).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 1 ('Compl. ¶38).
- Independent Claim 1 recites the essential elements of the pharmaceutical composition:
- (a) from about 10% to about 40% by weight of cinacalcet HCl in an amount from about 20 mg to about 100 mg;
- (b) from about 45% to about 85% by weight of a specified diluent;
- (c) from about 1% to about 5% by weight of a specified binder;
- (d) from about 1% to 10% by weight of a specified disintegrant; and
- A purpose limitation stating the composition is for the treatment of hyperparathyroidism, hyperphosphonia, hypercalcemia, and elevated calcium phosphorus product.
- The complaint does not explicitly reserve the right to assert dependent claims, but alleges infringement of the patent generally.
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are Defendants' proposed generic cinacalcet hydrochloride tablets in 30 mg, 60 mg, and 90 mg dosage strengths, as described in ANDA No. 206125 (Compl. ¶7).
Functionality and Market Context
The accused products are intended to be generic versions of Amgen’s SENSIPAR® tablets (Compl. ¶7, 25). As such, they are designed to be bioequivalent formulations for treating conditions including secondary hyperparathyroidism in patients with chronic kidney disease and hypercalcemia in patients with parathyroid carcinoma (Compl. ¶20-22). The complaint characterizes SENSIPAR® as a "first-in-class molecule" developed to treat an unmet medical need (Compl. ¶23). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint does not contain a claim chart or detailed factual allegations mapping the accused product to the claim limitations. The infringement theory is based on the statutory act of filing an ANDA seeking approval to market a generic drug that, if approved, would infringe the patent covering the branded drug's formulation.
’405 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A pharmaceutical composition comprising: (a) from about 10% to about 40% by weight of cinacalcet HCl... | The active ingredient in Defendants' ANDA products is alleged to be cinacalcet hydrochloride. The complaint does not specify the weight percentage. | ¶35 | col. 12:18-20 |
| (b) from about 45% to about 85% by weight of a diluent selected from the group consisting of microcrystalline cellulose, starch, dicalcium phosphate, lactose, sorbitol, mannitol, sucrose, methyl dextrins, and mixtures thereof | The complaint does not provide sufficient detail for analysis of the diluents or their weight percentages in the accused product. | N/A | col. 12:21-26 |
| (c) from about 1% to about 5% by weight of at least one binder selected from the group consisting of povidone, hydroxypropyl methylcellulose, hydroxypropyl cellulose, sodium carboxymethylcellulose, and mixtures thereof | The complaint does not provide sufficient detail for analysis of the binders or their weight percentages in the accused product. | N/A | col. 12:27-32 |
| (d) from about 1% to 10% by weight of at least one disintegrant selected from the group consisting of crospovidone, sodium starch glycolate, croscarmellose sodium, and mixtures thereof | The complaint does not provide sufficient detail for analysis of the disintegrants or their weight percentages in the accused product. | N/A | col. 12:33-37 |
| wherein the composition is for the treatment of at least one of hyperparathyroidism, hyperphosphonia, hypercalcemia, and elevated calcium phosphorus product. | The ANDA seeks approval to market a generic version of SENSIPAR®, which is used to treat conditions including hyperparathyroidism. | ¶7, 20-22 | col. 12:38-41 |
Identified Points of Contention
- Factual Question: The central dispute will be factual: does the specific formulation disclosed in Defendants' confidential ANDA submission fall within the claimed weight percentage ranges for cinacalcet HCl, diluents, binders, and disintegrants as recited in Claim 1?
- Scope Question: A potential issue for the court may be the proper classification of the excipients in the accused product. Whether a particular ingredient functions as a "diluent" versus a "binder" or "disintegrant", for example, could be critical to determining if the claimed weight percentage limitations are met.
V. Key Claim Terms for Construction
- The Term: "from about X% to about Y% by weight"
- Context and Importance: This term appears in every compositional limitation of Claim 1. The infringement analysis will hinge on whether the precise weight percentages of the components in Defendants' ANDA product are encompassed by these ranges. Practitioners may focus on this term because the interpretation of "about" can be dispositive, determining whether a formulation that is numerically close to, but not strictly within, the claimed range still infringes.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification uses the term "about" frequently when describing dosage amounts, compositional ranges, and process parameters, which may suggest an intention for the numerical values not to be read as strict, absolute limits ('405 Patent, col. 3:10, 3:22, 4:10).
- Evidence for a Narrower Interpretation: The patent provides detailed examples with specific, precise weight percentages for each component in a table ('405 Patent, col. 11-12, Table). A party could argue that these precise examples inform the meaning of "about," limiting its scope to little more than standard rounding or experimental variability.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that upon FDA approval, Defendants will induce infringement by providing a product label that instructs physicians and patients to use the generic drug for the patented indications (Compl. ¶43).
- Willful Infringement: Willfulness is alleged based on Defendants' pre-suit knowledge of the '405 patent, evidenced by their act of sending Amgen a Paragraph IV certification notice letter regarding the patent (Compl. ¶29).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central factual question will be one of compositional identity: Does the specific formulation of Aurobindo's proposed generic product, as confidentially disclosed in its ANDA, contain the same classes of ingredients within the specific weight percentage ranges required by Claim 1 of the '405 patent?
- A key claim construction question will be the scope of approximation: How should the term "about," which modifies every numerical range in the asserted claim, be interpreted? The court's construction of this term may determine whether Aurobindo's formulation, even if not identical to the recited percentages, is nonetheless infringing.